Pagoda SL Group
W113 Pagoda SL Group => Drive train, fuel, suspension, steering & brakes => Topic started by: Tyler S on February 22, 2016, 19:23:12
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I am having one of those indecisive "Well I minus well since I'm in there" moments.
I have already removed the intake and exhaust manifolds to fix a minor exhaust leak. This is usually the hardest part of head removal anyway so I am contemplating moving forward with head removal to inspect/rebuild the valve train. There really aren't any issues with compression or the head gasket. Just the occasional (very light) puff of smoke after days of not being started. I have 74k miles on the engine and from what I have read the valve guides will/should be due soon. The head has never been off the engine. I will be adding a few hundred bucks at the minimum for the head gasket, coolant etc..plus machine work if necessary. I already have a stash of all the other gaskets, hoses, water pump, timing chain, tensioner, cam sprocket, copper washers, and valve stem seals. There is some apparent wear on the valve stems (see pic) but without removal there is really no way to properly measure the guides and valves. There is not much left in the way of removal. Coolant (messy), Valve cover, Rockers, camshaft, Injection lines. This will also give me the opportunity to inspect the cylinder bore's condition as well as a really good cleaning. Original red engine block paint can be seen under all the dirt and grime. One thing that always makes me nervous is removing the hood. Do I open a potential "Pandora's Box" or put it back together and run it. Cost and my labor v.s. Piece of mind. What would you do?
P.S. If I do decide to move forward, I'll take you all along for the ride... ;)
Tyler
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This is what started it all. Leaking exhaust manifold gasket. It can sound just like valve train noise.
Tyler
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I think you could leave the hood on if you want to. Not much left to take the head off at this point.
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Messy coolant change? I bought this 7 or 8 years ago and has worked perfectly. Never a drop on the ground during a coolant change. And the valve has never leaked a drop.
This is the model number is used for the 280SE: F316 L Website below. They only mention as an oil drain but because there are no rubber parts, just brass and stainless, the coolant application works as well. I installed this on the lower right side of the block in place of the plug.
http://www.fumotousa.com/
I like this better than the older solid brass screw valve used on the early 60s cars. This one has a safety catch which makes it virtually impossible for it to open accidentally. Just a thought.
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Tyler, if she is a frequent driver you will continue to drive it, the time will come in my eyes, its pay me now or pay me later. You are so close to getting it done I would go for it. But from the help all of you have to give me for my projects it really depends on your time you want to invest. my two cents anyway. Thanks for the help on my injection pump.
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Definitely do it. You will regret it otherwise.
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I think I may go for it. Start fresh in the am. I'm going to stew on it if I don't. I'll spend the rest of today looking for a good machine shop that knows the nuances of these engines. Last thing I want is my head shaved below spec or my pistons and valves to "Bump Knuckles"
Wallace, That looks like a good idea. Will be a mess this time around but good for future changes. I wonder if that could be put into the oil cooler as well or if that's a little too sketchy.
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Hi Tyler,
if you have the space to store the hood safely then my suggestion is to take it off, much easier to work around the engine bay.
I'll be happy to give you a hand, just let me know.
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Alfred, Thanks much! I think I may pull the radiator and have it serviced so will be a definate. Another "while im in there" job. If im replacing all the hoses, water pump, thermostat, etc.. Why leave a weak link.
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Hi Tyler,
With all the work you plan to do you should take Alfred up on his offer to give you a hand with the hood removal. You certainly will not regret doing so.
You will have, as you know so much more room to do the work with the hood removed. However, if you elect not to remove the hood be sure to make and attach (what some of us call the best tool in our tool kit) a softener for the hood lock engagement so when your head comes in contact with the lock mechanism it won't hurt so much :)
Good Luck.
Dieter
PS. Do take photos others will benefit from it. As you know a picture is worth a 1000 words. :)
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Thanks Dieter, yes the hood will be coming off. Going to remove and service the rad and water pump.
Now to find a place to store it. My garage has accumulated too much stuff.
I'm thinking put the hard top back on the car and use the rolling hardtop storage rack. Can move it far far away while working.
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Tyler, if you need another hand, just let me know. I have done the hood removal before and the radiator removal and the hose replacement and a power steering pump replacement........
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Thanks guys. The last time I had my hood off I had my neighbor help me. Lets just say it was man-handled a bit much. Having both people familiar with how it works is key.
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Well we have liftoff. No major issues with removing the head. I am liking what I see so far. Standard size Mahle (81.98mm) pistons. Cylinder bore's are semi-smooth with no major scratches and minimal ridge. Cylinder Head thickness is 84.94mm. Cylinder's 5 and 6 look to have been running a bit leaner than the rest. Looks like cylinder 3 is the slight oil burning cylinder, bit of ash on the valves. I am contributing this to a valve guide/seal as there was a small amount of oil hanging around on top of the intake valve. A small head gasket failure between a water jacket and head bolt. This led to some corrosion in the head and a stiff head bolt, but minimal. So nothing major to report! ;D Next step will be to position the head on its side and add some paint thinner to the ports and check for valve leaks.
Tyler
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second set of photos.
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... I think I may pull the radiator and have it serviced . ....
Are you getting a new high efficiency core also? Let us know when you find a good repair shop, they seem to have all disappeared here.
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What was your compression numbers for this engine? If you have a pic showing all of the pistons that would be helpful but it looks like number one cylinder has a fair amount of blow by.
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Albert, Yes if I can find someone, Your right about them drying up. I used to use Cal's radiator on Balboa in Pacific Beach. Long since closed up. There's no market for them anymore. Everything out there is plastic tanks now. Not repairable. Plus C.A.R.B and OSHA didn't help.
Dan, My readings were all 170-175 with the exception of Cyl #3 which was at 160. And thinking the culprit is the valves. #3 is the worst offender (see Pic). But your right, even looking at the picture of the head you can see #1 is dark. Put the head on its side and poured some Kingsford into the ports. All the valves marked in yellow are leaking to some degree from a little to a lot. That's 8 out of 12.
Well, going to strip it down, take it in, and get some numbers.
Tackle the hood removal and cooling components while its being worked on.
Then a big cleanup!
Still looking for a local shop familiar with these. May give Onager a call in the am.
Tyler
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I have used Kinch's Radiator & AC when they were located in Escondido, they have now moved to Murrieta.
Unfortunately recent comments are somewhat mixed.
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So after enough calls to local shops to make my ear hurt, I have decided to send my Head up to Metric. A little more expensive with shipping and all but the last thing I want is this hacked together or having to question everything another shop did.
Thanks Alfred, I'll be buzzing you later in the week for a hand with the hood ;)
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Have you talked to these guys?
http://motorworkssd.com/
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Any areas on a piston that are clean and free of carbon usually indicate some amount of blow by. Number 1 on the head is much darker than the others which may indicate the presence of oil in that cylinder even though the compression numbers are good.
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Dan, In image 3531 above you can see #1 piston before I wiped it off. There is a slight clean spot in the upper right corner of the piston. They all had it in the same area but #1 was the most pronounced. Being on the right side of the engine, this would be the "unloaded" side of the piston during compression stroke?
When the engine was running there wasn't much blow-by with oil cap removed. Would slightly move a tissue placed over the opening but it was more of an in and out pulse. I am planning to change the pan gasket so should I pull 1 piston I can get to just to have a look at the rod bearings and rings? Will give me a general idea of health of the rest. I have an inside Mic coming in the mail to check the bore for taper and round.
Alfred, Yes I saw them as well. Around the same price. They are backed up a bit.
Tyler
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I've been told to look at the top outer edge of the piston which would be just above the top compression ring. I guess the blow by gasses will wash the piston clean to the point it looks new. Without taking everything apart there's no real way to determine what kind of wear you have.
Cylinder condition is about half of the story. Having a look at number 1 piston can't hurt.
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Yes Dan, he is catching on fast!
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Yes Dan, he is catching on fast!
So do I. Sometimes I catch on fast and sometimes I catch on slow, and sometimes I catch on half fast.
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Ha! Thanks guys! Having an automotive repair background definately helps. The key is to do your research ahead of time. Every car out there has its own quirks, idiosyncrasies, and difficulties. As well as tips and tricks. Being prepared for them makes for "smoother sailing". This group does just that. We get to exchange information for the benefit of all members!
So.. Being I am so deep into this repair, My engine compartment is screaming new paint please. I knew going in this wouldn't be a simple "get in and get out" job.
Tyler
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So before sending off the head to be re-worked, I decided to remove a few of the worst offending valves. Nothing is burnt but there is significant wear on the valve contact face. These may not be salvageable. The seats on the other hand look to be ok with only minor ringing on the contact area. The rotator's appear to be working correctly.The wear is very even around the circumference of the valve and seat. The guides show minimal wear but will be replaced anyway. If valves with excessive wear are re-ground and re-used, they will sit too far up into the seat, causing the valve stems to sit too high. You will run into problems with rocker arm geometry and the in-ability to adjust the valves. This will also cause the keeper grooves to sit too high, effectively reducing your valve spring tension. This could cause valve float or even worse, the keepers to come loose while running!
Tyler
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I wonder if he needs a job?
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Tyler,
Valves are fairly inexpensive on the aftermarket. Most like to replace them these days. If you follow MB factory specs on reconditioning the old ones, you should be fine. MB is fairly conservative on allowable wear and machining tolerances.
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Joe, I'm going to leave that one up to the machine shop. If anything is questionable they will get replaced. If too much meat needs to be removed then out with the old and in with the new. I already have a set of 3.5mm thrust shims if need be. Dont want to take it down any further than that.
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I always supply the machine shop with the factory specs and tolerances so no mistakes are made.
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Joe; Scanned, Copied, Printed, and in a plastic sleeve zip tied to the head. Also written what I want done. "Check for warpage. Inspect and Advise. DO NOT MILL without authorization."
Tyler
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We put the head in an oven and heat it up so it can be pulled straight again. This allows for minimum stock removal although the top surface of the head often needs to be touched up so that both surfaces are flat and even.
You can adjust for material removal by using cam bearing shims - I use one or two .015'' shims under each bearing. As long as you have intake valve recession at least .050 mm you won't have any clearance problems.
You might be one of the first on here to already know about rocker geometry - good work, young man!
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Dan, at what temperature setting and how long do you keep it in the oven. I think it is important to mention this fact.
Cheers,
Dieter
PS. How is the snow situation at your end? Any sign of spring yet? :)
Tyler,
Nice write up (in your posts) and photographic record. Well done!
Dieter
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Thanks Guys, I dont think I will have much of an issue with warpage. I just dont want a heavy handed machinest to go ahead and mill it without letting me know. I think anything less than .003 I will leave it alone. I think I may go buy a straight edge just to confirm it myself. I can also use it to check the deck.
Tyler
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Every head is different and there's a bit of an art to it but in general terms you would use about 400 degrees F for a 280SL head. The head is set up so that a block is placed under each end and a clamping bracket is place on top of the head in the middle ( or where the warp is ) and then the clamp is torqued down. If the head is more heavily constructed on one side as compared to the other then the heavier side would receive more torque. If you had a .005'' warp you would tighten the clamp so that it would pull straight and then a bit more to allow for elastic memory.
The head would then be heated for about two hours and then left to cool while still under tension. In some cases a second attempt may be required if needed. Cast iron heads need 700 degrees F and often more time to pull straight. On vintage heads ( or anything valuable ) the advantages are clearly obvious.
I had a head with a .015'' warp. Yeah, it was really hot! :-[ After treatment, a .003'' cut was all it needed.
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Here is a picture of the clamping setup described by Benz Dr.
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Great information for others Dan and Tyler, on the heating and clamping process prior to refurbishing the head sealing face.
Sometimes special procedures need to be developed to obtain results.
Many years ago I had issues (maintaining close tolerances) with final machining and grinding of multi stage forged and stress relieved compressor shafts (largest diameter 6" smallest [for thrust bearing sleeve and collar]1.5" diameter about 8 feet long). To overcome the issues I had the shaft only preliminary machined leaving 0.06" material for final machining and grinding in order to maintain 0.0002" TIR (Total Indicator Runout). Before this final machining and grinding took place the shaft forging was placed on the floor on V Blocks for 24 hours to self stress relieve.
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Yes we have shops that do this kind of straightening also. Care and experience still required or you can cause a crack in the head!
I also loan my set of Mercedes original factory valve guide installation tools to the shop to use. So the valve guide installation goes smoothly. Hopefully your shop has its own.
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Joe, Im sure they do. They are very experienced with these engines. How they started there business back in the 70's.
http://motorworkssd.com
When the parts driver came to pick up the head I looked in the back of his truck.
A Ferrari engine block
And 2 Rolls Royce 12 cylinder heads!
Made my little Pagoda head feel cheap.
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Tyler,
Is there a reason why you have not gone to Metric Motors for your cylinder head re-build, I would have thought they were the go to people for Mercedes engines in the US.
I was not impressed with the different engines in the rear of there van, as far as I am aware MM only works on MB engines, that must be a plus.
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Eric, three factors were involved in the decision. Not necessarily in any order.
Location: This company is located 40 minutes away from me and I will have the ability to go down there when he calls me after disassembly. I will be able to be involved in the repair. Had I decided for an "exchange" head or I lived closer to them, I would have gone with Metrics.
Shipping: It would have been expensive to ship the head and the thought of a newly refurbished head being freighted makes me nervous. All it takes is one good impact.
Experience: This group is on par with other specialists out there. I asked plenty of questions and got all the right answers. The machinest even volunteered information that I already knew but confirmed that they know the specifics of these engines. A few other members have also used them and can attest to their workmanship. Just because a company does work on other brands does not make them any less capable. The head will be rebuilt by a machinest that specializes in just MB. This guy knew all the tolerences off the top of his head! It will also be blueprinted with before and after measurments.
I guess all that really matters is the end product. Results of the work will be posted here in the coming weeks so we shall see.
Tyler
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Progress Report: The machine shop has found the head to be warped .012in. They are confident they can get this number down to .004 to .006 by straightening the head. They will then machine this amount from the head to make it flat. All machining and tolerances are being recorded during this process. The valves, guides, and seals are all going to be replaced. The seats are in good shape and will be re-ground. The end result will be a total of about .010in (.254mm) overall removed from the head height (top and bottom). This is still well within tolerance and could be actually done again down the road on its next repair. .010in cam bearing tower shims will be installed to bring the cam back up to its original height. Attention is also being made to the amount the valve seats are ground. The goal is to achieve a less than or equal to 1.0mm amount of material removed. First repair size 3.5mm valve thrust shims will be used to replace the factory 4.5mm thrust shims. Cam, crank, idler, and tensioner sprockets are all being replaced (see pic) because of wear.
Meanwhile I am making progress on cleaning the block and engine bay. The original red block paint is slowly showing its face. I think I will leave it.
Tyler
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.../...The original red block paint is slowly showing its face.../...
Er.. this is just the base primer glyptal red. All M-B engine blocks were finished in black. Discussed in our Forum several times previously.
/Hans in Sweden
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The black must be coming off with the grease! At least I will be able to see what is clean before painting :)
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I use anywhere from .015 to .030 thickness of cam shims. Some of my heads needed machining on the top and bottom surfaces so there have been times where .015'' wasn't really enough to get the rockers back into the right geometry.
I'm aware that you can use thinner lash caps but I really prefer to use standard caps and thicker cam shims. Cam shims also have the added benefit of raising the cam which also raises the cam gear. This will bring the chain back to its original range of tension and I suppose by keeping it tight it may last longer.
Your mileage may vary. :)
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Dan, The head will be cut on the top and bottom. By how much I wont know untill the straightening process is done. My Idea is to shim the cam bearings the same (or close to) amount of material removed to bring the cam back to original height. I may also need the thinner lash caps because the seats are going to be ground, raising the valve stem height. With the head being milled on top, this will lower the ball stud bases as well. We shall see.
Tyler
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Understood. Two slightly different solutions to the same question. Both will work. I think that mine may address both questions but it's pretty close in either case.
Even machine shops and mechanics will agree/disagree on a whole range of subjects yet still produce very similar work. :)
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Tyler. I painted my engine with 500 degree paint from Eastwood. So far its held up very well. it comes with a hardener so if you use it make sure you use a mask. It has a low sheen to it though they describe it as matt finish. I used the same paint on my radiator and overflow tank.
I had my head rebuilt by MCH (Midwest Cylinder Head). I had to ship it to them. My head needed to be welded to remove heavy pitting on two of the chambers. I think your head is in better shape. These guys did an excellent job of re creating the chambers. They straightened and machined it, and replacing all new valve guides and re cut valve seats. Total cost for / welding and machine work was around 650. I had my engine block bored out locally in NJ for $200. They did not deck the block as it was straight.
One thing that messed me up when I re installed the head was that when I re installed the manifold studs I did not use thread sealer. It turned out that one of the studs goes into a water passage so I had a slight leak of coolant coming out. I fixed this by removing it and using thread sealer. it fixed the problem.
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Dan, Absolutely! ;)
Thanks Pinder, I have a tube of thread sealer on hand. Will do the manifold studs in addition to the ball stud bases.
Tyler
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So with everything else going on I forgot to check ALL the camshaft bearings. The end ones looked good so I didn't see this until yesterday. :( New camshaft on order from Germany. None in the states. New bearings were available here.
I'm thinking with the warped head that it was overheated at some point. The head is warped up in the middle so it took out the center camshaft bearings. The gouge is too deep to repair with a new grind and undersize bearings.
Pandoras Box strikes again.
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That's a tough one and it's not all that common either. Most damaged cams have bad lobes but the main journals generally remain intact.
Is the cam junk or can it be saved?
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Dan, there is almost a 1mm deep groove gouged out of the journal on #3 so I'd say its junk. Too bad because the lobes are almost perfect. I already have a new set of standard size bearings so even if it could be repaired I would need another set of undersize. Oh, Well. I'll keep the old one for garage art.
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Tyler,
When I adjusted the valves. I found that one of my lobes (exhaust) has some were. I was thinking of replacing the cam but as the car seems to run ok. I may defer to a later time. How much is the new cam? I could not find one in the states. I was considering getting it splatter welded and re ground. Ive asked for estimates and will post prices. For now as its the cam and relatively easy to swap out Ill run the car as is.
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Pinder, I wish it was just a bad lobe. That only runs a couple hundred to repair. If they re-grind your cam after the repair, I wonder if they could put the 09 "hot cam" profile on it! This new cam just under $700 including shipping. Don't have an invoice yet so not sure how much of that was the cam itself.(taxes, shipping etc) Yes, none in the states. Germany has 57 of them! Keep in mind this is for a 250sl. Your price may vary for application. You may also need to replace the rockers and the cam bearings. I wouldn't run a new cam on old bearings or rockers.
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Those Camshaft journals are not under a lot of load. The groove should have no consequence as long a the bearing is good and the cam journal is up to specs. A lot of the early cams had a deep grooves cut into the journals from the factory. Of coarse new is always best unless you need the $700.00 somewhere else!
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Joe, this is definately not a factory groove. Its so bad that the groove sides had mushroomed up eating into the bearing. I had to heat the bearing just to get it off past this lip that was created. I thought about a used cam but theres just no way to know what condition you will get. I already have a new set of bearings and rockers so a new cam just makes sense at this point. Putting the 700 into new squareweave carpet woulda been nice! :-\
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Yes, I can see that is not a factory groove. Unfortunately it sounds like the cam bearing was damaged beyond use. Build up on the cam journal itself can be cleaned off by in a lathe, but if it is undersize then you have problems. New rocker arms are recommended when installing a new cam (ouch $) if new rockers, then new ball adjuster studs and pressure pads also (ouch $$). In most cases the good used rockers etc. will work fine. Inspect them closely.
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With all the other new parts I have collected over the past 2 years, the only things being re-used on the head are the inner springs, rotators, and valve seats. Other than the cam and bearings, the rest of the old parts are in good shape. But since I have new, why not use them.
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Yes, you can't go wrong with new!
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Picked the head up today. Final thickness after straightening and machine work is 84.5mm Have almost everything ready to re-assemble. New cam bearings, rockers, ball studs, ball stud spring clips, all sprockets, chain, tensioner arm pin, valve thrust pieces, oiler tube, and other misc parts. A set of .30mm (.0118in) cam tower shims are on the way to make up for the .012in (.006 on each side) the head was surfaced. Camshaft should be here next week. Sure does look pretty right after machining. :D
I learned somthing new today. The machine shop knurls the top outside part of the valve guide to keep the valve stem seals from slipping off! Gives them somthing to grab on too.
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.... The machine shop knurls the top outside part of the valve guide to keep the valve stem seals from slipping off! Gives them somthing to grab on too.
Can you posy a photo please?
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Sure Alfred, I hope these can be seen. It's hard filming with a potato.
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Got a question
If we know how much was cut from original thickness can we determine the shim needed for the cams? How about the spring spacers?
Thanks for a great post
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Looks really good.
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Erick, yes you would want to use a shim or a combination of shims closest to the measurment of total thickness of the head removed. In my case .012in was removed so I ordered .0118 (.30mm) shims. The valve thrust shims are a little different. The valves in my case were replaced, however the original seats were ground. There is a spec in the bbb for determining stem height v.s thrust piece measurment. In my case, 3.5mm thrust piece vs the stock 4.5 will be used. You need to take into account the cam shims being added to this measurment because the cam sits higher off of the resurfaced head.
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Thanks
Where can I find these cam shims?
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Thanks
Where can I find these cam shims?
Metric Motors. Listed in the "suppliers" list here.
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did you shim under the springs?
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No, If its out of spec you would need to replace the seats as well as the valves.
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FedEx dropped off the new camshaft today. It's a lot more refined than the old one. There is no rough casting area between lobes. This thing is ready to go back together. Busy painting the block and chasing threads with a tap, nothing too exciting. Next post will be with the head married to the block.
Tyler
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Making headway. Head and camshaft installed. Looks great with all new parts. Too bad the valve cover hides it all.
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Looks fantastic. Now you will have to make a "clear" valve cover or at least a viewing port.
Appreciate the updates.
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Making headway. Head and camshaft installed.../...
Nice to see your fine head refurbish work... thanks for sharing
/Hans in Sweden
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Very nice indeed. What is the red around the four cam bearings?
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Jonny, Assembly Lube. It goes on all contact surfaces. Unlike oil it stays put until you run the engine. Don't want a dry start.
Tyler
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I spin the engine over with the starter, spark plugs removed, until I get full oil pressure. Almost no load on any moving parts. I tried using an electric drill once and it almost broke my arm when I hit oil pressure. :o I figure the starter is a bit safer.
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Dan, Going to do that as well. With the valve cover off until I get flow to the cam oiler tube. Going to break in the cam @2500 RPM once it starts so I want that little bit extra insurance.
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Tyler,
I have a question, maybe I am getting this wrong (BTW the post is great I wish you to enjoy it once finished). You (they) took 0.003 from top and 0.003 from the bottom of your head. While skimming from the top drops the position of the camshaft wrt everything else (since the bearings are on the skimmed surface), skimming from the bottom reduces (only) the volume of the combustion chamber. In my mind, in order to correct the camshaft positioning I would shim it only for the top skim 0.003. If you are shimming the camshaft for the total 0.006 aren't you overcompensating, possibly affecting the valve kinematics? Or maybe I am missing something.
Radu
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Radu, Yes and No. Keep in mind my valve seats were ground so the valve stem height is actually a slight bit higher than before.
You want to shim the cam towers to bring the cam back to the height before the repair (measured from the block) so the total shim thickness would be as close to what was milled (top and bottom) as possible. This allows the timing chain to ride in its original path and keep the valves in time. If you were to leave out the shims or cut the measurment in half, The cam timing would be retarded as well as the possibility of the tensioner maxing out. As far as valve/rocker geometry, this will be made up with the correct thickness thrust washer pieces that sit on top of the valve stems. This determination is made last after the cam, rockers, and ball studs are installed. Hope that makes sense.
Tyler
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I used the same assembly lube. It worked out great. I also cranked the engine until there was oil visible at top. Spark plugs removed when that was done. Looks like your making great progress.
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Pinder, Getting there. Im taking my time and detailing components as they go back on the engine. Cleanup, paint, and aluminum cleaning takes way longer than the actual repair. ::)
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Yes takes time but worth the effort. especially if you cleanup the manifolds and valve cover plus the intake throttle body. I also cleaned up my wiring harness. I found lacquer thinner works pretty good to get the gunk off on the wire harness.
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just removed the head and a few exh valves have a whitish crust on them
What can this be?
Thanks
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Erick, Mine looked almost identical. Its ash. Most likely from burning oil.
My valve guides and seals were the culpret.
Check out the photos of them on page 1 of this post
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Got some ban news
Car ran amazing till I got bored and decided to remove the head for a little oil burning
The head has never been cut but one of the combustion chambers has been re welded . Does this look critical?
Would you reuse it or use an alternate head that measures 84.6?
Thanks
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Have the machine shop pressure test the head and then make a determination. If it was welded properly I dont think its anything to worry about. It must have burned a seat sometime in its life if it has never been decked.
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Great. It has never been welded showed a local Mercedes wiz
He said the same thing burnt seat
What would cause that whole area to be eaten up?
Thanks
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We weld up heads quite often. The water ports in the head will often corrode away and will need to be replaced. Sometimes the head will have corrosion around these water inserts so that would need to be welded. If the head is straight a very minimal cut would be needed to clean everything up.
I'm thinking a coolant leak in the head gasket caused it to corrode the chamber and maybe enough for the valve seat to come loose. We have had to weld the seat recess back in, machine a new area to accept the seat, and then install a new seat. After the seat is installed it would need to be cut to fit the valve. Only someone skilled with the proper machines can do this sort of work. Maybe not rocket science but not easy to do either.
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Thanks for the reply
The piston is pitted for that cylinder
Car ran great. Compression was 150 except the one with a lose guide at 130
Should I leave it like that?
Thanks
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Erick,
The stock thickness is 85mm.
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That was either caused by a lean burn or detonation. Probably a result of the burned exhaust seat. Double check your injectors after the repair. That single cylinder could have been running lean do to a bad injector.
I have seen engines put back together and ran with that kind of pitting. Its a gamble. Personally, I wouldn't run it like that. If it goes and you ruin the block then you will be out of pocket way more then you will be fixing it now.
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That's a 280 block - are you putting it in your car? That piston isn't in great shape.
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If the engine is already out of the car it wont take too much more work to put new pistons in. second repair pistons are relatively cheap on the internet for around $650.
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Lots of progress. Installed the new ball studs, rocker arms, rocker clips, and 3.5 mm thrust spacer shims. The valve geometry is almost perfect. The ball studs are exactly at the middle of their travel and the rockers are uniform and parallel. I can't believe how much tighter everything is with new parts! The old spring clips could almost be removed with your thumb nail.
What a joy it was setting up the valve clearances for the first time after assembly. My knees are killing me. :'(
So as it stands I am now back to where I started with the original project of replacing the manifold gasket.
Still lots to do but I see an end soon. Replaced the starter with the higher cranking amp one since it was easily accessable with the manifolds removed. Also replaced the battery cables.
New water pump, oil pan, oil pump pickup screen and gasket, side cover plate, every single seal and gasket with the exception of the rear main.
Cleaning up and painting all the ancillaries and brackets before they go back on the car.
A few days before contact I hope. The pile of "Star" wrappers is getting excessive :o
Happy Saint Patty's Day!
Tyler
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Looks Fantastic Tyler! I admire your attention to detail.
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Eric,
Water in the combustion chamber can also cause the pitting in the piston top. I have never seen the pitting cause any problems.
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It will eventually fill up with carbon and look like the rest on the piston tops.
I would polish off any sharp edges to avoid any places where you could get a glowing piece of carbon sticking out from the top of the piston. Not much of a problem with our cars but it is a big problem in 190SL's that tend to run on after shut down from this exact situation.
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Thanks for the encouragement
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Just a few progress photos. Looks like tomorrow may be the day. Need to install the fan and radiator. Add fluids, plugs, cap, and ign wires. Going with the blue MBZ coolant and Febi green power steering fluid. Castrol 20w50 with Lucas break in additive for the cam and valve train. After I get it dialed in, I am definitely going to pull the injector lines, linkage and coolant pipes and have them re-plated. Their poor finish really throws all the other work out the window.
Tyler
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Looking grand!!
Febi green power steering fluid - had not seen that before, had to look it up. Mineral or synth?
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Jonny, Going with the mineral based. Have no idea if my seals would handle the synthetic. Plan on changing it regularly anyway.
I have read a few articles about the use if ATF in power steering. It is known that ATF can cause excessive wear in power steering components and degrade hoses. Which is why most auto manufacturers have stopped using it. The additive package in ATF has a friction modifier for the clutches, which steering components don't have. It is also semi corrosive.
Tyler
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looking really. good.
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Mission Accomplished!!!! Links to 3 small video clips I took after its first start. Last set of photos below.
A couple minor issues such as running out of hose clamps and forgetting I stole the gas out of the tank for my boat!
It starts extremely fast now. Even when hot or after a 30 minute hot soak. I attribute this to the upgraded starter, corrected cam timing and better compression. The new starter is the biggest improvement to starting I think, Along with new battery cables. It is a lot quieter even thought I still need to go back in and re-torque the head bolts and adjust the valves. Oil pressure is excellent. Goes right to 45 when starting hot. Engine heats up much faster, I did replace the thermostat. Cam has been broken in @ 2500 rpm for 10 minutes. I will break it in further after final valve adjustment. Overall I am very happy. Just a few minor cosmetic issues to deal with. I will report back after its first drive! ;D
Tyler
https://www.youtube.com/watch?v=0SC63E4SVjY
https://www.youtube.com/watch?v=nMA_5nO9uIk
https://www.youtube.com/watch?v=a3Q8ss0ebew
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Well done! Thanks for the videos and keeping us updated on the process. That first drive should put a massive grin on your face. Enjoy.
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Great writeup
Should I use a ball hone to make a couple of passes while I am there?
Thanks
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Erick, Unless your replacing the rings and the cylinders are within spec and are not tapered or out of round, then leave it alone. You could make things worse. If your replacing the rings and your within spec then use a rigid hone. Those ball hones are garbage. You will never be able to tell where the cylinder wall low and high spots are and how far you need to take it.
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Ball hones work great on newly bored cylinders. Using a rigid hone to true-up worn cylinders is just wishful thinking. Hones are used basically for de-glazing the cylinder walls so new rings wear-in (break-in). However always remove the upper wear ridge with a ridge-reamer when installing new rings only. Installation of nice new round piston rings into oval-worn cylinders is a formula for disaster. You will certainly make things much worse if this is the case.
Yes I agree with Tyler, no need to de-glaze the cylinders if you are not installing new piston rings. That would cause additional ring wear on rings which are already broken-in.
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Re-torqued the cylinder head bolts last night and adjusted the valves this am. Took it for a spin. Runs excellent! Minor exhaust leak at one of the flanges but nothing major. Will try to cinch them up a little more. No coolant or oil leaks. Pulls a lot stronger at part throttle load. Did I already mention how well it starts!?!? Going to take it on a good long run after the hood goes back on. Then a nice bath.
So this is pretty much it for me with my repair on this thread. Will post if somthing comes up. I may move the videos above to my other youtube channel but will change the links accordingly.
Thanks all for tagging along ;)
Tyler
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Eric,
Water in the combustion chamber can also cause the pitting in the piston top.
For the record, here is a picture of the damage caused by corrosive combustion gases that resulted from a leaking head gasket. This also had a piece of something that hit the piston and the head, but that is another story. The moral to this is that if you know you have a head gasket leak, get it fixed pronto or your head will look like this.
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That kind of damage can be repaired by welding in with aluminium. It's not as bad as it looks.