Pagoda SL Group

W113 Pagoda SL Group => Drive train, fuel, suspension, steering & brakes => Topic started by: merrill on March 26, 2006, 18:37:50

Title: compression question
Post by: merrill on March 26, 2006, 18:37:50
went thru some receipts for my 66 230 sl today. found the following info from previous compression tests.

5/86 1. 140  2. 145 3. 150  4. 150 5. 135  6. 150
2/87 1. 105  2. 105 3. 120  4. 120 5. 115  6. 120

the compression was checked at the dealer, seems strange that it would drop in such as short time.  the car starts like a champ and runs ok. no spring chicken.  I do know the cam is just about out of spec and the motor, head is original.

I am trying to figure out if I should just pull the motor and send it to metric motos.

any ideas
matt
Title: Re: compression question
Post by: 68_white on March 26, 2006, 19:40:35
Consider having the compression test done at two or three independent shops.

You will be surprised with the variation in the results.

I had my engine tested at two places. I got very significantly different readings. So, I went to a third shop that confirmed the the first shop's reading.

Good luck.

HARRY

68_WHITE
Title: Re: compression question
Post by: ja17 on March 26, 2006, 20:28:12
Hello Merrill.

The compression should be taken when the engine is warm, or it will be lower. I agree it is not likely that the compression dropped in all cylinders in such a short period of time.

Joe Alexander
Blacklick, Ohio
Title: Re: compression question
Post by: Raymond on March 26, 2006, 20:40:19
Compression tests can vary with the temperature of the engine, the style of the gauge, and the technique of the mechanic.  So a second opinion, or third can be helpful.  The most important thing is the variation between the cylinders.  More than 20% difference between any two cylinders is an indication of problems.  Then, other test can more specifically pinpoint the issue.

If the engine isn't burning oil, or exhibiting other problems, it could run for a long time before you have to have a rebuild.  If you just want a rebuild, that is a measure of vacuum in your wallet.  ;)

Ray
'68 280SL 4-spd Coupe
Title: Re: compression question
Post by: merrill on March 28, 2006, 06:44:21
Heard from Gernold at SL tech.  he thinks the compression issue is stuck rings due to the car sitting.  

and after dad died mom started it once in a while but it did not get drived until I went home to visit every 6 months.

so, here is the real question, gernold suggested sending the motor to metric motors for a rebuild, will stuck rings unstick with driving or is the damage done?
Title: Re: compression question
Post by: Ben on March 28, 2006, 07:29:06
I know a guy who had the same situation with a '64 230SL, he filled the cylinders with penetrating fluid and left it for a month, turning it over every once in a while . Then flushed it out, changed the oil and the problem was gone !

Regards,
Ben in Ireland.
'64 230SL 4sp.
Title: Re: compression question
Post by: merrill on March 28, 2006, 11:50:22
Ben,
that is interesting, any input from anyone on if this is a good idea?
if so, any particular penetrating oil and how would one flush the system?  (change the oil a few times)?

matt
Title: Re: compression question
Post by: Ben on March 29, 2006, 02:40:50
I'm not sure what Pentrating Fluid he used but as far as flushing goes yeah the oil was changed a few times and the motor spun over without any plugs fitted !

I reckon the fluid would seep down the cylinder walls into the sump over a few days/week, so this would need topping up too, before a very full sump was emptied !

Regards,
Ben in Ireland.
'64 230SL 4sp.
Title: Re: compression question
Post by: merrill on March 29, 2006, 07:06:24
ben,
talked to a guy at work yesterday about this,  he had the same problem and used diesel fuel!

I guess I can call around and see if any hot rod shops have any ideas

matt
Title: Re: compression question
Post by: Ben on March 29, 2006, 07:31:00
Matt,
   I just confirmed my guy used deisel too !

Regards,
Ben in Ireland.
'64 230SL 4sp.
Title: Re: compression question
Post by: merrill on March 30, 2006, 19:19:17
follow on info from th mb club. my concern is I really do not know the mileage of this car.

If that's the case, can you give the mileage readings for the two compression tests?  - well this is hard be hard, since this car was bought in germany in 8/77.
the first receipt I have with a mileage reading is Jan-79 96619 KM.  I have no idea how many times the odo has rolled.  is 60,000 miles in 10 years reasonable for a european car? could it really be 120,000 miles?
Either way, here is my guess

compression 1     75,299.4 miles or 135,299.4 miles
compression 2     81,066  miles or   141,066 miles




Also, is there any chance that different compression meters were used for the two tests? - dunno, the work was done at the mb dealership in hawaii

If one makes the assumption that you drove the car very little between the two reported tests, there is a possibility that you do have frozen piston rings, but there is also some possiblity that you have some valve or stem problems.
- my dad retired in 85. so the car was driven less and less.  more short trips etc.
oahu is a small island.

Did the dealer repeat the second test after putting some oil in the cylinders so as to make up for any leakage past the rings? That's a pretty standard thing to do in connection with that test.
- yeah, I know, unfortunately there are no real notes on the receipt

The oil works, just temporarily, as a seal so that the readings eliminate the rings as a problem.

You also have to be sure that there isn't a stuck throttle valve or some other constriction in your intake system, depending on what type of engine you have.
- could be, I will check, other stuff.  I do know that the cam is about shot and I am willing to bet I need new valve stems etc
Title: Re: compression question
Post by: merrill on June 10, 2006, 20:28:24
uh oh,
so while I have been waiting for some parts to show up I have pulled the spark plugs and manually turning the motor and keeping the clylinders re filled with diesel to hopefully un stick the piston rings.

well, today I turned the motor and topped off esch cylinder, well, since it was so quiet I could hear a drip, drip drop, went back under the hood and sure enough it was coming from one of the cylinders.

so, any suggestions,  should I do a compression test, pull the head,
maybe one cylinder is at BDC and the diesel was able to run thru?

frustrated
Title: Re: compression question
Post by: ja17 on June 10, 2006, 20:41:21
Hello Matt,

How does the car run? Are  you getting a lot of smoke. Driving should not hurt as long as you keep oil in it. Driving it may give you some clues. I agree with Dan, compression tests may vary a lot depending on the condition of the gauge.

The heating up and cooling off cycle from running the engine may help free up rings if they are stuck. If you start oil fouling spark plugs, then the handwriting is on the wall, at least the head will need to be removed.

Keep us up to date.

Joe


Joe Alexander
Blacklick, Ohio
Title: Re: compression question
Post by: Benz Dr. on June 11, 2006, 11:07:42
Notice how the second test is roughly 30 PSI lower than the first on all cyinders? I'd say it's a faulty gauge or testing method if the engine sarts and runs well.

Dan Caron's
 SL Barn
benzbarn@ebtech.net
 slbarn.mbz.org
  1 877 661 6061
Title: Re: compression question
Post by: JimVillers on June 11, 2006, 19:14:27
Matt .... Did you have the throttle open when you took your compression test.  It must be wide open to get a good reading.

Jim Villers
190SL, 230SL 5-Speed, 190E 2.3-16 Kompressor, MGB 5-Speed
Title: Re: compression question
Post by: Benz Dr. on June 11, 2006, 20:45:57
No it doesn't. We've been through this before and I'm 100% sure on this. The engine will idle on the small amount of air that gets by the air acrew with the throttle closed, right?
In this case you will have all the spark plugs out and will only be trying to fill one cylinder with air. It won't make one bit of difference. The maximum will be the same open or closed throttle.

Some engines are VERY sensitive to throttle opening for compression testing ( I remember this Alfa once ) but not these cars. So that's not the problem.

Sorry Jim.

Dan Caron's
 SL Barn
benzbarn@ebtech.net
 slbarn.mbz.org
  1 877 661 6061
Title: Re: compression question
Post by: merrill on September 06, 2006, 06:37:53
so, this is interesting,

last weekend I found that the thermostat for the injection pump was not working,  AND the pin that connects the thermostat to the injection pump was missing.

so, the car was running rich all the time.

To make this more interesting the injection pump was replaced between the compression tests.  

I bet I have fried rings due to excess fuel being pumped into the system.   I doubt I had stuck rings.

Either way, when I used diesel to un-stick the rings, I could hear one cylinder a drip drip as the fuel ran out of the cylinder #5

I will get the pin, a rebuilt thermostat and see what happens.

sure wish I could pull the lower pan while the motor is in the car to pull the pistons inspect the cylinders etc...

matt



Matt
66 230 sl - "white"
78 300 D - Blue
98 C230
Title: Re: compression question
Post by: Vince Canepa on September 06, 2006, 09:03:01
I'm with Joe and Dan on this one - I don't think those readings are reliable enough to make a decision.  Also, I wouldn't get too excited by the "drip drip".  Piston rings have small gaps at the ends.  A light fluid like diesel oil will work its way past the gaps and drip into the crankcase.  I wouldn' be surprised if all the cylinders were dripping.  After you have amused yourself with the diesel, drain the oil and refill with fresh oil before starting the engine.  Then run the car.  I would drive it 1,000 miles or so and recheck the compression before making any decision.

Vince Canepa
1967 250SL
113.043-10-001543
568H Signal Red
116 Caviar MB-Tex
Title: Re: compression question
Post by: merrill on February 14, 2007, 19:25:39
so,
heard back from metric motors today, they gave me the following update

Your cylinder head has some corrosion but is fine (actually better than most).
  The block is standard bore but has substantial wear from ring travel (the 4-ring piston version will do that, as well as an enriched fuel condition). So we will need to finish it at the 2nd repair stage of +1.00mm = 83.00mm (no worries = standard procedure).
 Crankshaft and camshaft have normal wear. All in all just a tired assembly

I need to ask them about the status of the piston rings when they removed the pistons from the car.

matt

Matt
Austin Tx
66 230 sl - "white"
78 300 D - Blue
98 C230
Title: Re: compression question
Post by: Nate on February 14, 2007, 21:29:32
What does Metric Motors charge for a small block rebuild?
Title: Re: compression question
Post by: merrill on February 15, 2007, 07:51:03
Nate,

short block rebuild -  3,700.00
long block rebuild - 6,200.00


 http://www.mercedesengines.net/products.asp?cat=15

Matt
Austin Tx
66 230 sl - "white"
78 300 D - Blue
98 C230
Title: Re: compression question
Post by: rwmastel on February 16, 2007, 14:13:28
quote:
Originally posted by merrill

short block rebuild -  3,700.00
long block rebuild - 6,200.00
Is a 230SL engine a short or long block?

How many miles were on your engine, or do you know?

What's your engine number?  I wonder if I have the same 4-ring pistons.

Rodd
Powell, Ohio, USA
1966 230SL, Euro, Auto, Leather, both  tops
1994 E420
Title: Re: compression question
Post by: George Des on February 16, 2007, 15:25:55
Rod--Long and short block refers to the type rebuild. A long block rebuild is everything including the head unit i.e. valves, camshaft, etc. in addition to the block components i.e. pistons, crank, etc. A short block rebuild includes just the block unit and none of the head components.

George Des
Title: Re: compression question
Post by: merrill on February 16, 2007, 20:51:16
Rodd,

Is a 230SL engine a short or long block? - george answered this

How many miles were on your engine, or do you know? - actually I do not know, I have many recipts however the odo is in km

What's your engine number? I wonder if I have the same 4-ring pistons
I think the number is 12781-12-00419

matt

Matt
Austin Tx
66 230 sl - "white"
78 300 D - Blue
98 C230
Title: Re: compression question
Post by: rwmastel on February 17, 2007, 15:20:30
quote:
Originally posted by George Des

A long block rebuild is everything including the head unit i.e. valves, camshaft, etc. in addition to the block components i.e. pistons, crank, etc.
OK, so I have more money to save before making that call.

Rodd
Powell, Ohio, USA
1966 230SL, Euro, Auto, Leather, both  tops
1994 E420
Title: Re: compression question
Post by: merrill on February 18, 2007, 09:08:01
Rodd,
I will post photos of the motor when it is returned to me.
If it looks anything like the photos on the metric motors web site i will be happy.

The fuel injection pump that Hans at H&R rebuilt looks amazing.  I assume like new.  Also, the pump shaft rotates smoothly - no clicking -  I asked hans about this and apparantly the pump shaft wil click when it gets a plunger that is not moving smoothly and or stuck


matt

Matt
Austin Tx
66 230 sl - "white"
78 300 D - Blue
98 C230
Title: Re: compression question
Post by: doitwright on March 04, 2007, 12:55:09
This forum has to be the best source for information on the 113 cars.  I have had mine since last October and find the info hear addicting.  It is my 1st 113.  To make a long story short, I probably would not have bought this particular car knowing what I know now.  It was totally misrepresented by the seller in many respects.  After driving it home 800 miles with no problems and adding a quart of oil along the way,  I took it to my local independant Mercedes mechanic for an inspection.  He seemed to be very knowledgable about these particular models and actually had 2 others in his shop for service while I was there.  He went through my car and came back with a list of recommended services.  Included was a tune-up, trans service, and replace all belts and hoses.  I asked him to do a compression check to get an indication of how healthy the engine was which he agreed was a good idea.  He came back to me with the following readings:

Cylinder 1 - 150
Cylinder 2 - 130
Cylinder 3 - 130
Cylinder 4 - 140
Cylinder 5 - 95 - (goes over 200 with oil in cylinder and valve clearance)
Cylinder 6 - 150

He says you will need to rebuild the engine and he can do it between $8-9000.00

This news is of course very depressing to me so I start exploring my options.  Even thought of throwing in a can of "Engine Restore".  95 in cylinder 5.  Um, not good right?  One option was to find another motor perhaps even from a 280se.  So I find a guy locally who has a 280se for sale which he says runs well.  Now keep in mind my engine also seems to run well.  I do not see any smoke when it starts or is running.  I decide that before I will buy another engine, I will do a compression check on this possible replacement motor.

I go to the parts store and purchase a shiny new compression tester with the 14mm fitting.  Since I have not used one of these in a very long time,  I decide to try it out on my own 280SL 1st.  I start the engine (after battery charge).  It starts right up after sitting since November to let it warm up.  I read here that the compression test should be done on a warm engine.  Again no smoke.  After about a 10 minute warmup, I take out all the plugs, disconnect the coil wire (forgot to remove the fuel pump fuse) and start my test.  Here is what I came up with:

Cylinder 1 - 180
Cylinder 2 - 170
Cylinder 3 - 170
Cylinder 4 - 180
Cylinder 5 - 135
Cylinder 6 - 184

I call the mechanic who thinks he did his test cold.  He also asks if the car sat for a long while.  I think it did.  He says when a car sits, one cylinder will have its valve open whick allows humidity to enter the combustion chamber and may have caused the rings to stick.  The compression differences are relatively consistant across all cylinders but now I am thinking that 135 is allot better than 95 and I may just stay with what I have.

Do you think it would be worth while to put some diesel fuel (I believe it is fuel and not oil correct?) in cylinder 5 an let it soak for a while with the hope of freeing up a potentially stuck ring?
Title: Re: compression question
Post by: al_lieffring on March 04, 2007, 13:27:48
quote:
Originally posted by doitwright



Do you think it would be worth while to put some diesel fuel (I believe it is fuel and not oil correct?) in cylinder 5 an let it soak for a while with the hope of freeing up a potentially stuck ring?



Something like Marvel Mystery Oil would be a better choice than just fuel oil. Will it help? provably not, but it couldn't hurt. Be sure to change the oil after letting the rings soak before you drive the car.

The low compression on only cylinder #5 is often related to the design of the cooling jackets in the M130 2.8 litre motor block whether it is from a sedan or a SL. The bore on #5 and sometimes also cylinder #4 will wear much faster than the other cylinders.

It is just as expensive to rebuild an engine that is completly worn out as to rebuild one with just one weak cylinder. Drive the car for a while and see if the oil consumption is something that you can live with. (oil is only $2.50 a quart, a rebuilt engine $8,000.00



66 230sl
113-042-10-014715
904/396 blue, Ivory Tex
condition: not-as-rusty-as-before-bucket
Title: Re: compression question
Post by: glennard on March 04, 2007, 16:47:12
Frank, Would do a five minute 'Motor Flush' ( a quart added, then run engine for five minutes.  Change oil and filter.)  If you have the valve cover off, make sure the oil distribution tube( 10 mm tube running the length of the cam shaft) has no blocked holes in it.  It is secured by a cap screw and some clamps.  The tube has holes for the corresponding bearing and rocker arms, etc.  Number 6 gets the crud!
Title: Re: compression question
Post by: glennard on March 04, 2007, 16:54:49
Frank, Sounds like I'm due some attribution from your 'mechanic'.  My line is:  "I've been in this ( insert type business ) for 42 years, and this is the worst case of ( insert problem type) I've ever seen.  It is going to take me a little longer to fix, but I think I can do it- just for you."   Good for at least 50% more.
Title: Re: compression question
Post by: J. Huber on March 04, 2007, 22:33:17
If it comes to this: Unless you really like your mechanic (and get to ride in his new boat once in a while), I'd consider letting Metric Motors rebuild it instead. Might even be less and they are seasoned in this motor.

James
63 230SL
Title: Re: compression question
Post by: doitwright on March 05, 2007, 00:22:07
Thanks to all for your comments - and humor.  I have a can of the Motor Flush.  Have not used it yet because I wanted some opinions of the "mechanic in a can" possibilities.  Two people I talked to (not professional mechanics) said they would not use motor flush in a good runing engine since it may wash out some of the ?(cannot think of the name) that fill the grooves in the cylinder walls and keeps the compression as good as it is.  I am not sure I buy that argument either.  I plan to try the Motor Flush followed by the Marvel Mystery oil in cylinder 5, then do an oil change and see where I stand.  I suspect worst case is no improvement.
Title: Re: compression question
Post by: glennard on March 05, 2007, 02:31:24
Frank, If I had 135 to 184 lbs range, I'd expect at least 50K more miles without a problem.  Keep the valves adjusted to .003 and .007,  change the oil and filter every 3K,  adjust to proper idle mix, adjust to start on first crank revolution. Get new mechanic(i. e., Pagoda SL Group).  Pagoda Paradise!
Title: Re: compression question
Post by: merrill on March 05, 2007, 11:41:18
Frank,
for what it is worth, metric just finished my 230 sl longblock rebuild for $5,700 plus $300 shipping.

If you decide to pull the motor your self you could save a bundle.

You might try sending an e-mail to mike at metric motors.
he is very nice and will probably give you additional advice.

matt

Matt
Austin Tx
66 230 sl - "white"
78 300 D - Blue
98 C230
Title: Re: compression question
Post by: dasvinger on March 05, 2007, 22:46:31
quote:
Originally posted by doitwright

This forum has to be the best source for information on the 113 cars.  I have had mine since last October and find the info hear addicting.  It is my 1st 113.  To make a long story short, I probably would not have bought this particular car knowing what I know now.  It was totally misrepresented by the seller in many respects.  After driving it home 800 miles with no problems and adding a quart of oil along the way,  I took it to my local independant Mercedes mechanic for an inspection.  He seemed to be very knowledgable about these particular models and actually had 2 others in his shop for service while I was there.  He went through my car and came back with a list of recommended services.  Included was a tune-up, trans service, and replace all belts and hoses.  I asked him to do a compression check to get an indication of how healthy the engine was which he agreed was a good idea.  He came back to me with the following readings:

Cylinder 1 - 150
Cylinder 2 - 130
Cylinder 3 - 130
Cylinder 4 - 140
Cylinder 5 - 95 - (goes over 200 with oil in cylinder and valve clearance)
Cylinder 6 - 150

He says you will need to rebuild the engine and he can do it between $8-9000.00

This news is of course very depressing to me so I start exploring my options.  Even thought of throwing in a can of "Engine Restore".  95 in cylinder 5.  Um, not good right?  One option was to find another motor perhaps even from a 280se.  So I find a guy locally who has a 280se for sale which he says runs well.  Now keep in mind my engine also seems to run well.  I do not see any smoke when it starts or is running.  I decide that before I will buy another engine, I will do a compression check on this possible replacement motor.

I go to the parts store and purchase a shiny new compression tester with the 14mm fitting.  Since I have not used one of these in a very long time,  I decide to try it out on my own 280SL 1st.  I start the engine (after battery charge).  It starts right up after sitting since November to let it warm up.  I read here that the compression test should be done on a warm engine.  Again no smoke.  After about a 10 minute warmup, I take out all the plugs, disconnect the coil wire (forgot to remove the fuel pump fuse) and start my test.  Here is what I came up with:

Cylinder 1 - 180
Cylinder 2 - 170
Cylinder 3 - 170
Cylinder 4 - 180
Cylinder 5 - 135
Cylinder 6 - 184

I call the mechanic who thinks he did his test cold.  He also asks if the car sat for a long while.  I think it did.  He says when a car sits, one cylinder will have its valve open whick allows humidity to enter the combustion chamber and may have caused the rings to stick.  The compression differences are relatively consistant across all cylinders but now I am thinking that 135 is allot better than 95 and I may just stay with what I have.

Do you think it would be worth while to put some diesel fuel (I believe it is fuel and not oil correct?) in cylinder 5 an let it soak for a while with the hope of freeing up a potentially stuck ring?

The compression readings are not to far out of MB specs.for high/low cylinder difference.If it runs smoothly and doesn't smoke,or use oil I would keep driving.If oil consumption goes up you can probably change to a single grade oil and improve things.
Title: Re: compression question
Post by: doitwright on March 05, 2007, 22:47:15
Merrill,  Does your rebuilt motor look like what they show on the website?  If I go with the rebuild route, I would most likely go with Metric.  The have the parts and the know-how.  For now, I will follow Glenard's suggestion and ride it until it starts to act up.  Like I am sure allot of us are, everytime I see something that needs attention, I want to make it perfect.  Then I have to say to myself: "Woooh Cowboy. Remember you bought this car to drive and enjoy it, not turn it into a trailer queen".  Look forwrd to reading about your motor after you get it installed.

Frank K
1970 280SL
Title: Re: compression question
Post by: merrill on March 12, 2007, 20:39:17
Frank,
so, my motor was just dropped off today, and yes, it actually looks better than what is on the metric motors web site.

I will take some photos and post them.

matt

Matt
Austin Tx
66 230 sl - "white"
78 300 D - Blue
98 C230
Title: Re: compression question
Post by: Ziggy on July 31, 2008, 14:23:24
Are you supposed to do the compression test with a warm or cold engine?
I just did a check with an air temperature of around 90 and engine around 125 degrees, all cylinders were around 10 (bar) while the test I did half a year ago with the engine around 45 degrees had 3 cylinders only around 8 bar. Used the same gauge... about 1,5-2 seconds of cranking. Which reading would be right?
Title: Re: compression question
Post by: Rolf on July 31, 2008, 15:37:23
The BBB states that the compression should be measured at normal working temp ( cooling water temp 20- 80 degrees C. and with the throttle valve open.
Title: Re: compression question
Post by: glennard on July 31, 2008, 16:26:36
All plugs out, engine warm, butterfly open.  Crank until the gauge stops going up.  First rev- 30 psi, 2nd- 60 psi, 3rd- 100, 4th- 125, 5th -150 psi, 6th rev- same as 5th. or something like this.  If you have low one(under 150) squirt some 40W oil in the plug hole and try again.  If it goes up, it's the rings.
Title: Re: compression question
Post by: Benz Dr. on July 31, 2008, 21:46:20
I only do cold compression tests for the most part. It's what you have when you're trying to start the car and if it's isn't enough to do that, the rest doesn't matter very much. The difference between cold and hot won't be very much in most cases.
What you may not know is that the compression is a lot lower in a running engine - maybe 100 to 110 PSI on an engine that's 170 when testing with a compression tester. When testing we mormally look at the maximum amount that attainable. The first pump usually will give you about 90 - 100 PSI and that pretty close to the running pressures while driving. If you had 160 PSI while driving it would ping like crazy if it even ran at all.
Title: Re: compression question
Post by: glennard on August 01, 2008, 06:20:03
Ditto Benz Dr.  You want 'conditions' to be the same for each annual(?) test, all cylinders above 120 psi, all cylinders within 10% of each other, etc.  Do it twice for practice  The dynamics of your particular pressure gauge will dictate the buildup of readings.  The cylinder pressure goes from vacuum to max each 2 revs, but the gauge check valve takes about 5 complete 4 cycles to capture a level reading - thus the visible jumps on the gauge.  Good time to check the valve clearance, too.  And, make sure the oil tube holes are clear.  And ad infinitum--------Then it is PPP  Purring Pagoda Paradise