Author Topic: Engine rebuild 280 SL (Read 42474 times)

Pinder · « **Reply #50 on:** November 07, 2015, 23:52:53 »

block has Hex inserts. the block jas the engine number stamped. So are these the wrong bolts? I do not beleive the enggine has ever been open up before.

Benz Dr. · « **Reply #51 on:** November 08, 2015, 01:21:44 »

I would say they're the wrong head bolts. The correct ones are 115 and 145 mm long.

Cees Klumper · « **Reply #52 on:** November 08, 2015, 07:39:46 »

That could still work Dan if the lengths you quote are for the entire bolts. Pinder said he measured 110 and 140 from the bottom of the heads, so excluding the heads.

tel76 · « **Reply #53 on:** November 08, 2015, 08:29:09 »

Cees,
Have another look at reply's 46 and 47, the way Pinder measured them is correct.

Pinder,
You will also require the correct head gasket for that block.

ja17 · « **Reply #54 on:** November 08, 2015, 15:53:26 »

Interesting.... maybe you can answer a mystery for us? Are there spacer clips installed in the slots between the cylinders?

Pinder · « **Reply #55 on:** November 08, 2015, 22:46:18 »

This is a picture of the block. there are no spacer between slots between piston bores.

ja17 · « **Reply #56 on:** November 08, 2015, 23:42:16 »

Yes, no spacer clips Thanks!

tel76 · « **Reply #57 on:** November 09, 2015, 08:57:13 »

Joe,
If you remember we had a lengthy discussion about these clips/spacers, I sent you a picture of the one I was working on at the time.
I am a firm believer that they should remain in the block as there is a ledge for them to sit on.
Another member thought they should be removed.
Do you still have the picture, if not I could send it to you.
I will send the picture to Alfred and ask him to post it here.
I look forward to the resultant discussion.
{Photo added}

ja17 · « **Reply #58 on:** November 09, 2015, 14:20:25 »

Pinder believes his engine has never been opened but is not sure? Also we never found a part number or documentation for the spacer clips. I guess it is still a mystery. I will look for the photos.

Pinder · « **Reply #59 on:** November 09, 2015, 18:08:10 »

Correct that I am not sure if it has been opened up before or not, I know the car was last running in 1985 as that was the last NY motor vehicle inspection sticker. It had been in storage after that. unless it had the head off sometime between 1970 and 1985 ( a period of 15 years). current clock mileage is 52000. so that would be either 152000 or 52000. So cant say either way for sure. Not sure if any would would remove something from the engine even during a rebuild. Makes no sense to me. I would assume some blocks have the spacers and some don't. I cant see why spacers are added in the first place. I would think they restrict water flow.

Benz Dr. · « **Reply #60 on:** November 09, 2015, 18:13:03 »

At 152,000 miles there would be a lot of wear on the cylinders. At 52,000 miles you shouldn't see that much.

Pinder · « **Reply #61 on:** November 11, 2015, 02:14:36 »

I didnt see much wear. I did see corrison from sitting a long time. ?No lip at top. I am readt to put the head back on, I installed vavlues and new seals. machine show installed the vavlue guides and valve seats. any last advice before i install? I cleaned out all the head bolt holes.

Benz Dr. · « **Reply #62 on:** November 11, 2015, 23:07:16 »

Make sure you oil the threads on the head bolts and under the washers before you start to torque the head down. I leave it rest about an hour between each torque sequence.

Pinder · « **Reply #63 on:** November 12, 2015, 00:11:20 »

Will Do Dr Benz. Any specific type of Oil.

Benz Dr. · « **Reply #64 on:** November 12, 2015, 23:28:42 »

No, not really. I use ordinary engine oil. The main idea is to get a nice smooth pull on your torque wrench which is aided by lubing the threads at any point where friction would would be present.

Richard S · « **Reply #65 on:** November 12, 2015, 23:49:38 »

I thought that published torque values are with clean dry threads and are lower by a certain percentage if threads are lubricated.

Pinder · « **Reply #66 on:** November 15, 2015, 00:02:08 »

Need some help guys. I've installed the head and put the timing chain on. Put Chain pensioner on. checking the timing (crank at TDC and looking at notch on thrust washer. on Cam sprocket. if crank is bang on TDC (rotating crank clock wise to get to TDC on crank) the mark on the Cam tower is not bang on in middle of thrust washer mark. Is this OK or am I off a notcht? if I set the mark on Cam thrust washer to be exactly middle of notch on thrust washer the Crank shows almost 5 Degrees off TDC. This is a new timing chain.

Pinder · « **Reply #67 on:** November 15, 2015, 02:24:02 »

Here are some pics with Crank set at TDC and pic of Cam thrust washer showing where it its when Crank is rotated clockwise and set to TDC,

Pinder · « **Reply #68 on:** November 15, 2015, 02:26:34 »

crank pic

Pinder · « **Reply #69 on:** November 15, 2015, 02:35:39 »

My question is am i a notch out or is this is as good as it gets without chaning ALL sprockets.? Chain is new. Should I try moving one notch over and see where it all sits? Is it worth the effort or leave as is. I spent all day fishing out a dropped middle chain line from the oil pan so I would like to wrap this up.

Pinder · « **Reply #70 on:** November 15, 2015, 04:01:53 »

some updates. I torqued down the Cam sprocket to spec. after that when cam is at TDC the crank shows about 1.5 to 2 degrees off.

Benz Dr. · « **Reply #71 on:** November 15, 2015, 06:36:48 »

Quote from: Richard S on November 12, 2015, 23:49:38

I thought that published torque values are with clean dry threads and are lower by a certain percentage if threads are lubricated.

The BBB instructs you to oil the threads on the screws and oil under the washers.

Benz Dr. · « **Reply #72 on:** November 15, 2015, 06:42:10 »

Quote from: Pinder on November 15, 2015, 04:01:53

some updates. I torqued down the Cam sprocket to spec. after that when cam is at TDC the crank shows about 1.5 to 2 degrees off.

It's common for the notch on the cam bearing to be off slightly when the crank is at TDC. As long as it's off towards the manifold side you should not be in danger of having valves hit pistons. Look in the BBB for how to check cam timing. 2 degrees off isn't that much but it can be fixed with an offset key.

Pinder · « **Reply #73 on:** November 16, 2015, 00:05:16 »

Thanks Dr Benz. this is very helpful. I am going to leave it as is as I think its only slightly off and it is to the manifold side. I did draw a diagram to see how much the notch on the cam would move if I adjusted one tooth on cam sprocket and it would work out to be more off than how its set now so I didnt mess with it.

I now have the head on, IP timed correctly and just installed the water thermostat housing and alternator after a good cleanup. getting very close to firing her up. as i am cleaning and painting parts before i install this is taking a long time but looking forrward to fire up. Tomorrow I will be adjusting the tappets. They are way off (too tight).

Shvegel · « **Reply #74 on:** November 16, 2015, 01:43:33 »

Any machine work to the head or the block deck will cause the cam timing to be retarded. Which means the mark will move to the manifold side. Think of it this way if you slightly lower the head you get a bit of slack in the chain which will move the mark to the manifold side. If I am not mistaken Mercedes used to sell various thicknesses of head gaskets just for that occasion but an offset key for the cam will achieve much the same result.

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Author Topic: Engine rebuild 280 SL (Read 42474 times)