OM617 Engine Rebuild -- Chime In - PeachParts Mercedes-Benz Forum

greazzer · #1 10-11-2015, 01:06 PM

Finally, the engine (short block) is back from the machinist. Sat there way too long, so dealing with some flash, et cet. Dealing with some other issues not 100% expected. Some fasteners got lost (I think). Got a separate post looking for some washers. Secondly, all the fasteners, et cet., ended up in one box. Ultimately my fault for not managing this aspect of my project better, makes things a little bit of a PITA, but it forces me to memorize and document every fastener, washer, et cet., which may be a good thing.

So, I am rebuilding my first OM617 engine (turbo), 617.952. This came from a later in the build cycle 1985 parts car I purchased back in 2011-ish from a gent located in the back woods of Georgia. After 3 years at the machinist, I took everything back home in frustration. I have 100% confidence in the machinist and what he did so far. The block was stripped down, boiled out, liners removed, crank polished, new bearings, everything balanced, et cet.

Here's a picture with the head being ready to be installed. I am looking for the 22x washers and the 4 hidden head bolts. The 2 I have currently which go inside /underneath the valve cover (cam cover) are correct being 20mm threaded length. The 2 outside are wrong or at least wrong per the FSM since they are supposed to be 25mm threaded length and the 2 I got are a little longer, e.g., 28mm.

greazzer · #2 10-11-2015, 02:27 PM

There are 22 head bolts, excluding the four (4) "hidden bolts",

Why does the parts' catalog say that nine (9) head bolt washers are needed when there are 22 bolts? That is why I initially bought 9 washers. Are all the washers identical?

Mike D · #3 10-11-2015, 09:24 PM

Difference in nomenclature. The "head" bolts are the ones which secure the head to the cylinder block only. You are including the cam tower bolts in your total. If a bolt passes through a part other than the head then technically, it is not considered a "head" bolt. Makes sense in a engineering scheme of things. To remove a cam you remove the cam tower bolts only, etc.

If I remember correctly, only the bolts going through the machined flats (the ones under the valve cover) require the washers.

Hey, don't blame me, THEY make up the rules, I just play by them.

greazzer · #4 10-11-2015, 09:37 PM

The bolts which go thru the cam towers go thru the cylinder head and they secure the head to the block and are considered part of the tightening sequence in the FSM, so you lost me on your post???

The FSM lists 22 washers for the 22 bolts. The bolts per the FSM and how they are listed in all the parts catalogs have them as either 5 of the same, 8 of the same, and 9 of the same, (5+8+9 = 22) and under cylinder head bolts. The 5 are on the outside on the IP side of the block (driver' side), the 8 are on the cam towers, and the 9 are the remainder and they are all listed as cylinder head bolts. There are 4 bolts which go directly thru the head which are not stretch type of bolts but they are not categorized as cylinder head bolts. In the FSM they are all listed / identified as "A" in the tightening sequence.

There are 5 bolts which connect the cam bearing assemblies (3 + 2) to the head but do not go thru the head and these are not stretch bolts.

I agree with Leathermang, Roy, and Stretch that the 22 washers are now the same as MB made 9 of them thicker to "fix" the longer bolts so I will need to get 12 more thicker ones.

leathermang · #5 10-11-2015, 11:58 PM

I think you have found a legit and safe answer to continue your adventure with.

Stretch · #6 10-12-2015, 05:07 AM

Ah I see the washer issue is being discussed here too.

I've added what I hope is clear information in your other thread =>

looking for the pack rats again OM617 Engine Rebuild

Stretch · #7 10-12-2015, 05:11 AM

I must say there's something kind of comfortably primeval about the OM617

It does look nice!

Tip for the light surface rust removal =>

I like to use chrome metal polish and a rag to get rid of it in preference to the more conventional wire wool and light machine oil approach. (Wire wool is an effing nightmare on engines as it sheds swarf all over the shop - fluff from polishing rags isn't such a problem)

greazzer · #8 10-12-2015, 07:46 AM

Quote:

Originally Posted by Stretch

Ah I see the washer issue is being discussed here too.

I've added what I hope is clear information in your other thread =>

looking for the pack rats again OM617 Engine Rebuild

Yes, that thread has run its course ... I should have another 13 washers in hand in a few days Once they arrive, I will update this thread. So, first real operation is cylinder head install ...

5cylinder · #9 10-12-2015, 10:05 AM

Thanks greazzer and Stretch for posting the pictures of the OM617.952!
Oh yes!: "I must say there's something kind of comfortably primeval about the OM617" Indeed!

I have only done a cylinder head + head gasket replacement on the OM617.952 and these pictures bring a smile to my face. For me, the OM617 is such a joy! My 1985 300CD-T has only 204,000 mi. on it. So, perhaps I will have another opportunity to do another cylinder head + gasket replacement. On the one hand, not looking forward to it for the sheer fact of the work involved (it will be less work though doing what will be the 2nd time for me) but on the other hand, the chance to dive back into that model engine gives me some excitement!

I look forward to reading more about your work, greazzer.

Quote:

Originally Posted by Stretch

I must say there's something kind of comfortably primeval about the OM617

It does look nice!

Tip for the light surface rust removal =>

I like to use chrome metal polish and a rag to get rid of it in preference to the more conventional wire wool and light machine oil approach. (Wire wool is an effing nightmare on engines as it sheds swarf all over the shop - fluff from polishing rags isn't such a problem)

ROLLGUY · #10 10-12-2015, 06:24 PM

Are you in need of the other bolts? If so, I probably have plenty of them. I have bolts from several disassembled 617's. Let me know what you need..Rich

ROLLGUY · #11 10-12-2015, 06:30 PM

Quote:

Originally Posted by greazzer

There are 4 bolts which go directly thru the head which are not stretch type of bolts but they are not categorized as cylinder head bolts. In the FSM they are all listed / identified as "A" in the tightening sequence.

There are 5 bolts which connect the cam bearing assemblies (3 + 2) to the head but do not go thru the head and these are not stretch bolts.

The 4 bolts in the front near the timing chain are M8 SHCS. The 2 inside (black colored) of the valve cover are shorter than the 2 outside (yellow zinc plated). The 4 bolts holding the cam towers to the head are actually studs and nuts and washers (wavey).