S38B35 Timing Chain Guides

Specific conversations and info for the BMW E28 M5 and M535i.
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robertodonnell
Posts: 65
Joined: Feb 17, 2019 6:27 AM
Location: NSW

S38B35 Timing Chain Guides

Post by robertodonnell »

Evening boys. Well...it's evening here in Aus...

I am about to embark on a timing chain reco on my M5, has anyone got info on a vendor that sells a rebuild "kit" as such? I have just done a look at realoem and run a list of parts through Pelican, and the price is kind of up there! Was hoping someone would do a job lot for a bit of a discount, but I haven't found anyone as yet who does.

Cheers,

Robert
tylerrose
Posts: 23
Joined: Sep 27, 2020 8:18 PM
Location: Los Angeles, CA

Re: S38B35 Timing Chain Guides

Post by tylerrose »

Nope… unfortunately one of those “pay to play” things.
Randomg
Posts: 480
Joined: Jul 12, 2007 3:12 PM
Location: Seattle

Re: S38B35 Timing Chain Guides

Post by Randomg »

Unfortunately it's one of those unknowns that people just don't risk. There haven't really been that many timing chain failures from what I can remember. Also can't remember a timing chain ever snapping unless something else failed first.

When I looked at the guide rails, they had wear marks after 200k, but it also looked to me like it should be fine as long as you have plenty of material left, which I did. My engine builder Paul Burke told me I didn't need to replace the cam sprockets because he's never seen much wear on them. I did anyway.

If you're set on doing it for cheap, I'd replace the chain (just since I don't think it's that much), the plastic guide, upgrade to the s50 tensioner, the lower sprocket on the crank, and the idle sprocket. If the other 4 pieces look excessively worn (they usually don't from what I've seen), those too.

Not replacing some of the cam sprockets will probably lead to imperfect valve timing. Not sure by how much. If you slotted the sprockets, you could set them to what you want, but that's a lot of extra work.

Lastly, I'm just some guy on the internet with no experience replacing half of the components or first hand experience with a failure. I don't think it makes sense to gamble, but the above is what I'd replace if I were forced to do it on a budget.
robertodonnell
Posts: 65
Joined: Feb 17, 2019 6:27 AM
Location: NSW

Re: S38B35 Timing Chain Guides

Post by robertodonnell »

I had a mate with S38 experience visit me last week, and we had a good look down the front of the engine. Good news, I have no excessive wear and probably no need to reco the mechanism in the short term. Chain is good, sprockets have bugger all wear and all the tensioners are holding up well. I do intend on doing the S14 Evo Exhaust sprocket upgrade in due course, but for the meantime I can be comfortable I am not going to end up with engine failure, and that is the main thing!
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