take a look at my timing gear and let me know what you think

[irish44j]

Finally opened up the timing case on the M42 that's going into my early 318.

Already knew I need new main sprockets (which I have acquired already), but hopefully you guys can take a look at a few things and let me know how they look and/or how to check their condition

First, the lower sprockets. One looks very good and the other has very sharp points on it. I assume they both should look like the upper one, correct?



Here's the full case open. I do have one tensioner that has low wear, but is there any way to tell the wear on the tensioner/chain guides from here, or will I only know once I take them off? Also note that there are no pieces of the guides/tensioner in the case, so they haven't broken or anything.



This is the profile gasket? It looks to be sticking out a bit.



but on the inside all the way around it is pretty even. Looks to have a seal. Thoughts?



anyhow, thanks in advance for the inputs.

[bmwm42]

the crank has pointish teeth normal and the idler gear looks fine aswell

[bmwm42]

but id replace the cranksprocket with the newer updated style anyway no more than 55 bucks

[irish44j]

good to know, thanks. Also noticed I have the old-style chain guide, so that will definitely be replaced with the new-style one.

[bmwm42]

I have all the parts for the overhaul if you haven't purchased already

[Simon S]

Josh – I know you said you didn’t want to pull the head, and I hate to be like this.. but so long as the engine is out like you have it – I’d pull the head if I were you.

Check out this post and the following post to see what I discovered when pulling the head and main timing case off of my m42. Let’s just say that I’m glad I did. It’s the kind of work that isn’t much fun – but man alive, you’ll feel a whole lot better after it’s done.. that squished-out profile gasket would make me nervous.

sucks about having to get fresh head bolts.. and more gaskets. at least the cams don't need to come out..

also going to recommend an updated oil pressure relief valve & spring if it hasn't already been mentioned.

oh, and now is a good time to replace the oil canister to block gasket - if it isn't leaking (which it should).. and the canister bolts are known to snap, thus recommending fresh canister-to-block bolts.

[irish44j]

yeah, I'm still thinking about it since I have all winter, but it's also the thought of whether the extra tradeoff is worth it. This isn't a car that is driven much - only for rallycross more or less, so I would hate to spend so much time and money doing the profile gasket repair and all that, only to have something dumb happen like the guide sprocket arm break off or something that I can't control. I see no evidence of a coolant leak right now so it's a matter of "dont' fix it if it ain't broke" or not...

Also I fear that if I go that far I'll end up wanting to swtich to an M44 timing case, which is more expense, on a car where the goal is to keep things cheap.

Oil canister to block gasket has was just replaced already so at least that's good.

The more I see the problems that the M42 seems to have, the more I think about just keeping the damn M10 in there, since it's pretty much bulletproof and runs great (just with not much power)....

Thanks for the thoughts though, will definitely take them into consideration.

[irish44j]

btw, where is the oil pressure relief valve?

[Simon S]

yeah - the m42 is frustrating since it easily turns into a slippery slope. And while no one part is expensive, the volume of little parts add up quick.

It's not like m42s are time bombs - it's more like they do require some attention. They aren't Honda engines - and sadly, that's how most are treated.

Not sure what the benefits of the m44 timing case are(?). Seems like the idler sprocket was different - otherwise, the m42 case works fine imo..

Here's a photo of my timing case. The pressure relief valve is installed in the hole that you see at bottom/right.



This photo shows the original relief valve at left and updated assembly at right (oil pump mechanism is in the middle).

[AustinK425]

So I would have access to the oil pressure relief valve by dropping the lower oil pan? sorry to interject good stuff in here.

[twistednut]

So I would have access to the oil pressure relief valve by dropping the lower oil pan? sorry to interject good stuff in here.

Need to pull the upper pan to get to it.