removing m50 lower timing chain guides

[joey79]

To anyone with experience replacing the lower timing chain guides on an m50. Is it possible to replace the guides without having to remove the head?

[flyfishvt]

Yes it is. You have to remove the lower timing case cover. That requires removing the crank bolt and removing about 2 dozen bolts and the tensioner pulley for the a/c.

[joey79]

Yeah, I'm prepared for all that. I just read some contradicting info while searching. Is there any trick to it? It looks like a tight squeeze.

[flyfishvt]

No real trick just a lot of bolts. It's wedged between the head and oil pan so once you get all the bolts out you'll need to tap it with a rubber mallet to get it out. And I mean light taps and nothing more than a rubber mallet. That thing is aluminum and you can't pry it out or you'll damage the gasket surfaces.

[joey79]

I meant is there a trick to removing the chain guides. Like having to unscrew the mounting studs first or something like that?

[flyfishvt]

Not sure. I never removed them. I have a bare block on an engine stand and the lower guides are still on it. I'll snap some pics tonight and post them

It can't be that hard

[joey79]

Ok, thanks fly.

[flyfishvt]

You can see the guides in this pic. The one on the left pivots on that post on the bottom. There is a "C" clip holding it onto the post. The one on the right is stationary. It just pops off but its plastic and may break. I was able to get it off easily but I had easy acess to it because the engine is out of the car. Be prepared to replace it.

[joey79]

My stationary guide is already broken. That's my reason for doing this repair. I was worried that there wouldn't be enough clearance to get the new guide in with the head still on. Your picture does help though. I think I've come up with a plan.

Remove bottom pivot.
Snap bottom pivot into new guide.
Angle the guide as pictured, snap it on to top guide.
Rotate guide into position and thread bottom pivot into block.



Sound humanly possible? I'm not sure how much space there is to work with the head still on. Also don't know about the tension guide. It is a lot longer, but mine is the 09/94+ version that's all plastic, so it might have some flex to it.

[flyfishvt]

Sounds like a good plan. I'm glad to see you mention those pivots that thread into the head. My tension guide is plastic too. There isn't much room in there. It might actually be easier to reach from underneath. Now that the fan and pulley's and belts are off you'll have more room from under it.

[joey79]

Your tension guide (left one) in that picture is all plastic? I thought the early versions were metal with plastic just on the surface that contacts the chain.

[flyfishvt]

Early version? that pic is the block off a 94 M50. In any case you are correct. Its metal with plastic attached for the guide surface.

[joey79]

Yeah, 09/94+ the arm was entirely made of plastic.

[Reideezy]

Sorry to bump this three years later, but did you get the tensioner side guide I'm without removing the head?

[joey79]

Yes, I was able to change both timing chain guides without removing the head.

[Reideezy]

Awesome, did you have to remove the pivot to do so?

[Reideezy]

I sent you a PM. shoot me a text if possible

[highway1]

bump I'm in the same situation how were you able to remove the pivot bolt?

[Muzzlee]

Highway1 did u do it somehow? Can u help me?

[ozzyybr]

i have the same situation. How you removed?

[earnestbunbury]

I'm doing this right now and you can't get the tensioner guide off with the head on. This is on a m50 1993 Single vanos. The plastic chain guide had broken and the timing chain was rubbing on the timing chain cover by the water pump so long it wore thru that thick aluminum causing an oil leak down the front leaking toward the front seal. I did get the plastic chain guide and studs in with the head on in order to keep the chain off the new (to me) timing cover and from wearing thru again... hopefully. The stud that holds in the metal tensioner guide (with the circlip) is press fit in and not easily serviceable. After 200k + my tensioner guide surface looked good and same with the chain even with the aluminum contact for who knows how long. With the vanos unit having to be removed and replaced as a consequence of the cover being bolted in from the top, I had a quote of 1500$ to do this job and the only way this is worth it considering the value of these cars nowadays is by doing it oneself. Lower the oil pan some when replacing the timing cover as the water jacket part of the head gasket that seals the water passage is... weak after many years. Ugh, but that's another thread... GL my doods.

[JAgria]

Yes, I was able to change both timing chain guides without removing the head.

Sorry to bring this again afer some years!

But I've bumped into this situation like you guys and I can't remove the aluminium guid of without taking of the head

How did you do it?

Thank you!

[Khiggins13]

Sorry to bring this again afer some years!

But I've bumped into this situation like you guys and I can't remove the aluminium guid of without taking of the head

How did you do it?

Thank you!

I’ve found my way here aswell. Were you able to do it or did you have to remove the head? Thanks

[Williamfriis]

Im about to try this aswell, was it possible for you?

[blckstrm]

Seems like no one wants to update, and people aren't specifying M/S50 vs M/S52, but even you later guys to ask could report back with details.

That's how this works!

I'm not sure this non-removal route will work, but I'll report back in a couple weeks after I take a stab at it.