Datsun Roadster Forum-311s.org

Hi all,

Is it possible to replace the timing chain guide on a 2000 while the head is still on?

This is the part I'm talking about: https://datnissparts.com/x-upper-timing ... 060-25500/

Thanks,
Joe

Anything is possible, but the question becomes, is it worth trying? I'd say no, and here is why. You must remove the front timing cover which means removing the oil pan and front pulley. This in itself isn't a big deal. What is a big deal is getting the timing cover back on without catching the front of the head gasket and pushing it inward toward the chains creating a giant oil leak. (Ask me how I know.)

Do it right, pull the engine and transmission, remove the head, replace the guide, chains and tensioners, gaskets, and the headgasket. Install the timing cover, then the head gasket, head and put it back in the car.

Will

Will is right. My only question is why do you need to replace it?

One of the mounting ears broke.

To be clear, the tab that broke is the little short stubby one on the upper right and not the long tab that is only used for holding the cam sprocket when removing the head? If so perhaps you could just remove the inspection cover and mig weld it. With the other two bolts holding it I don’t think that the top tab would see that much stress excreted on it. Even if the weld didn’t hold it couldn’t fall off the block, as the bolt would still hold it on. Certainly would be much easier than removing the engine.

For clarity of Mike M's statement and in case the web image disappears one day, the red boxed item is what typically breaks off.
Send a photo of your break and some experts here will assess it.
.

Exactly why I asked... let's look at this carefully as the "evil L" is a known issue.

No, the other ear is the one that broke off in the image above.

Short stubby one.

Unusual thing to have break... sorry to hear that. If you have not done so, search the site for the "evil L" to help in your inspection and complete repair. If you end up pulling the head etc inspect your chain and gears and examine the L for chain strikes, and strongly consider replacing the chains if they are unknowns. We can help evaluate gear wear if needed. Unfortunately to do this you are into a significant disassembly project, however it's not beyond your ability given the correct tools etc.

It may be possible to effect a repair without disassembly (can it be welded in place? I'm guessing here...) but I would want to know what may have caused this to break and to really think this through as a broken L destroys engines. You're welcome to keep posting!

Thanks for the insight folks. It's not my car, it's a buddies I'm helping restore. I had the engine out last year for a clutch R&R, and just completed his suspension and interior. I went to go change his valve cover gasket and noticed the broken part. I figured pull the engine and head were the proper way to go about it, but I don't really have the time to take on such an undertaking and thus wanted to see if someone had a more expedient way of doing it.

Understood. If you don't end up doing the work, do refer the owner to the concerns about the "evil L" so that they or the shop/mechanic is aware and can effect a complete repair. The L has destroyed a few engines over the years, and we have developed specific things to protect the engine going forward. It is a strange place to have a break, but the guide is bolted down in 3 places, including the broken part, and it MAY be OK to run it IF the rest of the guide (namely the L) is OK. However, if it has some minor chain strikes it 1) may need a new upper timing chain, and 2) the tensioner needs to be shimmed. It would be a risk, but if it comes down to not being able to run the car due to cost then one may want to evaluate the pros and cons. You're welcome to post some pics. This is just MHO and others may disagree. Clearly the BEST solution is replacement along with a new chain etc., and then proper shimming of the tensioner. Hope this helps.

Basically what Mike said above...