Hello all,
I did a search and did not find my answer. My 1987 L98 has 104,000 miles on it now. It is running great but I'm concerend that maybe I should change the timing chain. Is there a mileage I should change it?

Thanks for any insight

 

The timing chain and cogs in a small-block are not 'maintenance' items; there is no mileage-based requirement to change them as there would be the timing belt in a modern overhead-cam engine. Normally, the timing components are simply replaced along with all other 'wear' components in the engine when it is rebuilt.

 

You should change them, yes. You may have a nylon cam gear which are prone to cracking and disintegrating due to age.

At 100k, the chain will be sloppy. 100k is a good interval on a SBC of your vintage.

Remember this is a 1950's design where 100k was considered the life of the engine. Since the chain is not kept tensioned with hydraulics like more modern deisgns, it is prone to stretch and sprocket wear.

GD

 

Probably not going to last much longer. Here's my original one at 117,000 miles. I was having idling trouble and wandering base timing when I went in to check it out.

 

I agree with Tootie... I just did mine at 114,000 and it was sloppy... and i felt a little performance boost from replacing it.....

 

Thanks everyone for your information. My local shop want over $1,000.00 to do it. That is with a new water pump. That's a bit more then I want to spend right now. I guess I better start saving....

 

That's not at all a bad deal for a timing chain on an 87 with the V belt setup. Technically you have to drop the pan to get the chain cover off. It's a job for sure.

GD

 

Just know that its mostly labor you are paying for.... a decent timing chain set is less than $100... as is a rebuilt water pump...add in a couple gaskets...

Its a pain taking the front of the engine apart, cleaning gasket surfaces, changing seals...cleaning parts... its just labor intensive... and as for the pan, you can leave it in place and modify the pan gasket, loosen it and drop it down a little.. or totally drop it.. i have done all three with no leaks on any of them.

I did my timing chain replacement for $55 and a weekend about a month ago... i also had all the tools like balancer puller and installer, crankshaft socket, etc... gotta have those to do the job.

 

You probably did not find an answer because there is no answer. 104K on the ticker, it's running great, and you are apparently looking for a problem which doesn't exist. There is an old axiom that a man who opens a can of worms will find worms.

Unless you have some really "special" 1987 SBC, you likely have a roller hydraulic lifter setup with steel crank sprocket, cast iron cam sprocket, and steel inverted link chain - NO plastic. That's the same arrangement used on SBCs until the Gen IV V-8s, with or without a chain damper. There are literally thousands of those (probably hundreds of thousands) which have gone 300,000+ miles in cars and trucks which never so much as had the timing cover seal replaced, running until the bodies rusted off.

If it is actually "running great" I would keep the worms in the can.

2¢

 

I love that worms saying. Never heard it. I agree with Vader. Another axiom is "Better is the Enemy of Good" - Murphy's law.

It's easy to keep an eye on it - base timing. It should always timing light to completely steady. The index mark on the damper should be steady and not wandering at idle. If it wanders at idle and not at RPM, then it's likely the timing chain.

 

TP has it nailed. Disconnect the EST and see where the base timing resides. If it's steady, no worries. If it wanders, the distributor should be investigated, and if that's good, consider the chain before it gets as sloppy as Tootie's example. The point is that they don't all wear out that fast. Then again, not everyone uses Pennzoil

 

Penzoil! Lol!!

 

You stated in your OP that the engine "is running great;" I see no reason for you to spend $1K at this time.

Sure, start saving your $$$---for some point down the road at such time as the engine is eventually worn out and requires a complete rebuild or replacement. Until that time comes---and you'll know when it arrives---if it ain't broke, don't fix it.

 

Every chain I have seen with over 100k looked just like his video.

GD

 

Unless it’s giving you real time problems I wouldn’t mess with it. My old ‘Bird lasted 283,000 miles before the the engine finally blew, and that was with no rebuild.
Now there’s no guarantee your engine will last THAT long, but if your seriously thinking about your timing chain right now, you might as well save your money for 1) A full tear down and rebuild or 2) an engine swap.

 

100% this.

 

Wasn't the factory service interval on the timing chain 100K miles on the 2-pcs RMS blocks? And wasn't this due to the nylon Cam gear ?

This is an 85 305 and the nylon was completely missing from this cam gear; you can see the ridiculous amount of slack this causes in the chain. ( You can *almost* remove the chain without removing a bolt ! )



The far right of this pic shows the change in overall size from a nylon cam gear with the nylon intact (on bottom of stack) and the same kind of cam gear with the nylon broken off ( on top stack )



IIRC the 87+ roller cam caused the cam gear change; right ??,..... ( those never used Nylon) Pretty sure the 87 Camaro Cam Gear is shown on the far LEFT in the pic above.

Like others here I think if your 87 (roller cam) is running good than i wouldn't spend 2 minutes worrying about the timing chain. If you HAD to open the engine for some other reason, sure: replace the chain. But if it's running good,....... don't go in JUST to replace the chain.