Timing Chain Recommendation?

[James B.]

I have a '67 L-79 with 52,000 miles, engines never been apart. I have had a metallic grinding sound at idle at the front of the engine for some time. Thought it was water pump or alternator bearings. Took things out of the system one by one this weekend and determined it must be the timing chain. Dropped pan, timing chain cover etc and sure enough I've got about one inch of play on the slack side of the timing chain; it was hitting the cover in two places. I am surprised it has stretched at only 52,000 miles (I know mileage is correct); after 43 years GM probably won't honor a warranty claim...
Any recommendations on sourcing a replacement chain and timing gear? I am told the original has nylon in the timing gear and replacement can be bought from GM but is expensive. Also that aftermarket sets are available with steel gears; those are more durable but are noisy. Durability isn't really an issue given the few miles I drive it. I would like to keep the engine stock as I may show the car and like originality.
If anyone has recently replace a chain and has a recommendation (or warning) please let me know. Thanks, JimB

[Timothy B.]

Re: Timing Chain Recommendation?

James,

I think 1967 is the first year for the nylon camshaft gear. IMHO I would replace with the earlier steel camshaft gear and timing chain.

Be sure to check the archives as this has been discussed before. The chain width may be different at 5/8" compared to the old 3/4" chain but I am not 100% sure. Someone will chime in with more info..

[Larry M.]

Re: Timing Chain Recommendation?

I would install a CLOYES Tru-Roller Timing Chain Set or a CLOYES Plus-Roller Set. Cost is reasonable and they are bullet-proof.

Forget OEM in this particular case. You will never know the difference, and it will last more than your lifetime.

Larry

[Joe C.]

Re: Timing Chain Recommendation?

I would install a CLOYES Tru-Roller Timing Chain Set or a CLOYES Plus-Roller Set. Cost is reasonable and they are bullet-proof.

Forget OEM in this particular case. You will never know the difference, and it will last more than your lifetime.

Larry

If you do that, then don't forget that you must clearance the block at the 12 o'clock position of the cam sprocket. The wider chain will interfere there if you don't.

Use billet steel sprockets with a 9 position crank sprocket so that your cam timing can be verified and adjusted if need be. The Liberty Engine Parts set: LT98500T-9 runs about $90.00, made in USA, and much less expensive than Cloyes.

[Clem Z.]

Re: Timing Chain Recommendation?

this cloyes set will work fine and it is a direct replacement.

[James B.]

Re: Timing Chain Recommendation?

Thanks for responses, guys.

Clem or Larry- with both Cloyes options will I have to relieve the block? Engine is in the car; it is hard to do very much and I don't want to do anything that might put metal shavings in the block.
Joe- Does the Liberty set require relieving the block.
Again, thanks, JimB

[Clem Z.]

Re: Timing Chain Recommendation?

Thanks for responses, guys.

Clem or Larry- with both Cloyes options will I have to relieve the block? Engine is in the car; it is hard to do very much and I don't want to do anything that might put metal shavings in the block.
Joe- Does the Liberty set require relieving the block.
Again, thanks, JimB

the one i posted is a direct bolt in replacement,no mods required to anything.

[Larry M.]

Re: Timing Chain Recommendation?

the one i posted is a direct bolt in replacement,no mods required to anything.

Clem:

Do you have a part number for Jim??

I was not aware of any interference with the standard Cloyes Tru-Roller in a Chevrolet small block. I have installed the TR in other engines without issue, but will believe Joe if he says the SB Chevrolet engine requires relief.

The one recommended by Clem should work fine....just need a part number.

Larry

EDIT: Try this link for additional info and part number: http://www.summitracing.com/parts/CLO-C-3001K/

[John H.]

Re: Timing Chain Recommendation?

Jim -

The standard replacement Cloyes timing set Clem posted will work just fine, will last longer than you will, and requires no modifications. It's not like you're turning a square-lobe roller with 600# springs.

[Joe C.]

Re: Timing Chain Recommendation?

Thanks for responses, guys.

Clem or Larry- with both Cloyes options will I have to relieve the block? Engine is in the car; it is hard to do very much and I don't want to do anything that might put metal shavings in the block.
Joe- Does the Liberty set require relieving the block.
Again, thanks, JimB

The Cloyes shown by Clem, above, is a single roller, and is good enough for a stock engine.

The one shown here is a double roller with steel, not cast sprockets. Yes, it requires a small amount of relieving which can be done with a die grinder in 5 minutes with no disassembly:



The relieving that needs to be done is on the boss directly above the cam journal, and involves only removing the corner along the upper edge. The two smoothed areas above the large block plugs are for oil return, and are not related to the timing set fitment issue:

[Jim D.]

Re: Timing Chain Recommendation?

I've used this Cloyes on several SB Chevy's, no mods. needed. http://www.cloyes.com/HighPerformanc...S/Default.aspx

[Clem Z.]

Re: Timing Chain Recommendation?

Clem:

Do you have a part number for Jim??

I was not aware of any interference with the standard Cloyes Tru-Roller in a Chevrolet small block. I have installed the TR in other engines without issue, but will believe Joe if he says the SB Chevrolet engine requires relief.

The one recommended by Clem should work fine....just need a part number.

Larry

EDIT: Try this link for additional info and part number: http://www.summitracing.com/parts/CLO-C-3001K/

part # C-3001K

[Duke W.]

Re: Timing Chain Recommendation?

Sealed Power makes an inexpensive steel OE replacement that will last well over 100K miles with a reasonable oil change schedule. You can look it up at napaonline.com and buy it over the Web or at your local store.

I don't think anyone makes a set with the nylon gear anymore, nor do I understand why people recommend expensive aftermarket timing sets.

Duke

[Joe L.]

Re: Timing Chain Recommendation?

James,

I think 1967 is the first year for the nylon camshaft gear. IMHO I would replace with the earlier steel camshaft gear and timing chain.

Be sure to check the archives as this has been discussed before. The chain width may be different at 5/8" compared to the old 3/4" chain but I am not 100% sure. Someone will chime in with more info..

Timothy------


1966 was the first year for a nylon toothed sprocket on a small block and it was the only year for the "wide" nylon toothed sprocket on a small block. Big blocks ALWAYS used a nylon-toothed cam sprocket from 1965 to 1974.

[Joe L.]

Re: Timing Chain Recommendation?

I have a '67 L-79 with 52,000 miles, engines never been apart. I have had a metallic grinding sound at idle at the front of the engine for some time. Thought it was water pump or alternator bearings. Took things out of the system one by one this weekend and determined it must be the timing chain. Dropped pan, timing chain cover etc and sure enough I've got about one inch of play on the slack side of the timing chain; it was hitting the cover in two places. I am surprised it has stretched at only 52,000 miles (I know mileage is correct); after 43 years GM probably won't honor a warranty claim...
Any recommendations on sourcing a replacement chain and timing gear? I am told the original has nylon in the timing gear and replacement can be bought from GM but is expensive. Also that aftermarket sets are available with steel gears; those are more durable but are noisy. Durability isn't really an issue given the few miles I drive it. I would like to keep the engine stock as I may show the car and like originality.
If anyone has recently replace a chain and has a recommendation (or warning) please let me know. Thanks, JimB

Jim------


You cannot obtain a nylon toothed cam sprocket for a small block from GM. You MIGHT still be able to get one from Cloyes IF you can find an automotive distributor willing to order you one.

For me, I use ONLY a Cloyes Tru Roller set for small blocks. The part number is 9-3100. Expensive? This set cost about 85 bucks from Summit.

The Cloyes 9-3100 has been around a LONG time. It's tried-and-true. It absolutely will not increase noise one iota. You will have rock-solid timing with this set installed. With stock-type sets after a relatively short time some stretch develops and the sprockets wear. Ever put a timing light on your engine and notice the timing mark "jumping around"? That's because of timing set wear. With a Cloyes 9-3100 this won't happen.

I have NEVER had any clearance issues with a Cloyes 9-3100. Attached is a photo of the last one I did and it required NO grinding of clearance of any kind. Can I guarantee that no small block will require it? No, I can't, but it's never happened to me.