JDBob62

How much slack should there be in a timing chain? I have between 1/4" and 1/2" on the right side (passenger side) leg. The left side is tight.

Thanks,

Nowhere Man

I believe there should be no slack but I am no engine builder

midyearvette

depending on mileage,valve spring rates etc, it is impossible to gauge how much is tolerable, for timing chain slack. opinions change by professionals like the weather. if it is a stock mild performance engine , you are probably ok here however just the fact that you do have some slack and it sounds a little on the high side, i would recommend replacing the whole set with an after market unit. you are already there and to cover up your work without replacing in my opinion would be wrong depending on how much more you plan on driving your car. a cloyes double roller is not that expensive and you have already done the labor involved. all you need is a lower gear puller and you are in business. be sure to install the lower rubber seal with a good bead of rtv, unless you have pulled the pan. ( i'll probably take a lot of heat for the last statement) but this works for me. also you may have to do a little grinding at the seal lip edges unless you have pulled the pan, to re install the front cover. the dowel pins may get in the way also, you can pull these and install them back after you secure the front cover. we have also re installed these without a rubber seal up front and just used a lot of rtv. but let it set up overnight before you run the mill.......jmho

jim lockwood

If that were on my engine, I'd change it. I use a Cloyes 9-3100 timing chain on the engine in my vintage racer (see avatar) and, after 4000+ racing miles it is still drum tight. You won't go wrong if you replace your timing chain and sprockets with a Cloyes' piece.

Jim

MikeM

It doesn't take too many miles on a stock timing chain to get that kind of slack. How many? I don't know. I know I've taken many engines apart that had twice that much slack and they still ran good.

If you're after maximum performance and you intend to put a lot of miles on the engine or you just want max performance, change the chain/gears out with new.

Otherwise, I wouldn't fool with it.

You can put your timing cover and balancer back on and measure how many degrees "slack" you have in the chain by rocking the crank back and forth until you feel it pick up the cam. Read the results on the timing marks.

A new chain has no slack by the way.

Nev Williams

Change to a good quality chain & sprockets. That last thing you want is for the cam timing to be dancing around all over the place.
This is what I found on my engine when pulled down - there were other major issues but this minor problem here mirrored the whole previous enginebuilders reco - cheap and nasty.



BTW I used a Comp Cams sprocket and roller chain set.
Neville

MikeM

If that pictured chain was OEM quality, it would run a long time yet. But, it looks fairly new and if that's the case, it's a junk chain/gears.

Years ago, it was time for a chain replacement when you could lay the chain down on a flat table and if the top of the chain sagged down and touched the bottom links, it was time to replace it.

When a SBC chain gets REALLY bad, it'll slap the timing chain cover and make noise.

Plasticman

Cloyes true roller for me every time. Have run one on a Twin Turbo'd boat engine, that saw 4000 on up all day, with no stretch whatsoever (after several years of abuse).

Now I have seen timing chains on Chevys that fell out when the timing cover was removed (especially those with the nylon coated cam sprocket teeth - my God what a design flaw). But they still ran before tearing them apart (most of the time). The 60-70's Pontiacs used the same basic design nylon teeth covered cam sprocket and failed (as in not running) between 60-90K miles.

Also note that a loose timing chain means that your cam timing is retarded (better for top end performance, but not so good for the bottom). If you are interested in top performance (across the board), replace the chain.

Plasticman

BADBIRDCAGE

Cloyes true roller is probably the best chain setup you can buy. In 15 years in an automotive machine shop I never encountered one failure or stretch.

Never encountered a total (catastrophic) failure of a stock replacement setup either but witnessed varying stages of stretch.

As mentioned above, install complete chain and sprocket set.

Rich

Silverblue64

That's good to know as I just installed one in my 327.
One question though, does a roller timing set have a little "chain/gear whine" when running? It doesn't sound like its hitting the timing cover.
I can barely hear it but it is noticable.

Thanks

BADBIRDCAGE

I have never personally observed (heard) what I could consider as a "whine" from a Cloyes true roller setup. Pete Jackson gear drive (even the "quiet" version) can be heard above open headers.

Rich

MikeM

A long time ago, roller timing chains would make some noise in new engines. They used them in trucks. I wouldn't call it a whine. Just noise.

I have Cloyes roller chains in four different engines now and I can't hear anything. Maybe times have changed.

Silverblue64

Rich and Mike, Thanks for the replies.
Eh maybe its just me hearing things.
This is the first Cloyes roller that I have installed. I've always just used the morse style timing chain sets and have never heard anything out of them.
Thanks again, I really appreciate the help.

JDBob62

Can someone give me sources for the Cloyes roller timing chain and sprocktes?

Thanks

BADBIRDCAGE

There are many sources.
220-9-3100 is the Cloyes true roller small block part number through JEGS Performance. They also offer a kit including the timing chain and sprocket set, new timing sprocket bolts, bolt lock, timing chain cover and silicone type sealer if you add the letter "K" to the part number.

The listings include all Chevrolet engines utilizing timing chains as well as other manufacturers.

Rich