taguy16

I replaced the fairly loose timing chain which was on my car's 350 engine with a new Cloyes C-3059K chain, and it seems even looser than the one I took off. I contacted Cloyes about this and the tech guy there wanted me to measure the center to center distance between the crank and cam in case the block had been line bored, which I did and it wasn't very far off from the 4.521" measurement their stock sets are made to (probably within a margin of error since this is such a hard measurement to make without literally having to pull the cam out of the block). Still, he thought I needed to get one of their double roller race chains in an undersized size; these of course are very expensive.

Has anyone here had an experience like this with a new standard replacement Cloyes chain being way too loose (you can push it in over 1/4 to 3/8" on both sides after it's installed), and if so how did you solve this dilemma? Are other brands or models of of chains better fitting, or am I going to have to go with some sort of solution like a chain tensions kit Speedway Motors sells? I can't ever recall installing a timing chain that was so loose it just hung off of the cam gear. This can't be normal, and I can't imagine what kind of trouble I would get into running such a loose chain.

Thanks for any help.

Vader

I believe Cloyes used to offer a chain set that was 0.005" undersize to correct for line-honed mains, part number 9-3100-5. It was a heavy duty true roller, and not a dual bicycle "race" chain it actually had some durability.

They offer a set for the LS series engines (part number 9-130Z-5) so they may still have one for the Gen I SBCs.

taguy16

The 9-3100-5 was what the guy at Cloyes recommended; that or the 9-3100-10. Seems like it's a trial and error situation trying to figure out which one to use. I think it would be better to have a tensioner to allow for any measurement discrepancies. Or, if one is starting to get into the hundreds of dollars for this, at what point do you consider switching to a timing belt drive, or a gear drive (although gear drives have their drawbacks)?

The Cloyes guy called these special chains "race chains", but don't race cars use belt drives for this purpose?

AlkyIROC

If a block has been line honed then the crank centerline is closer to the cam centerline and a shorter chain is required.

It doesn't matter which brand or style of chain you use, they will all stretch over time. Advantage of a chain is that they are inexpensive and relatively quiet. Double roller chains are slightly noisier than an OEM style chain.

Due to stretching, flexing etc which can change timing, I switched my race engine over to a Milodon fixed idler gear system. Very expensive to buy but once it's installed, you never need to worry about it again. Also with a fixed idler, it's quiet not that you can really notice it on my engine anyway.

I do not recommend the duel floating idler system. In the early days of my race engine, I had a set in my car for a day before putting a chain back in it. I would rather hear the sound of a blower belt than the sound of those idlers.

Fast355

iTrader: (2)

That chain is for a flat tappet or retrofit roller application not using the OE step nose cam.

That being said C3055 is what I use on those for a mild street application. GM used them in 1 ton trucks, boats and industrial engines. The single roller chains hold up practically forever under 6,500 rpm.

taguy16

I still don't understand why the chain in the new timing chain set I got seems to fit looser than the original. Also, it's hard for me to believe that this engine has been line bored based on the condition of the rest of the engine and the fact that this timing set I removed seems to be the original GM one. I'm starting to think I got the wrong model timing set for my engine: I think I might have gotten one for the pre-roller cam engines and I need one for the roller cam ones, because there apparently is a big difference.

You can get a new GM set for this engine still, but it's just a replacement set for well over $100. For half that I could get a "true roller" set from Summit that is supposed to be for roller cam equipped SBC engines. I'm trying to decide which would fit best and give me the best service life.

Fast355

iTrader: (2)

Does your engine have the cam retaining plate behind the cam gear? The wrong cam gear will not bolt to the wrong cam. The bolt circle is smaller on a step nose roller cams.

The style of chain you bought is garbage compared to the cheap single roller. The new ones are purposely loose. 1/4-3/8" is normal.

I have had a 200K mile L31 apart with the single roller chain and it was nearly like new. Very little wear on anything and the chain was not stretched out enough to even tell.

taguy16

No, I can't see any thrust plate there. So you think the C3055 is the way to go for my engine then? I ran the code on my engine and it was originally in a 1993 truck or van of some sort.

taguy16

I installed the C3055 chain and it fits way better than the C-3059K. Mine even had "GM" and GM part number cast on it. The crank gear is sure thinner on the C3055.

Vader

Well, technically it is a sprocket, not a gear, but I think you will be happier with the HD true roller design. At least it seems to fit properly.