Might be a dumb question, timing chains.
 

Picked up a 350 to put in old Blue, supposedly out of a '73 Chevelle/Nova or Camaro. 3970010 block, (two bolt) 333882 heads. Typical craigslist engine buy I suppose. We've been cleaning it up, getting ready to paint it and put the intake I got with the truck on it. Going back to as close to stock as I can, Q-jet and all.

I'd like to pull the harmonic balancer and change the timing set. It's just an old farm truck so I don't feel a real need for anything exotic. O'reilly's lists two different timing sets Cloyes' C3001K for "Light duty" or C3023K for "HD" engines. for the '71. Other than the obvious, does anyone know if they are 100% interchangeable? The center hole, is a larger diameter on the C3023K, but the bolt holes seem to be the same. Are there some cams with a larger end diameter?

They also list C3023SP and C3023X as options in the '73 cars alongside the C3001K. I have not changed a timing set in a long time, but I have always lived under the belief that all 350 timing sets were interchangeable.

Any help or advise would be greatly appreciated.

Re: Might be a dumb question, timing chains.
 

The sets are interchangeable. Myself, I always go for the heavy duty parts. Often the HD parts are double row versus single row.

That said, the size of the center hole is inconsequential. The cam is flat on the front other than the dowel pin sticking out. The cam gear in no way registers on the cam snout other than the three bolts and the dowel pin for alignment. The hole can be as big or small as the manufacturer feels necessary for their manufacturing process.
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Re: Might be a dumb question, timing chains.
 

Thanks!

Re: Might be a dumb question, timing chains.
 

Full agreement on going HD. Changing the timing set is easy. Hardest hard part is getting the lip on the timing cover past the front of the oil pan. Best option is to drop the pan a tad. It's a good idea to replace all the gaskets and seals on that craigslist engine anyway. Which reminds me. Look for a wear groove on the harmonic balancer from the timing cover seal. If so you can get a press on "speedi sleeve" to repair it.

Re: Might be a dumb question, timing chains.
 

Just a suggestion while the motor is still out, change the cam and lifters out also. As a garage owner since about 81, I cant tell you how many of them ive changed back in the day because the cam wiped a lobe off. Something about the metal they used in that era cams. Also, if the cam gear is plastic, and some of the teeth are broken off, pull the pan and clean it out so the remnants dont plug the oil pump screen.'

Re: Might be a dumb question, timing chains.
 

^^ Bob is right. Replaced a lot of SBC plastic toothed timing gears in my day. A new cam & lifter set is certainly a good idea. With the closed valley design of the Chevy small block you cannot inspect the cam shaft once installed.

As an aside ... the reason may cams of that era failed is due to the factory induction hardening process where the cam is heated electrically from the ends. Early on the center of the cams were not heated properly so were softer and lobes wiped easily. Pontiac V-8's with their stock double springs & excessive open valve pressures were very prone to this problem. Previously cams were flame hardened but GM went with the induction process with higher volume units somewhere in the late 60's to save money.

Re: Might be a dumb question, timing chains.
 

Really appreciate all the information. Took the timing cover off today, just a little slack in the chain, but it is getting changed. Dropped the pan as well, rod end caps are number stamped. Oil pan has very little sludge and no mystery debris at all. We are thinking that it was rebuilt at some point.

In a perfect world I'd go ahead and change the cam, but finances right now make it difficult. I'm going to get a gasket set obviously, but probably go with the current cam and hope for the best.

Re: Might be a dumb question, timing chains.
 

Don't let anyone sell you an overpriced gasket set.

You want FelPro KS-2600.

35 dollars from Rock Auto.

Parts stores will gouge the piss out of you on gasket sets if you let them choose their number which has the highest profit margin. My local O Reilly tried to get me right at 100 bucks for one recently, and I have a shop account with a discount.

That part number I gave you is a full FelPro blue stripe engine gasket set. It includes everything from the valve covers to the oil drain plug gasket, water pump gaskets, to the rear main seal, and every one in between.


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Re: Might be a dumb question, timing chains.
 

If the rod caps are numbered... it's already been rebuilt, as they were not stamped at the factory. Hopefully it was rebuilt fairly recent. I would hate to see you spiff up and engine with all the new parts to have nothing but an oil burner.

I have learned my lesson over the years that buying a used engine and trying to do anything with it other than a full rebuild, can lead to more headaches than wanted.

Hope yours goes smooth.

Gary

Re: Might be a dumb question, timing chains.
 

I sold a fair number of gasket sets while working in parts hell, never heard anything bad about FelPro products. I agree, no sense in spending big $$ for a gasket set.


All I have to go on is what the previous owner said, and how clean it looked when we pulled the pan and intake. All I can do is hope for the best, if I strike out, I'll find something else.