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After doing the disc brake conversion, I started on trying to get the car to run better than it was. I'm pretty handy, but haven't torn into a motor in quite some time, and always had someone there to help.
So I have a 1972 Cutlass Supreme with what I believe to be the original motor in it. The car sat for 10 years before the previous owner bought it. They were able to get it running, but said the top end had been gone through before it sat. Other than that, they couldn't tell me much about it.
The odometer says 44k, which I'm assuming is 144k, but there's no speedo cable in the car, so it could be more than that. It has an olds 350 with 7A heads, some pretty rusty hooker competition headers, an Eldebrock 1407 (750 cfm) carb, and a gm hei distributor. (no idea what year). Everything else looks stock, with the exception of a really small starter, and a newer steering box.
Following a lot of info on this site, I've done the following...
- fixed all vacuum leaks, at idle it has around 17/18, and holds pretty steady
- new plugs/wires/cap/rotor/coil/ignition module
- charging system is now working
- checked for full voltage at the distributor, which it does have.
- checked fuel pump pressure, which is 5.5ish
Timing is the big question here. Currently, it's at 14 degrees before top dead center. Anymore than that, and it idles fine, but trying to rev it up sounds horrible, almost like it's stumbling and it doesn't want to start then. I can push it to 18, and it idles even better, but will hardly rev at all, and then it backfires through the exhaust. It doesn't look like the harmonic balancer has spun to me, but there's a lot of paint on it.
I followed directions on here to check for play in the timing chain by moving the crank until I could see the rotor on the distributor move, and there's seem to be quite a lot of play, like 12 degrees before it starts to move. So I decided to check the timing chain, and this being the first time I've ever looked at an small block olds timing chain, I'm not sure if it's stock. It looks like a double roller timing chain, but the cam gear doesn't have any nylon on it, so I'm wondering if it's aftermarket. It definitely has some play in it.
So what I'm looking for is confirmation that the timing chain is indeed shot, and what replacement to get? I hear cloyes is good, and I also hear you should degree your cam when you put in the new timing chain. But I'm wondering if it's overkill, and a stock replacement would be fine.
That motor either really has only 44K on it or that chain has been replaced with a factory one. The plastic teeth on the cam gear would be gone at 144K. Aftermarket replacement chains have all-metal cam gears. Be aware that getting the front cover back on will be fun.
The camshaft timing gear shown does have nylon teeth. That is why JoeP is saying it's a low mileage motor or someone put factory type gear back. Seen timing chains with WAY more slack but would still definitely replace both gears and the chain. As far as degreeing a cam that is totally stock, let's see what some of our engine builders say but my GUESS is you won't gain much with everything else stock.
The camshaft timing gear shown does have nylon teeth. That is why JoeP is saying it's a low mileage motor or someone put factory type gear back.
This is what the stock gear usually looks like by 80K miles. The arrows are showing how much the timing chain has slipped as a result. Those marks are supposed to line up.
I have seen mid 70's motors with over 100,000 miles that looks surprisingly good, no cracks and a reasonable amount of slack. It was a 76 Cutlass 121,000 and change, I paid $50 for the car😁. It was parked due to a dying TH350, our 75's TH350 crapped out as well. I also picked up another 76 350, again looked good, supposedly 91,000 miles, which I would believe by the condition of the motor, well worth the $120, I paid. Joe, I assumed by the mid 70's Olds put better nylon on the cam gears or I got lucky.
May 14th, 2021, 06:00 PM
