1967 C2 ignition problem

[Jimmy B.]

Ok, my car is still running poorly and can barely pull its own weight before it dies. 1st it was reported we had "bad" (water) gas on the base over here in the U.K. I originally changed the carb from an otc 3810 to my totally restored 3810 721 dated for car and no change whatsoever. I then managed to get the car to stumble home where I drained the gas tank & the float bowls thinking that gas was the problem. Again test drive showed no acceleration, backfire etc. When I took it to an automotive shop here it was found that my distributor had came loose. I swear I never touched this!!! Anyway the mechanic who I have full confidence in set the timing to 10 deg. like my book says. The car idles beautifully but a test drive shows the car still stumbling, pop through the carb (now I just blew out my power brake check valve) and if I am lucky I can feather the gas peddle and get to 3500 rpm in 1st gear max. The car surges, shakes, etc. Does anyone have any ideas? My mechanic is thinking possibly my coil (original 202 still in the car) is having a problem. What about timing is 10 deg. to much? My engine is 100% stock. When I had it rebuilt I used a NOS Chevrolet 350 hp 67 cam, TRW 10.5 pistons with the exact dome as the originals however we did bore the block 30 over and did a 3 angle valve job w/hardened seats. This car was running beautiful now a 53/54 could beat me!!!

Suggestions please!!!

Thanks for your help in advance. We got sun here today and I am missing out!!!

[Eugene B.]

Re: 1967 C2 ignition problem

Jimmy,
Sorry to hear that your beauty is causing you pain. I'm not an expert, but I'll kick off this threat and others will chime in.

If it were me, I think I'd go back to basics and perform a compression check of all cylinders to verify that you haven't broken a valve spring or something like that.

If you have compression, fuel and spark at the right time, that's all the engine need to be happy. Setting the timing at 10 degrees BTC with the vacuum advance disconnected and plugged should be close.

If you have access to a set-back timing light, you can check the vacuum and centrifugal advances in the distributor. If OK, I'd check the black ground wire in the distributor that goes from the point's base-plate to the vacuum advance housing. This wire flexes every time the advance unit moves and can eventually fail from fatigue.

Hope all this helps, Jimmy. It least, it's a start and nothing I've said will cost any money assuming that you have a compression guage and a set-back timing light. If you don't have either or cannot borrow, I'd check the black wire in the distributor. It's a freebie.

Best of luck,
Gene

[Paul Reynolds]

Re: 1967 C2 ignition problem

Even though you still have the problem after changing carbs, you may want to replace that power valve in your new carb as the backfiring probably ruptured the disk. If it was bad enough to toast the Power brake valve, then the carb's power valve is probably gone also. This will create a constant rich condition or a constant lean condition, depending on where the valve got stuck when it blew. Either way, the car won't run well at all.

[Mike McKown]

If you don't know what is wrong,

Why not follow your mechanics advice and put another coil on it. If you have access to it, put it on an ignition scope. I don't believe your problem is fuel system related. Sounds like a coil, cracked distributor cap, condenser, or the distributor ground wire that is fastened to the vacuum advance link. Not necessarily in that order.

[Jim T.]

Re: 1967 C2 ignition problem

Every time your car pops through the carb it can rupture the power valve. When a power valve is ruptured it will not hold vacuum when it is supposed to be closed and not enriching the fuel mixture.
A quick test of the power valve with the engine is at idle, put a thumb or finger over the verticle vent tube of the carb, if the car dies right away the power valve is ruptured and requires replacing.
If the power valve is good, putting a finger over the power vavle will not immediately make the car die but it will if the vent tube is closed off to long.
Did you find any water in the carb or gas tank? You have the advantage over other car owners in that you can see into the tank with the cap off. If water is present you will be able to see it pooled at the bottom of the tank.
In the storage voids aboard an aircraft carrier water is actually used in fuel voids. The water does not mix, just stays on the bottom. As fuel is used from the void, more water is used.