2 Degrees difference... really?

[Metal Twister]

Hey guys I really dont know what I'm doing or what I did but 2 degrees made a giant difference.

I bought a donor Burb to transplant the guts into my k5 Jimmy frame. I did the transplant and got it running. I then started looking into what I have. It turns out its a 86ish crate motor with a bunch of smog crap on it and I presume a California carb. I pulled off most of the smog leaving the egr and capping off most of the other stuff. I saw on line that that motor is supposed to be set up at 10 degrees BTC. It ran but would spit and sputter. I then found a bunch of vacuum leaks that I repaired still with no luck. After a day of Dicking around with this thing I decided to time it at 8 degrees. Wow what a difference. The thing run great now? Should 2 degrees make that much difference? Wondering if I should try 6 Degrees now?

 

[bushmaster]

might be something else wrong ,usualy they like 12 degrees

 

[K85 Octane]

might be something else wrong ,usualy they like 12 degrees

yeah, was gunna say. As long as everything else is correct, the engine gets what the engine wants What kind of carb and HEI do you have? The computer stuff?

 

[diesel4me]

If it has mechanical advance weights in the dizzy,they may be stuck in the advanced position...in that case retarding the timing will make it run better,as its already too far advanced...

 

[K85 Octane]

but if the weights are stuck, it would run like poo once it gets going. I would think anyway

 

[Blue85]

If it has mechanical advance weights in the dizzy,they may be stuck in the advanced position...in that case retarding the timing will make it run better,as its already too far advanced...

No, advancing it will make it run better because there is no advance coming in with the revs. I don't know how he would be setting the timing, except with a strobe, so the stuck weights would already be accounted for in the idle timing - whether stuck "fast" or "slow".

But if it's computer controlled timing (I don't think CCC ever did this), there will be no weights...

This is easy enough to check. Remove and plug the vacuum can. Set base timing. Rev engine and verify that timing is advancing with rpm. Then plug vacuum can back in and verify that advance comes in with vacuum. Then you know that everything moves.

If the engine is idling better with less advance, it may be a setup that prefers a ported vac source for the vac can.

 

[Metal Twister]

Everything seems Ok? Vacuum advance is working well and no vacuum leaks any more. Carb seems to be squirting well... I did find the idle mixture screws out quite a ways and screwed them into 2 1/2 turns out. I took off the chock and now once it warms up which is just a short time here in So Cal it runs just great? Might throw some more timing in it just to see if that was the issue or not?