[Formulajones]

Originally Posted by TRADERMIKE 2012

THINGS THAT MAY MAKE A DIFFERENCE!



(5) Prove, by using the Degree Wheel and Dial Indicator, what the current Advance BTDC actually is! Because there is a discrepancy in the directions, according to Forum members, to whether or not the directions mean 4* @ the Cam is actually 8* @ the Cam and 8* @ the Crank means 16* @ the Crank. This discrepancy could mean that I am not advanced to 109-109.5 BTDC at all, I could be at 104-105 BTDC. Continued driving using the wrong setting is both dangerous to the Engine and could be why I am experiencing an increase in Temperature, causing Piston/Rod Knock and a major Heat issue associated with Rod/Piston Rattling. I have been calling this advanced Detonation: Heat soak by mistake. Even though the Cam Timing, in my case, is possibly too advanced, the symptoms sound the same as Ignition Timing. It is as if you were to turn the Distributor too far advanced, when you rotate the entire Dist. too far in one direction and forget to pull it back some while tuning your Engine. Pre-Detonation sound occurs and you can hear its nasty sound that causes the Aluminum from the Pistons to flake off and melt to the Spark plugs inner electrode porcelain area. You should inspect this area as I will soon. The trick that I read is to turn the Ignition Timing at the Distributor until you slightly hear this sound as the increase in RPM stops rising and then move the Distributor back in the opposite direction some and then lock down the Dist. bolt to the Blocks flat flange area, on a tune-up.

I'm not sure where to begin but for starters, you wouldn't or shouldn't be uncertain of where the cam is actually installed if you had a degree wheel on it and went through the procedure correctly.
Now it seems you're not sure if it's installed at 109 or 105 ICL? You really need a degree wheel on the thing, use the .050 method on the intake lobe and see exactly where the ICL is. Now that it's in the car you're going to have a more difficult time with it. Just moving keyways around and hoping it's correct without checking is for sure the worst way to go about it. You might get lucky and hit on something but it's certainly not your current over heat problem and shouldn't be causing detonation issues if the timing is correct.

Speaking of that, the trick is absolutely not to just turn the distributor until you hear bad sounds and then just back it down until they go away. That's a quick way to tear it up as well as give away a lot of missing performance. That distributor needs to be dialed in correctly.

For starters I'd set it up with 12 initial and put 20 degrees of centrifugal in the mechanical advance. This will give you 32 total to start with, which is very conservative. If it makes best power with more total you can simply bump initial to 14 or even 16 for 34 or 36 total. Only way to know that for sure is dyno testing or track testing. Either way, this is a very simple setup and a good starting point for most engines. If you find you want more total timing without the initial beyond 14 for example, you'll have to go back in, move centrifugal out another 2 degrees and try again.
From there dialing in the vacuum advance is imperative and a lost art it seems. I'd be putting about 10-12 degrees of additional vacuum advance on top of those total numbers for decent efficiency during cruise, and will help with engine temperatures as well as drivability and fuel mileage.

Explaining how to do all of this correctly over the internet would be writing a book, and seems to be too complicated for many. If that's the case I'd suggest sending that distributor out to someone qualified to set it up correctly. This is a huge player in engine temperatures as well as drivability. If it's not right, there are a lot of other things it will affect and just makes for a frustrating car to drive.