Inliners International Forums General Discussion Engines Setting/Fine Tuning Timing and Idle RPMs

Question pertains to 66 Chevy II, 194 6-cyl, 390 cfm 4 bbl holley, crane cams fireball electronic conversion ignition kit. I've been having a heck of a time getting my timing set correctly in this puppy. I keep "tweaking it" but just can't seem to get it right. Getting some sluggish operation and detonation at higher speeds -- 55 to 65 +/-. Here's the gauge at the balancer, I don't know what the A and O are for either. I know this should be basic, but I need some help. (Brain dead)
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- A
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- O
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Also, is 450 to 500 idle rpm good, or should I set it higher?

A little more to this...I picked up a vaccum gauge yesterday. A few people I've talked to say they used to just set the distributor where they got the most vaccum and left it at that. Is this good? As Far as my diagram, I'm guessing that the A is for Advance, and maybe the O is for Top Ded Center? Not sure.Which way advances adn which way retards the timing?

You are correct on the timing marks, A= Advance, and 0 =TDC.

Using a vacuum gauge to set timing will work. I haven't used it that much yet. I have a 327 that cracked a head and collapsed a piston. I set the timing per the factory manual and it didn't run that well. Having read about setting the timing with a vacuum gauge, I did that, and it ran much better. The down side, and I'm sure this was particular to my motor, it was advanced to the point were it was had to start sometimes. I guess what I'm trying to say is that setting the timing with the vac gauge will account for other problems. Check for pinging while your driving.

I'm sure there will be others chiming in.

Larry

It needs to be set with the vacuum line off, pluged @ the correct idle speed.

When the line is re-connected the engine speeds up, (this is normal) then reset speed adjustment.

A=advance

O=TDC

The lines are degree separation(s). This varies on Yr/model. Check a Motors Manual at your local Library, for a better desrtiption etc.

Good luck.

If your timing won't stay where you set it or it jumps around when the engine is running, check your distributor bushings. I had and engine that was like that, and the symptoms were just like you'd get with a vacuum leak, and it almost drove me crazy until I put a timing light on the engine and the timing wouldn't stay in one place. If your vacuum gauge gives you consistent readings, the dist bushing may be shot, so you might pull the distributor and check for play in the shaft. If it wiggles even a tiny bit, the bushing is history and the timing won't hold steady. At that point, it's probably time for a new dizzy.

Explain the vacuum timing. Does the vacuum gauge just go to an intake vacuum port and then you adjust the timing to where the most vacuum is?

Me and my son built a 292 and had a heck of a time getting it to run right! The motor was running hot,timing was changing,and at one point,it wouldn't even start! Turned out to be the cam gear shifting on the cam.Took three teardowns before we found it....walt