Hello everyone.

I got a timing issue/question hoping some of you experts can assist me with. I was checking timing on my '66 Cutlass that somebody prior to me owning it dumped a 1973-76 350 into it. (based on the number 8 stamped on the cylinder head). Using a cheapy Harbor Freight timiing light I had to dial back the timing all the way to 60 degrees to read TDC and this is with the vacuum advance disconnected. I stopped the engine and cranked the camshaft with a breaker bar so it landed TDC on the compression stroke. With blaancer's timing mark at TDC I pulled the distributor cap and noticed my rotor appears to be on cylinder 8 instead of cylinder 1 so one off.

I recall when I was buying the car the prior owner saying he just changed the rotor and cap. I believe that while he got the spark plug wires in the right firing order he may have placed them 1 post off on the distributor cap. I am not very knowledgable with engine timing, (but eager to learn more) could being 1 post off create this much advance timing and will simply moving the all the plug wires over to the left (counter-clockwise) 1 post bring that timing down to a more sensible number? Moving the distributor cap counter-clockwise was a no-go because one of the four hold-down clamps lands right on top of the vacuum advance. Oddly with all this advance timing the engine starts and runs decent although I had to enrichen the air/fuel a bit as it was running quite lean from when I first got the car.

Thanks you for taking the time to read. I greatly appreciate any assistance.

 

#1 is the LF, drivers side cylinder, connect to​​​​
​that plug wire. Four distributor cap holddowns sounds like the distributor is an HEI.
Remove the rotor and check that the weights and springs are in place and move freely.
Does the vacuum advance move freely when vacuum is applied and released?
Check the firing order 18436572, the distributor rotates CCW.
Check that the harmonic balancer is at zero when the #1 piston is at TDC, the outer ring of the balancer can slip.

 

Are you sure the balancer outer ring has not spun ? How does the car run ? It probably would not run well at all if it was truly at 60 degrees btdc.

 

I had a 76 350, I swapped distributors, started up and ran kind of crappy. It had 75 degrees base timing! These just under 8 to 1 motors tolerate mid 60's timing part throttle. I ran nearly 50 with vacuum advance at idle. But as said, check the balancer, for rubber ring damage. I have never seen one damaged enough to move on an Olds but could happen.

 

I think that kind of jives with what I am experiencing. The engine seems to run good but at WOT it feels like it the RPMs start breaking up. My guess is at that point with the vacuum advance it is just too much timing for the engine to handle.

 

This is a good diagram of the engine firing order I found on this site. I traced all my spark plug wires to make sure they are in the current firing order but looking at diagram I would say all my wires are one off so my number 8 spark plug wire is where the #1 is shown where the #1 is above, 1 is where 2 is and so on and my rotor with the blancer timing mark lined up I would say is pointing just a little counter-clockwise of the of the #1 in the diagram which would be #8 cylinder on my distributor with how I traced out the wires. I'm curious what kind of reading I would get with the timing light if I put it on the #8 spark plug wire instead of #1 (with timing advance disconnected of course).

 

Yes it is HEI. Question to check the vacuum advance is moving freely should I purchase one of those brake bleeder pumps that has the psi guage on it. I was watching a YouTube video about adjusting when the vacuum advance opens by using an allen wrench in the canister. He was using one in the video.

 

Only the aftermarket vacuum advance are adjustable and have about 20 degrees maximum of advance. The factory advance can have 30 plus degrees. Remember vacuum advance goes away at WOT. But 75 degrees, or more depending on the curve is too much WOT timing, mine also acted like it had misfire as well.

 

I moved all the spark plug wires counter-clockwise one spot and I could not even get her to start up. Set the plugs back to where they orignally were and it started right back up and idled away OK. My theory about the wires' positioning holds no water.

 

The wire locations are determined by WHERE the rotor is pointed. You'll have to pull the distributor out, rotate the distributor shaft a gear tooth or two and reinsert it for the diagram shown to work.

 

no, he doesn’t need to pull the dizzy out. when he moved all the wires one spot counterclockwise, he should have also rotated the dizzy the the same amount counterclockwise.

 

you were on the right track,, you should have also rotated the distributor one wire distance counterclockwise

 

The engine does not care which posts the wires are on as long as you can get the timing set with no interference.

 

Thanks for the tip. I'll give that a shot tomorrow.

 

CANADIANOLDS, pardon my ignorance I just want to make sure I have the method down pat. Should I reconnect all the plugs one post counrer-clockwise over and then rotate the dizzy OR disconnect all the plugs, rotate the distributor CCW and then reconnect them as shown in the diagram in this thread? I keep thinking if I reposition the spark plugs first and then rotate the distributor then my #1 will now be on #8. Unless I rotate the dizzy with the cap off.

 

I'd like to ask one last question to try to understand the positioning of the distributor and timing a little more. An issue with my dizzy I currently have is the vacuum canister hitting the vehicle's firewall. I can hardly turn it CCW any more due to this interference. So given what I already mentioned about the rotor pointing at #8 when the engine is brought to TDC and the interference I believe it was installed one or two teeth off. My question is if the distributor is off a tooth or two would it cause the type of reading where I have to dial the timing light all the way back to 60 degrees to get the mark on the harmonic balancer to line up?

 

It is possible the balancer is damaged and the outer hub is moving independently, I have not seen one do that on an Olds V8. There is a rubber rin absorber between the two pieces of balancer in the middle, inspect for damage. Retard the distributor, loosen the 9/16" hold down and turn the vacuum advance away from the firewall to do it. With the vacuum line removed and plugged, it should be around 20 degrees at 1100. I have found at least 5 curves in HEI but the most common is the 20 at 1100 rpm spec, so start there. I always like 1000 rpm in park, especially with the lean factory Qjet idle circuits, just more stable. If it won't stay running at 20 degrees base with the vacuum advance, unhooked and plugged, something is up. Good luck.

 

You won't necessarily see any "damage" to the harmonic balancer if the bond breaks between the outer ring and rubber or inner ring and rubber. Generally the initial ignition timing slips a little each time and can stop.
I actually had a harmonic balancer replaced under new car warranty on my 1970 W-30.

1. One thing to check is if you have the correct timing indicator on the front of the block.
2. Correctly and accurately verify the piston is at TDC (Top Dead Center) of the compression stroke.
3. View the timing mark and where it actually is.
Take pics at each step and post them.

 

But he should be able to see a noticeable crack in the rubber. Plus he should be able to actually rotate the outer ring on the balancer by hand. Yes, it should a plastic indicator but even the stock for his car should work with that later balancer. He can verify TDC just to verify something hasn't been mismatched.

 

A "noticeable crack" is just that. Its the bond between the rubber and the inner and outer ring that keeps the timing mark stationary.

He may not be able to rotate the outer ring by hand. If that was true, it could have almost rattled off the inner part by now.

 

I had a 3800 balancer fail where you could actually rotate the outer part, I believe it was common on those. Interesting you had one fail back in the day, never seen one fail even working in a garage on super abused reserve cars. Having one of these mid 70's 350's and run at 75 degrees, just not well, it may be super advanced. Easy, put to 0 on your balancer, get screwdriver and rotate a few degrees both ways by hand. You can even pull the valve cover to see what both valves are doing on #1. What timing indicator is on it?

 

The op said the car starts and runs decent. no way would it if it had 60deg initial

throw that timing light in the trash. never trust dial back timing lights, not even expensive ones

 

The cheapo HF timing light is certainly a possibility. Wish I had another classic car to test it against

 

Thank you for the ideas. I will definitely inspect the harmonic balancer this coming weekend. I've also thought about pulling the driver's side valve cover as was suggested while spinning the crank using a breaker bar and monitoring where the rotor winds up. Based on what I've experienced so far I would think it would land back on the spark plug going to cylinder # 8. One thing I did try doing is moving all the spark plug wires over 1 spot on the cap and rotating the cap CCW 1 spot over. Not sure why but the engine did not like that, I thought it was an excellent suggestion. It didn't want to start until I reverted back. Also I re-read some of my comments and need to clarify something I typed. I cannot turn the distributor clockwise because it hits the firewall. I can turn it CCW without interference.

 

another method which is somewhat foolproof even if the balancer has spun is pull out #1 plug and loosely put your finger in there to feel the pulse of air when turning over the engine on the starter, with the distributor cap off watch where the rotor points at every puff (compression stroke) thats where #1 wire should be on the cap. proceed counterclockwise with the rest of the wires in order of course
stan