Mr Shifty Sidney

I am a bit confused about what is going on with the timing on one of my cars. It is a 1970 Cutlass with 350 2bbl. I have owned this car for aprox 2 years but have not driven it very much. It was bought as a 78K mile car and I believe it to be. I had to replace the vacuum advance, so while I had the distributor out I removed the points and installed a pertronix module. I did not check the timing before I removed the distributor. Here is where the confusion starts.

When the engine is rotated to align the TDC mark on the harmonic balancer and 0 on the timing indicator the #1 pistion is not at TDC.
I then rotated engine till the #1 piston was actually at TDC, installed distributor and engine fired up immediately and ran smooth.
The mark on the harmonic balancer is now at approx 10 o'clock position instead of 2 o'clock position by timing indicator.

I thought it had jumped time, but if that was the case it would not run smooth would it?
Any help is appreciated.
Don W

oldcutlass

Have you set the timing with a timing light?

1970cs

Your timing marks are off due to the rubber part of the balancer has slipped.

Pat

Greg Rogers

Yep, my balancer slipped on my 70 Vista also. When I changed the timing chain I verified it. I also checked a extra balancer and the one on my 71- they were both ok but the original on the vista had slipped. I replaced it with the spare and now all is ok.

Mr Shifty Sidney

I think you are right Pat. Talked to someone after posting and that is what they suggested. I am going to compare the harmonic balancer with others that I have. Will see how the timing mark/crankshaft key are located and compare.

When I put a timing light on it, the 0 mark on the balancer is at 10 o'clock position. The engine runs good.


Don W

Mr Shifty Sidney

Greg Rogers

Still interested in any parts you may replace on your Vista. Your Vista and my conv. have build dates that are very close. Just keep me in mind.
I have some Vista parts if you need to do some trading.

Don W

oldcutlass

There is a line molded on the inner part of the balancer just below the rubber, you may have to remove the pulley to see it. It should line up with the outer line.

Mr Shifty Sidney

Thanks Eric.

Don W

Greg Rogers

I bought another 70 Vista for parts that make David's old car look like a beauty, but it didn't have a engine. I don't know the build date of this one, but I will check- should be able to tell by the VIN? I'll keep you in mind Don.

hullinger

In addition to a balancer shift you might want to also take a vacuum gauge reading AND go through the carb adjustments as well. Simple things like a vacuum leak, idle mixture settings, idle speed and having the vacuum advance on the wrong port can make your timing mark seem screwy. A vacuum gauge reading will help rule out other possible issues too.

Chris