I have read several posts on this forum that explain how the harmonic balancer may not show true TDC. But how far out can it get ???
I am pretty experienced in checking engine timing on British motors but this beauty has me stumped.
I have owned this car for just over a year and have never checked the timing before as it runs so well. Thought I would give it a pre winter check. I purchased a new Sealey TL93 timing light and on checking the timing tonight it showed the timing way out. It’s a bog standard 1980 that starts first kick and runs smoothly. I have the light pick-up with the arrow correct on no.1 ( front right from the front ), vacuum disconnected and plugged. On checking, the harmonic timing mark shows up somewhere down by the power steering pump ????? with the advance set to 0 on the timing light ?. I have yet to check mechanical TDC as I ran out time, but can it wander that much. The vacuum can points in the general direction of the front offside wheel so it looks OK, So I have concluded that either me or the light is buggered.
What am I missing ?

Cheers

 

Depending on how bad the rubber connecting joint has become, it could read anywhere. On my '73 big block the outer portion (the one containing the timing marks) was free spinning from the inner portion bolted to the crank shaft snoot. Even Lars could not time it.

Ralph

 

You are using the timing light wrong, move the dial on the timing light until the balancer mark reads 0 then read where the dial is on the timing light scale, that is how many degrees of adv you are getting.

 

I would suspect operator error as well.... but the harmonic balancer timing mark does not get anywhere near the fixed scale regardless of the dial position. got me stumped.

Thanks

 

Sounds like a timing ring slip, guess next step is to find tdc and compare to timing mark. Just in case you need it thought I would link to an tech article buy Lars (forum guru) for finding tdc:

https://www.corvetteforum.com/techti...=113&TopicID=3

 

If the timing mark is located towards the PS pump (clockwise seen from the front) with the timing light **** at the "0" position, the indication is that of grossly retarded timing. Since an engine will not run with the timing set like this, your situation appears to be a slipped balancer outer ring - a very common problem.

If you want a current copy of my TDC paper, drop me an e-mail request and I'll send it out to you:
V8FastCars@msn.com

 

Thanks for the info.

I am happy finding true TDC so I will investigate tomorrow.

Cheers

 

Thanks team...spot on. The balancer ring has slipped although I cannot shift it manually. I re-marked TDC and checked my current timing and it was just a tad out, but I leave it until I replace the balancer.
The local american auto shop has one in stock so not problem with a replacement. They hold 2 sizes in stock 63/4 inch or 8 inch. My current balancer is 63/4 so I will replace it with the same size. Why the 2 sizes ?.
L48 or L82 ??

Bob

 

These guys should be able to answer all your questions about harmonic balancers.

They can even fix your broken one.

http://www.damperdudes.net/