88 Volvo 765 tic Ignition Timing

lummert · Post by **lummert** » 07 Feb 2008, 13:46

Today I tried to check the ignition timing. Every time I advanced it the timing mark advanced by it self too far. When I retarded the timing it retarded too far on its own. Is this normal or do I have a harmonic balancer that is slipping? I ended up with the timing set in the middle of the adjustment range.

Thanks in advance for any input on this.

Post by **billofdurham** » 07 Feb 2008, 15:25

My book on the ignition system fitted to the 760 turbo has this:

Ignition timing is preset and programmed in the ECU (Electronic Control Unit) and cannot be adjusted.

It will, therefore always go back to the proper setting.

Bill.

lummert · Post by **lummert** » 07 Feb 2008, 17:59

Thanks billofdurham. I thought maybe that was what was happening.

Post by **sseir39** » 07 Feb 2008, 19:50

Bill is right. You can have a harmonic balancer that is slipping, but will not change the timing, just the perceived. If the rubber in the balancer is going out you might want to change it as they can be messy if and when they do go.

lummert · Post by **lummert** » 08 Feb 2008, 17:17

I am not sure if the harmonic balancer is going bad. It did not keep advancing, it just kept correcting the timing when ever I moved the distributor.

Thanks for your input

lummert · Post by **lummert** » 15 Feb 2008, 20:55

I stand corrected on the Harmonic Balancer slipping. I went out today with some the wife's bright nail polish and made a mark from the center hub to the outer pulley then started it up. Then shut it down. the marks were off.

Thanks for the input. Are Dorman Harmonic balancers any good?

Post by **sseir39** » 16 Feb 2008, 06:11

Not sure. I used an aftermarket unit with no problem. I was price shopping. Suppose it depends if you are into serious racing.

lummert · Post by **lummert** » 16 Feb 2008, 13:45

I looked up a harmonic balancer at FPC Groton and the have one from Scan Tech or MTC for $65.00

I found two at AutoPartsGiant.com

IMC $57.15
Dorman $73.64

lummert · Post by **lummert** » 20 Feb 2008, 19:22

Today I was checking on those harmonic balancers at AutoPartsGiant.com.
MTC Crankshaft Pulley $57.15 made in India.
Dorman Harmonic Balancer $73.64

Shipping is free on all orders $50 or more.

I think I will be going with the Dorman.