Timing Issue = Timing Chain or Distributor ?

[gstsaver]

I had my 87 5.0 vert running perfect. But it seems after I drive it for a while the timing goes out of whack.
I am positive the hold down bolt is tight and the distributor isn't moving at all.
I remove the spout and adjust the timing and it is good and runs well. I take it for a drive and it runs well for a while but then it starts not running well. I checked the timing (once again removing the spout) and it was way off again. Changed it back and all good...until the next time I drive it for a while....dejavu

So my question is: What could cause this. Could it be a bad timing chain or a problem with the distributor ?

 

[General karthief]

It would have to be the distributor, (that is my thinking) the timing chain slipping cannot be corrected by moving the distributor, look at the gear at the bottom of the distributor, it may be slipping. This is just an observation by someone that is not a certified mechanic and may not have really fixed anything in his life.

 

[gstsaver]

Thanks for the reply. Anyone else ever have this issue ?

 

[Mstng93SSP]

Never had that issue but I do agree that it seems to be the distributor.

 

[gstsaver]

What about the harmonic balancer - could that be the timing issue at all ?

 

[General karthief]

Roll the engine to tdc and the pointer at #1 and see if the pointer is at the 10 or 12* make sure you have it at tdc by pulling the #1 plug and verify. Look at the balancer, if the rubber is brittle replace it, if it has a ton of miles replace it anyway.

 

[rc46joe]

Make a mark on the distributor and block with a paint marker to see if the distributor is moving. The timing chain times the cam to the crank. If the timing is moving it’s in the distributor. Is the chain was so lose it was jumping teath adjusting the distributor would not correct the issue. If the balancer spun on the rubber the motor would be out of balance and you would feel that for sure. I’ve had it happen with a stock balancer and you’ll know when it happens.