Keeps Jumping Timing

[Lighthouse66]

`04 Sport Trac 4.0 SOHC

Has anyone a clue what might cause timing to keep jumping? I rebuilt the motor with all new parts. The only item that I am now questioning is the left timing chain casette. It was very tight and hard to move back and forth. I worked it a little and it seemed like it loosened up some, but I installed it thinking it would loosen up with time while running.

From the initial rebuild, it started up a few times. Then all it would do is crank. When I pulled the covers and checked the timing, it was off. So I re-timed it, put everything back together and after a couple cranks, it went back out of time.

I guess the next step is to re-time it and look at the chains while it is cranking to see if I can see where or why it is jumping out of time.

Any thoughts?
Thank You

 

[1AJeremyD]

I would have to agree with something not holding the chain correctly. If it is getting hard and soft on you then it is obviously doing this at 1500 RPM when the engine cranks over. Do what you said by looking at the cassettes and if it does it again grab another kit or just the cassettes. Let us know how it all goes!

 

[Lighthouse66]

After looking at the timing chains, while hand cranking the engine, the left side does seem to be not working properly. The chain guides do not move at all. I will be replacing the left side timing chain cassette and see how it runs after that.

 

[Lighthouse66]

Fixed It

After taking the front timing chain cover off, I seen that the Chain tensioner was destroyed.

It was due to the fact that the Left Timing Chain Cassette was bad.

Lesson learned for myself: never go with an aftermarket part for an internal engine replacement.

Replaced: Left Timing Chain Cassette, Main Timing Chain, Main Chain Tensioner and runs perfect.

 

[1AJeremyD]

Doesn't sounds like it was fun. Glad ya got it all replaced. Who was the company that you purchased the kit from? Did they offer any new part for you under a warranty?

 

[Lighthouse66]

I got a engine rebuild kit that included the 4 timing chains, tensioners and guides from Advanced Auto. Where they sourced the parts from, I'm not sure. They did offer a 30 day warrenty, but by the time I got around to repairing it and realized the part was actually defective, it was well over that. So huge lesson learned for me.