Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[mantaray]

A few weeks ago, I started up my Manta (2.5 V6) to move it out of the garage, she started fine but after about a minute it suddenly started to make a very loud  awfull tapping sound.
Tonight I started to investigate what has gone wrong. First thing was to look down the plug holes and see if there was any marks on the pistons, all looks fine. So he next step was to check the timing,  and I think I may have found the problem. Not sure how, but it looks like the timing belt has jumped a few teeth.
With the crank set to tdc, all 4 cams are out of alignment.  Cams 1 & 2 by 3 teeth,  can 3 by 1 Thoth and Cam 4 by 2 teeth. And yet all the tentioners look fine, and the belt is tort.

Any one else ever had this happen? Or can suggest how it has happen.

[Doctor Gollum]

Reset the timing and report back.

[Enceladus]

I'd reset the timing and refit the belt as suggested and then do a compression test as you may well have some bent valves. Make sure you use the timing tools especially the gauge. I'd also fit a new timing belt kit before using the car again.

As to what's happened? I imagine that the eccentric adjustment of the upper and/or lower guide rollers has come loose and shifted. Or possibly the bearings in the rollers have failed. Some clear close-up photos might help. However in a way it's irrelevant, since the valve timing is out then it needs to be fixed before the engine is run.

[Shackeng]

What mileage are the tensioners? Any weakness or stiction there may have caused this. 
Even if the compression check is OK, I would be very reluctant to run the engine until I knew, and had resolved, the cause of the timing slip. 

[Enceladus]

Is the engine a C25XE or an X25XE? Or what was the donor vehicle and model year?

[mantaray]

It's an x25xe.
Striped it all down and can't see anything wrong, so I'm going to fit a new kit and see how we go.

[countrywoman]

Checked my 3L yesterday that the top roller collapsed on and belt jumped 2 teeth and thats lost 3 cylinders.

[mantaray]

Well not good news I'm afraid. Finally found time to look at the manta again, fitted new Cam belt kit and timed it all up, not easy with the engine in the car,😈 turned her over and the good news is more tapping. So next was to do a compression test, cyls 2,4,6 all around 300psi, cyls 1&2 zero, f all🤢 and number 6 under 50 psi. So it looks like I'm going to have to lift the head and fit a spare one I have. Could really do without this, got so much on at the moment.

[dave the builder]

Well not good news I'm afraid. Finally found time to look at the manta again, fitted new Cam belt kit and timed it all up, not easy with the engine in the car,😈 turned her over and the good news is more tapping. So next was to do a compression test, cyls 2,4,6 all around 300psi, cyls 1&2 zero, f all🤢 and number 6 under 50 psi. So it looks like I'm going to have to lift the head and fit a spare one I have. Could really do without this, got so much on at the moment.

do you mean 1 & 3 & 5 
at least it's only one bank and you have a spare 

[Nick W]

I know you've had timing belt issues, but I think you should do the test again.


300psi is not credible.


your low numbers on the other cylinders do suggest bent valves.

[Migv6 le Frog Fan]

As above. Something not right with your test. Needs to be done again.

[mantaray]

My bad, should have been 200psi.
 Actual readings are
1 0psi, 3 0psi, 5 130psi,
2 200psi, 4 180psi, 6 175psi.

Anyway, already started stiping it apart, intake and exhaust are off, and should have the head off tonight .