fresh build drove 8 blocks timing belt jumped off bent 2 intake valves. Are vibrant tensions worth the money? running greddy timing belt.

 

Either you arent properly setting the tensioner or something else is wrong. Do you have both timing belt guides on the crankshaft timing gear?

 

yeah, sounds like something wasnt done right. i used pro 1 cams with an oem timing belt for over 2 years. you just have to make sure it tight. i dont even rely on the tensioner anymore. i use the old "coat hanger and pull" method.

 

yes both guides are on the crankshaft, i used a pry bar to tight the tensioner. there was no outward slank. just in ward.

 

correction the belt isn't coming off its jumpin teeth.

 

Something is probably binding and causing the belt to skip. What valvetrain are you using?

 

skunk 2 valve springs and retainers, omni power valves.

 

did you move the motor 15-25 degrees past TDC? because if you did not then you did not get all the slack out of the belt...

 

I picture the belt never being tight between the gears to begin with. And even if it did make it down the street thats just how long it took to happen.

You can "prybar" all you want, but if the tension isnt correct on the belt when actually tightening the tensioner then its not gonna do any good.


Its good practice to cycle the motor over a few times or more if need be to confirm everythings cool with the marks and tension before calling it good. Assuming the belt and tensioner were good parts to begin with, it would have to be something to do with the install.

Also the internal parts you listed (cams and vt) no matter what they are would have no bearing on skipping teeth.

 

how wouldn't that have anything to do with jumping teeth? if the camshafts are bound and not rotating properly, the crankshaft is still going to spin, moving the belt on the cam gears, aka "skipping teeth".

 

im assuming the parts are working correctly. While rotating the motor over it should be evident if somethings hanging up or not right. I would hope he could tell smooth rotation?

 

yeah, i see what you are saying. that is definitely something that should have been done before the motor was started. back to square one i guess. if the timing belt is tightened and adjusted correctly, the problem lies in the rotating assembly or valve/piston clearance.

something isn't right.

 

I just re-read and I see what you guys are saying.
What I was getting at was more about him mentioning all the product that might be involved with the belt jumping and I thought it was getting close to blaming or something.

Like pro 1 in the title...all the other parts ect. I didnt realize he was asked

Hopefully he could tell if the motor wasnt rotating like it should. Thats why I honestly feel like this is a belt install issue via prybarring.

You guys are right tho, if he prybarred to spec then hes got somethin else weird goin on

 

i have never had a problem with timing belts. the belt had no slack in it. i rotated the motor twice to check for slack. im gonna re check piston to valve clearance, but it was fine the first time, or so i thought. i think it had to do with the greddy timing belt. the valve train was fine.

 

how do you know that the valvetrain was fine? you just said that you bent two valves.

 

ya but before i bent the valves it was perfect. i gotta check the guides thats it. everything is new on the motor. valve job, omni power valves, springs, retainers, cams....every thing turned fine without hang ups.

 

sorry to bump, im having a similar issue where no matter how many times i tighten it, it comes loose, and the clearances should be all good, im making great power when the belt does stay on, (turbo car) it comes loose and jumps the hell out of the timing and ive been lucky so far with nothing bent.

 

Ive seen cams starting to seize in the head cause this. Hopefully thats not the case, but it might be worth pulling a few cam caps for inspection.