So my buddy pieced together his new motor. The setup is:

GSR block
PCT pistons
B16 head
JG valve train
CTR cams
GSR water pump
GSR oil pump
New OEM tensioner


The motor has jumped 4 times. First 2 times were a brand new OEM GSR belt. So he used a new gsr belt I had at my house. Jumped again. So finally I grabbed my buddy's Greddy belt and it went about 30 miles again and jumped. I know the timing is right. I know for a fact the belt was tight. What the hell is causing this. Were just trying to get the car running right to get tuned on Wed. What could be causing this?

The only used parts were the cams, rods, crank.

Whats going on?

 

when you turn the motor over by hand, does the belt get loose?

 

No. It's still tight after the timing has jumped. I don't get it.

 

how do you know the belt is jumping?

 

Cause I have checked it every time and the timing is off a couple teeth. The car will run fine and drive. Then it will die. I put the crank at TDC and it's off a couple teeth.

 

is your belt too tight?

 

I know it's good. I have done timing sooo many times.

 

you can keep trying theories, but you might as well just go back to basics, remove the belt, set the cams...paint mark the belt and cam pullies, don't turn it clockwise (It sounds like you know that). It can be really tough to troubleshoot, I've seen an overtorqued cam cap cause the cam to bind badly enough to make the timing belt jump. Turn the motor with the valve cover off and inspect everything as it moves. Once that's checked off, run the motor with the upper timing cover off (just idling) and watch the cam gears to see if one jumps or binds. It can be something really simple with the tensioner or it can be as complex as an overtorqued cam cap...sorry

 

Do a valve adjustment. And replace all the valves now since they are bent.

 

Jumping a couple of teeth on the cam gears won't bend the valves.

But I have to ask OP if you're doing the correct timing belt procedure? Are you SURE it's not too loose on the exhaust side between the crank sprocket and the exhaust cam gear? Make sure the belt doesn't flop around in that area while the engine is running.

 

this is going to sound stupid but make sure the dizzy is not back wards i have seen this done at least twice like i said it sounds stupid but i have seen this done before check if the dizzy is not forced on with the tooth backwards

 

****! I'm having the same issue, jumped twice. did a compression test and had good compression. Good point on the cam caps my exhaust was too tight and i did it to factory torque spec factory wants 20 ft lbs i did 15 ft lbs. But, I'm still having issues, how do i fix the cam caps i tried a diff set or what else could it be?
Belt tensioner, spring and timing belt is new. i'm using a gsr belt.
Please help me!

 

It turned out that the problem was the intake came was binding. I pulled the cams and realized that someone sold him a head with mismatched cam caps. Had the head line honed and it was fine.

 

did the valves get bent after the jumps?