4corners

With quite a few years on these forums I once again see the debate on another I5 list as to whether the JT 2.2 is a non interference or a interference motor when the t-belt breaks. Has anyone had a personal experience with damage to the valves when the timing belt broke on a JT motor? It would be nice to put this issue to rest. Posted on the I5 list as well.

AudiSport4000

I dont know for sure, thats just an educated guess. A long time ago before I started wrenching on the 4kq it developed a no start issue after leaving it parked over night after a long trip. The starter just spun. The timing belt ended up being really loose. One would think if the timing belt was that loose and the crank was only spinning, that I would have had bent valves, but I did not.

kelbrig1

No damage done to engine at idle. I turned the car on and walked away to let it warm up one winter day, came back and car was off. I even cranked the engine thinking it had just stalled before I popped the hood to investigate

86 Coupe GT

They note in the Bentley to assure cam alignment for head install, since there can be valve damage. I don't think it's as bad as the VW 16V's, but it would hurt things.

Carter

4000skq

no not interference

Suffolk

My JT belt broke at a traffic light, acellerate SNAP.......

Towed to the shop and new belt on.......

OLD rule of thumb, Turbo = interference.
OLD N/A engines (like the JT) not SO interference....
New motors....think interference!

That being said: like Carter says.....................all bets are off if belt goes at HIGH RPM.............
Valve float, jumped belt, timing off all can lead to bending valves.............

-Scott by BOSTON

Bernie

A friend was driving his 84 4kq down I5 to an instructor class in Portland. 1am, Exit 36, 75 mph the engine just lost all power and he coasted to the side of the road. A bolt had fallen into his timing belt and broken it (no covers installed). He had it towed the rest of the way to PDX and once he installed a new belt, the car ran perfectly for another 50k miles until sold.

High rpm, sudden loss of belt rotation, no engine damage=non interference. I helped him out of his situation, so I know this to be true first hand. Do not try this on an NF/NG or any turbo engine.

4corners

I keep seing this issue come up and I have never seen damage to a JT when the belt lets go but people still insist that your valves are history if the belt breaks at high rpm. I am on your side...Tom

audinutt

i was running 3rd gear wide open, accelerating @ 5500RPM when mine broke on my 4kq.

put a new belt and drove it for another 2 years.

-richard