How many BROKEN 3.5 timing belts bend valves?

sho510 · Jan 27, 2005

I'm trying to get a feel for just how "interference" this engine is. The book says it is, but I've put a few timing belts on LH-cars that had died at low engine speed. Usual cause was a broken tensioner pulley bolt, and a vehicle owner who was deaf or "had to get somewhere."

So: My question is: If the crank and one or both cams rotate independently, more than just a skipped tooth on the belt, what has everyone seen happen? I've never had one come in whose belt died while above 1500 or so RPM; does anyone have bent valve stories to tell, or is the book just alarmist? TIA.

Hypnos · Jan 27, 2005

I would say about 1/20.

It takes more then just one tooth off.

mb-lhs · Jan 27, 2005

The T-Belt's tensioner broke in my 1G. When the engine first died on me i didn't really know what was wrong yet, so i tried to start it back up again. Amazingly enough it fired up, but was running really rough. I think the belt may have slipped on one or both of the cams.

I got it up to 40 mph before it died a second and final time, and i tried cranking it untill the battery was nearly dead.

no damage whatsoever...

1994 LHS · Jan 28, 2005

I replaced my water pump & timing belt a year or so ago @ 125k. This past fall the car broke down on me while driving at speed - the motor was probably 2000-2500 rpm. No warning - "cruise" light came on for a second & then she died. After coasting to a stop, I tried refiring but all she did was spin over.
Upon disassembly, found the tensioner had crapped out to the point the bearing was shot & tensioner fell off. The cams & crank were WAY out of sync - way more than a tooth or two off. I think I got really lucky because the timing belt jambed at the crank pulley to the point where the belt tore & the plastic crank pulley cracked.
Although motor never appeared to interfere, you can bet my fingers were crossed after I relaced the belt, tensioner, & crank pulley. Bottom line, all was OK & I thank my lucky stars.

What I learned - ALWAYS CHECK/REPLACE TENSIONER ALONG WITH THE BELT!

Did your belt do more than skip, and did it bend valves?

Just skipped a tooth or two, no damage.

Skipped a tooth or two, bent valves.

Cam or crank sprockets came free of belt, no damage.

Cam or crank sprockets came free, bent valves.

How many BROKEN 3.5 timing belts bend valves?

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