I just bought a DA with an “unknown running issue”. First thing I did was checked the T-belt. It was loose, and when the mark on the Intake cam gear was straight up, the exhaust mark seemed to be 2 or 3 teeth off (the mark was more point towards the front of the car). I played with the rockers on the exhaust side and they seemed to have a bit more play than should be. When cranking the car it sounds okay, sounds like it spins a bit freely though. All signs seem to point towards 8 bent exhaust valves, but I was wondering if anyone knew exactly how much the timing can skip before valves meet the pistons.
I’ve had a handful of mis-timed engines and broken timing belts - never had an issue with interference. Maybe I’ve been lucky, I’m not sure. A tooth or two off shouldn’t be a problem. Having the belt be off by a tooth or two happens frequently while changing a timing belt and trying to get the mechanical timing correct - yet this doesn’t cause interference.
You should do a compression test, that will give you a better idea of what’s going on.
not to long ago installed my timing belt and the exhaust cam was off two teeth. car ran like shit but no problems. like colin said, when you set it all up for the mechanical timing it happens that it’ll be even a 1/4 turn off and yet theres no interference. in stock form there seems to be lots of room for error. its more of a issue once you have high compression pistons with agressive cams etc.
Thanks to both of you very much. I am hoping that because it is off just a couple teeth the exhaust valves are opened slightly and thats where my compression is sneaking out. I will adjust the timing and do a compression test. Thanks again!
yah…my timing belt was off about 5 teeth or so and it didn’t bend any valves. Make sure the key is in your crank pulley tho or you’ll never get it timed properly…and end up pulling the whole motor apart thinking there is bent valves.
Drove my car for months with the TB 2 teeth off on the exhaust cam. I was hunting down gremlins (fresh b20z swap with new belts, etc.) that may have caused the car to run like shit, and it turned out to be the TB. I fixed it and the car runs perfectly. No bent valves, no problems.
I had my belt broken other night and, before I realized that it was the case, I turned the engine several times using the starter.
I didnt have any bent valves. Are you shure that our engine is of the interference type??
Well on my 89 Prelude SI car ran great, hell of a quick little car. I blew the timing belt on it, didnt feel like it hit anything. I had it towed home changed the timing belt ran the car, thing smoked bad. Had the head sent out replaced at least four valves and valve guides. I put it all back together and it still smoked, a lot less but it still smoked. I think something else happened to the head, and def to the block. I didnt see anything wrong with the block. I should of taken it apart. Anyway the motor ended up blowing about 6 months after it was all back together for the last time. It had enough oil, i checked and filled frequently. So just change your belt on time. lol. I have planned to do the timing belt on my teg soon. Gonna buy some pulleys.