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Timing belt question


akilo55
02-12-2009, 02:57 PM
Hi Guys -- thanks for your past suggestions.

Same car -- new focus -- [but now have a new battery & new coil]

1990 Honda Civic SI Hatchback

Current problem -- tracked the cause down to a broken timing belt (it broke while I was driving the car).

The local Honda service manager says there is 1 chance in 4 that there is no damage to the valves.

Questions:

Rumor is that there is a way to tell if the valves are damaged. Is this true?

I am told that getting a rebuilt engine and taking the head off and using it is a good way to go (avoids getting a head that is warped). Is this true?

Any advice or suggestions would be welcome.

Thanks, Frank (Akilo55)

---

Guys -- Many thanks for your suggestions. The car will be parked for awhile, but in due course, it will get some attention. It sounds like you fellows have seen a lot of sick cars. Frank (Akilo55)

MrWrongsalive
02-12-2009, 08:27 PM
When I worked at the dealer we always just threw a new belt on and tryed to turn the motor with a wrench for a number of revolutions and see if it hung, if it didn't then we'd fire the engine up and make sure it ran good. As far as telling whether or not you bent any valves without putting on a timing belt...

Pull the plugs and maybe you'll get lucky and see part of a valve. Or if you know what you're doing then pull the valve cover set the crank pointer 90 degrees left or right and turn the cam and look for any excessive distance between the cam and rocker arms or for a spring that had popped out of its seat. Beyond that you have to take more stuff apart and it gets much more technical.

That would be my list of things to look for, maybe somebody else has a cool idea that I haven't heard of...

discnik
02-12-2009, 11:18 PM
You can put on a new timing belt then do a compression test on the cyclinders.
Any cyclinder compression below 100 psi and you are looking at replacing the head.

Good Luck !

Christ
02-17-2009, 07:45 PM
You can put on a new timing belt then do a compression test on the cyclinders.
Any cyclinder compression below 100 psi and you are looking at replacing the head.

Good Luck !
Yeah... unless one of the valves got hungry and took a chunk out of a piston, in which case, the head could be fine, and he might need a new piston set.

KoDKingVegeta
02-17-2009, 08:27 PM
The timing belt snapped when I was driving my old Sedan. Replaced the belt, and nothing was wrong.

Christ
02-18-2009, 10:18 AM
If you were idling or close to it when it broke, and your engine isn't horribly loose, there is a good chance you can just replace the belt and you'll be OK.

If you want to spy a bent valve, you need to take the valve cover off, and rotate the camshaft, like mentioned above. If any of the rockers "falls away" by even 10 thousandths more than OEM spec, then you have a valve that isn't seating.

10 thousandths won't stop your engine from running though, so you might get a great deal of life out of the engine even with slightly bent valves, or it may at least run long enough for you to buy my Z6 head and do a swap. :P

KoDKingVegeta
02-18-2009, 02:32 PM
If you were idling or close to it when it broke, and your engine isn't horribly loose, there is a good chance you can just replace the belt and you'll be OK.

If you want to spy a bent valve, you need to take the valve cover off, and rotate the camshaft, like mentioned above. If any of the rockers "falls away" by even 10 thousandths more than OEM spec, then you have a valve that isn't seating.

10 thousandths won't stop your engine from running though, so you might get a great deal of life out of the engine even with slightly bent valves, or it may at least run long enough for you to buy my Z6 head and do a swap. :P

Always trying to pawn ur stuff onto other ppl. :P

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