Timing belt intact but not moving?

[megadeathray]

Im driving along and Im driving along and I miss my turn. So I go to turn around in a driveway. Just about to put the ole girl in reverse and it up and dies. I had the radio up so I heard nothing. Thinking the worst I imedeatly take off the timing belt cover, timing belt is fine still in great shape. Had my dad try to start it while i watched the engine. When it turns the timing belt looks like it tenses up, the cam pulleys move just slightly. When the starter stops turning then the belt goes back to where it was ( it only moves maybe an 1/8 of an inch ). So I did some research and I think it might be the crank pulley has sheered. I hear its a common problem on 1gs and mine has 170,000 miles.

Does this sound like a broken crank pulley? And if it is, would trying to start turn the crankshaft when the camshafts aren't spinning and bend my valves?

I wanna get back on the road so any help is greatly apreciated!

 

[RotaryRyan]

I wouldnt do anything until i got up under there and figured out whats wrong. Dont turn it over anymore.

 

[Matrixhunter]

Hey looks like you have run into a similar problem i had a few days ago but mine was a bit more drastic was on the freeway going 130km/h and suddenly car died pulled over anyways long story short a screw got stuck in the timing belt cover at the bottom melted into the plastic and started stripping the timing belt balance shaft belt broke and so on timing got messed up aswell.

Anyways for your car likely the problem the crank pulley is either seized up or the bearing broken or some valves are stuck or your timing belt managed to slip somehow and it's off a few teeth hope this helps. Good luck

 

[RossY]

Um, if the starter was turning the crankshaft and the cam gears weren't moving then you may have some bent valves.

You see when the starter turns the crank, that moves the pistons up and down. Normally thats a good thing as long as the valves are in time with the pistons. However, as you mentioned, the cams weren't moving except maybe a small amount. This leads me to believe that the valves in your car that are currently opened, have just gotten a big kiss from the pistons as your tried to turn over your car.

If your timing belt still has tension on it then its possible one of your cams has seized making them impossible to turn. This would make it possible for the crank to turn while the cams stayed put.

If you want to test if your cams have seized put a socket wrench on the bolt that holds the cam gears on (I believe a 17mm) and try turning it clockwise. If one of them doesn't move, then your cam has seized. This should be done with the timing belt off.

A quick way to tell if you bent your valves would be to pull the valve cover and feel each of your rockers. If they are loose, or fall off the valves then its bad news for you

 

[Defiant]

Im driving along and Im driving along and I miss my turn. So I go to turn around in a driveway. Just about to put the ole girl in reverse and it up and dies. I had the radio up so I heard nothing. Thinking the worst I imedeatly take off the timing belt cover, timing belt is fine still in great shape. Had my dad try to start it while i watched the engine. When it turns the timing belt looks like it tenses up, the cam pulleys move just slightly. When the starter stops turning then the belt goes back to where it was ( it only moves maybe an 1/8 of an inch ). So I did some research and I think it might be the crank pulley has sheered. I hear its a common problem on 1gs and mine has 170,000 miles.

You've sheared off the teeth that were at the crank sprocket. Your valves are bent.
How many miles on that belt?

 

[ddavisaf]

You've sheared off the teeth that were at the crank sprocket. Your valves are bent.
How many miles on that belt?

I'm thinking the same thing ^^

 

[megadeathray]

Dead nuts Defiant. The teeth on the belt were stripped right off at the crank. My next question is this.

Is there a way to test my valves ( I know thier toast, but why not test first ) besides taking of the valve cover?
I heard that by disconecting the distributor and putting a compression gauge in each plug hole ( one at a time ) then turning the motor you can tell where your bent valves are. I'll be putting new belts on before then of course.

Also, anyone know which would be easier/cheaper, buying a rebuilt head, or replacing valves and guides ect... myself?

Thanks for all the help so far.

 

[ddavisaf]

http://www.dsmgrrrl.com/FAQs/compression.htm
That link is on how to do a compression test. If you register 0 on any cylinder, the valves for that cylinders are bent or broken. You'll need that timing belt on though in order to crank it.
I would just replace the valves and whatnot myself. No need in buying a rebuilt head.

 

[ragedylaser41]

how hard is it to replace the valves on a 90 4g63t? Uh, i don't believe my car has done the same thing - but I do believe the valves are bent - read my older post for the whole story

o yeah - i thought these motors were coil packs?

 

[ddavisaf]

how hard is it to replace the valves on a 90 4g63t? Uh, i don't believe my car has done the same thing - but I do believe the valves are bent - read my older post for the whole story

o yeah - i thought these motors were coil packs?

It's not very hard. A weekend will get it done for the average mechanic.
I don't understand what you mean by "i thought these motors were coil packs?"

 

['96_Talon_TSi]

A leakdown test would tell you if you have broken valves.

To perform a leakdown test put each cyl at TDC (top dead center) and fill it with compressed air through the sparkplug hole. You will hear leaking exhaust valves through the tail pipe and leaking intake valves by the throttle body. You will also hear leaking pistoin rings out the pcv valve (make sure to disconnect this before filling the cylinders) or a blown headgasket with bubbles in either the thermostat or coolant reservoir.

 

[ragedylaser41]

It's not very hard. A weekend will get it done for the average mechanic.
I don't understand what you mean by "i thought these motors were coil packs?"

yeah - i don't know either - wow now i feel like a complete idiot asking if the MSD ignition box i have here(MIS-4) would work. .

 

[Defiant]

Dead nuts Defiant. The teeth on the belt were stripped right off at the crank.

Yeah, sorry. You'll probably find the cheapest and best course will be to pick up a used head and give it a valve job. Thankfully, there's zillions of them around. I'd not bother testing the valves in your motor, they're done. Small chance you broke any, but if you did you sure don't want to be turning the motor over.
Your pistons and bottom-end are probably okay.

 

[megadeathray]

Your not gonna believe this. We do the compresion test, all cylinders are a go. WTF! So heres the theory. The cam pulleys were in exact 180 from being on the timing marks. The valves were all closed when the belt went. HAHA can you believe that!
Its a DSM miracle. I had it back on the road in a day. Now to deal with the gremlins in my suspension. Thanks again for all the posts.

 

[big4life99]

You've sheared off the teeth that were at the crank sprocket. Your valves are bent.
How many miles on that belt?

I agree with this man same shit happend to me belt looked intact until i pulled off the timing cover and had a bunch of the teeth fall to the driveway. Ended up with a ####ed head to of the valves where imbedded into the pistons and all other valves bent. I feel your pain dont cry. j

 

[mkgearhead]

Mine did the same thing. When I bought the car the belt was oil soaked and the teeth were peeled off at the crank gear. I put a belt on it to check and it fired right up. A new belt and cam seals and i've been driving ti for 6 months.