Help diagnose intermittent starting problem

[sidechoke67]

I have a 2001 Volvo 3.0L GSM-A. Last summer I replaced the original Volvo starter with a Sierra equivalent. Ever since then, after about 2 dozen or so smooth starts, I turn the key and hear an awful metal-on-metal clunk when the starter pinion engages the fly wheel. Sounds like gears not meshing and locking up.

First time it happened, I pulled the starter, and turned the motor by hand to inspect the flywheel. Flywheel teeth all looked good, starter pinion teeth all look good, so I assumed the Sierra starter needed a shim. I shimmed it and was good for another 2 dozen or starts.

Second time it happened, I thought maybe it needed another shim, so I put a 2nd one in. Again, turned the motor by hand and looked at the flywheel. Looked good as far as I could tell. Added the 2nd shim, and was good for a few dozen more starts.

Thrd time it happened, I finally heard that you shouldn't re-use starter motor bolts (I had been re-using 'em). Great, starter motor is coming loose...problem finally solved I thought. Bought some new starter motor bolts, put the starter back in, and was good for another few dozen or so starts.

Today, same thing happens on the water. I was going to try to loosen the starter motor and re-seat it, but I didn't have the right size wrench. So, I tried just turning the motor by hand - then it started right up. I should also add that my engine ran on a bit when I turned it off before getting the clunk on the next re-start try. I don't remember/didn't notice if my engine ran on any of the other times.

So...I'm no mechanic, but I'm thinking that my problem could be either that the Sierra starter is still off by a tiny bit - enough that every once in awhile the starter pinion doesn't engage the fly wheel exactly right.

or, my flywheel is a bit warped, or has gnarled teeth in a section? When I eyeballed the flywheel while turning the engine by hand, I didn't notice any bad teeth sections, but I guess it is possible I missed something.

Any other possibilities you guys can think of? I remember reading some posts here on how engine run-on can cause some kind of water lock...but I haven't been pulling plugs or anything when I turn it by hand....and today, I didn't turn it that much, and it wasn't that hard to turn - so I'm guessing that isn't the problem?

Thanks for letting me know your thouhts on any other possibilities.

 

[bubbadabulldawg]

Re: Help diagnose intermittent starting problem

Remove the starter and check the bushing at the end of it. I just picked up a Chaparral from a family member who thought the flywheel was bad and missing teeth because of problems trying to start the engine. I removed the starter checked the flywheel and it was fine, the starter on the other hand was wasted, end shaft bushing was missing causing the bendix not to line up with the flywheel and chewed the windings up inside also. Had it rebuilt for a Benjamin. Turns over like a champ. There is nothing wrong with the starter bolts they can be reused unless you cross threaded them.

 

[cr2k]

Re: Help diagnose intermittent starting problem

Negative on the starter bolts being reused. There is a knurled section that is an interference fit to index the starter. They can be reused in a emergency, but should be replaced each time. It is not the threads that is the problem it is the slop that one will get from the worn knurl that is the fit for the starter alignment.

 

[sidechoke67]

Re: Help diagnose intermittent starting problem

Thanks bubbadabulldawg - pulling the starter is on my list....again...at this point, I would love to find the cause with any certainty. I have thought I had this problem fixed several times now, only to hear that clunk noise on the water..

cr2k, Do you know if starter motor bolts are all the same? i.e. is it just important to use new bolts, or do I need starter motor bolts from (in my case) Volvo to ensure that the starter motor aligns correctly?

Also, FWIW, I pulled the plugs last night and turned the motor by hand. No liquid came out. Not sure if this was even a valid test at this point, since my motor ran fine for over a 1/2 hour after I turned it by hand on the water yesterday... So, I am assuming I did not have hydrolok based on it running fine after starting, and no water coming out last night ?

 

[Adirondack]

Re: Help diagnose intermittent starting problem

I have a 2001 Volvo 3.0L GSM-A. Last summer I replaced the original Volvo starter with a Sierra equivalent. Ever since then, after about 2 dozen or so smooth starts, I turn the key and hear an awful metal-on-metal clunk when the starter pinion engages the fly wheel. Sounds like gears not meshing and locking up.

First time it happened, I pulled the starter, and turned the motor by hand to inspect the flywheel. Flywheel teeth all looked good, starter pinion teeth all look good, so I assumed the Sierra starter needed a shim. I shimmed it and was good for another 2 dozen or starts.

Second time it happened, I thought maybe it needed another shim, so I put a 2nd one in. Again, turned the motor by hand and looked at the flywheel. Looked good as far as I could tell. Added the 2nd shim, and was good for a few dozen more starts.

Thrd time it happened, I finally heard that you shouldn't re-use starter motor bolts (I had been re-using 'em). Great, starter motor is coming loose...problem finally solved I thought. Bought some new starter motor bolts, put the starter back in, and was good for another few dozen or so starts.

Today, same thing happens on the water. I was going to try to loosen the starter motor and re-seat it, but I didn't have the right size wrench. So, I tried just turning the motor by hand - then it started right up. I should also add that my engine ran on a bit when I turned it off before getting the clunk on the next re-start try. I don't remember/didn't notice if my engine ran on any of the other times.

So...I'm no mechanic, but I'm thinking that my problem could be either that the Sierra starter is still off by a tiny bit - enough that every once in awhile the starter pinion doesn't engage the fly wheel exactly right.

or, my flywheel is a bit warped, or has gnarled teeth in a section? When I eyeballed the flywheel while turning the engine by hand, I didn't notice any bad teeth sections, but I guess it is possible I missed something.

Any other possibilities you guys can think of? I remember reading some posts here on how engine run-on can cause some kind of water lock...but I haven't been pulling plugs or anything when I turn it by hand....and today, I didn't turn it that much, and it wasn't that hard to turn - so I'm guessing that isn't the problem?

Thanks for letting me know your thouhts on any other possibilities.

Hydrolocking isn't something you want to be guessing at. Turning it by hand is turning it slowly, and can allow the small volume of water to escape as the piston compresses. Next time it does it pull the plugs immediatly and try cranking with the starter. Watch for signs of water. It has to be checked this way for the same reason you have to spin the motor at starting speed to do a compression test. A cylinder isn't a totally air tight/ water tight seal.

 

[6meter]

Re: Help diagnose intermittent starting problem

I have never replaced started bolts and have pulled hundreds of them. Sounds like you have an intermitantly bad starter. I was told by a factory Chevy tech from Detroit that the knurls were for the ground.

 

[sidechoke67]

Re: Help diagnose intermittent starting problem

Thanks guys. I hate the thought of going back out on the water without knowing this problem is solved, but I'm not sure what else I can do except wait for it to happen again so I can run more tests...

I have considered replacing the Sierra starter with the exact Volvo starter....problem is that the Sierra starter was around $130, and the Volvo starter is $400. It kills me to pay that much more, but it would be worth it at this point if I knew it would solve my problem.

 

[sidechoke67]

Re: Help diagnose intermittent starting problem

Now that I think of it...the very first time I put the new starter in last year, it locked up. I re-seated it, and then got a bunch of starts out of it before hearing the clunk.

I am just about to rule out hydrolock....but would still appreciate any other opinions.