Vibrations after clutch install possible?

SpicyOrange · 03-06-2005

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I am currently trying to chase down I am having with my 95 GS-T. I bought the car as a basketcase and had to buy a clutch and re-install the tranny. Now I have a bad vibration at that starts at 3500 rpm and up, and a light shake at idle, I originally thought that it was a balance shaft problem and replaced The belts and realigned the balance shafts. everything was perfect when I took it apart but I re-did it anyways. I bought the car with the tranny out because the kid took it apart to replace the clutch (Spec stage 1). He neversaid that he had these vibrations and I am starting to suspect a flywheel/clutch problem since the vibrations are definately in the engine area and not the tranny/driveline since it will vibrate with the clutch in or clutch out. moving or not moving. I have checked the motor mounts and found on the drivers side to be torn, but even holding a pry bar against it will not get rid of the shake. It feels like something is off balance.

Has anyone had balance problems with their aftermarket clutches? I have a SPEC stage 1 clutch that I just installed 300 miles ago and this motor has shaked since I got it running. How do you fix the imbalance problem? Can a machine shop balance the clutch and flywheel together?

Raptor · 03-06-2005

I don't know about the flywheel and clutch being balanced together as a unit separately from the crank, I would imagine it isn't a big deal. I will check for you in the morning. We always have the motors we build balanced with the pressure plate in place and marked for reference. You know, one thing I didn't mention the other day when you were here is that whoever did the work on the motor before may not have lined the gears up in the oil pump which would put the rear balance shaft out of phase as well. It still could pass the insertion test via the access hole in the block and be off enough to cause an out of balance condition. You wouldn't be able to tell if it was off a couple teeth(in the pump) while doing a timing belt. Not that I think that is the problem, just one more thing to consider. It still seems like a balance shaft issue to me. The clutch could be off balance as well, but it would have to be by a pretty fair amount for that kind of vibration. Not a common thing.

SpicyOrange · 03-06-2005

Thanks for all the help Mike! I really appreciated you taking a look at it for me. I am pretty much fishing for possible problems now. I found a couple threads on DSMtuners that had to do with vibrations after a clutch install but no one ever said how they fixed it. Their symptoms seemed Identical to mine and I was thinking it was possible that the clutch was mis-balanced or maybe the dowel holes weren't drilled perfect. I am really stumped. I might pull the tranny down and see if I can find anything and I will probally do the BS elimination then also. My roomate is gonna drive to work this week when he isn't busy and put it up on a hoist and check a couple things out for me since I am out of town this week.

Nick

SpicyOrange · 09-02-2005

Ok I still have this problem, I parked it for the summer and now I'm gonna try to get this thing running before winter. I have a bad vibration at idle, and right above 4000 rpms. I already replaced the timing belt and balance shaft belt since I thought for sure thats what it was, I had 2 people that are mechanics and that have done Timing belts in DSMs before so I'm %90 sure the shafts were lined up correctly, and I know they can line up and still be off, but I pulled the plug on the back of the motor and checked it myself.

So now I did a couple tests on the engine, First I did a leakdown test and starting from left to right it went as follows, %3-%5-%33-%25, obilvously there is something wrong with 3 & 4 (the two farthest to the right) And then I did a compression test, I got 175-170-150-160, still I think there is something wrong, I'm hoping head gasket, but I couldn't tell where the air was going in the leakdown test.

When I pulled the plugs to start these tests I noticed the plugs I installed looked like they were brand new (pure white ceramic with a hint of detonation), and they probally had about 100 miles on them since I changed them when I did the timing belt. So I got to thinking/hoping there was a lean condition, So today I did a fuel pressure test and I have about 44psi with the vacuum on at idle, and 62psi under WOT @14psi, so everything there seemed fine, no drop off in pressure.

Does anyone have any ideas what might be the problem?

EclipseGST · 09-02-2005

Did you check the oil pump gears like Mike suggested?

Also the cylinders 3+4 are on the left side... The farthest cylinder on the drivers side (Timing belt side) is #1.

Sounds to me like you could have a couple bent valves. Did you make sure the valves were closed (lobes on cams faceing straight up) when you tested each cylinder?

SpicyOrange · 09-02-2005

I think I'm gonna tear down the motor this weekend, Does anyone have a balance shaft stub shaft kit availible this weekend? Is Mike around still? I think he had the shit to do an elimination. I hope its something stupid like a bent intake valve, I checked the exhaust and crankcase for escaping air, I guess I never pulled the intake tube off to listen there.

**Goat Blower** · 09-02-2005

Bent valves and high leakdown rates don't cause an imbalance situation. I'm thinking Mike's got it right here. Do the balance shaft elimination, you can get the parts from Brookdale Mitsu for about $45. If that's not it, you might have a severely imbalanced flywheel, but I've yet to ever see that. My money is on the balance shafts.

SpicyOrange · 09-02-2005

So do you think I have 2 issues going on? and is brookdale mitsu parts dept. open on saturdays?

SpicyOrange · 09-03-2005

Quote:

Originally Posted by Raptor

You know, one thing I didn't mention the other day when you were here is that whoever did the work on the motor before may not have lined the gears up in the oil pump which would put the rear balance shaft out of phase as well. It still could pass the insertion test via the access hole in the block and be off enough to cause an out of balance condition. You wouldn't be able to tell if it was off a couple teeth(in the pump) while doing a timing belt. Not that I think that is the problem, just one more thing to consider. It still seems like a balance shaft issue to me.

So how do I go about checking this? do I have to rip the belts off? I have the motor down to the timing belt and I turned it over a couple times to check the alignment. Do I have to pull the cover off? If I do this will I basically be far enough into the motor to just ditch the shafts and replace with a stub shaft. Or is there a way I can test to see if the gears are off with out going any farther?

**Goat Blower** · 09-03-2005

You need to pull the front cover off to do this. When you pull off the oil pump gear cover plate. the dots on the two gears need to line up if you'r using a balance shaft. if you do the elimination, it doesn't matter. You need to take the cover off to take out the balance shafts anyways.