Engine Vibrating after "new" motor swap
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From: Missouri
Engine Vibrating after "new" motor swap
I located a ~50K motor and tranny and swapped it in to my 1st Gen IT7 racecar. It fired right off but I have a couple of questions.
The motor is running about 2K rpms when warm, and vibrating like crazy.... enough to loosen the air cleaner wingnut and knock every tool off of the fenders/roof etc.
The trailing ignition is jumping spark at the coil, jumping from alternating posts to the spark plug wire. When I put a timing light on the leading I can see a missfire every once in a while and the trailing is all over the place. I switched the trailing wires thinking I had them crossed and it got a little better but still does all of the above.
Direct Fire MSD with blaster coils on the leading, MSD 6a on the trailing with stock coil, Underdrive pully set from RB/Mazdaspeed.
What could be causing the jumping spark at the coil? Bad Plugs?Could the clutch being misalligned cause that bad of a vibration at "idle" in Neutral?
The motor is running about 2K rpms when warm, and vibrating like crazy.... enough to loosen the air cleaner wingnut and knock every tool off of the fenders/roof etc.
The trailing ignition is jumping spark at the coil, jumping from alternating posts to the spark plug wire. When I put a timing light on the leading I can see a missfire every once in a while and the trailing is all over the place. I switched the trailing wires thinking I had them crossed and it got a little better but still does all of the above.
Direct Fire MSD with blaster coils on the leading, MSD 6a on the trailing with stock coil, Underdrive pully set from RB/Mazdaspeed.
What could be causing the jumping spark at the coil? Bad Plugs?Could the clutch being misalligned cause that bad of a vibration at "idle" in Neutral?
Get some dielectric grease and put around the boot that should prevent the arcing. The vibration I can't really tell you if it's from the idle try to smooth it out once you figure out the ignition problem. Hold the motor above 5K there should be no shake the motor should be smooth. Hope this helps you out.
Thread Starter
Senior Member
Joined: Jan 2002
Posts: 350
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From: Missouri
I disabled the trailing ignition to take that aspect out of the mix and there was really zero change. Reved up to about 4K and there really is no difference. Disengage the clutch (pushing the pedal in) no real difference.
It's timed at about 10* BTDC at 2K.
When I idled the motor down to about 1,100 it was so bad that I thought maybe I forgot to tighten down the motormounts... but they are tight. The tranny mount was marginal when I reinstalled it, but I can't imagine that that'd be the cause?????
It's timed at about 10* BTDC at 2K.
When I idled the motor down to about 1,100 it was so bad that I thought maybe I forgot to tighten down the motormounts... but they are tight. The tranny mount was marginal when I reinstalled it, but I can't imagine that that'd be the cause?????
I saw something similar to this once.
1. Have you done a compression check on it?
It might have a bad side or corner seal.
2. Are you using the stock flywheel or a lightened model.
If it is the lightened flywheel did you change the front counterweight?
these were the causes of our problem.
Yes a misaligned clutch can make it vibrate. BADLY!
1. Have you done a compression check on it?
It might have a bad side or corner seal.
2. Are you using the stock flywheel or a lightened model.
If it is the lightened flywheel did you change the front counterweight?
these were the causes of our problem.
Yes a misaligned clutch can make it vibrate. BADLY!
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trickster
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