Checking Flywheel/Bellhousing runout ?
Thread Starter
Drifting
Joined: Feb 2000
Posts: 1,607
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From: Clarksville,Tn,USA TN
Checking Flywheel/Bellhousing runout ?
I am getting ready to install a resurfaced flywheel and rebuilt Muncie M21 back in to my other car, a 68 GTO. I also have a roller pilot bearing installed but cannot see any visable damage so is there any reason to replace it? I also will be replacing the clutch, pressure plate and throwout bearing.
I read a post on checking for runout on these items. How do you check it?? Can someone give me the nuts and bolts or procedure to do this correctly.
I have the motor and transmission out of the vehicle and have a dial indicator. Is it just the flywheel that you check?
Thanks for any info,
Neil in Tenn
I read a post on checking for runout on these items. How do you check it?? Can someone give me the nuts and bolts or procedure to do this correctly.
I have the motor and transmission out of the vehicle and have a dial indicator. Is it just the flywheel that you check?
Thanks for any info,
Neil in Tenn
Race Director
Joined: Nov 2000
Posts: 11,872
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From: Waterloo ontario Canada
Re: Checking Flywheel/Bellhousing runout ? (Nomad78SA)
You are checking the runout of the bellhousing. The transmission is to be on the centerline of the crank and sometimes the hole where the transmission fits in the bellhousing is off. They sell offset dowels to correct this. Acceptable runout is no larger then .005. Install the flywheel and bellhousing. Place a magnetic dial indicator on the flywheel and the pointer on the inside of the machined hole where the transmission mounts. It is not important to be in the exact center but try to be close and slowly rotate the engine watching the dial indicator. Set it at zero somewhere and check the reading at 12, 3, 6, and 9 o'clock. A good bellhousing alignment none of these reading are out by a few thousands. If the indicator starts at zero and goes to .010 remember this is total run out so divide it in half to get .005 from the centerline. If your reading are really out say .020-.03+ you divide the reading in half then order offset dowels to correct.
If this is not clear I'm sure others will jump in a help explain it.
Good luck
If this is not clear I'm sure others will jump in a help explain it.
Good luck
Race Director
Joined: Aug 1999
Posts: 18,126
Likes: 174
From: WI
Re: Checking Flywheel/Bellhousing runout ? (Nomad78SA)
Nomad,
Above is the correct way to "dial it in" The stock aluminum bell housings are usually pretty good and my new Quartermaster was excellent BUT it`s the blow proof scattershields that are WAY off. ...redvetracr
PS: I use the bronze bushings,i have seen the rollerized bushings disentigrate and for what the bronze ones cost you can change them whenever the car comes apart.
Above is the correct way to "dial it in" The stock aluminum bell housings are usually pretty good and my new Quartermaster was excellent BUT it`s the blow proof scattershields that are WAY off. ...redvetracr
PS: I use the bronze bushings,i have seen the rollerized bushings disentigrate and for what the bronze ones cost you can change them whenever the car comes apart.
