Dialing-in a scattershield

[DanEC]

Originally Posted by xb-60

Thanks for the responses. I had a look at the 'million dollar Cobra' thread, but it ran to around 80 pages and nothing relevant showed up on a search, but I get the idea.
So the clocking process trues up the scattershield alignment, and is an opportunity to check the flywheel for warpage (is yours aluminium, Dan?), and also the squareness of the gearbox mtg. face.
We then need to assume that the gearbox mounting holes on the scattershield are correctly positioned?
Never done this before with a purpose designed scattershield like a QT...so a further question:
Once the QT scattershield is dialled-in and screws torqued up, I should leave it fitted, and then fit the gearbox (Toploader) to the scattershield once the engine (with QT) is installed?

Cheers,
Glen

Glen - don't worry about the transmission bolt holes for the transmission. The transmission registers by the fit of the input shaft bearing retainer to the opening. That fit should be snug with no play.

My Cobra flywheel is aluminum but the one I had a bad experience with was a new Hays steel flywheel for my Corvette - it was warped out of the box. I had to have it machined twice before I could use it. I would torque the flywheel down and take runout checks around the middle of the clutch disc contact face just to make sure you don't have something really wacky like I did. It's hard to find a spec on this. The only one I have personally found was in my 67 Plymouth GTX shop manual - .005 inch. How that relates to modern transmissions like the Tremic I have no idea. For old Toploaders, Muncies and T-10s with a ball bearing input bearing and a wobbly input shaft, it's probably not real critical. For a modern transmission it might be. Blykins would be a good source to ask this question.

As far as the transmission mating face on the bellhousing - I've not done this but I guess you could bolt the bellhousing on, set up the mag base on the crank flange and the indicator reading on the outer area of the bellhousing face and rotate the crank and record measurements. If the bellhousing is machined poorly it could sure create transmission issues - but I'm not aware this has been an issue for anyone. With my old wobbly input shaft Toploader I didn't feel it was worth checking.

Once you have verified the bellhousing is mounting within tolerance, the dowels should keep it in place even if you remove and replace it. In my experience there may be enough slack at the dowel pins to bump a bellhousing maybe a thousand or so in one direction or the other - but it should go back to where you have it dialed in. Then you can remove it to install the engine if you want or install everything together.

Good luck.