I recently purchased a backplate mount from Performance Specialties for one of my TT Pro .46 engines. I was favorably impressed with the quality of the mount and proceeded to mount it to my engine. With the installation complete, I attempted to turn the engine over by hand. I am unable to turn the engine through a complete revolution. It feels like the piston skirt is contacting that portion of the mount the extends into the crankcase.

This is really aggravating! [:@] I'm glad that I didn't mount up the engine and hit it with my starter. What am I missing here, and what did I do wrong?

Thanks to all for reading this. Any and all input is greatly appreciated!

Probably a dumb question, but does it have a relief cut in the part that goes inside the case, or is it perfectly round??

Good Morning Chuck,

It is perfectly round, unlike the stock backplate, which has a flat relief on the top of the backplate that extends into the crankcase.

An even dumber question. Have you phoned Performance Specialties??

Ed S

NO, I'm still grinding my teeth! I'll wait untill I "chill out" a bit!

They fit the 40 not the 46. We use them for Quickie 424 racing. The TT40 and 46 back plates are identical and both have a cut out. The cut out on the 40 is not necessary. The PS mount does not have the cut out and only fits the 40.

Denis

I emailed Performance Specialties this AM and received this prompt reply:

"For an installation on the 46, the corners of the rear piston skirt need to be trimmed to clear the mount. TT 46 used to fit without modification, but they made a change somewhere along the line and the skirt measurement changed. If you'd like us to make the mod, send the engine and we'll be happy to do it for you at no charge.

Dave"

Mystery solved! Top notch service from a top notch company! Thank you, Dave!