Post by
float_6969 »
https://forums.nicoclub.com/float-6969-u780.html
Wed Jan 28, 2015 6:52 am
My machinist said that the bores distored about .0015", and it wasn't concentric. That means that with the torque plate on, it was a round hole. With the torque plate off, it was shaped like a 4 leaf clover. It's not VISIBLY shaped that way, but it measures that way. The opposite is true if you bore without a torque plate. It's round when you bore it, and goes out of round when you bolt the head on. In normal cars, with cast pistons and softer rings, this isn't an issue because the thermal expansion of the piston is far less than a what you get from most forged pistons. They also use more conformable rings. What happens with a forged piston is that if you bore without a torque plate, your builder has to run the clearances on the loose side to accommodate for that distortion. That makes for a noisey engine that doesn't make as much power as it could have.
All of that being said, I had a torque plate built for my last build and am more than happy to rent it out for a reasonable price. I think $100 for a torque plate rental is fair compared to other torque plate rental prices. BUT, I HAVE to have a deposit up front. It cost me nearly $500 to have it made. I would want a deposit of $500 up front + shipping costs both ways. Once I have that, I ship the torque plate. Once I get it back in good condition (no dings or deep scratches), I refund $400. I have to do it this way to make sure someone doesn't just keep the torque plate, or if they do, so that I can make a new one. PM me if you're interested.