What is an acceptable min. # on thrust side for a street driven 312??

Mars , Pennsylvania

As a general rule, it is preferred to have a minimum of 0.100” cylinder wall thickness. Because the non-thrust sides are typically smaller in thickness, boring is typically limited by the non-thrust side thicknesses rather than the major and minor thrust side thicknesses. In the case where core shift is extreme, then you can consider offset boring the cylinders to better equalize cylinder wall thicknesses.

Lorena, Texas (South of Waco)

THANKS TED .... I have a 312 that had a rusty cylinder we bored out to .060 and it still has a slight water mark and I was not thrilled about a sleeve....will check 1st of week and see what is there ... what company would I see about making a .070 set of forged pistons if it checks out??? this is just a street driven 32 roadster.... Regards Steve

Mars , Pennsylvania

Custom pistons will cost more than a sleeve and a sleeve will be just fine.


Lawrenceville, GA

Before ordering custom pistons make sure you can get rings. You could file fit 3.875" rings to 3.870" but you also need to look at ring thickness. 5/64" stuff is easy to get and inexpensive, this would be standard 283 scrub ring set. 1/16" thick rings are much more expensive. We have had some customs made by Racetec/Autotec recently. If you are using stock connecting rods make SURE you specify the width of the wrist pin end of the connecting rods, or any piston manufacturer will make them too narrow. Rods won't fit in the pistons. Yeah, I've made this mistake.You will also need to specify wrist pin diameter and Compression distance ( how far the wrist pin is down from the top of piston). Y-Block pin is .912" same as 289-302. CD will need to be in the 1.775-1.785" range depending on how far you want the pistons down the cylinder at TDC.

http://ford-y-block.com 

20 miles east of San Diego, 20 miles north of Mexico

Thank You Have a great Holiday Steve McD

Mars , Pennsylvania