Hey guys, just a quick question regarding bore and piston size. Doing a budget oriented turbo build with Speed Factory's no notch set, and was wondering about the piston sizing. The block I'm using has roughly 97,xxx on it, everything looks like it's in pretty good shape. I was planning on doing the hone myself at home to try and save some money. Was just curious if sticking with the factory 75mm bore with a hone would be okay, or if I should take it to my local machine shop and have them do it, and if I go that route should I be looking at getting it bored over? I just want to have a nice reliable build that isn't going to blow apart down the road.

 

The closer to stock bore, the stronger the block will be. If you can stay at 75mm and have the proper piston-to-cylinder wall clearance, do it. The reason that larger pistons are used is because the cylinder bores in the block are worn or egg shaped... in which case, you increase the size of the piston and bore and hone the block to fit the pistons.

 

I see, makes sense. This is my first endeavor into engine building so I'm learning as I go. I appreciate the information!

 

Check the cylinder walls for scarring or other damages. If it's clean, go with the 75mm setup. If it's not, have it bored 20 over (75.5mm). Speedfactory No-notch set does come in the oversized pistons too. That's what I am running.

 

if it is clean will the 75mm set just drop in? Also if not I know machining can get expensive and I’m trying to stay pretty budget. Could I run the No-notch rods with the factory pistons and get away with it? I know the stock rods are like pencils so I was wondering if there was a way to beef my engine up a bit without getting it machined quite yet

 

Stock rods and pistons use a pressed wrist-pin fitment... this means that the wrist pin "floats" within the pin bore of the pistons and the pin is "pressed" into proper centering position of the connecting rod. Aftermarket connecting rods, like the no-notch rods that you have selected, have a slightly larger wrist pin bore and the pin "floats" in the rod... meaning that your wrist pins would NOT stay in place with stock pistons and thus, crash into the cylinder wall !!! So NO... this will not work. You will need aftermarket pistons with "pin locks" on both sides to keep the wrist pin in place.