Rod and Piston combo question

Hey guys I have a question about a rod and piston combo available for our motors that is forged that doesn't require boring the block. Basically is there aftermarket rods and pistons that replace the oem ones without having to do machine work? Thanks!

 

The short answer is yes.

If you are alluding to a pop-n-drop build, they rarely go well. Surely possible, been done plenty of times, few have led to positive experiences.

 

Well, you'll be hitting up the machine shop anyways for a proper balance.

 

Manley recommends not balancing their rods. And it’s never a smart idea to put forged pistons and rods into the motor without machine Work. You’re just asking for a bad time.

 

So when I built my motor I got my cylinders bored, block cleaned and checked over, and head surface decked all for $275. Granted, that was a great deal, but if you want to save less than $500 in order to have an "easy" build, you're in for a bad time. The only block I'd toss pistons in would be a brand spanking new one, and even then your P2W isn't going to be as precise as it would be if you were to pay for the machining.

 

honestly it depends on the mileage on the motor and the long term goal of the build. I would have no problem doing stock size replacement on a well maintained properly running motor as long as the end horsepower goal was modest. You can use a borescope to inspect the cylinder walls through the spark plug hole and determine how to proceed.

 

Well it looks like I'm going with cp pistons and k1 rods. Hope it works out in the end.

 

By borescope, do you mean penis? If we're shifting the conversation to erections, I am in like flynn.

 

You’re a man of risk I see. My motor is very well maintained, and I would never be silly and do a pop and drop and expect that to last anywhere near 20k miles.

 

Please provide something other than opinion to back up your claim. If the bore is in spec it is in spec regardless of the mileage.

 

You’re correct on that, but some pistons require a certain hone in the cylinder in order for the rings to seat correctly during break in. Plus even though the cylinder may be in spec, the factory hone is going to be worn just due to simple operation of the motor, now with great maintenance the wear could be less, but it will still be present. Plus the factory cylinders were designed with a cast piston in mind, not with a 4032 or 2618 piston which have different expansion ratios during warmup. So you’re also causing more wear during initial warm up since you’re not getting a nice tight PWC without proper machining to match that piston.

 

If this were a small block chevy I'd say, fuck it and do it.

 

Piston manufacturers account for the different expansion of materials when stating a bore size. You make the Piston smaller accordingly not the bore bigger. Also a hone removes very minimal amounts of material so you can always hone the cylinder.

This all being said there are few instances where I would do a pop and drop. Mostly I would want to see the cylinders with my own eyes before ordering pistons. This would result in significant down time since you can't just get them shipped on two day prime. For a daily driver building a bare block and swapping would be a lot faster.