I borrowed a digital scale from my mother's soils lab that measures to the 1/100th of a gram and I plan on balancing my pistons, wrist pins, and rods for the new F Prod D16A6 engine. It has been a few years since I have done this process of balancing with the scale and a little hand file but you can get the parts perfectly static balanced with a little time and effort. I do this individually for the piston, wrist pin and the rods then figure to make a small fixture to hold one end of the rod steady thus letting me do it end for end.

I am doing new overbore pistons and reusing old rods (must be stock by rules) and wrist pins. I was told by some Honda builders not to even bother having them shot peened, that if there was a potential flaw, the rod would have failed during it's previous life. Just clean them and run them. Anyone have any thoughts on that?

Also, how can I get the wrist pins out of the rods at home as they have the old pistons on them. If I recall, stock the wrist pin is tight in the rod small end and the piston floats. Is this a press out or a heat and shrink out process?

Knee surgery next week means I should have lots of open time to site semi-imobile so I may as well be productive. After this, the real race engine can go together.

 

good idea....

only reason why i do not do this AT THE SHOP is cause we have no way of pressing the wrist pin out....thus the reason i have to take them to the machine shop to get them pressed off and on...and just have them balance the stuff while it is there!

slight heat and shrink...DO NOT PUT TOO MUCH HEAT ON THE ROD AS IT HAS A MEMORY!!! don't ask me how i know.... (engines had wrist pins back out cause machine shop heated them to RED HOT)

 

I always spend a few extra bucks and shot peen any OEM rods that I re-use. Especially in a d16.

Good luck with the surgery

Ryan

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by vtecvoodoo &raquo;</TD></TR><TR><TD CLASS="quote">I always spend a few extra bucks and shot peen any OEM rods that I re-use. Especially in a d16.
Ryan</TD></TR></TABLE>

Ok, what does shot peening usually cost? If I have to take it to someone to be properly pressed, maybe the shot peening would be a little extra insurance. Shold I do the balancing before or after the shot peening? I'n guess ing before so the filed places would get peened.

Any ideas on a normal cost?

 

check out http://www.powerhouseproducts.com they make alot of balancing tools and specailty engine building tools

 

Consider beam polishing the rods at the same time. This removes that ugly casting line that runs up the side of the beam. Every one of those little bumps is a potential stress riser. If you're considering ARP rod bolts, you should also have the big ends re-sized after the bolts are installed.

When a machine shop does the press out and in of the wrist pins properly, they use a grease temp marker on the rod, to get it to just the right temp, before moving to the press.

 

owen_the_soyboy on here has made up a little jig to put in a hydraulic press to press stock pistons off the rods. It's worked pretty well as he's done a few of them. Might wanna talk to him. I'm sure he'd be happy to give you some details or sell you one.

s

 

I had a local auto machine shop press the wrist pins out of 12 used rods that I had then I have brought them home to weigh. Once I have 4 that are close, I am going to take them back with the new Honda factory rod bolts and nuts and have them resized on the big end. Then back home again for the actual balancing of the rods, wrist pins and pistons.

The pistons are already within .5 gram of each other and the wrist pins are within .15 grams but I have the scale so I'll go ahead and make them all match. Then a final trip to the shop to have them pushed together. Got the cylinder head back the other day from John Schmitt of HART so most of the parts should be ready soon. I just have to come up with the time to do it.