wrist pin install

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63dartman

63dartman

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I have never attempted installing wrist pins on press fit rods. Now that I am at that hurdle I have to ask how it is done. Is there a tool or method needed? I did a little searching and it seems that the rod is heated to enlarge then the pin is installed by hand.
How do you guys do it? Is there any other way than using heat?
 
I do not recommend doing this by yourself for the first time. It's harder thing you think and requires another set of hands. Yes you can heat the rods or freeze the pins but making a positive stop fixture is a must and you have very limited time to put the pin in before the heat/cold transfers leaving you half way in. I would take it to your machinist and ask to watch then give it a go the next time around. This is just my two cents I'm sure another will chime in.
 
yeah, I figured I would need some type of jig to center the rod in the piston and keep it from moving as the pin is installed. How about putting the pins in dry ice?
 
If you really want to install the pins yourself have the rods converted to full floating.One heck of a lot easier..

Or just pay the machinist.
 
One the pin will not come out unless the locks are not install properly. With press fit there is always a chance it's not tight enough and will loosen up and the pin sides into the cylinder wall. I only do floating but that's me. My dad only does press fit. It's a personal choice.
There is also the theory more hp because the piston rod assembly has two pivot points instead of one. I've never seen a dyno test on that one yet.
Also their are a few machinist that say steel on steel is ok but I wouldn't trust it for street use. Have them bushed and an oil hole drilled on the top of the rod if you go that route.
 
What you can do is hone the small end of the rod to a floating fit,drill a small oil hole in the top, then assemble them with the spirolox. If the rod does happen to sieze on the pin, big deal that's the way it is in a press fit anyway.
 
that's odd. The speedpro pistons and pins that I'm getting ready to install have clips to hold the pin at both ends. Does this mean they are floating?
 
So, does that mean I need to have my rods bushed for floating pistons or does that mean the pins are sized to float in standard rods?
 
That means they can be installed either way. It's the rod that makes the difference. I bush factory rods and go floating. I do know some builders that simply hone the steel rod out and float them that way. It's like he said previously... I dont agree on doing it that way. Just my choice. It's $75 to have my rods bushed during the re-do, and it is "the right" way to do it. I have a rod over and the fixture, but honestly, I suck at it...lol.
 
consider aftermarket rods that are already bushed and have HD bolts.
Eagle SIR rods(if a small block)are around $250(?)...plus they are brand new.Bob
 
So, If I have my rods bushed does that mean rebalance? My whole endeavor here is replacing pistons without rebalancing. The new pistons are a matched set and have been checked for weight uniformity and they are all good. Also the weights match the old pistons very closely.
 
hi, if you have rods bushed, rebalancing is not required, how ever, using eagles or other rods will require rebalance. the least expensive is to take rods and pistons to a machine shop, and pay to have them pressed on. as for pressed vs floating concerning power. it's a mute point. if you have them pressed, do not install locks. i have ran steel on steel rods and pins before. the key is to drill oil holes in pin bores of pistons to intersect with hole from oil ring grooves, this will pressure feed the pins. then hone rod bores with .001 clearance max. race pistons have oil holes already in them.
 
thanks everyone for the info. I think I am just going to have my rods bushed so I can do the install myself. I know it's not the cheapest route.
 
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