Floating Wrist Pins

[Mark H.]

I'm using Keith Black pistons in the rebuild of my 327. Got the engine components back from the machine shop this week and found the pistons mounted on the rods, but they appear to be of the free floating variety and the end locks have not been installed. Any tricks here, or do I just walk them in with a screwdriver? Any lubrication needed at installation? the pin itself has been oiled (there are small puddles in the piston from where it has dripped down.

Thanks for any tips. Can't wait to get her all put back together.

[Dave Cote NCRS#38525]

Re: Floating Wrist Pins

Mark,

Installing the locks is a pretty straight forward deal. There are two types of locks, but I think the KB's are the snap ring style locks. They are a little easier than the spiro locks. Apply some assembly lube to the pins and just make sure that when you install the locks that they are seated in the groove that is cut for them in the piston. Also, make sure that the radius on the rod is pointing in the correct position for the piston. A small screwdriver will work just fine. Good Luck

[Joe L.]

Re: Floating Wrist Pins

Mark-----

Are you SURE that the piston pins are full floating? The controlling factor in whether an engine has floating or pressed fit pins is the rods, not the pistons. Many pistons can be used either way if they're set-up for it and KB usually are. NO 327 ever used full floating pins. So, if you used your original rods in the rebuild, and unless you gave instructions for them to be converted to floating pin, the will not be floating pin.

In a floating pin design, you should be able to press out the pins with your hands if the locks are not installed. DO NOT install piston pin locks on pressed fit pins.

[Mark H.]

Re: Floating Wrist Pins

Thanks, Joe, you've helped me avert disaster. I should have asked if I had floating pins. I just assumed I did - the lateral movement of the pin in the piston was enough that I could see both of the grooves for the locking pins and I assumed they should go in. I reused the stock rods, didn't pay to have them converted, and can't budge the pin in the rod. I've also verified that the pin area of the skirt on the new pistons is wider than the same area on the old one's, hence the appearance of greater lateral movement of the pin in the piston. The locking pins will stay in their little envelope.

Live and learn.