I got a set of CAT h beam rods and SRP pistons. Both are for floating pins. When I installed the pistons on the rods, I had to use a rubber malet to drive the pin inside the rod. I couldn't do it bare hand. Granted it wasn't a 10lb hammer either, but I had to give it a few good taps to get it in (and yes I oiled everything). My question is: is that how it's done?
Granted, it isn't hard to do, but I always thought they would go in bare handed.

your thoughts are apriciated

 

Im kinda courious about that aswell. IVe only had experience with pressed pin set-ups but mmy 400 will be full float.

I just had my pressed ones done at the machine shop. But I feel they way overcharged me for something that took them 15 minutes.

What exactly is the procedure for putting in a pin, and how is pressed install different from floating?

 

honestly i couldn't tell you....but i do know that when i got back my CAT rods and TRW pistons from my machinist he said he test fitted and took care of the pin fitting

so maybe he prepped them somehow *shrug* They go in like butter on my TRWs with NO oil

 

I wish I had a web cam so you could see me cringe reading this.

With oil or assembly lube the pin should slide right into the piston and rod, with no needed help.

If it does not, check to see if it goes into each one by themselves. My guess is that it's the rod, because pins come pre-fit to pistons almost always now.

Now the problem is the pin clearance on the rod's small end. What needs to be done is to have the rods honed out to the needed clearance on a hone. Most times guys just slip the pins in and if they go call it good. A good race shop will check the clearance to see that it's around .0008. Now on high end rods they are almost always perfect, and the accuracy goes down with price. Most Scat I's need to be checked and will have one or two off.

Just one more little detail that you pay for with a quality build up.

Bret

 

i'm assuming it's not somethin I could do myself...need a special machine for that correct?...

 

A full floating setup is what he is talking about, where you have a lock holding the pin in the piston and rod. Usually it's a wire, true arch, sprilo lock that is installed at the end of the piston.

The pressed setup means that you heat the rod up so that they whole in the small end grows and then you press the piston pin in the rod thru the piston, then it doesn't need a lock.

You'll also notice that a rod where it's a "floating pin" is bronze bushed. Except for some high end setups that use a coating on the pin which doesn't need the bushing.

Bret

 

Well if the pin and the bushing in the small end of the rod are not screwed up now, you'll need a machine shop with a Sunnen Hoen that can do that for you. They will know if they can do that or not.

Bret

 

Sorry!

 

nop they aren't screwed up, can't see a mark on either ones...oh well it'll go to the machine shop monday hopefully.

 

Right I knew most of that. Ive just never personally installed either, but I watched a guy do my pressed pins. So floating pins with bushed rods should not need to be installed at a machine shop where there is acess to somehting to heat it with. I should be able to do it myself if I follow the correct procedure right?

 

you no tell me damn right!

 

lol. @ the cringe statement.


You wont know if you hurt the rod till you take it to a machine shop, but it sounds like you are probably ok.

As others stated, with some oil it should slide right in. you should be able to feel any play, but it also shouldn't bind. .

And yes, full floating rod/piston setups can be installed at home.

 

They should slid in like butter, no hammer necessary just a light coat of engine oil

 

Floating setups are easily done at home, you may stab yourself in the finger a couple times as you are learning to use the spirolocks. The pressed pins are done with a small oven that has an adjustable jig setup so that the pin is pressing into correct depth.

 

lol ain't that the truth!