KB944 pistons

[Flash]

I still haven't wrapped my head around the floating pin concept. I understand their 1.353" compression height if they allowed for the use of the eagle 6.150"rod, which would leave the piston .0045" below deck(my machinist shaved my head the bare minimum .004", so I would've done that as well had I been lucky enough to get the rods off ebay for $200 like someone did). Does anyone know if the eagle rod can be pressed on any 4.0 piston, or does it have to be a floating pin piston? Would/could you have to buy floating pins to put in the KBs?

Pressed fit is a interference or press fit in the small end of the rod, causing the motion of the piston rod or pin to be in the piston only! the press fit of the rod hold the pin in place.
a floating piston pin floats in the rod as well as the piston. it takes thumb pressure to install instead of heat and pressure to install/uninstall. The rod can't hold the pin in place with this method so there is snap ring and a groove on each end of the piston rod......or i should say piston pin

The piston pin is the same diameter for both set ups
If the piston has snap ring groove in the pin area, it can us either type rod.................which is yet another Question to ASK!
DO THE NEW KB PISTON HAVE A SNAP RING GROOVE FOR A FLOATING TYPE PIN??????????
The only real difference between a pressed fit rod (like the stock 4.0 and 258) and a floating rod, is that the hole in the small end of the rod is bored out larger and a brass bushing is installed to give a floating fit instead of a pressed fit.

Flash

[oletshot]

Nothing new to add, just wanted to give credit where credit is due. Back in Feb. when the forum was new, there was a post by jsawduste about KB pistons where he stated that he didn't understand the need for the KB pistons. He stated that you can buy custom Diamond pistons directly from Diamond for less than $500, and that KB's wouldn't be any cheaper than that. Guess he deserves a pat on the back, he hit the nail on the head.

And my wife says that I don't admit when I'm wrong.

[oletshot]

Do the KB's come with fitted wrist pins? Or is this another added expense that will be forgotten when comparing to cast piston sets.

[Flash]

Do the KB's come with fitted wrist pins? Or is this another added expense that will be forgotten when comparing to cast piston sets.

If you mean, will the piston pin bore have it's final honing done, before the customer receives it?.........I'm positive of that.

I don't remeber if it comes with the pin its self....................But if it don't, i would bet that they don't sell enough to pay for there new mold
Stuff like that would spread like wild fire.


I would have to agree with you as well as jsawduste, if you can still get a set of Diamonds for under $500, with the quench we all want and compression.......Well just the price of a set of push rod would tip the scale, let alone what decking the block would cost.

If your just looking for a piston that won't ping and has similar quench to stock, then the KB woud be cheaper..........But not by much!

Well that puts an answer to #1 option I put up above
#1 How much more is a custom piston compared to this one?


Flash

[gradon]

The pistons do come with pins, and I was told that the KTM kits come with the rings as well.

[Reelm n Rubi]

I just recieved a set of these pistons. They are fine pieces, and I paid $450 +shipping. Summit tried to charge me $900+ for these and I told em to stick it. I ended up getting them through a Wholesale rep who had them drop shipped to me. I've spent 4 weeks trying to get these pistons; finally! Pins are included.

[John]

Can you CC the piston top and let us know actual CC volume? Is the pistons cut for a snap ring or a spiralax ring to enable floating the piston pin? You would see a circular groove cut around the diameter of the piston where the pin goes, one on each side of the pin bore in the piston.
John

[Flash]

Can you CC the piston top and let us know actual CC volume? Is the pistons cut for a snap ring or a spiralax ring to enable floating the piston pin? You would see a circular groove cut around the diameter of the piston where the pin goes, one on each side of the pin bore in the piston.
John

I too, would appreciate this info............did you buy the 9.1 or the 10.1 pistons?


Flash

[Reelm n Rubi]

The pistons are not cut for spiral locks. I bought the 9 to one set, the 10 to 1 set is part number KB945. I'm running a supercharger and a Hesco aluminum head so 9-1 is perfect. I thought the dish volume was around 27cc for the 944's.

[John]

We have several thoughts on those pistons, few verifications. You just provided one of the first. Not set up for floating pins. Thanks
John

[gradon]

That's too bad about those pin locks. The 944s are supposed to have a 21.7cc dish, so you better do the calculations right before you end up with too much compression for the blower. I wish I had your budget for a build.

[Flash]

We have several thoughts on those pistons, few verifications. You just provided one of the first. Not set up for floating pins. Thanks
John

Vary disappointing to me!..........Are the Eagle rod a pressed fit rod or is it floating? I thought that they were full floaters...........Something tell me. I'm wrong.

Hay Reelm n Rubi, got any pic's of them beauty's ( pistons )

Flash

[Reelm n Rubi]

When I get home from work I'll post some pictures of the pistons. The dish volume might be 21.7cc, I haven't calced anything in a couple weeks while waiting for parts. You can get away with a extra 1/2 to a full compression point with an aluminum head. I run floating pins in my Mustang, but don't see the real nead for it with my Jeep because of the rpm range it's opperating at (under 5500 rpm). I'll agree that it would be a nice option though, as long as the price remained the same.

[John]

"Vary disappointing to me!..........Are the Eagle rod a pressed fit rod or is it floating? I thought that they were full floaters...........Something tell me. I'm wrong."

You have it right. they are floaters.
John

[John]

Info on the Eagles

Jeep 4.2L, 258 c.i.- 2.095 crank pin/.912 piston pin/1.063 b.e. width
C-C LENGTH NOTES GRAM WEIGHT PART NUMBER
6.150 +.025----------660--------------CRS6150A3D

John