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Re: KB pistons
Posted: April 10th, 2008, 6:44 am
by tirod
Of course no idea yet of valve reliefs and max cam lift advised? I bet those running Yella Terras want to know.
Re: KB pistons
Posted: April 10th, 2008, 8:21 am
by kris
gradon wrote:How many people are considering these? Is it worth asking KB for a group discount if we can deal with them direct and skip the middleman markup?
If they are available in the next 4 weeks and are no more than 9.2:1 I'd take a set.
Ive already started my teardown so I dont want to wait much longer. Let us know what you find out.
kris.
Posted: April 10th, 2008, 11:04 am
by kris
Re: KB pistons
Posted: April 10th, 2008, 11:43 am
by oletshot
Pin height puts piston .023" below top of stock deck. Guess they had to put some clearance so you can deck your block without your piston sticking out the top.
They got the stroke wrong "3.905"? Maybe that's were some of the clearance came from.
Re: KB pistons
Posted: April 10th, 2008, 11:48 am
by seanyb505
3.905" is definitely the .030" piston size. 4.2 cranks have 3.895" stroke.
Re: KB pistons
Posted: April 10th, 2008, 12:10 pm
by Flash
If it real set .023 down in the hole and it said the dish was 60cc

..............we we would have to have 10 pound of boost just to make it run
for the 9 and the 10:1 with a 59 cc head added to there "little" calc it said 7.0:1 on both pistons..............
I don't think they have all the spec's loaded right.........Just yet
Vary coool to see it on KB!!!!!!!!!!!!!!!!!!!!
Flash
Re: KB pistons
Posted: April 10th, 2008, 12:18 pm
by oletshot
seanyb505 wrote:3.905" is definitely the .030" piston size. 4.2 cranks have 3.895" stroke.
I realize the 4.2 stroke is 3.895", that's why I said they got it wrong.
I know you can't answer this but, why list the .030" oversize in the stroke box when they give a list of sizes in the sizes box?
Re: KB pistons
Posted: April 10th, 2008, 12:37 pm
by John
Well that' really underwhelming so far....................
I really hope it is a couple errors.
John
Re: KB pistons
Posted: April 10th, 2008, 1:04 pm
by seanyb505
Yeah thats my guess too, like flash said they still have some bugs to work out. I want a picture...and price.
Re: KB pistons
Posted: April 10th, 2008, 1:38 pm
by gradon
So 1.358", eh? I was kinda hoping for the 1.38" comp height and use the money saved on decking for the price difference in the KBs over the Sealed Powers. Hopefully they didn't come up with that number based on a 3.905" stroke. I hope they give actual dish measurements. If they are claiming a 10:1 ratio w/ no machining, then they have a mid-teen dish. The 9:1s would have a mid-20s dish.
Re: KB pistons
Posted: April 10th, 2008, 2:13 pm
by Flash
When they say "Effective Head Volume: 60cc" I wonder if thats with the cc above the piston to the deck also
For an example say the pistons dish is only 20cc but there is 40cc figured into the piston, do, to were it is in the bore............just speculating here.
That might make the compression more accurate..........
I will have to play with the numbers when i get home tonight and see what i comes up with.
Flash
Re: KB pistons
Posted: April 10th, 2008, 2:21 pm
by Flash
just another thought, piston is .023" down in the hole, and with a .043 head gasket.......that make quench at .066........thats not bad and any decking of the block would make it better.............but i was hoping to see Quench in the .050-.055...........
Flash
Re: KB pistons
Posted: April 10th, 2008, 3:56 pm
by seanyb505
gradon wrote:So 1.358", eh? I was kinda hoping for the 1.38" comp height and use the money saved on decking for the price difference in the KBs over the Sealed Powers. Hopefully they didn't come up with that number based on a 3.905" stroke. I hope they give actual dish measurements. If they are claiming a 10:1 ratio w/ no machining, then they have a mid-teen dish. The 9:1s would have a mid-20s dish.
What about the money saved for not having to buy 4.2 rods and reusing the 4.0 rods? And again like Flash said, quench would only be .066 which is still better than stock and doable with 9.1 CR.
Re: KB pistons
Posted: April 10th, 2008, 4:12 pm
by gradon
I would still sell the recon'd 4.2 rods and buy recon'd 4.0 rods instead of using ~125K rods(in my case, but maybe they are fine--I haven't taken the bottom end apart yet). The comp height would be perfect for some 6.150 eagles though. . .
Re: KB pistons
Posted: April 10th, 2008, 5:50 pm
by Flash
gradon wrote:I would still sell the recon'd 4.2 rods and buy recon'd 4.0 rods instead of using ~125K rods(in my case, but maybe they are fine--I haven't taken the bottom end apart yet). The comp height would be perfect for some 6.150 eagles though. . .
Ahhhhh That's it! they would want this piston to fit as many variable as possible, and there you go.....Eagle rod
Flash