KB pistons

[gradon]

I filled out the web contact on Monday and haven't heard back. My project is basically on standby at this point. My brother comes back from the GULF on Monday for 2-3 weeks and I wanted him to be a part of the install, but I don't know if that will be possible.

[dwg86]

Just got a call from kb. They said the pistons are done and will be ready to be shipped by the end of next week. He said they wiil be able to be purchased by anyone who sells kb pistons(summit, jegs, or your machine shop). Still don't know the price. He said the comp ratios are figured using a .052 head gasket, 60cc combustion chamber and pistons .010 below the deck.

[gradon]

That's good news! My brother will be back Monday(from the GULF) and will be leaving 2.5 weeks after that, so I will probably have less than a week window b/t when I have the pistons in hand, when the machine shop finishes the block work, and when it gets put together and installed before he has to go back. It's coming down to the wire--very exciting.

[gradon]

So here's Summit's email to me about the uem-kb944020-6:

"Hello. I can place the order for you. They are 478.69 for the set. I will need your name, address, phone number, credit card number and expiration date to process the order for you. Thanks"

I have no idea if that price includes the rings and shipping costs, but @ that price we are in Ross and Diamond piston territory. If you go to Summit's site, you find v8 sets of KB forged pistons from $330-$450(~$40-55 a piston for most apps). I asked what that price includes and am waiting for the response(probably on Monday). Hopefully they miscalculated based on a set of eight, vamos a ver.

[Flash]

Yeah i was figuring them to be $50-$60 a slug which would be about $100 less then what they are asking

I wonder what some of the other outlet will be selling them for?

It is nice to have a ######.......Kinda


Flash.

[jffffl]

Has anyone ordered their new K & B forged stroker pistons yet?
If so, what is their ETA, or do you have them.

[gradon]

I was sent a 2nd email verifying that $478 is indeed what summit is charging for them, but they didn't answer my ? if that included rings and shipping, so I'm still wondering. I also notified Flatlanderracing and Jegs that KB made new pistons for us Jeep Strokerheads and to let me know how much they'd be. Bob B. @ KB told me he couldn't sell direct due to the agreements made with the above distributors, but asked me to keep him updated. I asked him who they were gonna ship them out to today, so I'm waiting that response too. I'll pony up the money to get them since I've been planning the build with them, but you best believe I'll contact every KB supplier that'll get them until I find the best price.

[Flash]

Do you know what style of rings they when with? standard or metric?

Flash

[gradon]

On KB's site, they are standard:
Ring Packs
2-5/64
1-3/16
So forgive me for my ignorance, but are rings piston model specific, or are any 3.895"(I'm going .020" over) 5/64" and 3/16" rings gonna work(I will opt for the molys)? I would get rings made by KB-Silvolite, of course.

[dwg86]

I am a little disapointed in the comp distance and price of the KB pistons. The pistons are still .030 below the deck. The 9.1 is figured in with .010 below the deck and a .052 head gasket. That is .062 quench. Still have to deck the block .020 or you would still have .082 quench. So for about $100.00 more you could have a set made with better quench and whatever compression you want. Now I guess you could use a .043 gasket and mill .010 off the block and have a better quench, but will pushrod length be an issue? Just my 2 cents

[Flash]

On KB's site, they are standard:
Ring Packs
2-5/64
1-3/16
So forgive me for my ignorance, but are rings piston model specific, or are any 3.895"(I'm going .020" over) 5/64" and 3/16" rings gonna work(I will opt for the molys)? I would get rings made by KB-Silvolite, of course.

any standard ring(Not "mm" but "inch" measurement ) that is ment for a 4.0L, bored .020 over will work just fine...........
I would call then and ask that question, before taking my advice


Flash

[Flash]

I am a little disapointed in the comp distance and price of the KB pistons. The pistons are still .030 below the deck. The 9.1 is figured in with .010 below the deck and a .052 head gasket. That is .062 quench. Still have to deck the block .020 or you would still have .082 quench. So for about $100.00 more you could have a set made with better quench and whatever compression you want. Now I guess you could use a .043 gasket and mill .010 off the block and have a better quench, but will pushrod length be an issue? Just my 2 cents

I don't understand were you got the .082 Quench, but i agree, that they should have tightened up the quench......at least another .010".

According to my figure the .043 gasket would put the quench in at .053. And that is way better then a basic stroker that would give you .080+ Quench with a lot more then 9.1 compression.

They did this because, there need to be a buffer zone,.........so they don't have to deal with some one using a heavily shaved block and, not knowing that, thats what they have, and smash all six piston at 4,000 rpm, into the head(as he/she didn't understand that the piston sticking out of the block by .025 was a problem).
Customer thinking that he bought some real p.o.s. for piston, and proceed to give KB hell for it.
That same "over shaved" block with these piston, wont hit the head,......just end up with more compression than he/she may have bargained for.
YEAH I don't like it either,


Flash

[dwg86]

rod length+comp dist.+1/2 stroke... 6.123+1.353+1.948=9.424. Stock deck height 9.453 so 9.453-9.424=.029. On kb's web site they used .052 as a gasket thickness so... .029+.052=.081. Ok I don't know where I got .082 either.
Using a .043 gasket would be .029+.043=.062 quench. Is my math right? It's early and I don't have a calculator

[gradon]

I'm gonna have the block decked .025", which'll leave the piston .0045" below the deck. I wanted a comp height of ~1.37", which would give some room to have the block decked and a lil tolerance room.

[Flash]

rod length+comp dist.+1/2 stroke... 6.123+1.353+1.948=9.424. Stock deck height 9.453 so 9.453-9.424=.029. On kb's web site they used .052 as a gasket thickness so... .029+.052=.081. Ok I don't know where I got .082 either.
Using a .043 gasket would be .029+.043=.062 quench. Is my math right? It's early and I don't have a calculator

I'm sure they are, I WAS CHEATING
You said that The 9.1 is figured in with .010 below the deck and a .052 head gasket.
I simple figure .010" (Piston below deck a TDC) and+043 for the head gasket= .053' Quench.

If those numbers turn out to be correct, from KB, the only advantage would be a lower compression ratio......Quench isn't going to be much better.......................

Has any one actually measured the crank center line to deck height?????????

This is why I Question the factory spec to be right.
The stock chy 340 piston compression ratio(1968-72) is 10.5:1 and when you buy a replacement piston, it is also called a 10.5:1 piston............My exact compression ratio came out to be 9.4:1 .......Why? Because the blue printed spec for the heads combustion chamber was 64CC.................Every single head that came from the factory with 71-72 cc combustion chambers
If you wanted a "blue print spec eng, you had to shave something like .030 or .040" of the head............and then you had to do a percentage of the head shave to the intake shave or the head wouldn't seal to the intake............NOW YOU HAVE A 10.5:1 ENG

I think KB need to give us a quench spec with that 9.1:1

Has any one done a compression ratio check on a stock 4.0L eng..........I should have done it to my spare4.0L eng when i had the head off for porting. I cc the head, i know what the head gasket thickness is..........just never cc the piston to deck at TDC.


Flash.