Jeep Strokers

Hello I am new to this site!
I've done some looking around here, lots of great info here.
I just want to make sure I understand this stuff.

If I take a 258 crank and rods and your standard 4.0 rebuild kit with pistons (probably speed pro pistons) Deck the block, I would have a 9.5:1 compression stroker motor.

Or I take the 258 crank, the 4.0 rods and lest say a 2229c - Silvolite piston- i wouldn't have to deck the block to zero to get the good quench height

Did i get this right?

Aaron

anyone???

AaronJ wrote:Hello I am new to this site!
I've done some looking around here, lots of great info here.
I just want to make sure I understand this stuff.

If I take a 258 crank and rods and your standard 4.0 rebuild kit with pistons (probably speed pro pistons) Deck the block, I would have a 9.5:1 compression stroker motor.

Or I take the 258 crank, the 4.0 rods and lest say a 2229c - Silvolite piston- i wouldn't have to deck the block to zero to get the good quench height Did i get this right?
NO, the piston would hit the sylinder head ! with the longer 4.0l rod
Aaron

Well,.... mostly.
all 4.0L piston must us the the 258 rod when the 258 crank is installed(stroker)
Even tho you have a longer stroke, the piston sets lower in the bore at TDC.
If you deck the block, you get better quench(Piston is further up the bore) but also raise compression.
More detailed explanation can be had in are FAQ's section under Compression Ratio FAQ here's the link, so you can find it the first time.

viewforum.php?f=27
Lots of good facts in there.

The 2229 is a good piston to have the dish deepened so when you shave you head, the compression won't be to high.

Up until recently thats what you had to do go get a good quench and keep the compression down.( or have a custom piston make $$$$$
KB decide to build a actual Stroker piston for our 4.0L, 258 crank/ Stroker. you can get it in a 9.1 or a 10:1 compression ratio with fair quench, and better quench if you deck the block. A much easier approach to a stroker, but don't expect to by a stroker piston for anything close to the price of a stock 4.0L piston.
O and the KB stroker pistons, they us the longer 4.0L rod that couldn't be used before
Here's a real good thread on the KB stroker piston, and the info we have learned so far.

viewtopic.php?f=5&t=55

Flash

I will likely go with the 258 rods and the 4.0 pistons.
Compression is not a big issue at 6000 feet elevation. I can get away with a little more.

thank you

AaronJ wrote:I will likely go with the 258 rods and the 4.0 pistons.
Compression is not a big issue at 6000 feet elevation. I can get away with a little more.

thank you

YUP, i live at 7000 feet and fill the same.

Probably take 20 or 30 of the deck of the block, and still be ok
Just remember when you take that much off, you will need new push rods.

One more advantage with the KB stroker pistons/long rod rod combo is that the piston skirt or bottom of the piston don't travel below the cylinder bore. (Piston is more stable in the bore........Less chance of a piston knock when cold.)

A simple stroker is a lot cheaper

The KB944 Stroker piston comb addresses some of the pit falls, that has been cause of a few stroker piston failures.........small percentage, but it happens.


Flash

So which pistons would be the best choice for the 258 crank and rod stroker?

Take a hard look at the 2229. You can pick up it's specifications in the FAQ section and then model it on the compression ratio calculator.
John

The h825cp piston has a higher comp distance, for a better quench...1.592"