help with combo (4.6)

Post by **silver03cobra** » February 8th, 2015, 12:46 pm

my set up:
1993 4.0L block
1993 4.0L rods beamed and shot pinned arp bolts
4.2 crank (cw?) Still in yj
comp 239-4 cam kit
0603 head ls1 valves self ported
96-98 intake gasket matched
62mm tb
Doug thorley header
96-98 fuel injection (xj)
24lbs ford injector
what I want to know is what compression ratio and quinch do I want for 87 pump gas.
lookin at 2 different pistons..
ic944
OR
http://www.bulltear.com/catalog/product ... cts_id=242
thoughts???
my jeep is a spring over axle. It gets a lot of axle wrap... hp/tq numbers are not really the goal... just a nice sounding fuel injected yj with some extra cubes.

Post by **Cheromaniac** » February 9th, 2015, 2:17 am

You'll need a tight quench (preferably 0.040"-0.050") and a DCR of 7.5:1 or less to have the best chance of running 87 octane gas.
If you haven't already ordered the cam, I suggest you change it to a 68-231-4 to get a more even spread of torque from 750-5250rpm.
The 4.2 crank in your YJ will be a 4cwt version with a short 54mm nose (same length as 4.0 crank) so it'll drop straight into a stroker without modification.

Post by **silver03cobra** » February 9th, 2015, 8:50 am

Thoughts on pistons??

Post by **Cheromaniac** » February 9th, 2015, 11:10 am

silver03cobra wrote:Thoughts on pistons??

Bulltear.

Post by **silver03cobra** » February 9th, 2015, 6:05 pm

Ok.. so they are reputable?

Post by **Cheromaniac** » February 9th, 2015, 8:45 pm

I've heard a lot of good feedback on the Bulltears so the answer is yes.

Post by **silver03cobra** » February 9th, 2015, 10:18 pm

Oh good.. so my understanding is if I use a 96-98 head use that intake... same with the 99+ is this correct... picking up a 96 grand head and up for 150.00 (valve cover, rockers, intake,injectors *24lbs* ,tb*stock* and wire harnesse)

Post by **Cheromaniac** » February 10th, 2015, 3:25 am

The favored curved runner intake manifold that you want to use is found in '99+ WJs and '00+ TJs/XJs.
From '96-'98 the older log-style manifold that appears on all '91-'99 models (except '99 WJ) was used.

Post by **silver03cobra** » February 11th, 2015, 9:07 am

What's the best way to tune this set up

Post by **Cheromaniac** » February 12th, 2015, 2:20 am

You're going to end up with this recipe and apart from using oversize injectors, you may not need a tune:

4.6L low-buck stroker

Jeep 4.2L 3.895" stroke crank
Jeep 4.0L 6.125" rods
Custom forged +0.030" bore pistons, compression height 1.380", dish volume 23cc
9.6:1 CR
CompCams 68-231-4 206/214 degree camshaft
Ported HO 1.91"/1.50" cylinder head
Mopar/Victor 0.043" head gasket
0.043" quench height
Ford 24lb/hr injectors for '96-'04 engines
264hp @ 4900rpm, 324lbft @ 3500rpm

Post by **Retlaw01XJ** » February 12th, 2015, 8:40 am

Cheromaniac wrote:
silver03cobra wrote:Thoughts on pistons??
Bulltear.

Or KB IC944

Bulltear= $475 Custom made to your specs!
http://www.bulltear.com/catalog/product ... cts_id=242

KB IC944= $402 from RPM Machine. Will require decking of the block for optimum deck height/quench distance/compression ratio
http://www.rpmmachine.com/shop/index.ph ... ail&p=5972

Both use 4032 alloy.

Don't count on either of them being in stock, may take a few weeks to get them.

Post by **silver03cobra** » February 16th, 2015, 6:20 pm

Yea... I can wait... want it all done by end of may...

Post by **silver03cobra** » February 16th, 2015, 6:22 pm

New question! !!! I can get a full wire harnesse from a 96 grand cherokee (Auto). Will this work?

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