gzweber said:
Hi I am building my second stroker motor, but unlike the last time where I went for economy and reliability. This time I am going for all out top-of-the-line performance. So...In doing so I am having custom forged pistons made and I need to know the specs (most importantly the volume) on both the pre 91 and post 91 4.0 cylinder head. Thanks for any help!!!
The combustion chamber volume of the stock 4.0 heads (HO and non-HO) is quoted by the Mopar Engines book as being between 55.2-58.2cc. I've ported two 4.0 heads (one junkyard '95 head for my old 4.0, the other's the original '92 head that's now on my stroker) and cc'd both of them. One was 56.5cc and the other was 57.0cc so that gives you some idea.
You don't have to buy forged pistons to get a 9.5:1 CR on your stroker. If you copy mine but shave 0.010" from the block surface (nothing from the head), the CR will come to 9.42:1.
My stroker performs great but it still hasn't reached its full potential yet. I know exactly how to get there though and here's what's needed:
1. 10W-30 synthetic oil instead of 20W-50 dino oil (Mobil 1 going in next week).
2. Ishihara-Johnson crank scraper. I have one in a box ready to go in.
3. Roller rockers. If Quadratec will give me the Yella Terra YT6627A's for a discounted price (retail price is $440) if we get a group buy going, I'll buy them.
4. '99+ intake manifold. They're hard to find here and expensive (minimum $180). If I can get one cheap, I'll be very happy.
At the moment, my stroker's putting out an estimated 260-265hp. With all these extra tricks, I could get closer to 280hp or 1.0hp/ci (my stroker's displacement is 4563cc or 278.5ci).
___________________________________
1992 XJ Laredo 4-dr -
4.6L I6 HO Stroker - 177k miles -
AX15,
NP231,
D35c,
D30
Estimated
261hp/322lbft, 1/8 mile =
[email protected], 0-60 =
5.9secs
Websites - Jeep 4.0 Performance,
4.6L Stroker Build-Up,
Dino's Jeep Tricks