XJ 4.7 Build
Posted: April 28th, 2009, 2:33 pm
So I thought it was about time I posted my build on here, I've been researching and dreaming of building a stroker for quite some time, and finally have the opportunity. Back in October I took my Jeep down to Slade, Kentucky for some serious wheeling. After an 8 hour drive down, my 4.0 decided it had enough, and broke a rod, punching a hole in the side of the block at 1am on the side of the parkway. After a very expensive trip in a uhaul towing the jeep back to Michigan, I decided I finally had the reason I needed to build a stroker. I have some experience rebuilding engines, I've already done two 4.0's, and I had done a lot of research on strokers. First I'll list my vehicle setup, then the build recipe.
'95 2 Door XJ
4.5" Rustys Lift
32" BFG M/T's
Manual transmission, stock 3.07 axle gears (for now).
I was planning on doing a fairly budget minded build, but at the same time, I only really want to do this once, so I've spent a little extra on some things. Here's the parts list so far.
4.0 Renix short block - $50
Complete 258 - $75
Comp Cams 68-232-4 Cam Set (lifters, springs, timing set) - $300 Ebay
'00 Intake - $50
Centerforce DF Clutch - $50
Rusty's Intake (already installed)
Cat back exhaust (already installed)
DIY Port and Polish of existing 4.0 head
Victor Reinz head gasket
Speed Pro hypereutectic pistons dished to 20cc's
Dodge 318 Magnum Injectors
I took the block to the machine shop and had them test, clean and bore it, they had to go .060 over to remove all the scoring, so I'm now looking at 4.66 Liters. The ground the 258 crank .010 under, reconditioned the 258 rods, and hung the pistons. When I got home, I realized that the pistons were not the ones I had asked for, but rather sealed power 525P's. Bummer, I really didn't want cast, and the combustion height is also .010 lower, so I have to have more decked off the block. When assembled it measured about .046 below the deck, much lower than I was hoping. I'm still debating whether to stick with these pistons, or try the hypers. I'm aiming for somewhere in the .045 range for my quench height, as I feel this is the most important factor in reducing detonation. I'm planning on dishing the pistons to keep my CR down. On the calculator, here's the numbers I come up with:
4.66 liters
SCR 9.79:1
DCR 8.46:1
Quench .0455
This is with a deck clearance of .0025 and a piston dish volume of 21cc's (using the cast piston).
I have a few concerns:
1. Decking approximately .045 from the block makes me think I'll need new pushrods so my lifters don't have too much preload.
2. Not 100% sure that my Comp springs will work on the 4.0 head yet, haven't really checked, but have read that there aren't many springs out there that will fit without modification.
Any opinions/Input is welcome.
'95 2 Door XJ
4.5" Rustys Lift
32" BFG M/T's
Manual transmission, stock 3.07 axle gears (for now).
I was planning on doing a fairly budget minded build, but at the same time, I only really want to do this once, so I've spent a little extra on some things. Here's the parts list so far.
4.0 Renix short block - $50
Complete 258 - $75
Comp Cams 68-232-4 Cam Set (lifters, springs, timing set) - $300 Ebay
'00 Intake - $50
Centerforce DF Clutch - $50
Rusty's Intake (already installed)
Cat back exhaust (already installed)
DIY Port and Polish of existing 4.0 head
Victor Reinz head gasket
Speed Pro hypereutectic pistons dished to 20cc's
Dodge 318 Magnum Injectors
I took the block to the machine shop and had them test, clean and bore it, they had to go .060 over to remove all the scoring, so I'm now looking at 4.66 Liters. The ground the 258 crank .010 under, reconditioned the 258 rods, and hung the pistons. When I got home, I realized that the pistons were not the ones I had asked for, but rather sealed power 525P's. Bummer, I really didn't want cast, and the combustion height is also .010 lower, so I have to have more decked off the block. When assembled it measured about .046 below the deck, much lower than I was hoping. I'm still debating whether to stick with these pistons, or try the hypers. I'm aiming for somewhere in the .045 range for my quench height, as I feel this is the most important factor in reducing detonation. I'm planning on dishing the pistons to keep my CR down. On the calculator, here's the numbers I come up with:
4.66 liters
SCR 9.79:1
DCR 8.46:1
Quench .0455
This is with a deck clearance of .0025 and a piston dish volume of 21cc's (using the cast piston).
I have a few concerns:
1. Decking approximately .045 from the block makes me think I'll need new pushrods so my lifters don't have too much preload.
2. Not 100% sure that my Comp springs will work on the 4.0 head yet, haven't really checked, but have read that there aren't many springs out there that will fit without modification.
Any opinions/Input is welcome.
