Build Plan: Dino's 4.7, a few ?'s

[Ruffestneckaround]

Jeep is a '98 XJ Sport 4 door with a 5 speed. Dana 44 Rubi rear end, 4.10s. Currently on worn out 32's, going to 33's after I finish this build.

Already Have:
Comp 68-232-4 Cam
Mopar Springs
Cloyes Dual Roller Timing Set

Hopefully Those parts will work with my Stroker Plan

Straight off off Dino's Site:

Jeep 4.2L 3.895" stroke crank
Jeep 4.0L 6.125" rods
Keith-Black Silvolite UEM-IC944 +0.060" bore pistons (What dish size do I need for these pistons if I mill the block 0.020"?)
CompCams 68-231-4 206/214 degree camshaft (Mine will obviously be the 68-232-4)
CNC ported HO 1.91"/1.50" cylinder head (Maybe in the future, skip it for now)
Mill block deck 0.020"
Mopar/Victor 0.043" head gasket
0.051" quench height
Flometrics F&B 68mm billet TB
Accel 26lb/hr injectors with stock 49psi FPR for '96 and later engines.
271hp @ 4900rpm, 333lbft @ 3500rpm

Will this engine run on 90 Octane? (I get that for the same price as 87 at most places in Canada)

My Head was already milled 0.005", milling the block 0.020", will I need new pushrods?
Exactly what machining do I need? I went to a shop and they had a "V8 rebuild package" with a price of 1800, I realize a stright 6 is a bit less work, so does that sound right?

I have some questions as to what is required for Machine work, and what are "Extras", I had a look at the FAQ's and I'm thinking:

Block:
Hot Tanks
Bore and hone cylinders
Line hone bearing bores
Press cam bearings

Crank:
Planning on buying a rebuilt that has been shortened and comes with a matched set of rod bearings, is this a good idea?
Chamfered oiling holes

Rods:
Reuse stock rods, shoudl I just get them shot peened and checked for striaghtness?

Head:
No work since it was recently done for the cam swap.

What are the rotential problems with having this engine run good once the rotating assembly is built and I get it in the Jeep?

What would I need to worry about as far as "Tuning" goes? Just plug in the new injectors and go?

Thank you for any help and suggestions.

[Cheromaniac]

Jeep is a '98 XJ Sport 4 door with a 5 speed. Dana 44 Rubi rear end, 4.10s. Currently on worn out 32's, going to 33's after I finish this build.

Already Have:
Comp 68-232-4 Cam Good choice.
Mopar Springs
Cloyes Dual Roller Timing Set

Hopefully Those parts will work with my Stroker Plan

Straight off off Dino's Site:

Jeep 4.2L 3.895" stroke crank
Jeep 4.0L 6.125" rods
Keith-Black Silvolite UEM-IC944 +0.060" bore pistons (What dish size do I need for these pistons if I mill the block 0.020"?) They're 21cc so you don't need to add volume. Just polish the dishes and remove rough spots.
CompCams 68-231-4 206/214 degree camshaft (Mine will obviously be the 68-232-4)
CNC ported HO 1.91"/1.50" cylinder head (Maybe in the future, skip it for now) Port it yourself.
Mill block deck 0.020"
Mopar/Victor 0.043" head gasket
0.051" quench height
Flometrics F&B 68mm billet TB
Accel 26lb/hr injectors with stock 49psi FPR for '96 and later engines.
271hp @ 4900rpm, 333lbft @ 3500rpm

Will this engine run on 90 Octane? (I get that for the same price as 87 at most places in Canada) Yes

My Head was already milled 0.005", milling the block 0.020", will I need new pushrods? Yes, they'll need to be 0.025" shorter i.e. 9.600".
Exactly what machining do I need? I went to a shop and they had a "V8 rebuild package" with a price of 1800, I realize a straight 6 is a bit less work, so does that sound right? Sounds a lot to me.

I have some questions as to what is required for Machine work, and what are "Extras", I had a look at the FAQ's and I'm thinking:

Block:
Hot Tanks Yes.
Bore and hone cylinders Yes.
Line hone bearing bores Shouldn't be necessary.
Press cam bearings Yes.

Crank:
Planning on buying a rebuilt that has been shortened and comes with a matched set of rod bearings, is this a good idea?
Chamfered oiling holes Yes to both.

Rods:
Reuse stock rods, shoudl I just get them shot peened and checked for straightness? Yes.

Head:
No work since it was recently done for the cam swap. Just polish the combustion chambers and remove rough spots.

What are the potential problems with having this engine run good once the rotating assembly is built and I get it in the Jeep? Use GM EOS and Rotella 15W-40 for the cam break-in and next 3000 miles.

What would I need to worry about as far as "Tuning" goes? Just plug in the new injectors and go? Pretty much but it would be a good idea to add a MAP adjuster in case you need to fine tune the fuelling.

Thank you for any help and suggestions.

[Ruffestneckaround]

So all of the blocks are the same height and I can plan on using those pistons and decking my block 0.020"?
Do I need to factor in what was taken from the head somehow?

About the Crank, if I get one with a matched set of bearings, the bearings will fit my block and rods for sure? Or should I get one with no bearings and let the machine shop size them? If I do decide to get it align honed, will that change what main bearings are required?

I think I get it, I just want to make sure I've considered everything here.

Thanks again.

[4.whoa]

If you get bearings with it,make sure they are for the year block you're using(the tangs are different - don't remember when they changed)

The head being milled only effects comp it wont change how the pistons fit unless they are domed( I don't think anyone has those)

[Cheromaniac]

So all of the blocks are the same height and I can plan on using those pistons and decking my block 0.020"? Yes. Deck height is 9.450"-9.456" on all 4.0 blocks but you'll still need to check deck clearance with a dial indicator.
Do I need to factor in what was taken from the head somehow? Only in so far as you'll need shorter pushrods to correct the lifter preload.

About the Crank, if I get one with a matched set of bearings, the bearings will fit my block and rods for sure? Depends. Rod bearings are the same for all years but main bearings are different in 4.0 HO blocks (locating tang in center) from 4.0 Renix/258 blocks (locating tang offset).
Or should I get one with no bearings and let the machine shop size them? That might be the better option. Suppliers of 258 cranks will usually also supply 258 bearings and the 258 mains won't fit in the 4.0 HO block.
If I do decide to get it align honed, will that change what main bearings are required? Possibly but align boring the mains shouldn't be necessary unless block was severely overheated and has warped.

[Ruffestneckaround]

So I should be good if I specify that the 258 crank will be going in a '98 4.0 block?

Also, with the deck heights varying by 0.005", what final measurement should I be looking for after decking the block 0.020"? I'm probably wording this wrong, but I'll do my worst...What I mean is that if I deck the block 0.020", that means I could have up to 0.005" difference in what's left depending on my block. Does that matter? Is there a measurement I should be worried about instead? Instead of saying deck 0.020" off the block should I be asking a shop to leave x amount after decking the block? Does that make sense?

Thanks once again.

[4.whoa]

Don't fixate on decking.020 unless you know absolutely all the history of the block,just deck it enough to get the deck height (or quench) you want. It could be .020 or .005 or who knows what if someone else did some work to it before being all these 4.0's have been around for a while now,you never really know..................measure twice, cut once

[Ruffestneckaround]

Thats kind of what I'm asking, what is the measurement of what I should be left with? I'm the second owner and I doubt this engine's been worked on in that regard.

[unlimitedrubicon]

Just tell your machinist to zero-deck the block and they will measure how far down the pistons are and cut the block enough that the pistons are level with the block, or close to it. Unfortunately there can be some variation in rod length leaving one or more piston slightly lower.

[Ruffestneckaround]

Is that what I'm trying to achieve by decking the block 0.020"? Is that the aim with this "recipe"?

[4.whoa]

You are decking the block to get desired quench( the distance between the top of the piston and head - head gasket +or - how much below or above deck). The best way to do it is have the shop mock it up,measure it, and machine as needed. generally its better to have a tighter quench,but if you don't compensate by further dishing the pistons or chamber the compression goes up a little, wich may be good or bad depending what you're after.

[unlimitedrubicon]

Yes, by zero decking the block you will be able to get a better (tighter) quench which is ideal in most cases.