4.6L "Poor Mans" Questions

[go4lo]

I've been researching strokers for about a year now and I would like to move forward with building either Dino's 4.6L "Poor Mans." The block I'm using is a '99 4.0L with 173K and 0630 head. The motor will be going in my MJ project that will be running all of the wiring and fuel system from the '99 XJ.

If I go with the "Poor Man" option and use the 677cp .030 overbore pistons will I need to have them dished any further than the stock 17.5cc?
Will the block or head need to be milled any?
Seems as though the Mopar Perf. HG is hard to find, would this one work: FEL-PRO Part # 530SD {PermaTorque Severe Duty™}?

Thanks

[AIbandit]

I've been researching strokers for about a year now and I would like to move forward with building either Dino's 4.6L "Poor Mans." The block I'm using is a '99 4.0L with 173K and 0630 head.
Are you sure? 99's came with the 0331
If I go with the "Poor Man" option and use the 677cp .030 overbore pistons will I need to have them dished any further than the stock 17.5cc?
http://www.jeepstrokers.com/calculator This is located at the top of the forums. If your CR gets to high they need to be dished more.
Will the block or head need to be milled any?
If the head is warped yes, Block decking is not required.
Seems as though the Mopar Perf. HG is hard to find, would this one work: FEL-PRO Part # 530SD {PermaTorque Severe Duty™}?
Make sure you use that calculator and enter the hg's compressed height.

Thanks

Everything you asked about changes your compression ratio.

[go4lo]

I am 110% sure the head is 0630, it's stamped on the top plus the '99 XJ's did not come with the 0331 heads, those came in the 2000-2001 XJs with distributorless ingnition. I still have a distributor.

I was under the assumption that if I went with the "Poor Man's" recipe below my CR would be ~9.25:1?

Jeep 4.2L 3.895" stroke crank
Jeep 4.2L 5.875" rods
Sealed Power 677CP +0.020" bore pistons
9.25:1 CR
Stock 4.0 HO camshaft
Ported HO 1.91"/1.50" cylinder head
Mopar/Victor 0.043" head gasket
0.088" quench height
Ford 24lb/hr injectors with stock 39psi FPR for '87-'95 engines, stock injectors with stock 49psi FPR for '96 and later engines
248hp @ 4900rpm, 303lbft @ 3500rpm

[AIbandit]

I am 110% sure the head is 0630, it's stamped on the top plus the '99 XJ's did not come with the 0331 heads, those came in the 2000-2001 XJs with distributorless ingnition. I still have a distributor.
:thumbup: yeah the Zj did sorry
I was under the assumption that if I went with the "Poor Man's" recipe below my CR would be ~9.25:1?

Jeep 4.2L 3.895" stroke crank
Jeep 4.2L 5.875" rods
Sealed Power 677CP +0.020" bore pistons
9.25:1 CR
Stock 4.0 HO camshaft
Ported HO 1.91"/1.50" cylinder head
Mopar/Victor 0.043" head gasket
0.088" quench height
Ford 24lb/hr injectors with stock 39psi FPR for '87-'95 engines, stock injectors with stock 49psi FPR for '96 and later engines
248hp @ 4900rpm, 303lbft @ 3500rpm

Yes but if you mill your it then you're increasing your CR by decreaseing your quench.
If you decrease your deck you increase your CR.
Notice the 0.043 head gasket. That's it's compressed height these very, either increaseing or decreasing your quench.

[Cheromaniac]

If I go with the "Poor Man" option and use the 677cp .030 overbore pistons will I need to have them dished any further than the stock 17.5cc?

Not unless you've had the head milled. My head wasn't and I merely sanded my piston dishes smooth, so even with the 0.043" Victor-Reinz HG (Mopar is the same), the SCR came in at only 9.25:1 and I can run 87 octane.

Will the block or head need to be milled any?

Not the block but if the head is slightly warped, you'll need to have it milled flat.

Seems as though the Mopar Perf. HG is hard to find

The Mopar part no. is 4529242. It's made by Victor-Reinz and the V-R part no. is 5713.

[SilverXJ]

Try these number for the .044" HG:

MLS .044" compressed head gaskets:
Mopar Performance P4529242
Jeep 53010587AA
Victor Reinz 54249S (available from Carquest using 54249, no 'S')

[go4lo]

Anyone know why the 677CPs are specified for the 87-95 blocks and the H802CPs are for the 96+ Blocks? Obviously the pin heights and dish volumes are different between the 2.

Any reason why I can't use the 677CPs in my '99 XJ block?

Sealed Power (Sterling) hypereutectic H802CP/H825CP----1.592" 15.1cc
Sealed Power (Sterling) cast aluminium 677P/677CP----1.585" 17.5cc

[gradon]

You can use whichever piston, just make sure you get the correct rings(802s are metric, 825s and 677s are standard).

[Cheromaniac]

Anyone know why the 677CPs are specified for the 87-95 blocks and the H802CPs are for the 96+ Blocks? Obviously the pin heights and dish volumes are different between the 2.

Any reason why I can't use the 677CPs in my '99 XJ block?

You can as long as you get matching rings. The H825CP and H802CP are identical except that the 802's use metric size rings instead of imperial. Just use the correct rings for the pistons and you're good to go. BTW, my stroker is built on a '00 block.

[go4lo]

IF I decided to use the KB944 pistons with my existing 4.0L rods what would be pros and cons of this versus using 258 rods and 677cps?

With the KB944s does the block deck or head surface need to be milled?

Dino's recipe for 4.7L "medium buck" states that the block deck needs to be milled .020?

Just trying to explore all options.

[thecrew2999]

Jeep 4.2L 3.895" stroke crank
Jeep 4.2L 5.875" rods
Sealed Power 677CP +0.020" bore pistons
9.25:1 CR
Stock 4.0 HO camshaft
Ported HO 1.91"/1.50" cylinder head
Mopar/Victor 0.043" head gasket
0.088" quench height
Ford 24lb/hr injectors with stock 39psi FPR for '87-'95 engines, stock injectors with stock 49psi FPR for '96 and later engines
248hp @ 4900rpm, 303lbft @ 3500rpm

never use a thicker head gasket to lower CR on a engine, if you had 9.7 CR and use a thicker head gasket to lower the CR to 9.25 you might get more ping then you would with the 9.7 CR..
the proper way to lower CR would be threw pistons get them dished more to get the lower CR not using the head gasket..

also having the pistons dished could increase HP because they redirect the flame during combustion...

i dont get why so many of these stroker builds use thicker head gaskets to get the quench any better, i mean if your getting custom pistons made why not get them dished more anyways?

you also relise the higher you go in quench the more chances the piston will rock when it gets to the top of travel

im not real sure what the jeeps like the best but judging from these being low rev engines and such id assume a .035 quench height would be good since its good for most quench engines anyways and with that height it keeps the pistons cooler and reduces hot spots which can lead to DET and can create more HP...

[go4lo]

What do you guys think about this combo? I've playing around with the calculator and I "think" I'm using it correctly.

4.7L +.060
Bore: 3.935"
Stroke: 3.895"
Combustion Chamber: 58cc
Deck Clearance: .0215"
Gasket Thickness: .044"
Gasket Bore: 4"
Dome/Dish/Valve: 21.7cc (KB944s)
Connecting Rod Length: 6.123" (stock 4.0L)
Cam Intake Dur: 253.3* (Stock 4.0L)
Cam Lobe Separation Ang: 114.3* (stock 4.0L)
Advance or Retard: 0*(Non Renix 4.0L cam)

SCR: 9.34:1
DCR: 7.71:1
Quench: 0.0655

[gradon]

That combo shouldn't ping at all and might get away with 87 octane.

[woodjeep]

Are you sure about your deck clearance. I was under the impression that everyone uses the 258 crank AND rods because if you used the stock 4.0 rods (longer) with the 258 crank you would need to get custom made pistons, because if you used the 4.0 rods it would push the standard pistons well past the zero deck. Unless those kb944's are custom pistons

[AIbandit]

What do you guys think about this combo? I've playing around with the calculator and I "think" I'm using it correctly.

4.7L +.060
Bore: 3.935"
Stroke: 3.895"
Combustion Chamber: 58cc
Deck Clearance: .0215"
Gasket Thickness: .044"
Gasket Bore: 4"
Dome/Dish/Valve: 21.7cc (KB944s)
Connecting Rod Length: 6.123" (stock 4.0L)
Cam Intake Dur: 253.3* (Stock 4.0L)
Cam Lobe Separation Ang: 114.3* (stock 4.0L)
Advance or Retard: 0*(Non Renix 4.0L cam)

SCR: 9.34:1
DCR: 7.71:1
Quench: 0.0655

Are you sure about your deck clearance. I was under the impression that everyone uses the 258 crank AND rods because if you used the stock 4.0 rods (longer) with the 258 crank you would need to get custom made pistons, because if you used the 4.0 rods it would push the standard pistons well past the zero deck. Unless those kb944's are custom pistons