Rock Crawler Build

[BryGuy]

I've been reading about strokers for quite awhile now and my brain feels like it's going to explode. I'm rebuilding an '88 Jeep Comanche and I'm ditching pretty much everything but the frame/unibody and the interior.

I live in Newfounland, Canada (at sea level) and my Comanche will be used as a part-time daily driver and primarily for rockcrawling..... Heavy duty axels and 37"+ tires...etc, so lower RPM's and High Torque is the name of the game.

The most important aspect of the build for me (other than more power) is reliability. I don't want to break the bank or push the envelope at the cost of reliability.

With the above in mind I'm leaning towards the "4.6L Low-buck, low CR rockcrawler" build

I've recently purchased a '96 Cherokee to be used as a donor vehicle for my build. So i have the 4.0L H.O block which should be casting #53020569 which is supposed to be a desired Casting. Based on the above build I know I need the following:

Jeep 4.2L 3.895" stroke crank (preferably from 1972-80 Casting #3214723 with 12 counterweights, 66lb, 64mm nose)
Jeep 4.2L 5.875" rods (Part #3180444)
Silvolite UEM-2229 +0.030" bore pistons
Increase piston dish volume to 30cc
CompCams 68-115-4 192/200 degree camshaft
Ported HO 1.91"/1.50" cylinder head
Mill block deck 0.035"
Mopar/Victor 0.043" head gasket
0.058" quench height
Accel 24lb/hr injectors with stock 49psi FPR for '96 and later engines

Which should get me a 8.75:1 CR with a 0.058" quench height, producing 240hp @ 4700rpm, 315lbft @ 3000rpm.

I've read through a lot of members builds, of which many are similar in design based on one of the 1/2 dozen recipes. It's after the basic remedy that I'm utterly confused as there's tons of other parts that seem to differ in everyone's builds and I have no idea what else is needed to complete my build.

1. Do I use my Donor 4.0L block for all the other parts, or are there other parts that should be bought new?
2. If some other new parts are needed are they simply new OEM parts, or do they need to be upgraded?
3. Is there a link or write-up that might point me in the right direction?

Any/all feedback and advice is welcome. Thanks in advance for taking it easy on an ill informed noob.

[doc65]

Lets see:

New bearing that match the grind on the crank, but the year of the block
Timing chain, your call, anything from an OEM replacement up thru a Cloyes or Rollmaster double roller or anywhere in between
With that much decking, and depending on what you do with the head to get it flat; you may need non stock length pushrods
Depending on which crank you get you may need a spacer to go between the balancer & the Bolt/washer
Depending on the lift of the cam & the age of the springs as it relates to seat preasure you may need new valve springs
Oil pump, again your call OEM up thru melling or equivalent high volume(the HV does put more preasure on the distributor gear, cam gear & timing chain set)
And of course gaskets to match the year of the block & head

There are many more options and ultimately its your call how carried away you get.

[Missourian]

(EXCERPTS - Missourian) I've been reading about STROKERS for quite awhile now and my brain feels like it's going to explode.

I've read through a lot of members builds, of which many are similar in design based on one of the 1/2 dozen recipes. It's after the basic remedy that I'm utterly confused as there's tons of other parts that seem to differ in everyone's builds and I have no idea what else is needed to complete my build.

1. Do I use my Donor 4.0L block for all the other parts, or are there other parts that should be bought new?
2. If some other new parts are needed are they simply new OEM parts, or do they need to be upgraded?
3. Is there a link or write-up that might point me in the right direction?

Any/all feedback and advice is welcome. Thanks in advance for taking it easy on an ill informed noob.

1. Yes and perhaps a HV Oil Pump, Double Roller Timing Chain and other high performance options.
2. Not really needed on a "Low Buck" build.
3. That I will leave to more knowledgeable folks here.


Personally, I am building the "Modified - Poor Man's" STROKER using the 4.0L rods, forged Keith Black pistons, a new 4.2L Crank and used FORD /Bosch 24# injectors. My effort is very similar to yours and it calculates to a 25% power increase.

[BryGuy]

Thanks guys.

Missourian: I was searching around for parts and info, and I stumbled upon a post of yours on Metrocrawlers.com that stated:

I want the baseline improvement of a stroker over stock. I do not want rocker arm problems that will cost me anther $600 to fix with roller rockers. I want 87 octane no ping performance and I do not want to have to have to reprogram anything for great performance out of an inline 6 cylinder. I want the reliability that the 4.0L engine is promised but did not deliver for me in my 4.0L in a 4.6L stroker.

That statement represents EXACTLY what I'm looking for out of a Stroker build. Thanks for your PM as well. So based on the info you guys provided and on the additional reading I did, I'm shifting towards a modified Poor Man's receipt:

Jeep 4.2L 3.895" stroke crank - Scat Crankshaft Part #9-4.2L-3895
Jeep 4.0L rods - Reusing
Keith Black UEM-IC944-020 pistons
Increase piston dish volume to 30cc
Jeep 4.0L camshaft - Reusing
Accel 24lb/hr injectors with stock 49psi FPR for '96 and later engines - Part Numbers??????
New OEM new bearings, seals and gasket, hydraulic lifters
High Volume Oil Pump
Double Roller Timing Chain
Ported HO 1.91"/1.50" cylinder head
Mill block deck - To be determined
Quench height - To be determined

[Missourian]

Accel 24lb/hr injectors with stock 49psi FPR for '96 and later engines - Part Numbers??????

For me, that would be a Bosch 0 280 155 849 going into a 2000 Jeep Wrangler.

Injectors are application specific and there is a pretty good FAQ on injectors and a few threads on this site specific to application that should provide the information that you need.

[IH 392]

CompCams 68-115-4 192/200 degree camshaft
Which should get me a 8.75:1 CR with a 0.058" quench height, producing 240hp @ 4700rpm, 315lbft @ 3000rpm.

I never used that cam in any of my simulations but there are cams that will offer better power in more usable RPM ranges, personally I would consider that cam unacceptable for a crawler.

[Cheromaniac]

CompCams 68-115-4 192/200 degree camshaft

I never used that cam in any of my simulations but there are cams that will offer better power in more usable RPM ranges, personally I would consider that cam unacceptable for a crawler.

That cam has similar performance characteristics to the stock '96+ cam so it's a very good low/medium rpm torque cam. Therefore if you already have the aforementioned stock cam, keep it and save your pennies.

[IH 392]

That cam has similar performance characteristics to the stock '96+ cam so it's a very good low/medium rpm torque cam. Therefore if you already have the aforementioned stock cam, keep it and save your pennies.

Must be enough difference, my simulations with the stock '96+ cam (@ 4* advance) show a peak HP of 231 @ 4500rpm and the torque peak @ 2000 rpm of 336 ftlb, but that's where the graph/chart starts too, torque may very well peak more at a lower rpm?

So I agree, if your OE '96 cam is in good shape run it and save some $.

[BryGuy]

Thanks guys. In post #4 I revised my list to:

Jeep 4.2L 3.895" stroke crank - Scat Crankshaft Part #9-4.2L-3895
Jeep 4.0L rods - Reusing
Keith Black UEM-IC944-020 pistons
Increase piston dish volume to 30cc
Jeep 4.0L camshaft - Reusing
Accel 24lb/hr injectors with stock 49psi FPR for '96 and later engines - Part Numbers??????
New OEM new bearings, seals and gasket, hydraulic lifters
High Volume Oil Pump
Double Roller Timing Chain
Ported HO 1.91"/1.50" cylinder head
Mill block deck - To be determined
Quench height - To be determined

I've also just located what appears to be a great shop in my area to: Constantines Engines & performance. I just fired them off a preliminary email to get the ball rolling.

[doc65]

I've spoken to KB about opening that piston up, and you can't go that far, 30cc's, the desk is too thin. if you cut the D shaped depression out to full circle hence no quench area, and go down about .022 which is their max recommendation the they say you will wind up at 26-27 cc, they also said in a followup email that keeping the D another but going .022 deeper would gain about 3 cc and wind up at 24cc dish, I like that number, and if I didn't already have a set of short rods & new 677's ready to go off to Oleshot for dishing to 24-25 I would do it, but based on KB's statements you cant get to 30 CC's

[BryGuy]

I've spoken to KB about opening that piston up, and you can't go that far, 30cc's, the desk is too thin. if you cut the D shaped depression out to full circle hence no quench area, and go down about .022 which is their max recommendation the they say you will wind up at 26-27 cc, they also said in a followup email that keeping the D another but going .022 deeper would gain about 3 cc and wind up at 24cc dish, I like that number, and if I didn't already have a set of short rods & new 677's ready to go off to Oleshot for dishing to 24-25 I would do it, but based on KB's statements you cant get to 30 CC's

Thanks doc65.

I actually forgot to remove the piston dish line from the build. Here's the revised build:

Jeep 4.2L 3.895" stroke crank - Scat Crankshaft Part #9-4.2L-3895
Jeep 4.0L rods - Reusing
Keith Black UEM-IC944-020 pistons
Jeep 4.0L camshaft - Reusing
Accel 24lb/hr injectors with stock 49psi FPR for '96 and later engines - Part Numbers??????
New OEM new bearings, seals and gasket, hydraulic lifters
High Volume Oil Pump
Double Roller Timing Chain
Ported HO 1.91"/1.50" cylinder head
Mill block deck - To be determined
Quench height - To be determined