Jeep Strokers

The engine is coming out of my MJ sometime in the next few weeks so that the engine bay can be repainted, so its time to get started on the stroker. Right now i've got two major questions...which build and what parts. As for the builds, I'm looking at these two:


basically the 4.6 low CR rockcrawler build (234hp @ 4500rpm, 311lbft @ 3300rpm), with a stock head gasket and pistons dished to 28cc instead of 30cc.

or


basically the 4.6L Low-buck stroker build (262hp @ 4800rpm, 325lbft @ 3500rpm)

The extra HP of the second build would be nice, but the truck will eventually be my DD...how much would the larger compression ratio affect reliability and would i be able to run mid-grade gas at sea level?

What i'm going to need the most help with is getting all the parts together. Here's my list so far...
'92 4.0L engine currently in vehicle (I also have a '91 4.0L that been sitting on an engine stand in storage for the better part of 6 months)
Jeep 4.2L crank
Jeep 4.2L rods
Pistons: Silvolite UEM-2229 .030 bore dished to ??
Camshaft: TBD
Injectors: Ford 24#
FPR: Hesco HES9195FR

Miscellaneous parts
99+ intake
header: TBD (probably borla 17020)
exhaust: borla 2.5" in and out
throttle body bored to 62mm

Input on camshafts and rods would be appreciated. Besides what's above, what else am i going to need to get my hands on? Will i need a rebuild kit, is a HV oil pump (like the Melling M167HVS) necessary, etc....i've gone thru the faqs several times and most of the build threads, and its mostly the little details i'm unclear on.

Thanks in advance

Just a heads up, both of those images are exactly the same (both are http://www.knwd.net/images/MJ/stroker1.jpg)

HV oil pump isn't necessary. Most people prefer it for the idea of getting "more oil" into the oil galleries of the engine. Some people feel that it pumps TOO much oil and will evacuate most of the oil to the valve cover and starve the lower end of the engine for splash lubrication purposes. I personally chose a standard flow pump. Stock jeep engines with stock oil pumps run hundreds of thousands of miles with out issues (given proper maintenance). Unless you plan on running loose tolerances on everything to squeeze out every extra HP possible, then HV pump isn't necessary. However, from what i have come across, it is usually listed cheaper then the STD flow.

Cam selection is going to depend on your usage for the truck. There are lots of great daily driver cams, but its how you want to truck to perform thats going to decide the best cam. Meaning if you are gonna race honda civic's and get high RPM usage, pick a cam with high RPM range characteristics. If you are mudding/rock crawling/4 wheeling, then a low end torque cam will be for you. Best thing to do there is check out the project threads with completed engines and see what you think of people cam choices and what they are using their truck for.

Thanks for the heads up on the images...i looked over the thread i don't know how many times before i posted it and still missed it.

Won't be rockcrawling anytime soon after the new paint, but performance at low RPMs is more important. Just went over the cam thread in the faq section...way too much thinking at this hour, so it's back to the project threads.

How is the new axle coming along? After reading thru your thread a couple weeks back, i immediately stepped up my search for a reasonably priced D44 to replace my D35.

Boilermaker wrote:Won't be rockcrawling anytime soon after the new paint, but performance at low RPMs is more important. Just went over the cam thread in the faq section...way too much thinking at this hour, so it's back to the project threads..

Yes, the cam section is a lot to absorb. Keep reading over it, google for information on jeep camshafts you should come across other projects and hopefully they will describe why they chose the cam that they did.

Its too early to tell for which compression ratio you should go with. Cam selection is vital before deciding what compression ratio to aim for, as the cam will affect your dynamic compression ratio. What altitude are you at? You definitly want to run 87 octane or do you prefer 93? You need to figure these things out to guide your cam selection. Again, there are plenty of DD cams out there. I was shooting for better low end, and i wanted "factory" mopar parts. Fortunatly i was able to land a discontinued camshaft (thanks to some help from this forum). I liked the lower end of the 30AB cam, and i like the design of the wider lobes that cover more of the face of the lifter. If you aren't looking to build a wild stroker, then possibly the stock cam could be good for you. I think the cam grind changed in 96 to a dual pattern, but not sure what year the cam was retained with a cam plate. Just some stuff to think about

Boilermaker wrote:How is the new axle coming along? After reading thru your thread a couple weeks back, i immediately stepped up my search for a reasonably priced D44 to replace my D35.

Glad to see other people planning ahead based on my experiences! Its a work in progress. I got back late last night from NC after 5 days to visit family, so not much progress has been made since my last post. I'll wait to update my thread when it gets closer to being completed. I did get the gear pattern and backlash checked tonight, and i'm ready to assembly the friction discs into the carrier and get my proper rolling torque for the pinion. I sand blasted and painted the backing plates for the rotors. I'm still waiting on a few parts to arrive from NAPA to make a complete parking brake assembly. I should have it to the point of getting the D35 out this weekend and getting my pinion angle set and weld the perches on. Again, i'll update and hopefully have some new pics to go along with it then.

I chose the Isky 133125/26 cam. It has a dual pattern with more lift and duration on the exhaust side for better torque. The exhaust ports are smaller than the intake ports on our heads. It performs similarly to the stock cam, but with more oomph. Wakes up around 2700-2800, so you do have to wind it a little.

My machine shop said I shouldnt need a HV oil pump as it never sees offroad, and wouldnt be spending a lot of time just idling around.

For rebuild kit I went to Falcon on ebay. If you check my project thread I mentioned it and I think theres a phone number in there too. Brian was a grat guy to deal with, helpful, and you can buy a la carte it's not just some prepackaged box in shrink wrap like other places.

The Silvos are thick pistons. Mine were machined to 30cc. Ah, bananas

Your thread is what sold me on the Silvolites, from what i read previous it seemed that 26cc was kind of the safe outer limit for dishing. Somebody correct me if i'm wrong on this, from messing with the calculator spreadsheet, the advantage of the larger dish basically a lower CR. Does lower CR = more reliability, ability to run less octane w/o pinging, but less HP?

btw, thanks for the heads up on the rebuild kit...being able to pick and choose parts for the rebuild will be very helpful. i remember the posts on the first page about falcon, and pics of the parts later on in the thread. I'm heading to the machine shop after work today or tomorrow morning to work out some details.

Boilermaker wrote:Your thread is what sold me on the Silvolites, from what i read previous it seemed that 26cc was kind of the safe outer limit for dishing. Somebody correct me if i'm wrong on this, from messing with the calculator spreadsheet, the advantage of the larger dish basically a lower CR. Does lower CR = more reliability, ability to run less octane w/o pinging, but less HP?

btw, thanks for the heads up on the rebuild kit...being able to pick and choose parts for the rebuild will be very helpful. i remember the posts on the first page about falcon, and pics of the parts later on in the thread. I'm heading to the machine shop after work today or tomorrow morning to work out some details.

You have half the equation, now go to the FAQ section and read up about Quench................then you will have 2 valuable tool to make the best compression for the octane you choose............

Heres the link to make it easer for ya. viewforum.php?f=27 Then go to the bottom one called "Compression Ratio FAQ"
Theres lots of grate stuff in there as well!!!!!!!

Flash

I too have used Falcon and picked the parts I wanted. For the most part their prices were lower than anywhere else and they had pretty much everything I needed. Although they don't have the new Victor head gasket, but I have a MP waiting for me at the dealer and I am pretty sure it is the same thing. BTW, Car Quest sells Victor gaskets and that is where I purchased the previous head gasket.

I really wish there was some fast and hard rule about quench vs dcr vs octane.

one quick question about head gaskets while i take in all the info in the compression faq and play with the CR calculator. Should i just place an order for this gasket at summit and try local dealerships while its on back order?
What is the difference, if any between the Victor and Mopar Performance head gasket and where's a good place to get one if the MP gasket becomes difficult to find?

I've been using stock thickness for gasket size in the various calculators because i was under the impression that the better ones were tough to come by.

A little bump for some progress and some new questions. The engine is coming out of the truck wednesday and being dropped off at the machine shop. Right now, these are the parts i'm looking to use:
Piston: Keith Black/KB Pistons Silvolite 2229030-6 .030 over dished 25cc
Camshaft: Isky 133125/26 Isky 142.00
Crankshaft: Stock 258 46lb, 4wt, 2" snout, casting #3727
Rods: 258 rods 707 casting
Gasket: Mopar Performance P4529242
Injectors: Bosch 24#
Lifters: Crower "Cam saver" 66031X3-12
Valve Springs: Mopar Performance 5.9 springs #5249464
Oil Pump: Melling 167hvs
Fuel Pressure Regulator: Hesco HES9195FR

Which when i plug it into the calculator gives me this:


I haven't seen anybody dish this KB piston an odd number (i've seen 26, 28 and 30cc's)...so is a 25cc dish possible?

If anybody see's any mistake in the number's i put into the calculator (or better tweaks to help me fix a problem i'm not seeing), please let me know. Given the above i hope to be able to run on no more than 89 octane gas @ sea level. The isky cam is listed as special order on their site, i plan on calling them tomorrow and finding out exactly what that means.

The gasket you listed is now .037 MLS. You may want to use this number to see how it effects your DCR. Also, after you punch in the new gasket size, see how far away you are from an even 8 DCR. Thats what i'd shoot for with .050 or lower quench. In other words you may not need to dish the pistons as much as 25cc's

I would set deck clearance at .0" and go with the thinner head gasket to get a good quench.

.037 quench may be a bit on the low side. I'd be slightly concerned about piston/head slap at higher RPMS

He isn't going to be spinning high RPMs so I don't think that will be a problem

The gasket you listed is now .037 MLS. You may want to use this number to see how it effects your DCR. Also, after you punch in the new gasket size, see how far away you are from an even 8 DCR. Thats what i'd shoot for with .050 or lower quench. In other words you may not need to dish the pistons as much as 25cc's

Playing with the numbers, with the .037 thick gasket and .011 deck clearance=.048 quench. Change the piston dish to 24cc and the cam to the comp cam and now i'm at 9.33:1 SCR with a DCR of exactly 8 (i couldn't get the numbers to work out as well with the isky cam). With the isky cam potentially unavailable the comp cam is now an option...comparing the comp cam specs for street performance in the faq, it seems to fit my needs. should i be concerned about the SCR going up to 9.33:1?

.037 quench may be a bit on the low side. I'd be slightly concerned about piston/head slap at higher RPMS

He isn't going to be spinning high RPMs so I don't think that will be a problem

I'm not going to take the MJ to the dragstrip...but with a stroker i'll probably have my foot in it more. Maybe i'd be tempted to blow some ricer off the line, but that would be about it.