Jeep Strokers

I have a TON of questions. First off, is a stroker reliable as a daily driver? The car is not mine, it is my dads and Im doing all the work.. he is a real estate agent and drives all over and I need it to be very reliable. I dont want to build Frankenstein.. already built a weedeater like that.

Our 2002 JGC 4.0 broke a piston skirt about a month ago. I'll post a pic soon. The plan was, and still may be, to just rebuild the 4.0. But I read about the strokers and now here I am. I have read all of the recipes but I still need help.

I need the jeep to run without any pinging or detonation on 87 octane gas as it is a daily driver. That would mean I need the compression ratio down a little and I want to run the stock valve springs/locks/retainers so I probably should run the stock camshaft as well. I plan to run 677p pistons, the 4.2L crank + rods and use the stock head gasket. Im not sure how to get the CR down and keep the correct quench, that I need help with.



Also guys if you honestly dont think the stroker would be a good idea for a reliable daily driver let me know... I dont want to open a can of worms and invite mr. murphy to come in and do what he does best. If the stroker isnt a good idea and I just decide to rebuild the 4.0, is there anything I can do while Im in there to get more out of it and still run 87 pump gas?

Can the stock 42re auto tranny handle this additional power?

Thanks all.. Glad I found this site. Sorry for playing 21 questions.

Could I do a mixture of the "low cr rock crawler" and the "poor mans stroker"?

By mixture I mean using Silvolite UEM-2229 +0.030" bore pistons dished to x amount of CC's and the stock camshaft? Just trying to figure out how to get the CR down so I can run 87 pump gas 100% with no issues... Ill wait for input from someone who actually knows what their talking about. lol

from what i've been reading, if you can get to dcr of 8to 1 or lower ,you should have no trouble . you can dish pistons deeper (but 677's already there) you can run .043 gasket, you can deck the block . polish head . the stock cam is my choice and came to it by good advise .you dont have to punch it out to .030 unless it needs it . you can go square and save some for later . i went with h802's just for a closer to stock pin height (less decking,if any) . i should have looked into stock .020 overs . with the 4.2l rods even better quench than the 802's . but i dont know what the dish is on the stockers and i just jumped at the 802's . i couldnt find the 677's coated . read up on faq's look for quench info . apparently , you can run a bit of compression more than you'd think and get better results (power,mileage) with an ideal quench . look at the recipe list on junker to stroker and see what the dcr's are and play with things as to your budget . machining is the real killer . up here in boston area it's expensive as hell . so now i just gave you a micro piece of info . all i got lol . others here will have waaaaay more to give just dig in . and yes they are as good as stock if done well . luck

go to the compression calculator at top of site and work with it . pistons have a limit to how much they can be dished . all you can do is ask . mine will safely go to 20cc for sure . but i got that from looking at builds of others . i'm going square 3.895 x 3.895 . my piston pin height gives me .038 deck clearance . piston dish is 15.1 cc rods are 4.2l at 5.875" gasket is vh .043 . cam is stock 98 so i get 9.32 scr or there abouts and 7.73 dcr or there abouts . see? find your deck clearance with your pistons ( 677's) and calculate from there . i got under 8-1 with no decking or dishing just polish head to 60 cc's . this gives me quench of .081 . not the best but i think i'm done machining and want to build . i could deck it closer and dish deeper and stay pretty close to the same dcr and have a monster but i'm poor . lol . so it's up to what you want .

Decided to just rebuild the 4.0 for the reliability.

You can build a stroker that is just as reliable.

This is where I am... this was my concern too as I need reliability. I really want 150k+ miles out of this motor.


So I am going with the mild (Modified "Poor Mans") STROKER.

Keith Black Pistons
HESCO 4.2L Crank
Stock 4.0L Rods
BOSCH 0 280 155 849 24# fuel injectors
Stock cam & lifters
Stock head (and hardware)
High Volume Oil Pump
9:0 CR (adjusting the gasket /deck height to accomplish)

go with smaller gasket and polish the head .out to 60cc

KTMrida4life wrote:Decided to just rebuild the 4.0 for the reliability.

You can build a 4.6 stroker that's just as reliable by following the KISS principle. I came up with the modified "poor man's" recipe 'cause the only non-stock internal engine parts in that engine are the 258 crank and Keith Black IC944 pistons. With everything else remaining stock, the same reliability should be maintained and if you port the head, you'll also have a nice slug of power.

My 0331 head is cracked in two locations rendering it a to be replaced item. I have contacted Alabama Cylinder Head about their reinforced replacement head and then I spoke with their sister performance company that offers the same head that is ported and polished with 2.02" intake 1.94" exhaust valves.

Would going with the larger valved and port /polish reinforced head be the way to go or is it just the porting and polishing?

The reliability issues really arent with internal engine parts. I meant more along the lines of possible detonation/pinging, too much fuel (running rich), bad gas mileage, insufficient cooling system, etc etc... and not to mention its overkill.

Is there anything I can do to the 4.0 to get a little more power while Im in there? Ive already ordered parts... .030" over pistons, stock camshaft.. I think Im gonna port the head. Anything else thats easy or not really?

read the compression article in faq's . many times mileage stays same or goes up!! the smaller quench seems to negate the problems associated with higher compression .

Our 4.7 gets about the same as my lil bro's 4 banger, so I'd say our gas mileage went UP.
Still running great at 1k miles. Even if you are doing the low buck build, get the better parts and a GREAT machinist.
It will do so much for your piece of mind knowing you are running with quality parts with quality work.