Jeep Strokers

So I pulled the head off my 95 ZJ the other day after seeing water squirting out from the side of the engine. I figured it was a head gasket and would have it back on the road pretty quickly...yeah right. Surprisingly the head gasket was was not blown...it was a corroded freeze plug. While I could have fixed this and been back on the road quickly I decided the engine really needed to be cleaned out so why not rebuild it...if I'm going to rebuild it why not stroke it!

When I say it needed to be cleaned out I mean it! The coolant passages in the head gasket were practically sealed shut with rusty scale. This crud is is also in the radiator since I pulled the petcock, shoved a wire brush in there and even with having a hose running into the radiator nothing came out the drain hole!

The oil side of the house was was equally as nasty too. The engine was burning a little oil so that should get fixed in the process too.

Anyway, on with the plans. I'm really leaning towards the 4.2L mini stroker using the 232 crank. I found a reconditioned crank with bearings by Standard Crankshaft (are they any good?) on Rock Auto for about $155 with no core charge listed! The pistons look to be a heck of a lot cheaper than the ones I'd need if I used a 258 crank. I don't need the thing to be a power monster and by keeping the power power down some (vs doing an all-out insane build) the rest of the drivetrain should last longer (in theory at least). I'm going to try and pull the engine in the next week or two, sooner if I get my my garage cleaned up a little more.

I'm not going to save up the money for a "stroker kit" but rather piece things together to stretch the dollar as far as it will go. It's been a little while since I was in the market for engine parts though so I have some homework to do. Besides Summit, Jegs, etc. are there any good places to look at that will have quality parts at a good price? I hate to say it but are the ebay kits worth saving a few bucks over somewhere like Rock Auto? Im obviously not going to order my pistons until I measure the cylinders, but is there any reason not to pick up that crank now? I'm anxious to get started getting started!

So if I do go with the 232 crank based 4.2 mini stroker, the recipe calls for dishing the pistons unless you want to run the premium gas burning 10:1 "wilder" setup. As a workaround, is there any reason I couldn't lower the CR by increasing the combustion chamber volume? My thought is that it would both save money up front (I could do the chamber myself but I have never dished a piston) and in the event I ever have to replace any pistons down the road I could just use of the shelf ones rather than having them machined before use. Am I chasing my tail on this one or would this be a viable option?

Primordial wrote:is there any reason I couldn't lower the CR by increasing the combustion chamber volume?
Am I chasing my tail on this one or would this be a viable option?

Increasing the chamber volume is definitely a viable option. Each 1cc gained will lower the CR by 0.1 so you could do a combination of chamber and piston dish enlargement/polishing.

Cheromaniac wrote:Increasing the chamber volume is definitely a viable option. Each 1cc gained will lower the CR by 0.1 so you could do a combination of chamber and piston dish enlargement/polishing.

Awesome. That might just be the way I go then.

This is the direction that I'm leaning as well. I'm a few steps ahead of you - already have that SC crank from Rock Auto and the 2229 pistons. I'm moving at a snail's pace though... so let us know how it goes, ok?

Just fyi - stopped by the machine shop this morning and they're telling me that there's no way they could possible get 5cc's out of the head.

Knoxes wrote:Just fyi - stopped by the machine shop this morning and they're telling me that there's no way they could possible get 5cc's out of the head.

I used LSx valves. They are dished on the undersides, which adds to the chamber volume vs the flat type stock 4.0 valves.
I deshrouded the valves and opened up the chambers to the head gasket size. I ended up at 62.8cc from 58cc..could of gone further but didn't. This head will not end up going onto my project because I either got tired or lazy and opened up the 6th chamber just passed the gasket, shaved it .1" and its still past the gasket.
Grabbing another head and doing it over lol.

Desertjr wrote:

Knoxes wrote:Just fyi - stopped by the machine shop this morning and they're telling me that there's no way they could possible get 5cc's out of the head.

I used LSx valves. They are dished on the undersides, which adds to the chamber volume vs the flat type stock 4.0 valves.
I deshrouded the valves and opened up the chambers to the head gasket size. I ended up at 62.8cc from 58cc..could of gone further but didn't. This head will not end up going onto my project because I either got tired or lazy and opened up the 6th chamber just passed the gasket, shaved it .1" and its still past the gasket.
Grabbing another head and doing it over lol.

Did you need different seats or guides or do stock replacements work? What about springs locks and retainers? Anything need to be done to the spring pockets?

Primordial wrote:

Desertjr wrote:

Knoxes wrote:Just fyi - stopped by the machine shop this morning and they're telling me that there's no way they could possible get 5cc's out of the head.

I used LSx valves. They are dished on the undersides, which adds to the chamber volume vs the flat type stock 4.0 valves.
I deshrouded the valves and opened up the chambers to the head gasket size. I ended up at 62.8cc from 58cc..could of gone further but didn't. This head will not end up going onto my project because I either got tired or lazy and opened up the 6th chamber just passed the gasket, shaved it .1" and its still past the gasket.
Grabbing another head and doing it over lol.

Did you need different seats or guides or do stock replacements work? What about springs locks and retainers? Anything need to be done to the spring pockets?

I'm running 100% LSx stuff now, springs, locks, retainers ect. Previously was a comp spring recommended by my motor guy simce i was going to. Rn the mopar 229, now I'm back to a stock cam & 1.7 rockers, so LSx springs are more than enough. Mine are installed at 1.7 height and hit coil bind right at .498 I think. My stock cam & 1.7 ratio give me .433" of lift I guess. So I'm more than fine.
Guides are reamed because the lsx valves are slightly bigger...this is nice if you had worn guides already Spring seats are cut to get the correct install height & spring pressure. Locks and retainers are LSx as well.

I am running ls6 valves, which are roughly 1/2 the weight of the normal ls1 or reproduction ls6 stuff. The ls1 stuff is already lighter than stock 4.0 stuff by a few grams each...so my ls6 stuff is less than half the weight of the 4.0 stuff. Should be great for free'er revving, more quite and more reliable motor. Again these valves have a dished underside which adds to chamber volume. Mine were cut down from 2.00" intake to 1.95". Exhaust were 1.500", cut down to 1.44" I think.