After 6 years of slacking, I am building my MONSTER!!!

[RustyJP]

Hey there everyone, My name is Nathan and I am located in Southern CA. After 6 long years of delays, financial indecision and utter confusion, I am finally starting to build my MONSTER! Any and all input you guys have, would be much appreciated. My project vehicle is an '88 Wrangler with 436,000 miles on my tired little 4 cylinder and I have to say that she has served me well. Currently, she has 35" BFG's on a 4" lift. I am completing a gear change from 4.11 to 4.88's in an effort to keep my gearing as close to stock as possible. I would like to run 87 octane fuel and I am trying to find out what ECU is in my project motor to determine a manual or automatic tranny.

My immediate question for everyone is does rod angulation in these motors affect engine life? My jeep is a daily driver and I want to keep her purring, therefore, I was considering going to the long 6.123" 4.0L rod with a forged piston to reduce angulation and piston wall wear. What are your thoughts?

[Muad'Dib]

Science / Math / say yes, it should last longer with a longer rod... However, its my opinion that its not worth the associated cost's to achieve this. There have been no real world reports saying one way or the other.

If your on a tight budget go short rod.

If your wallet is feeling heavy build a long rod.

[Flash]

Your thread title indicates,(MONSTER) this stroker will not be a mild on. if your going "wild" i would most defiantly go with the long rod.
If you going mild(which would be a big HP and torque improvement over the 4 syl) Then the short rod would be fine.

I like the long rod just because it keep more piston inside the bore at BDC Your wallet will still have to be the final decision.

I would thing, the stroker would be Happy with the 4.11 and 35"............................If you haven't started on the gears, STOP and put that $$$$$ into the stroker project. I thing my advice is a little bit to late thew

[RustyJP]

Hey Flash...Thans for the head's up and the recommendations, but I am actually doing the Ford 8.8 upgrade with disc brakes and I have already done 90% of the work. My thoughts are that the extra gearing will help take advanyage of the newfound torque in the stroker and should help add to the MPG. The cam should help take advantage of these changes.

[Flash]

Welcome aboard Nathan !!!!!

For got to say that before.

[RustyJP]

OK…So I have finished taking all of my initial measurements to begin the machine work on my block and I am running into a few snags! Here is a listing of the parts that I am using and the measurements that are creating my confusion.

’89 4.0L block (53005535)(9.45085 deck height)
’79 .010 under 12 CW Crankshaft (3214273)
258 rods although I do not remember the casting number off hand (5.7837 center-to-center)
Sealed Power 677CP pistons (1.581 pin height and 13.8 to 14.4 cc dish)
95’ HO Head (7120)(combustion chambers are 55.8 to 58.2cc)

My concern is that according to Jeep my block height should be approximately, 9.429 to 9.435 on a non-HO block, but my measurements lean more towards an HO block spec which would fall into the 9.450 to 9.456 range. This in turn leaves me .0485 in the hole! I do NOT want to remove .040 from the block as it will drive my compression through the roof! My other concern is removing that much material from the block, as I do not know if the tops of the blocks came in different thicknesses depending on the casting numbers. Has anyone else run into this issue? Supposedly, Jeep recommends a .0215 deck clearance, but that would create a .053 to.064 quench depending on the gasket, which I think would be to high. One of my thoughts was using an unfinished rod from an aftermarket source to create my own custom center-to-center. Or another was to order a semi custom piston to adjust pin height and dish to reach my desired compression. If I go that route, does anyone know of a source on the west coast or even CA?

I do NOT want to take my combustion chambers beyond 60cc’s as I will be using slightly oversized intake and exhaust valves (1.95 int and 1.53 exh). My goal is to achieve a .045 to .050 quench and I will be using a .032 head gasket if I can find one…lol. If not I will be using the VR .041 gasket instead which only increases my quench issue. Please help this newbie find a solution or am I just over thinking things here? Thanks.

[lafrad]

Well, i took a pre-emptive step to getting the piston closer to the right deck height... I offset ground the crank (slightly) to give it more stroke.

Technically, a 0.040" bearing can add a full 0.020" to the radius of the stroke (come up 0.020" more in the bore), a 0.060" bearing even more. the stroke gets pushed out the full 0.040" or 0.060".

with the specs that we are running in on these motors, there is ZERO chance that grinding under these small amounts would cause any premature failure in the system...

In my case I brought the piston up to just under 0.010 deck height without having to deck the perfectly flat block... it should give the 0.050" quench...

talk to your crank grinder before they attack the crank if this is an option for you...

[yuppiexj]

I like this idea...instead of decking the block and dealing with valvetrain geometry issues. get better quench and a bit more stroke too. sounds like a win win to me.

[gradon]

I'm not sure if those renix blocks have a shorter deck than the HOs--pretty sure it's a misprint/wrong info found in the mopar books. It'd be interesting if true, cause the renix would have to have different piston pin height, rod size, and/or crank stroke if it is indeed .020" shorter as written(cause that .021" deck clearance would be close to 0, compression would be higher, etc). My brother plans to use a renix block in his build with the 6.150" eagles, so I guess we'd better buy a nice caliper and measure so we know what block to start working on. Anyone else find a renix block to be shorter than the HOs?