Jeep Strokers

My set-up's in my sig. Runs on 95 octane RON without pinging even in 115*F heat. Would I change anything? Yes, two things:

1. Use the '96+ stock cam with 1.7 roller rockers (more torque at lower revs, as if I don't have enough already!)
2. Use longer 4.0 rods with custom hypereutectic pistons for zero deck clearance, keep CR the same at 9.25:1.

I have pretty much a simple setup. 4.0 bored .040 over, head planed .010 to fix warpage, stock pistons, 258 crank and rods. According to the calculator, I've got 9.7 CR, a horrible .100 quench, etc. I've got the compcams 68-231 cam with stock springs. Not real pretty but it works OK. It's carbureted with a quadrajet and an offy dual-port. I run 93 octane and it doesn't ping if I retard the timing enough! I live easily under 1000' sea level.

I would change:
- My attitude next time and not be so %&$#@ cheap!!!

- I'd dish my pistons some and deck the block for better quench for less pinging.

- Probably spend the extra cash and get the mopar spring set.

- look into getting a cam with even better off-idle power - that's where I do all my driving. Although I'm hoping the q-jet and dual-port manifold will help with the off-idle response.

eliv1 wrote:

tigerShark wrote: i wouldnt really call this a "stroker". youve got the standard stroke for your 258 block. cool steup though. how much overbore is that?

it is exacly a stroker, just 258 block. since it is a 258 crank, and 4.0L standard pistons (0.125" overbore) giving the displacment of 4.5L.

Well guys, this is exactly a stroker. Check your AMC I-6 history.

The 258 is a "stroker" by production. The 258 is a "stroked" 232 having the same bore but the stroke being increased from 3.50" in the 232 to 3.895 in the 258. These engines were built simultaneously and offered as the base and optional engines. The 232's stroke is longer than the 242/4.0 by .090" but is uses the same rod length so you could also say that a 4.0 is a bored and de-stroked 232.

Ill agree that boring a 258 is not usually advisable but he worked with what he had available.

Is an engine not high enough performance if the block casting came with a fuel pump opening ?
What about the rumored mexican 4.5's... A 258 crank, 4.0 bore, and a fuel pump on the side of the motor ?

Why the debate here ? I thought that was what the yahoogroup was for.

kris.

My sig. says it all. The engine doesn't ping on 89 octane at sea level.
Would I change anything now? No. I'm very happy with my stroker.
Could I have built my stroker differently? Yes. I could have used the '00 cam and timing set that came with the donor short block and added 1.7 YT roller rockers instead of 1.6's.

Well guys, this is exactly a stroker. Check your AMC I-6 history.

The 258 is a "stroker" by production. The 258 is a "stroked" 232 having the same bore but the stroke being increased from 3.50" in the 232 to 3.895 in the 258. These engines were built simultaneously and offered as the base and optional engines. The 232's stroke is longer than the 242/4.0 by .090" but is uses the same rod length so you could also say that a 4.0 is a bored and de-stroked 232.

Ill agree that boring a 258 is not usually advisable but he worked with what he had available.

Is an engine not high enough performance if the block casting came with a fuel pump opening ?
What about the rumored mexican 4.5's... A 258 crank, 4.0 bore, and a fuel pump on the side of the motor ?

Why the debate here ? I thought that was what the yahoogroup was for.

kris.

I still disagree, not that it really matters. If his block had left the factory as a 232, then yes, it would be a stroker, but it didn't. It was stamped as a 258, boring it to 3.875" does not make it a stroker. It's an overbored 258, splitting hairs, maybe, but the way I read it, that's the definition. If he took a 232 block, put that 258 crank in there, bored it to accept 4.0 slugs, then he would have the exact same engine he has now, but it would be a stroker.

I'm definitely NOT saying he is unwelcome. I hope evil1 doesn't feel that way.

http://www.colorado4x4.org/vbb/showpost ... tcount=117

First, like the site should have found it before the build.
93 4.0 original in my yj
258 crank turned 0.10 mains and throughs
.030 over bore
mopar stage one cam
matching springs
24lb injectors
surface head
valve job
plastaguage berrings
factory oil pump
I have a 01 up intake not installed yet.

Should have
decked the block

Absolutly love the power off road low end tourque is awsome. I still get 16mpg average with 33x12.5-15 4.11 gears and manual trans. It has lifted the lf tire in a turningtake off.

any dyno numbers on any of these builds??

4wt 258 crank
4.2 rods
Silvolite 2229 Pistons dished 30cc .030 over
Isky 133125/26 cam .453"/.465" lift
Crower camsaver lifters
24# injectors from Lincoln Mk VIII
Reused stock springs
Deck milled .045
Head milled .015 (total milled amount makes .060 rocker arm shims convinient to use)
.052 Headgasket
.0565 quench
8.98:1 Compression ratio
Bright Chrysler Hemi Orange Paint! (Good for 75 hp, at least)

Its not quite broken in yet so I havent fully explored the limits, but it is a very smooth running engine. First tank is premium, no pinging; I will lower the grade in subsequent fill-ups. No dyno numbers. If you want them you can pay for them.

I would change:
Not buy pistons that were already dished out, buy the same pistons new and have them dished to 26 to get 9.33 CR and take advantage of smaller quench.

I probly will change:
Port and polish spare head laying in my bedroom. Im assuming since I havent taken it above 3500 I will have valve float with reused stock springs, so Ill probly install whichever springs Isky recommends. Try to locate .043" Head gasket to get CR to 9.13. Small improvement, but improvment nonetheless.

Well, I did get to do it differently.

Started out with stock bore and pistons, 4.2 crank and rods, and a crane cams CRN-753905 (for a lower "dynamic CR"). Just not the torque I had hoped for, lots of piston noise.

v2.0- 4.2 crank, 4.0 rods, kb944 pistons .030 over, and a mopar P4529228ab "RV" cam. This is the ticket. Now I'm worried about u-joints and axles instead of ping and piston slap.

Bottom line- $480 for pistons only sounds like a lot of money. They're really the way to go.

Heck, you think the KB944s + 4.0L rods develop that much torque than a 4.2 rod setup? KB told me that when I was asking querstions before I purchased. From what I read the longer rod will give you more torque, but I didn't think it would be that more noticable.

Also, I probably asked you this already, but what piston clearance did you install them at?