Jeep WJ - Need Stroker Build Advice

[PhantomWJ]

I have acquired the following used long block for the build; from oil pan to throttle body, intake manifold to exhaust manifold.

The head is about six months old, I have receipt. The PO experienced slight piston slap when he decided to pull it and replace it with a used engine, it was the wife's Jeep. I pulled the pan, and from what I can see there is no scarring/gouging or damage to the cylinder walls. Though if there was, I think the .020 overbore would take care of it.

Also, I have a 4cwt AMC 258 crank and rods.

I "think" the least expensive route is the 4.6L Poor Man's Stroker.

I plan to reuse, port match and polish, the head of the donor block. Port the throttle body 68mm. New stock camshaft. And try and obtain the rest of the parts on the poor mans stroker list, which leaves nothing left.

Aside from dropping it off at the machine shop, what do i need to do? The obvious will be done, hot tank to clean parts and magnaflux to detect cracks, over bore .020 over, what else. Is everything just as straight forward as replacing old pats wih new parts as would be in an overhaul or engine rebuild?

Pistons? I see these http://www.summitracing.com/parts/uem-3242hc-020 and these http://www.summitracing.com/parts/slp-6 ... /make/jeep and a bazillion others. All of which, look the same to me.

So, which one should I get, im going .020 overbore...

[PhantomWJ]

Here is the other side of the block....that i picked up for $200



Current 4.0L w/195K miles, so I want these Stroke built before mine goes "plunk"

[Cheromaniac]

The UEM-3242HC pistons are 0.007" taler and will give you a correspondingly lower quench height so they're a better choice, but the resultant static CR will also end up being ~0.13:1 higher.
A 68mm TB would be overkill on a poor man's stroker; 62mm would suffice and it matches the intake manifold plenum opening.

[PhantomWJ]

I probably did mean 62mm... and if i didnt, i do now.


Ok, I see the difference of .007", as you stated, in the compression distance based of the information on the site.

Which are the two are a beeter choice? What difference does this make to me at this point? Would all this information matter after I take the engine in to the machine shop and detemine what will actually need to be done to both the head and block? It seem like im putting the cart before the horse, am I?

And, should I wait until then to buy any particular set of piston? after I get some definitive numbers?

Are there other options out there that I dont see? I google the pistons you listed on the site but result is zero, at this time.

BTW, thanks for the response.

[FlyinRyan]

I respectfully disagree with Dinos assessment that a 68mm TB would be overkill. Especially on a 4.6 with headwork.

Come see me for tuning, I've tuned a variety of strokers that have great drivability and make awesome power.

[Cheromaniac]

I respectfully disagree with Dinos assessment that a 68mm TB would be overkill. Especially on a 4.6 with headwork.

I guess it depends on the type of use that you'll be putting the Jeep through. My 4.6 has a ported head and with a 65mm TB, the throttle response is razor sharp and it needs careful modulation of the throttle to prevent jerky progress when crawling in first gear in slow traffic or offroad. I can only imagine that a 68mm TB would make the throttle tip in even more sensitive unless you can tune around it.

[PhantomWJ]

The UEM-3242HC pistons are 0.007" taler and will give you a correspondingly lower quench height so they're a better choice, but the resultant static CR will also end up being ~0.13:1 higher.
A 68mm TB would be overkill on a poor man's stroker; 62mm would suffice and it matches the intake manifold plenum opening.

Its been a while.

I have taken the intake/exhaust manifold off, valve cover and all the miscellaneous junk attached to it.

I also order the KB UEM-3242HC piston I listed above. Next change I get the block and heads are headed to the machine shop.

Next on the list are the other rebuild parts that will be purchased after the machine work and before the rebuild.

[PhantomWJ]

So these came in...

[ruffy01]

It's all happening now

Keep us updated, it's nice to see progress.

[PhantomWJ]

Is pin height the same as compression distance? the same as compression height?

My pistons are spec'd with a Compression Distance of 1.592 in....is this the distance from the center of the pin to the top of the piston edge? Same as piston ring height?

[PhantomWJ]

Does this make sense?

[SilverXJ]

Is pin height the same as compression distance? the same as compression height?

yes

My pistons are spec'd with a Compression Distance of 1.592 in....is this the distance from the center of the pin to the top of the piston edge?

yes

Same as piston ring height?

No.

Does this make sense?

Pretty much except the piston ring height. Might want to check your deck clearance.