Jeep Strokers

One more thing. Is there any true advantage to running the long rod combo? Everyone seems to recommend it and I've been reading here and there, but I have yet to see the reason for it in a NA application.

Taken from StrokerEngine.com

"Basically we want a Rod to Stroke ratio of 1.55:1 or higher to reduce side loading force on the thrust side of the piston to minimize friction. This becomes more critical above 5500rpm. The factory Chevy 400 had really short 5.565 rods and a 3.750 stroke having a 1.48:1 ratio. This motor works fine to 5500rpm, then you can experience a hard or harsh feeling for the motor, not vibration but kind of like it. By putting 5.700 rods in this motor it well happily buzz over 6000RPM with a 1.52:1 ratio.

Next we want a piston with better than 1.250 compression height, the distance from wrist pin centerline to piston top.
The greater the compression height meaning the longer the piston skirt, which in addition to transferring heat, keeps the piston vertical in the cylinders.
When we increase stroke length the piston is push up above the top of the block, so we move the wrist pin further up towards the rings, pulling the piston top back below the top of the block. Additionally we often install longer rods with the longer stroke to keep a good rod to stroke ratio, which also requires moving the pin up piston."

crusher242 wrote:One more thing. Is there any true advantage to running the long rod combo? Everyone seems to recommend it and I've been reading here and there, but I have yet to see the reason for it in a NA application.

Im of the opinion that it doesnt matter in our engines. Go either way. I built a short rod stroker and i doubt i would see a difference between what i built and the same build but with long rods and Forged Pistons. If anything mine is quieter.

crusher242 wrote:One more thing. Is there any true advantage to running the long rod combo? Everyone seems to recommend it and I've been reading here and there, but I have yet to see the reason for it in a NA application.

From the stroker page of my site:

The 4.0L connecting rod/IC944 piston combination offers 155g less reciprocating mass than the 4.2L rod/677P piston combination (1275g v 1430g), thereby giving this engine a potentially higher rpm capability than the traditional "poor man's" stroker.

I do remember that now. Thanks Dino. I'll still stick with my short rod combo though. I'm running the 54mm snout 4 weight crank, so I can make up for weight savings there. Does anyone have the answer to the question last page about if I will need new pushrods if i deck the block? I only ask as I just got free new replacement rods.

crusher242 wrote:Does anyone have the answer to the question last page about if I will need new pushrods if i deck the block? I only ask as I just got free new replacement rods.

Depends on how much you deck the block. If the lifter preload is too high you could just shim the rockers.

Thanks again Dino. You do us all a great service. So today I went to check over some of my parts and saw something I overlooked. I think I found a big issue. When I got the 4.2 rods, the guy never put the bearing caps back on their rods. I'm going to try to match them up if possible. So...am I gonna have a problem with the rods if I can't match them up? I was dreading something like this.

look on the side of the rod and the cap. there is a stamp (ie: #1) to indicate each pairing

My '01 had some sort of laser-etched lettering on each rod.... CD , CE, etc.
Or compare the mating surfaces of each rod and cap. Look for stains or other unique characteristics that should be on both rod and cap.
Or look at the machine marks on the sides of each....they should match across the parting line.
If all else fails, assemble and measure each one. Good luck.

Cheromaniac wrote:

crusher242 wrote:Does anyone have the answer to the question last page about if I will need new pushrods if i deck the block? I only ask as I just got free new replacement rods.

Depends on how much you deck the block. If the lifter preload is too high you could just shim the rockers.

Spec is 0.020" to 0.060" preload on the lifter. So there's some room there for milling the block or head.
Also take into consideration the valve job..... it will sink the valve a little in the head, raising the valve stem height. But the shop should grind the valve tips to keep the height in spec.

Thanks for the replies. This site really does help out. Now another question... 677p vs. 677ap. Any differance, or just a different PN?

I'm still looking into injectors as thats really the only thing I can't seem to figure out. From what I understand, my 99' TJ uses a 66% duty cycle. So a 240 hp stroker will require about a 27lb injector at 49 psi (25lb at 43.5 psi). I'm being told on JF that 0280156048 from bosch would be the ticket. Any thoughts?

27 will be too larger. Search on here as I posted a few options that will work better.

Any other info on those injectors? That number doesn't bring up much.

SilverXJ wrote:27 will be too larger. Search on here as I posted a few options that will work better.

97-04 4.0L's are 23.2 lbs/hr @ 49psi according to a few sources around here. With 27 lbs in a stroker, I would think the PCM is going to adjust the pulse width in closed loop to compensate for injectors that are "too large". Open loop could be a different story. No?

And everyone wonders why I'm stressing over injectors Anyhow, anyone think this is a good deal? http://www.ebay.com/itm/Sealed-Power-Je ... 2c6232053e They're the 677ap. I know these arn't coated, but am I just asking for trouble with them dished to 28cc?