Jeep Strokers

Everything started a couple of weekends ago when I pulled the oil pan after hearing the an annoying "tick" get a lot worse! I found about 1/4 of the #4 piston in the bottom of the oil pan. The picture makes it look a lot worse than it ended up being. Amazingly there was no damage to the cylinder wall!


So I decided since I needed to replace the piston, might as well upgrade while we're in there. Plan is to go with a 4.5L Simple Stroker from Dino Saava's 4.0 performance site. I modified it a little bit b/c the 677cp pistons were hard to find.

Specs:

* Jeep 4.2L 3.895" stroke crank
* Jeep 4.2L 5.875" rods
* Sealed Power H802CP standard bore pistons (dished to 18cc's)
* 9.25:1 SCR
* 7.96:1 DCR
* Stock 4.0 camshaft
* Port & Polish cylinder head
* Mopar/Victor 0.043" head gasket
* 0.081" quench height
* stock injectors with stock 49psi FPR for '96 and later engines
* 247hp @ 4900rpm, 300lbft @ 3500rpm (thats what Dino's site says)


I also decided to bore the TB out to 62mm and replace the exhaust with a Magnaflow. Everything has been ordered at this point and should be here by the end of the week. So for now, onto the teardown pics...

Engine out (it was a real PITA to get it out with 5" of lift and the ARB on the front):


Getting ready for the stand, but didn't have the correct bolts


We got it on the stand the following day and torn down.

And the parts start rolling in!
H802CP standard bore pistons, dished to 18cc (Thanks to Oletshot!!!)


OEM throttle body bored to 62mm (Thanks to Oletshot again lol!)


Hot tanked & Sandblasted head


Victor Reinz Gasket Set, Melling oil pump, Piston rings, Cloyes Timing chain, Clevite Main bearings, AMC 258 Rods


Magnaflow 12586 2.5" muffler 5"x11"x22"



The head will go in for the port and polish and I'll have the machine shop install the pistons on the rods Monday. Hopefully we'll have her up and running sometime next week!

Also in but not pictured are the 4.2 crank rod bearings, 4.2 crank, and hi-flow cat.

have you got part numbers for these parts? what kind of cash flow so far? nice pistons too!

Where did you get your crank and rods?

I got the crank off of Ebay. VT.engine was the sellers name. Price was 175 shipped and its the 4wt. short crank so it should bolt right up. I found the rods through and they were $60 + $10 shipping. The rods turned out to be a mix of 707's and 352's but they're weight matched so I guess thats fine.

I had all of this typed up as it was ordered, but my laptop HD crashed, so this is all typed from memory/receipts I had laying in front of me:

So after 3 weeks, the rebuild begins. We spent yesterday afternoon rebuilding the bottom end. According to my calculations, the deck clearance was going to be ~ .0385". We ended up with an average deck clearance of .042 with a variance of + or - .003. That means my SCR will be 9.19:1 & DCR will be 7.61:1 with a .080 quench height (VR head gasket mic'd at .038"). I'm not real thrilled about the .080 quench (would prefer it tighter), but its better than the number in Dino's recipe so we'll see how it works out.

We finished up the installation today! The 4.5L started right up on the first try. The motor acted like it hadn't even been out of the jeep. Both Chris and I were pretty amazed. We'll backtrack a bit to get caught up with the pics.

Installing girdle spacers on bottom end. We gave the oil pan some hammer lovin to clearance it enough to fit.


Measuring deck clearance. 2000 WJ head, 4.2L Rods, H802CP pistons. Deck clearance was .043-.040.


Ported


Painted up


Ready to go in


Re-installation


FINALLY DONE!



I took a video of the startup but it sounds terrible because the fly wheel was rubbing the inspection plate making an awful noise. For a second I thought we were F'ed! Turns out the inspection plate got stepped on and bent, so after straightening it out its working great. We let it idle for a while, then changed the oil. Took it for a 10 minute test drive and everything looks good

Still need to get my exhaust installed, its too quiet right now!

Cool--It's a wild feeling to have it start on the first try.

Did you reuse the old cam and lifters?

What tool did you use to clean the block deck?

Yes we reused the cam and lifters. Silver, I'm not sure what he used to clean it. That was done while I wasn't there.

rradford9 wrote:. Silver, I'm not sure what he used to clean it. That was done while I wasn't there.

It looks like he took a 3M scotchbrite pad on a die grinder to it... eek

Drove the jeep home today and around town tonight. No pinging on the 87 octane gas that was in the tank before the build. Next time I fill up, I'm going to mid-grade just for kicks. I'm seriously thinking about taking it over to a dyno after the engine gets broken in to see what kind of numbers it makes. I'll keep the thread updated with how the stroker is working out. Thanks for everyones help so far

Got the exhaust installed yesterday. LOL @ my gas tank, I really need to get a skid or have one built!

http://www.youtube.com/watch?v=qru3gC4riX4

Swapped out the magnaflow for a Flowmaster 50 delta flow and reinstalled the tail pipe. I like the FM much better than the magnaflow. Also took the WJ to the dyno today. The tech estimated the engine torque at 275 @ 2900 RPM.