Building a New Stroker

[MarineJRM]

I was told that the #1 and the #6 piston were off about .015 from eachother and they decided to take .033 off across the board to make it true and flat.

[SilverXJ]

On mine it was a difference of .005 front to rear.

[MarineJRM]

Havent updated this in a while. The engine is in and running well on 87 octane and is still a TON more powerful than the 4.0 that was in the XJ. I am going to list my parts and specs for anyone looking to build a 4.6 stroker to run on regular unleaded.

4.0 Block bored .020 over and decked to 0.003
4.2 4 balance weight crank
4.2 707 cast rods
Ford EV6 #24 Injectors
68-232-4 Comp Cam
Comp Cams High Energy hydraulic lifters
Comp Cams Magnum push rods 9.6 inch
0630 Head ported and polished with complete valve job
Intake Ported and Polished
APN Header
Mopar Performance Head Gasket
Mopar Performance (Cloyes) True Double Roller Timing Chain
2000 Cherokee XJ Intake Manifold Ported and Polished
Throttle Body bored out to 63mm (Thanks SilverXJ on this one) http://www.strokedjeep.com [email protected] (his name is Jeff Leigh)
Federal Mogul Speed Pro Hypereutectic 825 Pistons dished to 20cc's (get with Oleshot on this forum for some very quality work on dishing)
Federal Mogul Speed Pro Moly Rings
Federal Mogul Speed Pro Bearings
Federal Mogul Oil Pump
Complete FelPro permadry rubber gasket kit (the valve cover and oil poan gaskets are super nice)

This put me around 8.3 DCR and I am running very nicely on 87 octane at the moment. I am having an SCT employee tune this thing for me as I am sure it is not running "Optimally" Further updates to come on the tuning...

[MarineJRM]

Well I got the first tune setup for 93 octane and it is nasty. The amount of HP and Torque it added on the arse dyno is nuts. I am going to be taking it to the dyno next week and finding the exact numbers for the stock tune and the sct tune. Then all I have to do is send the WOT air fuel ratio to him and he will fine tune the PCM from there. Well worth the 375 for the hardware and custom tuning of the PCM...

[amcinstaller]

how do you think that cam would do as a street/strip cam? do you find teh acceleration to be pretty good? im planning to use this cam as well, and i also like the felpro permadry gaskets for oil pan and valve cover. WWAAAAYYYYYY nicer than cork. would never go back.

[MarineJRM]

The drivability of the engine build that I did is great. The 68-232-4 cam is great for the fuel injected daily driver and part time off roader. I am going to the dyno thursday with the SCT tune and getting a few more details of the air fuel ratio for the tune to be dialed in a little more. I will post all the details after I get it all done.

[MarineJRM]

Not too Shabby

http://www.youtube.com/watch?v=CRRlSbiX0Rk

[gradon]

And the torque was. . .
Nice looking Jeep!

[maxparrish]

I'd like to add 40 HP to my 98 TJ engine...not much. I don't want to spend over a grand AND I even want to do less. No engine pulling or extensive custom work.

Could I not grind the heads lower and/or use thin gaskets to increase the CR to 8.65 or so? Maybe concave the stock pistons a bit? How much would that help? Would I need a new cam?

I don't mind putting in a new crank, as long as it is drop in (i.e. no custom cutting).

Am I unrealistic?

[SilverXJ]

Decking the head won't get you any where near 40 hp. Dishing, as you call it "concaving", the stock piston will lower the compression ratio. The stock pistons already have a dish. I have no idea how you would swap the crank with out removing the engine though.

[dwg86]

I'd like to add 40 HP to my 98 TJ engine...not much. I don't want to spend over a grand AND I even want to do less. No engine pulling or extensive custom work.

Could I not grind the heads lower and/or use thin gaskets to increase the CR to 8.65 or so? Maybe concave the stock pistons a bit? How much would that help? Would I need a new cam?

I don't mind putting in a new crank, as long as it is drop in (i.e. no custom cutting).

Am I unrealistic?

You can't just drop in a 258 crank in the 4.0. The pistons will hit the head. You would have to use the 258 rods with the 4.0 piston, or use the 4.0 with kieth black or custom pistons.

[maxparrish]

Sounds like there is not much one can do - but I remain curious on how you might significantly increase HP without stroking AND without buying pricy super-turbo charging.

What about the old hot rod tricks - a new cam (505 claims 50 HP increase), removing belt fan and using electric, some porting, etc.?

The 505 cam claims seem unrealistic, but?

[lafrad]

A new cam, remove the head and have 0.020 milled off, and hit all the ports with a carbide to clean them up and open them up a bit.

Probably give you 20-40 hp and some more MPG.

[MarineJRM]

You can do a stroker build while it is in the Jeep. You will have to remove the transmission from the back of it though and take the head off and all of that. It is alot more effective removing the engine and going through it. People have done a good bit of 4.5L strokers with just dropping in the crank and rods. I can only assume that they run like crap or something close to crap.

[Chrisb009]

MarineJRM....just a a few questions in regards to the build you did earlier in the year as I am looking to stroke a 4.0 for the CJ7 project I am working on. How has your mpg been with this build? How has reliability been with the components used....any issues thus far?

Thanks,

Chris