To stroke or not to stroke?

[ruffy01]

Engine rebuild time early new year & the question is ^^^^

I was originally just thinking a stock rebuild with a nice RV grind cam but I'm now contemplating a stroker.
I've been driving a stock '96 Limited I bought & it hammers, compared to my '94 Sport with 4.11's & 33's.
A mate recently also bought a stocky & thought the same, compared to his XJ with 4.11's & 33's but after changing diff's, lift & wheels across to the stocky it became the same sluggish XJ as the other!

Obviously 33's even with 4.11 gears bog's the old 4.0L down.
So, will a fresh 4.0L feel the pinch as much? Am I likely to be dissappointed?
I'd like to retain the same get up & go the stocky XJ has but with the 33's.

To stroke or not to stroke, that is the question??

Oh, question #2: Does the ECU need to be recalibrated with a stoker or is it "plug & play"? :)

[Raisins78]

Mopars long motor stroker (4.7L, bolt in, attach alternator, A/C etc to the engine and drive away) is meant to be a plug and play, if you buy the matched injectors with it.
It then runs the factory tune, and injector pulse timing, but the bigger injectors match the increased displacement.
The long motor is around $3500-$4000, and everything is new or reco'ed from Mopar....thats got to be worth some insurance of a decent build and reliability.

Part number P5155209 from the Mopar performance catalogue

[Tezza]

I have a couple. If your rebuilding the only extra thing to do is add a 258 crank (I allways ballance any build) and you have 50 more hp straight up and bag loads of TQ.
If you only use a small cam, under 0.460" you will have no problem in any model, but in an OBD1 you can adjust your fuel ratio easy and I found mine does not even know my camper or hills are there with a good suply of fuel.
If you want neck snapping performance well you get used to any power level
and I know blook with lS1s wanting more.
Cheers Tezza

[kyphonii]

I would be thinking about a turbo with 3lb boost if I wanted a 4.7 litre, bet it cost less than a rebuild.

[Raisins78]

I would be thinking about a turbo with 3lb boost if I wanted a 4.7 litre, bet it cost less than a rebuild.
Bet it doesn't if its done right

[kyphonii]

Bet it doesn't if its done right

3lb would give more torque than a naturally aspirated 4.7.
There is no need for intercoolers or misc stuff at 3lb. your injectors would deal with the increase air so just a turbo and waste gate. The simplest set up is all you need to best a 4.7. I understand the tune is not altered at under 7 lb so were is the expense. 3lb is so little as to be negligible. But $4000+ for a 4.7 is a bit much for the modest increase offered.

[ruffy01]

Thanks for the replies everyone.

Turbo's not an option, the engine is tired & needs a rebuild, so the turbo setup would be additional to rebuild costs.
I can rebuild to stock spec's (with an RV cam) for <$2000 or rebuild & stroke to 4.7 for under $3000.

I'm not looking for neck snapping performance (if I was, it wouldn't be in a Jeep).
I just want to maintain speed going up hills, highway, without having to kick back 2 gears & rev it's tits off, like it does now :(
I'm planning a 'semi' around Aus trip in a couple of years & want the XJ to be up to it. Comfortable power for overtaking & towing is the goal.

I think I'll go the stroker option, so are upgraded injectors necessary & readily available? (I will have a look myself after this reply)

Are there any other potential issues I should be aware of?

It's the Limited that will be getting built. It's registered as a '97 but the build plate say's May '96. Pre-update with OBDII.

[ruffy01]

Ok, I just found this website: http://www.jeepstrokers.com/forum/

Now I just need to find more time to read.

[kyphonii]

Theoretically the head used on the < = 95 is the best from memory, pre emissions.
If your engine man can swing a modest increase in compression you will up your torque.
Dont fall for the, you must get monster injectors and increased air flow thing. If your not running over 4000rpm then you not going to need additional fuel air, just focus on the 2000 rpm as it's the torque range and the cruise rpm. Fuel air at 2000 is bugger all.
Just a quick note, I pulled a gas conversion of a 99 XJ and the gas inlet has a restrictor, it is tiny, makes me laugh at all the high flow and add ons that some buy for theoretical performance increases.

[Tezza]

You sacrifice a lot of power without larger injectors mine was over 15 percent air fuel ratio and felt like a revvy rice machine with stocks performance much better with just under 23lb injectors I now run 27lb but have opened the airflow right up and yes opening up the airflow is a waiste of time and money with an OBDII. unless you convert to OBDI or aftermarket as I have.
Towing and kicking back in the gears is more a problem you have running an auto the engine has no problem.
On my last Cape York run I wished I had a manual as it just reeved all the way up the ranges and the xj autos run real hot under constant load.
I have 2 PWR coolers to try not to boil the oil again.
Cheers Tezza

[ruffy01]

You sacrifice a lot of power without larger injectors mine was over 15 percent air fuel ratio and felt like a revvy rice machine with stocks performance much better with just under 23lb injectors I now run 27lb but have opened the airflow right up and yes opening up the airflow is a waiste of time and money with an OBDII. unless you convert to OBDI or aftermarket as I have.
Towing and kicking back in the gears is more a problem you have running an auto the engine has no problem.
On my last Cape York run I wished I had a manual as it just reeved all the way up the ranges and the xj autos run real hot under constant load.
I have 2 PWR coolers to try not to boil the oil again.
Cheers Tezza

Thanks Tezza.
I was reading up on the injectors (on the link I posted above).

OBDII doesn't respond to a bigger throttle body??
Aftermarket option?

[dan-cj7]

This is the best stroker thread on this website.

http://www.ausjeepoffroad.com/forum/showthread.php?t=94435

Look for Dino Savva on google - the stroker master.

I've built mine as a 4.6L. I went the KB piston route with a new comp cam.
I had to go 30thou over on the the piston and 10thou over on the main bearings. Had the crank balanced and the head reconditioned. I think I paid the rebuilder $2800 and I supplied the pistons and cam. I can't tell you about performance I'm still rebuilding my Jeep. The web has heaps of info you just have to spend the time to research it.

[anthonygubbin]

Hey Ruffy what did you decide on? I too have been sussing out whether it is worth building a stroker and can not decide. I looked at the Mopar site but could not see the 4.7 engine, even though it came up with the part #. I am wondering if it worth just putting rings & big-ends and then building a killer head and exhaust system and get the OBD 2 ECU remapped to suit the new components.

Regards A

[Gildo]

Do the stroke, then figure if the turbo is worth the next butload of cash...

From what I've read, the stroker is usually a happy happy ending :)

I have the 258 crank, the dished Keith black pistons, the ford 12 lb? injectors, adjustable map sensor, SS extractors, and a bunch of cool bits for the Comanche build all waiting for my return...
Thinking a custom programmable ecu rather than the stock is likely the best option, maybe MEGASQUIRT?

Does Anyone in OZ know how to REALLY do this?

[dan-cj7]

You can say that again.....

I think you meant to say 24lb/hr injectors.

[Richo]

You can say that again.....

I think you meant to say 24lb/hr injectors.

Thats why he said 12 twice. Gildo's like that......

[ruffy01]

Thats why he said 12 twice. Gildo's like that......

:lol::lol::lol::lol:

I haven't found a reason not to stroke.
From research, if I shoot for ~9.6:1 comp, a .450" to .470" lift cam, 12lb + 12lb :) injectors (or even 27lb), 62mm throttle body & extractors then the OBDII shouldn't complain too much.

I'm still researching & any further advice is greatly appreciated.
The build should commence in a few months.

[ruffy01]

Hey Ruffy what did you decide on? I too have been sussing out whether it is worth building a stroker and can not decide. I looked at the Mopar site but could not see the 4.7 engine, even though it came up with the part #. I am wondering if it worth just putting rings & big-ends and then building a killer head and exhaust system and get the OBD 2 ECU remapped to suit the new components.

Regards A

The old saying, there's no substitute for cubic inches, keeps me heading down the stroker route.
I don't want a "hottie" so to speak but increasing displacement by ~40ci's is theoretically worth 30-40hp & more low down torque without compromising drivability.
As long as I can be certain that the OBDII can handle it.
I do have the option of rebuilding the '94 Sport OBDI if necessary but would much prefer the '96 Limited.

[Eli]

Hi Ruffy

I think stroking is a great idea. I'm planning to do it myself. Have done a lot of reading. Check out these sites which are the most comprehensive coverage of the stroker for the 4.0L engine. Both from the same guy Dino Savva.
http://www.jeep4.0performance.4mg.com/stroker.html - his information website

http://www.angelfire.com/my/fan/stroker.html - his diary of progress

[99xjstroker]

I have built 3 of these stroker easy modification to do. The crank needs to be shortened on some years of the 258 where the balancer pulley goes on. Besides that its pretty much an engine rebuild. The engine will work ok with the stock injectors but best to go with 24lbs injectors 99 and down youcan get from accel 99 and up go to the parts store get a set of mustang svt 4.6L supercharged injectors and they are a direct fit 24lbs injector. These strokers are awsome . Lots of torque but they will not hold up to long with a turbo and stock internals.

[ruffy01]

I have built 3 of these stroker easy modification to do. The crank needs to be shortened on some years of the 258 where the balancer pulley goes on. Besides that its pretty much an engine rebuild. The engine will work ok with the stock injectors but best to go with 24lbs injectors 99 and down youcan get from accel 99 and up go to the parts store get a set of mustang svt 4.6L supercharged injectors and they are a direct fit 24lbs injector. These strokers are awsome . Lots of torque but they will not hold up to long with a turbo and stock internals.

Thanks for that info mate. I have no intention of going Turbo.
So no tweaking of the OBDII required??
I hope not.

[Gildo]

Yeah 24lb, it's been a while I need to read up again before building. :)