4.0 to 4.6 stroker information

[XJ4IV]

OK so one of our customers has a 1980 CJ7 and he currently has a 4.2 motor and after talking with our boss and the customer we have talked him into letting us build him a stroker motor using new 4.2 parts mixed with a junkyard motor that we are fully rebuilding as well.

today I received the 4.0 donor motor out of a 93 XJ and started ripping it apart.
Thus far as far as pictures for comparison here are the two piston rods side by side
http://i1133.photobucket.com/albums/m590/XJ4IV/IMG066.jpg
As you can see on the TOP of the piston rods the 4.2 rod is slightly shorter
by 1/4 inch
and what you can't see from the angle of this picture is that the piston on the 4.0 is slightly shorter as well by another 1/8 inch
so the optimum choice is to use the 4.2 piston rod with the 4.0 piston and to use the 4.2 crankshaft


and here are the two cranks side by side
http://i1133.photobucket.com/albums/m590/XJ4IV/IMG068.jpg
its VERY hard to see the SIZE difference here however the two cranks do offer a different rotation depth where the 4.2 crank has a longer or deeper rotation.
basically the way this stroker works is rather than boring a motor over and creating a very think sidewall you increase the depth inside the motor by making a deeper stroke hence a "stroker motor"
I looked up the dyno results to show an increase in torque to approximately 325-350 ft/lbs of torque by doing a simple 30 over bore which is a standard for a rebuild however our customer may decide to go 40 or 50 over to increase HP and torque.
our customer has also opted to go with a 60mm throttle body and ceramic exhaust manifold and we will also clean out some material on the intake and exhaust manifolds to allow better flow we will also most likely be replacing the cam at the customers request, though he has not decided which cam he is opting for yet so I will keep you posted.
if you have ANY questions about this build please ask away and if I don't have the answer I will ask the boss about it
as for pictures of the build I have elected to take on most of this build with guidance from our boss so I have a better understanding of how this all is done so I will do my best to get pictures.
Thanks guys

[XJ4IV]

well in talking with the customer yesterday rather than try to sell the old 4.2 with the most wanted parts NOT included he has decided to salvage the goodies from within his current motor and have them checked over by the machine shop.
yesterday I was able to pull off those fenders and header piece and fold the hood back to the windshield (bonnet to the windscreen for your out of U.S. folks)
and get to breaking his motor apart. today Im down to removing three more bolts for the transmission and the two motor mounts and OUT SHE COMES!
the rest of the day I will be taking the head off and cleaning it for resale
as well as breaking down the block for resale and removing the crankshaft and pistons for reuse! pics to come of the teardown tonight

[TeXJ]

thats pretty cool!

[OrangeXJ]

My 2 cents on the stroker. When my son lost his HO engine I was thinking on building a stroker. After talking to several of the jeep shops in the area they told me you don't get the bang for your buck. I'm not bashing the stroker but you spend around 2k for the stroker kit time and money to build it and install it you got about 3k in it. I got a re man with a 36k warranty for $1150 $950 to pull and re install.

[Mudderoy]

My 2 cents on the stroker. When my son lost his HO engine I was thinking on building a stroker. After talking to several of the jeep shops in the area they told me you don't get the bang for your buck. I'm not bashing the stroker but you spend around 2k for the stroker kit time and money to build it and install it you got about 3k in it. I got a re man with a 36k warranty for $1150 $950 to pull and re install.

I am looking into building one. The hard part will be getting the crank at a decent price. If I can find that then I think it's financially doable.

[TeXJ]

But you are missing the point, you will have more HP and torq! For a lot less than getting a V8 in your jeep.

[Mudderoy]

But you are missing the point, you will have more HP and torq! For a lot less than getting a V8 in your jeep.

I think the V8 would be pretty cheap, getting it fabbed in there wouldn't lol

I've been reading this one... :link: (http://www.angelfire.com/my/fan/stroker.html) "From Junker to Stroker"

[bigjim350]

I think the V8 would be pretty cheap, getting it fabbed in there wouldn't lol

I've been reading this one... :link: (http://www.angelfire.com/my/fan/stroker.html) "From Junker to Stroker"

If emission wasn't an issue you could put a v8 in a xj for the same price as a decent stroker build. They already sell motor mounts that place the v8 in the perfect postion without any mods done to the jeep.

[Mudderoy]

If emission wasn't an issue you could put a v8 in a xj for the same price as a decent stroker build. They already sell motor mounts that place the v8 in the perfect postion without any mods done to the jeep.

I think a LT1 would be a cool engine to have in a XJ.

[TeXJ]

I think a LT1 would be a cool engine to have in a XJ.

forget the LT1 go for a new 5.3, or LQ9!

[Mudderoy]

forget the LT1 go for a new 5.3, or LQ9!

Stock 4.0 or 4.6 stroker will be my choices... :D

[TeXJ]

Stock 4.0 or 4.6 stroker will be my choices... :D

If it broke stock then why not upgrade to a 4.6? :D

That's what I'd tell the wife haha

[XJ4IV]

Greg when you guys did the rebuild did you use the HO motor, that will make a TON of difference when it come to thestroker rebuild. the numbers are out there and mostly what these folks are looking for is low end torque for offroading purposes.
the difference between the old motor and the HO motor was a few tweaks here and there to the existing motor like opening intake and exhaust ports PLUS what lots of folks DON'T do when performing this stroker build is the dont take the tedious time to port match everything while under torque meaning on the crank journals you need to torque those to spec THEN do your cylinder boring because when your talking 3/1000 to 4/1000 of an inch then when you torque those bolts down things can change about 1/1000 up to even 2/1000 plus the piston rods NEED to be balanced perfectly and a decent set of pistons is needed for your new bore you really cannot use the factory ones anymore due to the new bore.

[4.3LXJ]

Sounds like what you need to do is align bore the journals then

[OrangeXJ]

Greg when you guys did the rebuild did you use the HO motor, that will make a TON of difference when it come to thestroker rebuild. the numbers are out there and mostly what these folks are looking for is low end torque for offroading purposes.
the difference between the old motor and the HO motor was a few tweaks here and there to the existing motor like opening intake and exhaust ports PLUS what lots of folks DON'T do when performing this stroker build is the dont take the tedious time to port match everything while under torque meaning on the crank journals you need to torque those to spec THEN do your cylinder boring because when your talking 3/1000 to 4/1000 of an inch then when you torque those bolts down things can change about 1/1000 up to even 2/1000 plus the piston rods NEED to be balanced perfectly and a decent set of pistons is needed for your new bore you really cannot use the factory ones anymore due to the new bore.

Scott don't get me wrong. For the cost to stroke one if you are not going to use the gained HP and TQ on a reguler basis is not worth the money.

[bluedragon436]

Since I have been researching doing a stroker build on my 4.0, I have been looking at doing the budget stroker, using stock 4.2/4.0 parts with the exception of the cam and a few other minor parts, which I would upgrade anyways on my 4.0. I wouldn't be looking to spend the higher amount of money on an actual kit.. If I were going to do that, then I would pick up an already build setup or do a v8 swap... Look forward to seeing more on this build, as well as pics.. as this will help me as I make the decision to do mine or not..

[Mudderoy]

Since I have been researching doing a stroker build on my 4.0, I have been looking at doing the budget stroker, using stock 4.2/4.0 parts with the exception of the cam and a few other minor parts, which I would upgrade anyways on my 4.0. I wouldn't be looking to spend the higher amount of money on an actual kit.. If I were going to do that, then I would pick up an already build setup or do a v8 swap... Look forward to seeing more on this build, as well as pics.. as this will help me as I make the decision to do mine or not..

Yeah if I do a stroker, I'm not buying a kit. Way too expensive, or at least it seems based on prices I'm seeing for the components. Crank and rods seem to be the biggest cost.

[bigjim350]

Well here is my point of view on the stroker. A stock 4.0 already has plenty of weak spots that are prone to cracking. Looking at the block that Matt has the first cylinder wall so thin after seeing that I will never do anything other than a stock build. Also the lifter gally is thin and prone to cracking. And that is on a stock block and a stock build. Once you stroke it and add the tq and hp it makes it even more prone to cracking. Also living here in the south its very hard to keep one cool. Seems to me it would be almost impossible to keep a stroker cool down here. Have been around a ton of jeep people down here and have never seen anybody running a stroker, except for one which was a weekend warrior only. For a DD it seems like a very bad idea.

[bluedragon436]

Yeah I would be able to get plenty of performance out of using the stock 4.2 crank and rods. I'm not looking for anything to rep the Jeep apart.. just something to have more fun with, and maybe even get some decent performance out of the gas mileage that it has..

[XJ4IV]

OK what are the emmisions issues folks are running into, The shop dropped that motor into the CJ last week and the owner hasnt had a single issue with it, it WAS a carbed motor but now it is a EFI

[bigjim350]

Well he isn't having an issue cause he doesn't have to pass emissions tests

Sent from my VM670

[XJ4IV]

but what are the problems?

[TeXJ]

why would there be an emission issues?

[4.3LXJ]

That is what I would like to know. But I am all eyes and ears on this

[bigjim350]

It has to do with the ecm. You will need to have a very nice programmer on a an obd2 jeep, and/or do some custom mapping on the fuel and ignition curves on obd1 jeeps. You have more cubic inches to feed. So you will need more fuel, and a bigger fire. If your not tuned for it you will either run too rich(bad emissions) or too lean (bad motor). Just saying its not a simple cheap bolt in that will be perfect unless you address all the areas.

[modestmar00xj]

really cool! all good information for a good winter build!

[LizardRunner]

This is where I get most of my stroker build info. http://www.jeep4.0performance.4mg.com/stroker.html Might be of interest to others.

[LizardRunner]

Here's a complete build list for a budget stroker motor. This one doesn't really pump up the heat but it has plenty of extra torque. I removed dollar amounts paid since this was a few years ago and things have gone up in price. I think you can still do this build for under 2k though, and if you sold the old engine, you can recoupe some of the costs. For those who love the adventure of making horse power and torque... Enjoy !

Bottom end

Junkyard '00 Jeep 4.0 I6 short block (incomplete):
Reground AMC 258 crankshaft #3214723 & Clevite 77 rod bearings #CB-960P-20(6): Federal Mogul main bearings #FM7211M.030:
Crankshaft rear main seal #05018594AA: Crankshaft pilot bearing #53009180AB: reused
Reconditioned AMC 258 connecting rods:
ARP rod bolts (AMC 258) #112-6001:
Sealed Power 677P +0.020 pistons #STL-677P20:
Hastings +0.020 cast piston rings #667:
Clevite 77 camshaft bearings #SH-549S:
Crane camshaft CRN-753905 & lifters CRN-99278-12: $179 from Summit Racing
Main bearing studs: stock '00 reused
Main bearing girdle & retaining nuts: stock '00 reused
Main bearing girdle spacer kit (14 hardened 5/16" steel washers):
Crankshaft sprocket #53020443 & timing chain #53020444: stock '00 reused
Camshaft sprocket #53020445: stock '94-'98
Camshaft sprocket bolt #83502890 & washer #J3173284: stock '92 free with block
Crank harmonic damper #33002920T:
Crank pulley spacer: free
Pioneer brass freeze plugs x7:
Oil pan: stock '92 free with block
Oil pump: stock '00 reused
Victor Reinz lower gasket set #CS-5713X:

Top end

Cylinder head (spare '92 DIY ported):
Valves: spare '92 reused*
Head bolts: stock '00 free with block
Pushrods: stock '92 free with block
Mopar Performance valve springs #5249464, retainers #4452032, & locks #4529218:
Stock 1.6 ratio rocker arms: stock '92 free with block
Valve cover: stock '92 free with block
Victor Reinz upper gasket set #HS-5713Z:

Miscellaneous

Distributor Lucas #53006150: stock '92 reused
Oil filler cap #53020555:
Flowkooler high-flow water pump #1747:from Flowkooler
Robertshaw 180* thermostat #330-180:from Flowkooler
Mopar oil filter #5281090:
Champion RC12LYC spark plugs:
Mopar serpentine drivebelt #53010269:

Engine Shop Work

0.020" cylinder overbore & hone
Press in new cam bearings
Press pistons onto rods
Regrind valve seats
Clean, polish, & lap valves
Acid dip valve cover
Press freeze plugs into block
Cut crank pulley spacer

Now first rule of High performance engine building, taught to me by Smokey Yunnick a long time ago. " EVERY THING MATTERS!" "if you aren't going to be a perfectionist on every little detail don't start this type of project simply because it will come back and bite you in the ass." Believe me when I say the above is oh so true.

[4.3LXJ]

If Smokey said it, it is true. Great engine builder.

[TeXJ]

Did somebody say Smokey?

http://cdn.faniq.com/images/blog/087f6e2172a029781c78ca182fb79eea.jpg

https://encrypted-tbn2.google.com/images?q=tbn:ANd9GcRbAs4xbmvIFM5mXXsMoZOpjeeGP25ic TFfR7AY9RX5OUuUD8hs3g

[XJ4IV]

It has to do with the ecm. You will need to have a very nice programmer on a an obd2 jeep, and/or do some custom mapping on the fuel and ignition curves on obd1 jeeps. You have more cubic inches to feed. So you will need more fuel, and a bigger fire. If your not tuned for it you will either run too rich(bad emissions) or too lean (bad motor). Just saying its not a simple cheap bolt in that will be perfect unless you address all the areas.

so on my older OBD1 and my adjustable MAP sensor provided by one of our vendors is the ticket? I hope so, I have the ability to adjust the rich/lean of my air fuel ratio electronically rather than allowing my jeep make the adjustment for me.

[dagr8tim]

I'm still playing with this idea if I can get a decent donor 4.2. I've got a spare 4.0 from a 98, a 2000 intake, and I'm searching for a 95 head. I would like to put a slightly hotter cam in and do some mild head and manifold work.

[LizardRunner]

Did somebody say Smokey?

http://cdn.faniq.com/images/blog/087f6e2172a029781c78ca182fb79eea.jpg

https://encrypted-tbn2.google.com/images?q=tbn:ANd9GcRbAs4xbmvIFM5mXXsMoZOpjeeGP25ic TFfR7AY9RX5OUuUD8hs3g

Ummm wrong Smokey's there :smiley-laughing021:

This Smokey http://image.circletrack.com/f/9408531+w750+st0/ctrp_0801_04_z+smokey_yunick+.jpg http://cdn-img-b.infibeam.net/img/b13f9f3e/060/2/9780931472060.jpg?hei=200&wid=160&op_sharpen=1

[dagr8tim]

I think I have his book in kindle format. I should go back and re-read it.

[LizardRunner]

I think I have his book in kindle format. I should go back and re-read it.

He put out several books, Power secrets is one of the "bibles" for chevy hp. I also have one from him on the 350 chevy. My treasure though is a binder from the short while I was a driver on his team.
http://www.carrollshelbymerchandise.com/images/artwork_and_signs/DC-TERLINGUA-LARGE-W.jpg

[dagr8tim]

He put out several books, Power secrets is one of the "bibles" for chevy hp. I also have one from him on the 350 chevy. My treasure though is a binder from the short while I was a driver on his team.
http://www.carrollshelbymerchandise.com/images/artwork_and_signs/DC-TERLINGUA-LARGE-W.jpg

Share the wealth.

[TeXJ]

He put out several books, Power secrets is one of the "bibles" for chevy hp. I also have one from him on the 350 chevy. My treasure though is a binder from the short while I was a driver on his team.
http://www.carrollshelbymerchandise.com/images/artwork_and_signs/DC-TERLINGUA-LARGE-W.jpg

on the terlingua thing, I was coming up from austin, tx, and there was a truck with two mustangs and they had the Terlingua racing team on them...any relation? This was 6-9 months ago, or even longer, time blends with me :D


I also saw the tow truck here in Allen, TX about a month ago, Terlingua racing on the side.

[TeXJ]

Ummm wrong Smokey's there :smiley-laughing021:

This Smokey http://image.circletrack.com/f/9408531+w750+st0/ctrp_0801_04_z+smokey_yunick+.jpg http://cdn-img-b.infibeam.net/img/b13f9f3e/060/2/9780931472060.jpg?hei=200&wid=160&op_sharpen=1

:D just trying to put a smile on somebodies face, or really confuse others :p