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[Brachunky]

Could someone please explain what generally goes into the conversion of a stock 4l to a stroker! Is this something thats been done by anyone on here?

[Dave69]

pirate4x4 is the best place to start

[ferretjuggler]

Basically the use of the crank from the older AMC 258, the 4.2L I6 usually found in CJ7's and the like.

Gives about 4.6L I think.

Read up as much stuff as you can on this.
Some guys in the US have sunk serious time and money into strokers.
IMHO the results are usually disappointing.

Basically what sounds like a good idea in theory but no good in practice

[donk498]

http://www.jeep4.0performance.4mg.com/stroker.html

[mr_s]

Wonder if a small block chevy would fit in... Bet it would...

[wildwood]

5.3 LS v8s are the hot ticket as there are sooo many of them.

But a big block 454 will fit.....just needs cooling sorted.......big rad about 30"x20" should do it
 

[ferretjuggler]

WILL a SBC fit in an XJ?  (I assume that's it's prospective home)

IIRC you can squeeze a SBC into a Willys MB but an AMC V8 is that little bit too big.

Just shows how little I know about XJs not my cup of tea really.

[isle of man]

The only 4" stroker I know of - that was any use (purely medicinal), was the part of a sex act, the other should be good to keep a boat moooooored !!!

[JamesH]

WILL a SBC fit in an XJ?  (I assume that's it's prospective home)

IIRC you can squeeze a SBC into a Willys MB but an AMC V8 is that little bit too big.

Just shows how little I know about XJs not my cup of tea really.

SBC will go in - Novak do a kit but it is $$$ and includes mounts, adaptor plate, rad and headers.

I started on the stroker route following a build / tech advice by Dino Savva that would give a 4.5l stroker. Then there were lots of horror stories about failed cams and the lack of a difference in ooomph from a 4.0 that means it still sits in the parents' garage waiting full assembly and maybe roller rockers if I think it's worth it.

At the moment the 4.0 works, the Jeep does it's thing and all is good.

[Delk]

I am one of the few people on here running a stroker and I am more then happy with it.

Several people on here have more money then brains and think the only way forward is to spend big money and buy the shiniest and newest parts. If you wish you can build a reliable and cheap stroker that will gain you 40 horsepower. If the V8 is the only option the next thing people will be telling you is you are not man enough unless you install a twin turbo LS7 with 700 horsepower.

The stroker made a big difference in my jeep especially at motorway speeds. It brought back the normal performance that was lost after the installation of big lifts, tires and the extra weight of winches and armour plate. Unfortunately you don't get magic rocket speed but that's not the point.

What you need for a simple stroker
crank - used 258 for a cheap as you can get
pistons - two options, KB stroker pistons or standard pistons with rods from a 258
injectors - slightly larger to accommodate the change in fuel requirement

This leaves you with a good increase in power and all your original equipment.

What you may want as extra
voltage adjuster for the map sensor - this is a small electrical do dad to modify the signal for air pressure so you can fine tune the engine.
cam - not required but you can install a larger cam. A large amount of the cam failures that everyone had were with the high lift Crane cams and there is a reason the company went bust.

After this you can waste as much money as you want
Roller rocker gear
Roller cam - not easy in a 4.0 and again a lot of failures because people put rollers on a reground cast cam and they fail.
Ali head
This list is endless.

If you want a reasonable bump in power a stroker is a good option and you can do it far cheaper then a V8 transplant. On the other hand the people that are upset are the ones looking to make 400hp. It can be done but you will end up spending twice as much as a conversion.

The other bonus for a stroker is that it is plug and play if you pick up a second hand 4.0 as donor. You can build up the engine ahead of time and install it easily in a weekend. You keep the original jeep equipment, ECU, AC, alternator, PS pump, fuel injection system and everything. You don't need to make any wiring changes to get it running and the gauges work as they should. Plus it will look completely stock so your Mot and insurance man wont have a clue.

[JamesH]

Delk, what cam and injectors are you using? I have a Crane  and no idea on injectors

[wildwood]

Spot on......
What Delk says is soooooo true.
The Nutters at JP Mag.......(bulldog now has ALL my copies ) went High Zoot$$$$
And tried to build a 4.9 or 5.0 litre.......
And as Delk says they had catastrophic cam failure.......
Ultimately regardless of what they did the engines when rebuilt only lasted 25,000 miles.

So yes. Go cheap with established parts as Delk did, or install something that fits your gearbox thereby saving on Adaptor Kits.......
On paper if your TJ pushes out 190 BHP
And the big block I am looking at pushed out 250 BHP.......... The difference in trouser enhancing
Horsepower might not seem worth the bother........

It's when you realize that one powered a 2 seat light weight Jeep
The other powered 3.5 tons of work truck that was rated to flat tow 7.5 tons.

That is when you'll really get to know what Torque figures represent........ And how with that amount of torque you can lift the left front wheel.........

Oh yes

[Delk]

You can run a stroker on the stock cam but I ended up installing a mid range Comp cam and it has been fine. My stroker has been up and running for roughly ten years and 50 thousand miles.

My injectors are slightly larger ones out of a Ford Mustang. They are cheap and plentiful on Ebay in the states and I picked up a pack of 8 new ones so I can check at home for the specifics if needed.

The torque figure on the stroker goes up quite a bit more then the HP figures!

The only issues I have ever had is the distributor gear broke once. Its not because its a stroker but I used to live where the average daily temp was 32 degrees so I installed a high volume oil pump. When its cold the oil pressure is really high and this puts a lot of extra strain on the little dizzy gear.

[Brachunky]

Delk, thats a great insight on building a budget stroker & sounds like a reasonable project for a diy mechy like me! Thanks for the info