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[ferretjuggler]

Anybody running a 4.0 XJ/YJ engine in a CJ?

Thinking about one as a DD

Would I get a fuel consumption I can live with?

I got axles ranging from 4.10 to 2.73

[Bulldog67]

minimum shud b 4.7 V8, minimum

[Mike Pavelin]

A 4.0 HO puts out more power than a stock 360 anyway IIRC. MPG would be similar to a 4.0 TJ with equivalent gearing, tyres etc. Probably about 20mpg on 31s.

[Bulldog67]

I was think WJ 4.7 V8 etc etc if ya gonna go to that effort anyhow

[ferretjuggler]

If a Jeep comes with the 4.7 already in it that is fair enough, use it.

Otherwise the 4.7 V8 has got a rep for being weak easily blown and mega expensive to fix.

The XJ straight six, however, has earned itself the nickname "the Anvil" for good reasons apparently, with 300-400K clocked up in some cases.

Add to that the whole conversion kit is available at stooopidly low prices- it's called a damaged/rotten XJ and I know a Birty who paid £50 for a good one

As for being more powerful than an AMC V8, well I'd question that, certainly more than a 304, and more than the most strangled emissions controlled 2bbl 360s (just 144BHP )

But there a lot of horses in a V8 which you can let out quite cheaply

[JamesH]

The 4.0 is going to be a much more reliable engine and easier to get hold of. Remember that it'll need the wiring as well. Sorting wiring for a 4.7 V8 could get very messy indeed.

I'd think exactly the same as Mike for mpg. a stock XJ can get slightly higher 22-24 from memory but that's smaller tyres and probably lighter too.

[Panic mechanic!]

so what  no one has finally got round to saying is..... it will be like a 4.0 yj 

[ferretjuggler]

It will be like a YJ without stoooopid square headlights

Or a transmission I aint keen on not to mention the axles and the really naff plastic dashboard.

[Panic mechanic!]

so thats like the stupid square headlights and plasticky dash they have on fsj's?.........lot more plastic in a fsj as well.

[Bulldog67]

no square headlight on my Bastard 

and retro plastic is cool coz its got enuff shit in it to kill ya, so its sorta livin on the edge plastic 

[Mike Pavelin]

Of course you could just put a CJ front clip on a 4.0 YJ and save a whole load of work.

[Bubba]

 

[IrishCJ6]

I was looking at doing the XJ/TJ 4.0l swap in mt CJ6, but remember the transferbox attached to the AX15 has the front drive shaft on the opposite side to the CJ's, so you can adapt a Dana 20/300 but the adapters aren't cheap. The next thing is the wiring, again can be achieved and there is kits you can buy but these also aren't cheap. So you may be able to get the engine cheap but the rest of the mod costs

[Marmaduke]

Could also just do a head swap keeping the same trans setup put a 4l fuel injected head on a standard 4.2l block. Good write up on jeepforum.com

[eastryjeep]

It's got to be a specific head for that conversion hasn't it?
1/2" bolt diameter and not 3/8" I think, but whether you then use a 4.0 or 4.2 litre gasket I couldn't guess.
Then there's some jiggery pokery to be done with oil and/or water galleries too.
All of which leaves me wondering if you are not just stuffing up a perfectly good 4.2 that you could get an aftermarket fuel injection kit for.

[Mike Pavelin]

Jim Waitt (JimmyJ) fitted a 4.0 head and fuel injection on his 258 YJ. A lot of work I think

[apache]

if anyone is interested I have a spare 4.0ltr that originally came out of an XJ, went into a YJ (which then broke the auto gearbox) and has now been sat for about 2.5 years, I need the space so for £100 it can be yours.... otherwise its off to the scrapyard (can't be arsed with ebay). It ran well before the gearbox broke, previous owner couldn't be bothered to repair it.

unfortunately there's no ancillaries as I've robbed them for spares... but the ecu and all the wiring is there

[Bubba]

if you really had a hard on for injection in a cj7 then you would be better to use the whole 4litre engine and do the work to sort it rather than half of a 4.2 and the top of a 4.0

[Mike Pavelin]

  A pre 97 XJ or a YJ motor with the harness and matching ECU. No immobiliser nonsense to deal with on those, and all the correct sensors would already be attached to the engine. You would still have to be pretty confident with electrics to do the job though.

[ferretjuggler]

I was looking at doing the XJ/TJ 4.0l swap in mt CJ6, but remember the transferbox attached to the AX15 has the front drive shaft on the opposite side to the CJ's, so you can adapt a Dana 20/300 but the adapters aren't cheap. The next thing is the wiring, again can be achieved and there is kits you can buy but these also aren't cheap. So you may be able to get the engine cheap but the rest of the mod costs

You can get a Dana 300 onto an AX15 (and possibly an AW4 too) for less than £30

You just gotta cut approx 13mm off the AX15 output shaft, cut off the front cone off the D300 input bearing holder (where the oil seal fits) and substitute the open input bearing for a single sided sealed one (hence the £30, I got mine off eBay though, NOS)

Only 5 of the 6 bolts will fit up IIRC not a problem unless you're a total perfectionist.

[wildwood]

Yup had a Dana 300 flipped on the back of my AX15 and then when that burst a NV 3500

Now I got another Dana 300  right way up on the NV ................ with a Klune between the two works well

Way to go unless you won the lottery and get the 3 speed Atlas ..... blah blah blah............. didn't exist when I did this tho.....