block for stroker question

[whitneyj]

I've done a little searching and can't seem to find exactly what I'm looking for. I've got a lead on a complete 94 4.0 and was trying to find how compatible it would be with my OBDII computer from my 00. I've been on jeepstrokers.com and have been spending a couple months on there for the stroker build, but can't seem to find anything about taking an older block and putting it in a newer XJ.

 

[jeepinwi]

Any block can be made to work with any computer system. The big part is using the throttle body for am OBD2 4.0 so it has all the correct sensors. The block is simply a big chunk of metal. Its dimensions did not change from 94 to 2000.

 

[gradon]

The 94 has a temp sensor in the back of the head that feeds the dash gauge that the 2000 doesn't, so leave it in as a plug. The 2000 header will be too small for the 94's 7120 head, so you'll have to replace that.

 

[bigdaddyjlove]

Also, Renix blocks are supposed to be a better metal mix (high nickel iron?). Plus Renix blocks have a tapped hole for the knock sensor. HO blocks do not

 

[Dr. Dyno]

He has an '00 model so I don't think he'll care about the knock sensor boss in the block because he doesn't have a sensor.
I don't think the Renix blocks had any more nickel than the HO blocks.

 

[bigdaddyjlove]

Ok, I used a Renix block for the stroker in my '98 TJ, and I plugged the hole. I don't think its really needed, as its a blind hole, but I had a pipe plug handy.

As to the metal in the block, someone here (5-90 i think it was you) posted that AMC had specced a higher quality iron and when Chry-mo-co took over they lowered the spec to the same iron as in the rest of their engine line up. I could be wrong, but it was on the internets. Doesn't that make it true?

 

[whitneyj]

awesome. I might just pick it up then.
As far as the head goes, I've got the two pre-cats on integrated with the exhaust manifold, so I'll probably just reuse my 00 head.

 

[ehall]

block dimensions are more or less the same, although as stated the RENIX blocks are generally considered the strongest

heads are a big deal though since there are different ignition setups, exhaust ports, etc

 

[5-90]

Ok, I used a Renix block for the stroker in my '98 TJ, and I plugged the hole. I don't think its really needed, as its a blind hole, but I had a pipe plug handy.

As to the metal in the block, someone here (5-90 i think it was you) posted that AMC had specced a higher quality iron and when Chry-mo-co took over they lowered the spec to the same iron as in the rest of their engine line up. I could be wrong, but it was on the internets. Doesn't that make it true?

That would have been me. I've been unable to fully confirm, but research indicated that AMC did tend to a higher nickel content than ChryCo (somewhere around 5% instead of the 1-1.5% that ChryCo tends to,) which makes the castings much tougher than than typical.

This is probably so, since AMC did tend to overbuild (every AMC Gen-2 and Gen-3 V8 came with forged crank & rods, for instance) because they were consistently behind the 8-ball and couldn't really figure out how to do things "on the cheap" like everyone else - they didn't have the time. Recall that AMC didn't come up with an inline four for release until 1984 (although they also came up with the aluminum V-block four-cylinder "Mighty Mite" engine for an airliftable vehicle for the Marines...) They generally tended toward taking designs offered by other people and improving them - the principal reason that AMC was able to offer an effective V8 in such short time after the partnership with Packard fell apart was because they snagged one of the lead engineers from Kaiser - who had designed their V8! So, they weren't starting from a "blank sheet" and that saved a good year or so.

As far as being able to get an actual composition - I'd like to, but have not yet had the opportunity (I've got an AMC block that I'd be willing to sacrifice a small chunk of to get analysed. I've also got a ChryCo-era RENIX - the two can be told apart, since the AMC blocks got an AMC logo cast into them, and the ChryCo got the Pentastar instead. I'd like to get a small bit of an HO block to complete the comparision - I don't think it would matter which year. Anyone got access to a spectrographic analysis setup? Be nice to put this thing to bed, since I've even been doubting myself a bit...)

And the D&T hole for the knock isn't really a "pipe" thread - I think you can block it off with a short M10-1.25 screw and call it good. Use an M10 setscrew, perhaps?

 

[imboostedru]

I know that when I tried to put a newer 99+ motor in my 96 there were problems with mounting the accessories. I guess they changed the location of the bolt holes on the front of the motor. You may want to check that.

 

[ehall]

yeah the power steering support bracket changed in '96 or thereabouts but the difference is in the intake manifold (which has a threaded hole for the pump). there were a lot of other changes to the TJ and WJ 4.0 layouts in '99 though.