IslandCherokee

My 88 XJ has had an engine swap or rebuild in the past. The block still looks fairly "new" with lots of paint still on it, no grease etc. Someone put 4.0 HO emblems on the liftgate. That got me wondering if someone did an HO swap in the past. How do I determine what I've got under the hood?
Thanks!
Todd

cruiser54

http://www.justanswer.com/jeep/2p5bm...determine.html

DFlintstone

The casting # are here. I gather it's just the head that is different, the manifolds and block can still be earlier, but the head is what counts...Top left on the head, 2686, is the pre 90.

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

IslandCherokee

Thanks guys! I'll have a look and see what I've got.

IslandCherokee

I found the block # - 801M27. The first digit is the year- I assume that's 88 and not 98?
I cant see a head casting #. When you say top left-is that at the front of the head or on the drivers side? Is it visible with everything bolted to it?

cruiser54

It's half way down the top of the head on the driver's side.

DFlintstone

Yes it's visible, just back from the 4th bolt, facing up.

IslandCherokee

So you're saying that's the top of the head meaning the VC must be removed, right?

cruiser54

Valve cover removal is unnecessary. Go have a look.

DFlintstone

X2^, . Might be stuff caked on there, an old toothbrush might be handy. The 4 numbers are about 3/8 of an inch tall.

caged

my renix has a 95 motor and it has an unused temp sensor plug on the thermostat housing.

also, you won't get the benefits of an H.O. cause you still need to use the renix head and intake as far as i know.

DFlintstone

I gather from Cruiser, (and others) that you can indeed use the HO head on ether block. Cruiser did a writeup on that found in his, (or my) signature.

cruiser54

Cruiser’s HO into Renix Swap
This swap is easier than some will lead you to believe, generally those who have never done it. Those of us who have done it, like myself, will share with you the things that need to be done for a successful swap. Just think of it as swapping in a long block.
The HO and Renix have some differences but none that can’t be overcome very easily.
Any HO engine from an XJ or ZJ through 1999 can be used. One running change was that the rear of the head was no longer drilled and tapped for the temperature gauge sender beginning in the 96 model year. The sender can be relocated to the threaded hole in the thermostat housing taken from the HO engine. You’ll have to extend the wire to that location. Some brave souls even drill and tap the HO head for the sender.
You will be using the intake and exhaust manifolds from your Renix, along with all your sensors and wiring. Since the intake ports of the HO are slightly different, you use the Renix gasket. Exhaust ports are identical.
You will need to use your Renix distributor as it is different than the HO because they use different fuel management systems. The flywheel or flexplate from the Renix must be used so your CPS gets the correct signals. The valve cover from the Renix allows you to keep your CCV system intact and requires no modifications.
The HO block will have a plug in the coolant galley on the driver’s side of the block, closest to the front, which needs to be removed so your Coolant Temp Sensor can be installed in it’s place just as it is on the Renix. It requires a 5/16" square drive or a modified 3/8" drive that has been ground down to fit. Do this before installing the engine.
As for the knock sensor, which is located just above the oil pan on the driver’s side of the engine about mid way, all the blocks I’ve seen are threaded for it. If not, I’ve heard they may be drilled but not tapped. Tap the hole if that’s the case.
　
Revised 03/28/13
　

caged

yeah but you still don't get the added 12 horsepower. not that it even matters. lol.

cruiser54

8 HP. 89 and 90 were 182 HP. 87 was 173. 88 was 177. Only at the top end, and with not a bit more torque. The HP came from the bigger throttle body (58mm vs 52mm) and a better exhaust manifold for the most part.