A remanufactured 3.1 wouldn't be much more $$$ than a reman 2.8, I'd recommend that option. The increase in torque over a 2.8 would be worth it.
You'd want a 3.1 out of a 4WD Rodeo or 4WD P'up. Or, the mid-90 series GM FWD minivans had the same block (cast-iron heads, TBI intake manifold, same motor mount points, and starter on the correct side already to fit a Trooper).
Since you're spending all that $$ on a reman'd motor, why not give yourself an easy upgrade while you're at it? 2.8 and 3.1 are the same block, the only diff is the stroked crankshaft and pistons to match.
I'd recommend (whether you use 2.8 or 3.1) that you use a clutch from a Rodeo/P'up 3.1 (4WD MUA-5 Tranny only). This is a 24-splined clutch disc with a larger diameter than the 2.8's clutch disc and is a much better setup with a lot more holding power. A direct swap for the 2.8 clutch with no mods whatsoever.
Don't forget to install a new pilot pushing in the crankshaft.
The intake manifold should be sealed with the latest-recommended GM sealant (yes, they really do specify a certain sealer for this). Pick up a cartridge of it (for use with a caulking gun) at your GM dlr. Be sure the intake is properly torques as loose/leaking intake is a problem area for this motor.
GM uses metal-to-metal seal on the exhaust manifolds, Felpro and others have a nice gasket which will be much better, not leak, and probably help with the busted man bolts issue. Be sure to replace any questionable bolts and use anti-seize on the threads. I upgraded my exhaust man bolts (except for the special ones) with higher-strength items. None have busted yet!
A quality valve gasket like Fel-Pro should seal just fine, use a sparing coating of Permatex Ultra Copper, Hi-Temp Orange or equivalent "O2 Sensor Safe" RTV.
By all means replace the dist. O-ring, it's a known problem area too.
Far as removing the engine goes, you have a couple of choices there for wiring; either disconnect all the wiring harness on the motor and peel it off, leaving it in the engine compt; or, disconnect the O2 sensor wire, pull it back from the driver's side by the cat, all the way to the pssgr's side back of the motor, then disconnect the motor harness and pull it out along with the motor. The O2 sensor wire is the only thing keeping the engine harness from freeing up. And Never cut this wire thinking you can just splice it later! It's a special shielded wire and splices just don't work right.
-There isn't enough clearance to split engine/tranny and have the trans pilot shaft make it out of the clutch fingers without destroying the clutch. You'll need to drop the axle to gain more room.
-Axle is held on with 2-per-side monstrous bolts up into the frame, if you have a good air compressor and an impact wrench it'll help immensely.
-Unbolt the front driveshaft at the transfer case and swing it out of the way. It'll give you a lot more room to work around engine stuff, underneath.
Invest in a set of metric Gear Wrenches, you can't believe how much they help when working in the tight spots around this motor. I found the straight ones without a toggle to reverse ratcheting action will fit into tighter spots than the 'bent-headed' wrenches.
-To get at the very top bell-housing bolts, 2 things help; a very long set of 1/2"-drive extensions and breaker bar/ratchet/impact, and/or removing the motor mounts off the block, once you've got a pick on the motor with a hoist.
-You'd use the long extensions to reach from over the tranny, fwd to the bellhousing bolts. They really are that bad of a fit to the firewall.
-Pulling the motor mounts off the block allows you to lower the engine down just a wee bit more, and that may make it possible for you to fit a Gear Wrench in there and get at least some of the bolts loose from inside the engine compt.
-Needless to say, pulling the hood is just about mandatory. Be sure you mark the hinges so you can get everything bolted back up to its original position. And save all the hardware, very frustrating to be ready to bolt the hood back on and can't remember where the bolts went!!!!! <img src="/forums/images/graemlins/angry.gif" alt="" />
-On your A/C unit, some are shimmed so when you unbolt it, be sure to note the position of any shims and put them back the same way. This was a factory TSB regarding serpentine belt vibration so you really need them if they are there. If you have enough room to get the hoses out of the way, you may be able to keep from losing your Freon. I never had that problem 'cause none of the rigs I worked on had a working A/C system!
That's all for now, I'm sure something else will come to mind. Keep up the questions and we'll get you there!
HTH...........ed
