Thread: Fitting a '92 3.9 RRC motor into a '94

Customer came to me the other day with his '94 RRC soft dash, his mechanic replaced the head gaskets after skimming the heads etc, still blows out the coolant of course. So I said to him, you either get a complete reco top hat motor or I fit a second hand 3.9 that came out of a diesel-converted '92 vee belt RRC. Now I know that I should remove/swap the crank, do a freshen-up with new rings, bearings etc but the motor I had was a sweet runner. Try it out, I say.

Firstly I said, it can't be that hard to extend the keyway. I stripped down the donor motor's front cover and the stuffed motor. Removed the long and short keys, plugged all the gaps with a welding glove, used a slitting wheel on the 4" angle grinder:



...to extend the keyway. A steady hand, good light and a bit of test fitting and the key sat just like on the damaged motor:





Short key is lying next to the reinstalled long key, chains pulleys etc test fitted before proceeding...

Now a few tips for the installing of a replacement motor. People who know me know how many hours I take to think up shortcuts, so after much deliberation here's some for engine fitting.

Firstly, strip everything you can off the old motor, Inlet manifold and heads, front pulley, front cover, starter and engine mounts. Now the motor is compact enough that a simple engine crane can lift what's left out without removing the bonnet even. Once the engine mounts are off, you can lower the engine to get spanners behind the engine to get at the top 4 bell housing bolts. The lower 4 you get with a selection of socket set universals, spanners etc. It's also easier to get the starter out while the heads are off.

You will end up with the engine coming out very easily, leaving it like this:



The a/c compressor and bracket are wedged up to the driver's side, the plenum top is over the passenger side, the manifolds are still on the pipes because that saves snapping the flange studs and needing new gaskets. There's enough space to wriggle the block out as the engine mounts are gone. A piece of scrap metal between the auto's sump and crossmember (25mm square tube or similar) is holding the gearbox to a convenient angle for removing and refitting, the round inspection hatch is off the bottom of the bellhousing as the bolts you remove from the torque converter fall through here if they slip out of the socket.

There are a number of minor differences between the motors, including things like the placement of the fuel pressure regulator, so the inlet manifold comes off. This allows the hoist to get cuddly with the motor, plenty of height under the bonnet. (That's being propped up by a piece of pipe to the side at maximum lift.)

Now I am refitting the replacement motor, I haven't yet removed the PS engine mount but will as soon as I notice it hitting the manifold.



See even the radiator is still in, that's how much room there is to spare. Pull it out if it bothers you, I work alone so I am willing to take the risk.



Engine down to the bellhousing, as I have left all the bolts in the bellhousing, I can just slip under the car and tighten the bottom most two bolts. Lift the engine slightly and remove the block under the trans sump, lower away and do up the 4 top bolts into the back of the engine. Although the heads are still on the replacement engine, a smallish open/ring spanner will get all four top bolts to an adequate tension.

Now I lifted the engine, fitted up the engine mounts, exhaust manifolds and starter motor. I diced the dreadful allen key bolts from the starter and replaced them with a couple of spare manifold bolts. This makes starter replacement a quick job in the future.

Originally Posted by chazza

Nice one bee utey!

Have you a photo of how you jam the torque converter so that the crank pulley nut can be tightened?

I couldn't see anywhere to stick a bar in on mine, so I took the sump off and used a bit of wood,

Cheers Charlie

No photo, it was dark and grubby under there! I removed the round little plate as mentioned, poked a 12mm socket tee bar between the converter bolt pad and the flex plate, and against the crank boss. Held it up with a wood block then leaned on the crank bolt undoer, no stress.

Another useful method is to figure which piston is after firing TDC, feed a couple of metres of nylon rope down the plug hole, crank it backwards against the pile of rope. Hasn't damaged anything for me yet, you need to use a reasonable amount of rope to not stress the piston, rod etc.

Also I believe there is a 1/4 BSP plug which lines up with the flywheel teeth for a crank locker, I didn't investigate it further.