94 engine in a 91Q

[Q45tech]

We had a ragged out 91 come in with what seemed to be a working 94 engine conversion............lots of jury rigged wiring splices to CAS, MAF and ignition modules on valve covers and the front right vacuum solenoids......no codes so it can be done.

It didn't look pretty but ..........the owner bought it from a pay here ATL lot.......no info on who did it.

[AZhitman]

PMQ?

[PalmerWMD]

Dennis:Did you, could you, take pics?

Fred...

[Q45tech]

Byron got the Best look, I heard about it as it was leaving.Obviously one would need all the oem 94 connectors [from the wiring harness] to fit the 94 sensors much as what one would have with 2 side by side cars [a wrecked 94 donor engine car].

This might be problematic with a JDM take out engine where you don't get the wiring harness------but some come with connectors and wires cut off.

You could substitute the 90-93 valve cover center insert with coil driver and use the 90-93 coils and harness.

But you still have all the under plenum R&R and valve cover reseal and new front and rear main seal, thermostat water pump hose clean up replacements while the engine is easy.

Probably save $500-$650 over doing the guides on a 90-93 engine swap.

Not sure I would want to be the first one [splices] and the bug work out.

So this will not be a T3 option for out of staters till a few successful ones are evaluted for a time period to gauge problems/solutions and come backs.

[elwesso]

Lets review the major differences of the 90-93 engines vs 94, performance wise..

90-93 has different intake runners..90-91 has sodium filled exhaust valves

What else is there... Even if you swapped out the 90-93 lower intake runners, assuming the 94 fuel rail would bolt up, that should make performance equal and not have to mess with the guides, correct??

Am I missing something?

[Q451990]

From seeing how quickly Byron can do a guide swap, I would think that's easier than cutting and splicing the wiring anyway...

Unless there's a huge price difference for the swap or it's getting too hard to find 90-93 donor engines, I'm not sure I'd go to the trouble.

Heath

[elwesso]

I agree with heath.....

IIRC everything is "plug and play" but the harness connectors are different shapes..

[Q45tech]

The 94-96 heads have a single oval port to match the lower runners oval output. And the better less prone to clog 4 hole injector streams

[PalmerWMD]

Wes:

According to the Infiniti brochure from those years the 92 still had sodium filled exhaust valves.

So 90-92 with sodium filled according to the pubs.

Fred..

[elwesso]

Oh I stand corrected!!!

So dennis, I ask, objectively, how much difference do the lower intake runners along with the heads make???

[PoorManQ45]

PMQ?