Miata - engine is out - what to replace?

Need some advice. I'm still new to working on Miatas.

So I have a 90 base Miata that a friend gave me. It has 180k miles on it and I have been freshening it in preparation for Spec Miata.

Long story short, I decided to replace the engine and trans with a lower mileage unit (90k miles) from a car an acquaintance was parting out.

While examining the engine on the hoist in the garage, I noticed a bunch of old grunge all over the engine - particularly the back of the motor and passenger side. The slave was caked up with a thick layer of crap as was the bell housing. I washed and scraped all that gunk off and it looks great now.

Peaking into the bell housing with a flash light reveals that the inside of the bell housing is a bit wet (oily) and very black and rather gunky looking. I'm going to separate the trans and see what it looks like. The clutch was replaced 1-2 years ago. I expect to replace the trans and rear engine seals.

I'm also replacing all coolant hoses and the plug on the rear of the motor.

Valve cover and CAS do not appear to be leaking currently. It seems that it might have already been resealed.

Is there anything else that I should replace or work I should do while the engine is out? I prefer to do as little as possible right now so that I can get the car back on the road but I don't want to overlook something that is very difficult to do once the engine is back in the car.

Thanks in advance.

Install 3.8L 1999-2004 Mustang engine ;)

and I was thinking LSx

Grab the Spec Miata Constructor's book from Advanced Autosports. Good stuff.

With the engine out, I'd replace or at least inspect every seal on the engine. Rear main, CAS, valve cover, front crank, cams, all the belts, etc. It'll only take an hour or two and will be a lot harder later.

Keith wrote: Grab the Spec Miata Constructor's book from Advanced Autosports. Good stuff. With the engine out, I'd replace or at least inspect every seal on the engine. Rear main, CAS, valve cover, front crank, cams, all the belts, etc. It'll only take an hour or two and will be a lot harder later.

Already have that book.

That is a longer list than I'd hoped for...

What about the oil pan? Do they tend to leak?

Thanks

Well, you don't necessarily HAVE to change all those seals now. But it's a lot easier when the engine is sitting on a stand than it is with the engine in the car, and it's a quick piece of work. Short term pain, long term gain and all that happy stuff.

Oil pans don't tend to develop leaks, no. I'd leave that on.

water pump, clutch, pressure plate, T/O bearing, pilot bearing, resurface flywheel, rear main seal, oil pan gasket, engine/trans mounts...

While it's out - since you've replaced the hard to get to parts that were probably the case of the grunge you saw:

Water pump Timing belt and tensioner Accessory belts Front and rear crank seals CAS seal and valve cover gasket (I know, not leaking now, but much easier to deal with now, and they will leak eventually) Check motor mounts - they deteriorate rapidly on these cars for some reason Input shaft seal on trans Clutch, pressure plate, flywheel inspection, maintenance Radiator hoses Clu

I separated the trans from the motor. Nasty dirty bellhousing...

All done and clean now

This is what the rear of the motor looks like after I pulled the trans:

Motor after cleaning: