What to replace before installing new (used) engine

[cjpacitto]

Just bought a 16v "S" engine to drop in my 944 (8v). (got all the necessary stuff to make it work too... at least I think I did) The 16v engine is an 87 and supposedly has 76,000 miles on it (the odometer on the car shows 76k and is currently working. Who knows if it has always worked though...). What would you recommend replacing before I actually install the engine? So far, I'm planning on the following:

- oil pan gasket
- rear main seal
- front main seal
- balance shaft seals
- timing chain tensioner pads
- water pump
- timing belts / rollers
- AOS seals (o-rings)
- oil dipstick seal (o-ring)
- send injectors to witchunter
- new clutch
- exhaust wrap on headers
- new motor mounts

Debating whether it would make sense to replace the head gasket before installing it. What kind of mileage do these things usually get before head gasket failure? Is head gasket failure even linked to mileage or does 23 years take its toll on a head gasket regardless of the miles it has seen?

Would rod bearings be warranted at 76k miles? Can they be replaced with the head still on? (assuming I don't do the head gasket)

Any other thoughts or suggestions?

[KrazyKarl]

The head gasket was still in decent shape on my 116k mile S2 when I pulled the head of because of a crack. While replacing it probably isn't necessary, like a lot of things it's easier to do now with the engine out of the car. Pretty much the same story with rod bearings, unless there is evidence the engine has lived a hard life the rod bearings are probably in good shape at 76k. They can be removed with the head on and without removing the crank.

I would suggest replacing the oil cooler seals and gasket while the engine is out, along with inspecting and replacing the OPRV seals.

[HondaDustR]

At $70 a set, I would throw new rod bearings in just because hopefully the motor will not have to be disassembled that far again since it's getting a new oil pan gasket. People say to replace rod bearings at ~120K just to be safe and they can be done with the head still on. If it's a weekend car that doesn't see any miles, it might not be worth it, but still... I'd do it even then, since speaking from experience doing the oil pan gasket and rod bearings with the engine conveniently upside down on an engine stand, I don't have any desire to know what exponential PITA factor would be involved when doing them with the motor still in the car. Peace of mind and knowing you hopefully won't have to pull the oil pan anytime remotely soon would be worth $70 in my book, especially if you like high revs, which the 16v certainly does.

If it were me, I would replace the cam chain and tensioner pads just to be safe. That failure gets really expensive in a hurry.

When you say Balance shaft seals, be sure you include the rear plug o-ring, and don't forget some Locktite 574 to re-seal the housings. Another job 10x easier when the motor is out of the car. Same deal with the oil cooler seals. $40 now will be 10x easier than $40 plus another PITA job later if they start leaking, assuming they don't leak already. They say 87 was the worst year for seal failures. I don't know if that includes the 16v motors, but if the seals are original, they are probably the red ones, which means they are milkshake timebombs. The updated green o-rings are reliable. Just make sure the galleys are smooth, as they should be, but mine weren't, the o-rings don't stand up to any abrasion, and you can guess what resulted...

If the head gasket isn't leaking, I wouldn't mess with it, and that's one of the few jobs that really wouldn't be much harder with the engine still in the car, except for maybe removing the exhaust headers and bending over the car scraping the block surface clean.