porsche mania

I've managed to find an early 993 engine, so non varioram, for a price I can't refuse. The engine is stripped already and I've been able to measure everything with a set of verniers and the engine appears to be very low mileage or at least very recently completely rebuilt. My plan is to 3.8 and cam the engine and then slip it into my c2. I already have spare heads for a 964 that I've already rebuilt along with many other nos 964 engine parts. What I want to know is what the differences are with the 993 engine so I know what parts are interchangeable. I know the 993 has hydraulic lifters which I'll be changing back to mechanical but am I better off using the 964 heads or are the 993 ones easy to adapt to mechanical lifters? Will my existing wiring loom and sensors fit the 993 engine or will I need to source this also?
I've been considering doing this work myself as I've rebuilt a fair few engines albeit motorcycle ones! And I also did a lot of the wilork when the original c2 motor was rebuilt. If it gets too much I have plenty of professional help on stand by so I may as well have a go!
I should be picking the motor up in the next week so I'll put some pictures up of the big box of bits I get!
Thanks in advance, Jim.

Rocket Rob

Sounds like an interesting project. The one item that I can think of right away is that the 993 exhaust flange bolts are opposite the 964 style, so you will have to either modify the heads or your heat exchangers

budge96

You should be ok with the exhaust flange studs pretty sure the heads even
964 have the holes existing for the later stud arrangement .
As far as the engine harness you should be ok as well , it simply connects
the rear fuse box with the starter , alternator and oil pressure.
I guess the question is are you using your 964 intake and ECU or are you going to the later 993 ECU and intake ? If so it of course has a different
harness.
The earlier intake and brain will work on the 993 though and yes mechanical
valve train can be retrofitted to the 993 heads..the RS mechanical.
Sounds like a cool upgrade..Bert

justin-in-athens

I think you'd definitely want to move over to the 993 intake and ecu so you can take advantage of the maf vs the old afm sensor on the 964. You will probably want to have a custom chip made for that ecu, as the '95 is the only 993 that is chipable.

apanossi

993 pistons and crankshaft are slightly different in weight than 964. Specifically, 993 pistons are heavier but crankshaft is lighter. Not sure what happens if you mix and match.

porsche mania

I'm sure I remember reading that some where. The crank of the 993 and the rods I'm sure are lighter. The 993 has smaller journal's on the crank which makes the 964 crank more desirable to build a track motor. I'm sure the little end on the 993 rod is larger than the 964 rod but I'm sure is the same length. I have a 964 crank laying around so may go this route if I decide it's necessary. Does anyone know if the cases are the same?

porsche mania

Is there a way going having to change the ecu if I use the 993 intake. I planned to use it as I'm sure that's where the power gains over a standard 964 motor are?

Earlydays

The majority of the power gains between a 964 and a '95 993 (non-VarioRam) is the revised exhaust system.

budge96

The cases are the same I believe it's the crank , rods and bearings
which vary depending on the crank used .

Normandy 964

I have a 993 non-varioram in my C4.
I can't tell you anything about the engine internals, but I can tell you about the rest of the installation.

MAF/Motronic - I assume that you want to keep the inlet manifold and MAF, so you will need the 993 Motronic and engine harness. This link has some great info on the harness modifications needed : http://forums.pelicanparts.com/porsc...need-help.html
I saw in a thread somewhere that you need a 993 Motronic without 'Driveblock' otherwise you need to change to the 993 alarm too. I can't confirm this, since mine doesn't have the immobilizer system.

Exhaust - I would also assume that you want to use the 993 system since it is much freer flowing. The standard mufflers don't fit inside 964 rear wings, either you have to modify them to drop them down a bit or do as I did and fit smaller ones (Supersprint).

Oil Hoses - The main oil feed on the 964 is routed around the back of the engine, this won't work with the 993 exhaust so you have to make a hose which goes under the engine and through the wheel arch up to the filter housing. The other option is to change the oil tank and thermostat/filter housing to a 993 set up and use all 993 hoses.

Air intake - The air intake rubs against the bottom of the spoiler. I cut away a little of the 'trumpet' on the inlet.

Heater hoses - the hoses from the heat exchangers to the flapper boxes need to be longer. I just bought a couple of meters of hose from a motorsport shop and cut it to length. Be very carefull how you route it and attach it away from the starter.....mine almost caught fire when the metal spiral in the hose shorted out on the + of the starter !