upgrade from 2.4T to S

I am considering an engine rebuild. I would like to increase horsepower at the same time. From Bruce Anderson's book it looks like the main difference between the "t" and "s" engine are the heads and the cams. Is the a correct assumption or is there something else that would need to be changed at the same time. I have also been told that I should just drive it until it breaks and then bolt in a 3.0 engine from an SC. Any suggestions?

Actually, there are four other significant changes for an 'S' engine: distributor, pistons & cylinders, injection stacks, and 'space cam' inside the injection pump, so it is not a trivial change, or inexpensive, by any means! The 'S' crank and rods were 'nitrided' by the Tenifer process, but most people making the 'S' conversion have not needed to go to that length, there being sufficient reserve strenth in the 'E' and 'T' components. The 'T' plastic 'injection stacks' can be modified as mentioned by Bruce Anderson, as can the injection pump, too! A quite rewarding project, much more fun than a 'plain' rebuild on a 'T' MFI engine!!!

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Warren Hall
1973 911S Targa

Thanks for the reply Warren. I have been thinking about changing out my MFI and would then change the distributor anyway. That would take care of that problem. I thought from the specs that the cylinder and piston size was the same for the T and S and the valves were bigger with a different cam. Must have mis-read that section. I may just pass on upgrading my 2.4 and look for a 3.0 in trouble and rebuild it. In this area most used 3.0SC engines are going for about $4500 to $5000 dolloars with the electronics.

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John Birkett
73'T Targa

If you want to go to 'S" spec, you can. But, most do not just go S spec, the mix and match to suite their own needs of Performance.

One note, you did not need to replace you cylinders with S Birol cylinders, you have cast iron and they will do fine. We use the cast iron when building 2.5's over bore all the time, the heat will stay down enough.

On compression, you can just bump your compression to 9.0:1 by flycutting your heads thats only under $200 and you have a better matting surface. If you want to go realy high compression, then just replace the pistons,. but not with S, go a set of Billet, that has a lighter wrist-pin and comes valve pocketed to your camshaft choice.

Then for heads, just port them out with your manifolds to match, the vlave size is the same.

Then you can just re-curve your dist for any spec you may need in your Performance set up, but do NOT spend $700 on an original S dist, if you want to spend money go CRANK-FIRE!

Now on finding a 3.0, if THIS is your route then look for a 1978-1979 SC 3.0, this motor will be the simplist, since there is not brain or wirring harness to mess with, also the have he larger ports and manifold runners, but ALL 3.0's are around 20 years old and at 10,000 miles put on a year, thats 200,000 mile old engine, so rebuild time again.

One note to, if you are going to spend the money on a 2.4 S spec, then why not just go 2.7 or 2.8, since the crankshaft and rods and heads are the same, you will just need Pistons and Cylinders, you will need to Time Sert the case on a 2.4 or 2.7, BUT the 2.7 will need Performance head studs as will a 3.0 and a 3.2.

A nice 2.7 will put out around 225HP and will pull hard with the transmission you have, your transmission is a 7;31 sam as a RS or RSR.

When buiding a motor look at ALL your options.

Good luck with what ever way you choose and good advise from the list.

Roy at http://www.motormeister.com