If you want to buy all new pistons, cylinders, heads, crank, and possibly induction, then you can use the factory published numbers to answer your question.

if you are certain that you do not want to cut the spigots on that case then you can build it as a T/E/S in various displacements of 2.0/2.2/2.4

you will have anywhere from 120hp to 180hp
you can make radical modifications past that for another $5-10K
if you want more power.

the most economical thing to do with that case is to keep it stock at 120hp

If you want more power then the most economical thing to do would be to use a different motor. You already do not have a numbers matching motor for your chassis so it wouldn't really hurt resale.

you can buy a 3.0 motor for 4K-5K, with 190hp and that is about 1/3 of the cost of building something similar out of your block.

the question is somewhat impossible to answer, because you haven't defined how much money you want to spend.
as well as how much hp you want to have.

if you want 10hp more than your stock parts will provide, that may be easily obtainable with a few bits and pieces.

if you want 50 - 100hp over what your stock parts will provide that is going to be very expensive. For that reason, people have tried to give you good advice in their response, that you may want to buy a larger motor and save $

you can build a 911 motor at nearly any HP output you want, but the cost of doing so varies greatly.

The beauty of doing horsepower with displacement is that you can build a relatively low compression engine to meet your horsepower target.

You want compression over 9.5:1 to help the low end with the cams it would take to make some high end horsepower in a 2 liter.

I see you are in Stockton and High Compression and California's 91 octane gas are not a happy marriage unless you twin plug the engine.

as a reference point.
I have a stock compression 2.0S with 9.8:1
I blend 91 octane gas with 105 octane unleaded race fuel at a 50% ratio

makes gas rather pricey, but should keep the motor happy with a computed 98 octane.

just wanted to throw this in for the original poster's benefit.

brant

I use 91 octane in Cali when I drive down with no perceivable issues on my 2.0S. It might be wise to dial back the timing a bit if you live there, but I haven't heard anything definitive on this.

Another bump for a thread I'm closely following. I'm also looking to get the best from my 2.0 case.

My 1968 911L 2.0 engine is completely apart at the shop and now it's decision time. The car is in decent shape, and very stock. I plan on keeping it that way for now, and using it for fun weekends/occasional DE's/historic rallies, etc.

I want to use the original numbers matching 2.0 mag case. I realize that swapping in a 2.4/3.0 may be more economical in the short term, but I only want to do this once.

I can do a stock rebuild at 130hp, or modify the existing engine. I'm seriously thinking of buying Mahle 2.0S P & C's, some head work, rejet my Webers, S cams, and end up with essentially a Euro 1968 "S" at 160hp.

Another option is to get 2.2 S P & C's and bump it up to a 2.2S engine, but I'd like to keep it in the 2.0 class as a solid basis for possible future vintage racing classes ;)

http://forums.pelicanparts.com/uploa...1155550322.jpg


Any thoughts would be greatly appreciated.

Thanks,

"....as a solid basis for possible future vintage racing classes "

I'd think a suitably-built, non-numbers matching engine would be more appropriate for that purpose. Tuck the orig. engine in a corner of your workshop for the time being. Do they have concours judges at the vintage races too? (nope).

MHO,
Sherwood

There is always the issue of layshaft and layshaft bearing wear in a 2.0 alloy case. The layshaft runs directly in the case with no removable insert and good layshafts were hard to find last time I looked for one. I would make sure I had a plan in place to address this issue before I dismantled the engine and for sure would not buy any parts until I had surveyed my crankcase.

So, let's say the case is good and if you don't want to bore the case for larger bore pistons and want to use readily available pistons and cylinders, I would go with a 2.4 bottom end (70.4 mm crank, short rods) with stock 2.4 S pistons at 8.5:1 CR or 2.2 S pistons which will give over 10:1 CR on the 70.4 mm crank.

The latest Mahle pistons I have used are made with Nikasil cylinders (really nice, better than original Biral) for the 2.2 and 2.4 S replacement parts so you should probably install a case squirter set to cool the pistons.

I like to use the early pre-74 oil pump, the one with the small pressure/large scavenge pump along with the oil bypass modification normally used with the later pump. This keeps some oil out of the case which appeals to me. Also I use the late SC venturi oil screen pick up on the suction side of the scavenge pump which I feel also helps lower the level of retained oil in the crankcase. Using the later small bore camshaft oil line fittings restricts flow to the cams and increases oil pressure with the small oil pump. I have used the late pressure bypass springs and the late hex head relief valve screw caps. I have only done this on a racing engine.

If you use 84 mm bore pistons I would go to 2.2 heads rather than use the 2.0 modified for the 84 mm bore which I am told some have done. Besides a more flat combustion chamber that fits the bigger bore, the 2.2 heads have bigger valves...which I like.

I am sure many have other opinions......

Hold on tight! I will have a complete '67S/68S 2.0 top end, including pistons, cylinders, heads, cams, cam towers...the whole shebang for sale very soon. I am swapping the '67S top end out on my '69S for a correct '69S set. This should definitely do the trick for you. I can vouch that it is very, very fun to drive and the leakdown numbers are excellent.

Kenikh,

You have a PM. :)