2.0 Engine Build Advice from the Community Experts

[danwiniger]

I have an early '68 T Engine. It is the Aluminum Case, with counter balanced crank. I am trying to come up with a plan to increase the HP slightly, around the 140 to 160 range? I was thinking of starting with a JE set of 81mm 9.5:1 P&C's. Can I use my T heads, (modifications needed?), and T-Cams (Re-ground?) to achieve a good street running engine? It is going in a '66 911 chassis, so I want something close to the feel of an original '66, with a little more kick. Would these heads work with the JE P&C's, and what kind of Compression ratio would I end up with? Would a new set of Valves, and new set of Cams be required?

I know the Mahle 2.0S P&C's are probably recommended over the JE's, but for street use, what are you gaining with the Mahle option? Are they really needed...........On a budget, but want long term reliability.

Any advise would be most appreciated.

[NeunElf]

I have an early '68 T Engine. It is the Aluminum Case, with counter balanced crank. I am trying to come up with a plan to increase the HP slightly, around the 140 to 160 range? I was thinking of starting with a JE set of 81mm 9.5:1 P&C's. Can I use my T heads, (modifications needed?), and T-Cams (Re-ground?) to achieve a good street running engine? It is going in a '66 911 chassis, so I want something close to the feel of an original '66, with a little more kick. Would these heads work with the JE P&C's, and what kind of Compression ratio would I end up with? Would a new set of Valves, and new set of Cams be required?

I know the Mahle 2.0S P&C's are probably recommended over the JE's, but for street use, what are you gaining with the Mahle option? Are they really needed...........On a budget, but want long term reliability.

Any advise would be most appreciated.

I'm not the worlds most experienced engine builder but the interplay of all the choices you have starts to get into my real field, systems engineering.

First: Does JE make piston & cylinder sets now? Could you mean LN Engineering "Nickies" cylinders with JE pistons?

I suspect Nickies/JE Pistons & Cylinders would be just as good as Mahles for street use as long as you get the right ones.

It sounds like you're trying to build a 901/05 engine (the Weber-carbureted engine used in the later part of 1966). With the 1967-style exhaust headers (like SSIs) that everyone uses that should give about 140 hp DIN. The 901/06 introduced for the "normal" 911 in 1967 used the 1967-style exhaust headers with a milder camshaft for about 130 hp DIN.

Personally, I would stay with the stock 9.0:1 compression ratio. Pushing to 9.5:1 could make your engine very finicky to tune.

The 911S ran a 9.8:1 compression ratio but with a hotter cam that closed the intake valve later so it's effective compression ratio was about the same as the 901/015. The 911S camshaft does not work well without the 911S cylinder head's bigger valves.

Here are the camshaft specifications from the Little Specification Booklet. The 901.105.109.04/901.105.110.04 camshafts (usually called the "Solex" cams because the profile's the same as the 901/01 Solex-carb engine) was the hottest camshaft Bruce Anderson recommended without the 911S engine's big valves:

Web-Cam can probably re-profile your cams. If not, they can make new ones.

You should also try to get your carburetrs right for a hotter cam. Here are the Weber specifications from the Little Specification Booklet:

I've never worked on Webers but maybe you can convert yours.

I don't know a whole lot about the cylinder heads. A 911T has the same valve diameter as the 911 "Normal." The 911T valve springs are a little softer. Maybe a little judicious work on the ports would be a good idea.


What I really recommend: get Bruce Anderson's Porsche 911 Performance Handbook and Wayne Dempsey's How to Rebuild and Modify Porsche 911 Engines 1965-1989

[ajwans]

Also search the Pelican Parts engine rebuild forum. Look for John Cramer's posts tagged 901/05

http://forums.pelicanparts.com/tags/901/05.html

You will spend a few hours there but it will be worth it.

andy

[Richy]

Your '68 heads probably have the same size valves as the '67S , so some porting and cams and you're close . Valve springs are the same , but shimmed differently for s cams . You should probably get the rods shotpeened and balanced as per Bruce Anderson's book . A 2.0 liter with Solex cams and '68 heads with the larger valves is a very nice engine for the street , and will still have some early 911 with Solex's personality , although with Webers .