???? 1970 2.2 T with Zeniths

degreeoff1 · 03-23-2005, 06:27 PM

Is the above 1970 motor compatable with 2.2 S pistons and S+ cams?

Thanks
Josh

FrayAdjacent911 · 03-24-2005, 07:24 AM

I'm curious about this, too.

jpnovak · 03-24-2005, 08:26 AM

Yes, but the jets will have to be replaced for optimal performance. jetting is based on peak power (among other things). The S cams and pistons will shift the torque curve to higher rpms.

Fantastic engine though. The othe issue you will run into is locating the 2.2S pistons and cylinders. These are not so easy to find.

jstobo · 03-24-2005, 12:10 PM

You will have to change the venturis in the Zeniths also. Bruce anderson's book has aneat formula for calculatiing venturi size. Weber venturi's work if you get a spacer to shim them. They are not as tall as zenith venturi but much easier to get.

mpeastend · 03-24-2005, 04:49 PM

Not to hijack the thread but I have a related question. I have a 70 911T 2.2 as well (with weber's) and a stock exhaust. Would I have to rejet or change emulsion tubes, pilots,mains, etc. if I put on a sport exhaust either from Dansk or mb911? Would the decrease in backpressure require this? Thanks MP

jluetjen · jluetjen's Garage

mpeastend; The easy answer is go ahead and put on the other exhausts. I doubt that you'll need to change the emulsion tubes since you're not changing the cams. If it has issues, you'll know that you need to fix the jetting. If it works, leave it alone.

COLDBASS · 03-25-2005, 06:43 AM

???? Hmmm, I must be losin it. I thought that S pistons and cams in the T motor would require different heads/valves for optimum performance. Also, I thought that there was a potential issue with piston to valve clearances...I'd better take more accurate notes or drink less Bass Ale...

jluetjen · jluetjen's Garage

I agree. To really get the best of your cams, you'll need to open up the ports (especially the intakes) to 35 or 36 mm. The valve sizes for the 2.2T are the same as for the 2.2S and the 2.7RS in fact. If you don't open your ports you'll loose about 20 HP at higher RPMs, but still have most of the S cam's "peakiness" at low RPM's. Piston valve clearance shouldn't be an issue as long as you're using S pistons with S cams.

COLDBASS · 03-25-2005, 03:07 PM

Quote:

Originally posted by jluetjen
I agree. To really get the best of your cams, you'll need to open up the ports (especially the intakes) to 35 or 36 mm. The valve sizes for the 2.2T are the same as for the 2.2S and the 2.7RS in fact. If you don't open your ports you'll loose about 20 HP at higher RPMs, but still have most of the S cam's "peakiness" at low RPM's. Piston valve clearance shouldn't be an issue as long as you're using S pistons with S cams.

Ah, I see said the blind man. Thanks for clarifying my confusion. Now I remember, this just wasnt a cost-effective upgrade for me. My 2.2T motor was recently rebuilt prior to my purchase of the vehicle. Just wasnt worth the additional expense to build it up.