bassam

I got a 1971 race car two weeks ago and trying to solve some poor running issues, when I'm driving the car all seems normal till I reach 2800 rpm, it starts missing and running really rough till about 3500 then it runs good with couple of misses at 5500 rpm. The problem is worst if I floor the car real quick and its less pronounced if I go gradual on the gas pedal. From the build sheet of the car here's what I know about the motor:

2.2L
pistons 85mm 10.5/1 compression
crank 66mm stoke
heads 38 intakes and 36 exhaust
valves 46 mm intake and 40mm exhaust
cams: 284 degrees intake and 270 exhaust

46 PMO carburetor
46/38 cis manifolds
46/38 venturis, 150m, 180 a/c, f16

took the car to the dyno, the car requires 100 octane but wasn't available so did some runs on 93, (I know, wont do that again) it is running very lean from 2800 to 3500 (this is when its running really rough) then it starts pulling nice but lean as well. Did some searching and I'm thinking maybe I need bigger main jets? or is it just tuning what I have? will race fuel solve the lean problem? here's the dyno runs:

race911

It really has 46s? I think maybe on one of the 2.4 or 2.5s with RSR cams we tried that back in the Fred Flintstone days, but I can't recall.

Suggest you work with an expert to get things dialed in..................

Ed Hughes

+2.2-pretty hard to dial a motor in over the Internet.

Steve Weiner-Rennsport Systems

Bassam,

You need some serious revisions to the "package" and I have a lot more questions about your engine.

Call me as this one is FAR too complex for e-mails or Forums.

bassam

Yes, 46 PMO's. I'm not an expert but I thought they are too big for the motor too. I posted the same question on pelican and it seems with my Flintstones cams, 46 will work (according to couple of replies) one is an engine builder. Now the motor was built in 2002 and the car has few hours on it. I called PMO and they suggested to go with size 60 idle jets and 160 main jets. I ordered the parts and will test the new setup when I get my hands on them. Thanks for the reply and here's other feedback I got on the other forum:
http://forums.pelicanparts.com/porsc...ace-motor.html

this is the cam I have:

bassam

Will do, thank you Steve.