Pmo V Weber

[JV911SYDNEY]

Greetings,

Inspired by the recent carb conversion threads i've decided to take the plunge. i have a few questions and thought i'd call on the collective knowledge of pelican.

Engine is a rebuilt (standard spec) '83 3.0 with SSIs & monty

1. differences between pmo & weber, pros & cons, what's better?
2. are webers still available new?
3. i've found a set of used webers at the "right" price. how much to refurb?
4. above webers came off a 2.7. are the manifolds the same?
5. cam choices...964 or other?

thanks in advance,

Jeremy

[Steve@Rennsport]

Jeremy,

Operationally speaking, there is no comparison between Webers' and PMOs'.

PMO carbs have many useful features that Webers' do not have; ball-bearing mounted shafts, center hung floats, high resolution idle & progression metering circuits, and sight-glass windows to check & confirm float levels.

Webers' are long out of production and the American-made ones (Carter) were terrible.

Used Italian-made ones are good but are NOT cheap to properly refurbish. Aggressive cams wears the throttle shafts & bushings rather quickly.

The 2.7 manifolds may fit but it depends on what size the ports are at their bases. Your SC has smaller intake ports than most 2.7's. PMO does make them specifically for your 3.0 of the correct size.

964 or 20/21 cams will both work.

[Porsche-O-Phile]

If money were no object, I'd say PMO all the way. However for the price of a PMO conversion, you could buy (and refurbish) two sets of Italian Webers. And probably have money left over.

Something to consider.

I have heard that PMO's support is good, which counts for something. At some point I will probably spring for a set, but given how expensive they are, it might not be for at least 2-3 years.

[JV911SYDNEY]

thanks steve, excellent info as always

so determining factor will be cost to rebuild and manifold (extra cost if not correct)

the guy with the webers is going to email me some pics and stats which i'll post

[JV911SYDNEY]

thanks jeff!

the beauty of the PMO is that it comes as a complete kit. i dont know at this stage what else i'll need with the webers in question

[ael911]

Jeremy, your car is gorgeous. The winner for me was PMOs and I'd say you get what you pay for. Check out my recent conversion thread if you haven't already done so. The PMO kit has just about everything you need except a torch to heat the old studs loose as in my case.

If you decide to go with PMOs, Steve Weiner will point you in the right direction.
Andy

[JV911SYDNEY]

thanks andy

your conversion thread is what tipped me over the edge! gorgeous!!!

Steve Weiner is a great guy, always very helpful

[JV911SYDNEY]

oh any suggestions on where to source cams?

couldnt seem to find 964 or 20/21 cams with our host

any other tricks when ordering?

[Mr9146]

PMOs are nice ... if you can tune 'em.

[RWebb]

think a PMO is harder to tune than a Weber?

if so, why?

[JV911SYDNEY]

Originally Posted by RWebb

if so, why?

+1

i've had twin webers on other cars and they werent hard to tune. a good dyno run initially and voila!

[Mr9146]

Originally Posted by RWebb

think a PMO is harder to tune than a Weber?

if so, why?

Not harder, just different.

[justinp71]

What kind of MPG are you guys getting with carbs? I am thinking about a cis to carb conversion, but its hard with gas at $4/gal.

[richemj]

Originally Posted by JV911SYDNEY

oh any suggestions on where to source cams?

couldnt seem to find 964 or 20/21 cams with our host

any other tricks when ordering?

John Dougherty Racing Cams.... http://drcamshafts.com/ ... the "Steve Wong" of cam design!

[justinp71]

I agree, I just got his DC19... Does anyone have any experience with this cam?

I saw a post awhile back (can't find it anymore) someone ran this cam in a 3.0 CIS car with the cam retarded for more torq and it ran very well...

[Formerly Steve Wilkinson]

I have PMOs on a 3.35-liter twin-plug SC and get from 13 to 17 mpg in typical sporty but definitely not crazed rural driving. My absolute best all-highway, trip-to-the-Glen mileage was 19.

As for PMOs versus Webers, one major advantage is the utter completeness of the PMO kit. I replaced CIS (obviously) with the PMOs and every last thing I needed to do so, and to do so as a total amateur, was in the PMO kit.

They are _very_ simple to tune. At worst, you'll need a couple of dyno runs by a pro (Rick DeMan of Nyack, New York in my case) to lock down the basic jetting parameters, and you probably won't ever have to touch anything again, but if you do, PMO's instructions are crystal-clear. PMO is also there to respond and help. ("Mister Weber, can you hear me now?")

[Formerly Steve Wilkinson]

I have PMOs on a 3.35-liter twin-plug SC and get from 13 to 17 mpg in typical sporty but definitely not crazed rural driving. My absolute best all-highway, trip-to-the-Glen mileage was 19.

As for PMOs versus Webers, one major advantage is the utter completeness of the PMO kit. I replaced CIS (obviously) with the PMOs and every last thing I needed to do so, and to do so as a total amateur, was in the PMO kit.

They are _very_ simple to tune. At worst, you'll need a couple of dyno runs by a pro (Rick DeMan of Nyack, New York in my case) to lock down the basic jetting parameters, and you probably won't ever have to touch anything again, but if you do, PMO's instructions are crystal-clear. PMO is also there to respond and help. ("Mister Weber, can you hear me now?")

[ael911]

I think I can get close to 20 mpg if I cruise softly. But it's hard to drive civilized when you hear the sounds the carbs make. With my lead foot, I'll see about 15 mpg and many more trips to the gas pump.

[moneymanager]

Nearly everyone knows the PMO is a way superior product. But some don't recognize that the cost is very competitive. I assembled my motor two years ago. At that time a decent set of Webers, unrestored, was $1200--1600; I'd be amazed if they are less today. That didn't include $200+ worth of air cleaners, a device to control CIS fuel pressure, big pieces of linkage, hoses, manifolds, and, most of all, the several hundred dollar rebuild that was in my future. The PMO's were more than competitive.

[Formerly Steve Wilkinson]

That's exactly what I meant when I posted that everything--everything--is in the kit.