PMO vs. Weber on 2.0-2.7

[Joe911]

The long term trend seems to have been to replace MFIs with Webers - but Webers are wearing out and will be needing expensive rebushing etc. over the next few years.

I will be needing a set of carbs for an early mag case engine and am considering either used Weber 40IDAs ($700-1200 for a good set) or a set of 40mm PMOs.

The issues are - (1) what is the chance of getting a good set of Webers on the used market - which very much depends on how "used" they turn out to be and (2) Where to send them for high quality rebuilding?

AND OF MOST INTEREST TO ME (3)How great are the PMOs ($2100 as per Panorama advert)? Can anyone comment from personal experience with PMOs vs. Weber 40IDAs? I assume they are better than a new set of Webers but how much better? Are they worth the extra $$$ in the long run?

[Early_S_Man]

Well, you aren't really comparing apples to apples when talking about $2800+ PMO's with manifolds to a set of used Webers with manifolds, but ...

Check with Jack McAllister about the cost of getting used webers rebushed ... I think you could buy TWO COMPLETE sets and have them rebushed before coming close to the cost of the first set of PMO's! Not that the PMO's don't look and run great out of the box!!!

[Hatari]

Joe,
The typical going rate for a set of used Webers seems to range from $1,000-$1,200 complete with linkages and manifolds. I sold a rebuilt set of bare carbs last year for $800 plus shipping. Here's the bottom line for rebuilding...I know that many shops quote around $800 for rebuilding the set, but consider this:

The rebuild kits for a pair of 40IDA3C's (for complete overhaul) are about $90 (last ones I bought). This will replace all gaskets, needle valves, o-rings, etc.

Floats (if you can shake them and hear fluid, then they need to be replaced). I had to replace 2 out of 4 on the last set I rebuilt. They run $28 or so ea.

"Weber Carburetors" by Pat Braden is $12-$20 and is available at good book stores...gives step-by-step instructions on the rebuild with photos all the way.

IF...the throttle shafts are loose, then the carb will suck air at idle and impossible to really tune...they will also vibrate and make a knocking noise which really freaks you out until you know what it is. Oversize shafts are available from Pierce Manifolds. They range from $35-$45 ea. (depending on whether long or short ones, each carb has ). I had to replace one out of 4 one the last set. Pierce also align bored and installed that one for $65 and it made the carb absolutely as good as new.

So... let's see:
$1,100 Set of carbs, linkages, manifolds (used-estimated)
$ 100 Rebuild kits for both (est. with shipping)
$ 100 R&R 1 throttle shaft (parts, labor, some shipping)*
$ 56 2ea. floats*
$ 20 Pat Braden's book
$ 60 Unisys
$ 15 gallon of good carb cleaner for soaking
$1,451 estimated total

*May not need.

Also, the rebuild procedure is really basic and simple if you follow the instructions. When Warren encouraged me to rebuild my top-end earlier this year, I was really grateful for the money I saved and having the benefit of knowing exactly what was done. If you tackle, it let me know, I have easy initial set-up set of instructions which will start the engine up as soon as the float bowls are full. Then you fine tune with a Unisys.

Even if you have a shop perform the rebuild and pay the going rate, you'll still save some money.

Good luck...
Jack McAllister

[Early_S_Man]

Just to augment what Jack said quite well ...

The Weber floats are brass, and soldered together, and the pivot bracket/tab is spot-welded on, or soldered, depending on age. Sometimes after thorough cleaning, the defects can be seen. Hard solder, either 100% Tin, or Tin-Silver alloy, can be used to repair pinholes or cracks, perhaps with a very tiny patch of thin sheet brass or copper. Likewise with the pivot. If you may have to replace them anyway, it is worth the effort to attempt repairing them, or getting help from someone with a propane torch and soldering experience ... but they DO need to be dry, and free of gasoline fumes before any attempt at soldering is made!!!

[Oldporsche]

A good machinest can help you with a worn set of Weber's. It isn't difficult to bush these carbs correctly. The setup of the equipment is probably the most difficult. I have seen the carb bases repaired with bushings and oversized shafts both. I have even seen repaired shafts.

I believe that the rebuild costs previously stated will cover the cost very well. Take a look at Bruce Anderson's book about the venting.

There is a lot information out there on these carburetors. Some tuners on the "left coast" (in more ways than one) have really solved a lot of the problems.

BTW, soldering with a good soldering iron and some acid flux (if you can find it) solder will repair those floats very well.

I happen to have a set of Weber's on a Bruce Anderson type 2.7L motor. They work very well.

Good luck,
David Duffield

[RLJ]

Buy the PMO's! After having PMO's and Webers buy the PMO's. This is your Porsche you are talking about not the parts hauler. There are times whin being CHEAP will bite you in the ass. There are some things that you should not mess with. IMHO buying used out of date carbs is a waste of money. The PMO's have more to offer than the old carbs.

People waste a ton of money on these cars cause they read all or most of the crap published in the "Mags". Belden 8mm spark plug wire that is cheap per foot, works great (my engine builer says anything more is a waste of money and if anyone here has won more IMSA races than he has I will listen to them), but they would rather spend their hard earned bucks on over rated ignition wire and then buy cheap headers. Some things on cars are importland, somethings, the difference between good and race quality, the normal person will NEVER see the difference so THINK about where you are gong to spend your money and what the reward will be.

Randy Jones
1971 911