PMO conversion, it's done...almost

ael911 · 12:54 PM

I thought I would share with everyone my latest project. Replaced the CIS with PMOs. The quality of Richard Parr's product is just absolutely top notch and well produced. The biggest hurdle for me was the intake stud removal. I broke one stud due to lack of patience and without the use of heat. Luckily, there was about 1/2 inch left of the stud exposed and a stud puller with lots of mapp gas got me out of the woods. I can't wait to hear how these babies sound after I get the throttle linkage shortened so I can achieve full throttle. Thanks to Steve Weiner for all his help and advice.
Andy

BEFORE

DURING

AFTER

JP911 · JP911's Garage

Sorry to hear about the broken stud. I had grappled with my exhaust studs (and broke several), but my intake studs came out without issue.

Congrats on getting the PMOs installed, though. I absolutely love mine! You should consider having a local shop with a dyno give them a once-over when you're done with the install. I was surprised to recently find out that mine were set up way to lean (as delivered by PMO). All is well now, but my assumption could have lead to catastrophic failure. All is well now, but my mech had to bump me from 165 mains to 190s!

911pcars · 10:05 AM

".....but my mech had to bump me from 165 mains to 190s!"

The jet sizes used by countless other owners indicate a finite boundary for those using Weber/PMO carbs. 190 main jets are really rich. 150's or thereabouts would be more like it. However, I can't answer why that size works on your engine. Your mileage would be in the low teens or less with that size.

Are you sure your tech didn't mean air correction jets instead of main jets?

Sherwood

Formerly Steve Wilkinson · 03-13-2008, 02:52 AM

When I had my PMOs dynoed soon after installation, they were way too rich as delivered. Rick DeMan said the car was "a superfund pollution site" as originally set up.

KevinS · 03-13-2008, 03:12 AM

Those sure are pretty. I just love carbs. Mainly becuase I know how to work on them. Kind of.

304065 · 03-13-2008, 03:26 AM

Quote:

Originally Posted by Formerly Steve Wilkinson

When I had my PMOs dynoed soon after installation, they were way too rich as delivered. Rick DeMan said the car was "a superfund pollution site" as originally set up.

Rick's sense of humor is as finely tuned as his 800 hp GT1 turbo.

shbop · 03-13-2008, 05:45 AM

I did this, not too long ago, and ended-up with 150 mains. Webers though, not PMO.

ael911 · 03-13-2008, 06:57 AM

I hope my 135 mains aren't too lean, but I trust Richard's judgement and I will eventually have a reputable shop double check them for me. Thanks for the advice JP911

JP911 · JP911's Garage

Quote:

Originally Posted by 911pcars

The jet sizes used by countless other owners indicate a finite boundary for those using Weber/PMO carbs. 190 main jets are really rich. 150's or thereabouts would be more like it. However, I can't answer why that size works on your engine. Your mileage would be in the low teens or less with that size.

Are you sure your tech meant didn't mean air correction jets instead of main jets?

I understand that PMO sets up the carbs based on their experiences with other engines, and has done so effectively countless times. However, my engine is unique so I should have had the setup double-checked right after I installed the carbs but I didn't. Point is, I made a big assumption (gamble?) and that was foolish.

ros74911 · ros74911's Garage

Andy, looks really great. i'm saving money to get my car done too. don't know what are the pros and cons on having a pmo, twin-pluggin, or swapping a 3.6. i think, money is the issue for me.

p.s. yes, i would love to hear it. i heard jon's 3.5 twin plug. awesome car jon.

Shearer9 · 03-13-2008, 09:42 AM

They look fantastic ! Well done Andy.

mark D · 03-13-2008, 10:07 AM

I have a 75'S with PMO's. I started with 160 mains but they were too rich went back to 150. Looks great you should love it.

wachuko · wachuko's Garage

I love the looks of that setup and plan to do the same on my '83 SC.

Congratulations on your PMOs!!

Kemo · 03-13-2008, 10:26 AM

That sure does clean up the engine bay! looks incredible

Steve@Rennsport · 03-13-2008, 10:35 AM

FWIW,.....

Richard @ PMO generally gets the jetting close but IMHO, nobody should EVER assume that its optimal for each persons's engine as they differ.

Variations in local fuel composition. ignition timing, compression ratio, camshafts & valve timing, displacement, exhaust systems(!!), local temperatures and altitude all play major roles in what the final jetting will be. In short, everything,...

Add the wear & tear unknowns of an engine that is not new and one soon finds out how difficult it is to generalize.

We dyno each and every carburetor conversion (new engine or not) to ensure that the AFR's are correct and anyone doing or contemplating such things should NOT skip this critical step. Assume nothing as its YOUR engine and if you are a DIY'er, you bear the responsibility to see that its not only safe to run but realize maximum performance.

Well done, Andy. I'm going to keep your pics around here to show others who are thinking about doing the same thing.

ael911 · 03-13-2008, 12:54 PM

Thanks for all your help Steve, and I wish you were close by so I can get the AFRs checked by a pro. Anyone know of a reputable shop near me with dyno and carb tuning abilities?

911Freak · 03-13-2008, 01:16 PM

Steve, Andy or anyone else know if the PMO's can be set-up in order to pass Ca smog emissions parameters?

I've been drooling over this setup, but am apprehensive due to stringent emmision parameters...

I've read in many threads most people just flat out saying it is impossible to use Webbers or PMO's in a Ca smoged 911...but with such tech expertise I find it difficult to dismiss the probability of tweaking the AFR & CO2 etc to fall within the parameters..some the domestic cars that pass are freakin nasty! There's gotta be hope, no?

Maybe the PMO Fuel Inj setup instead?

I ask this b/c I notice Andy is in Ca...but may be exepmt due to the MY of his 911...

My current '81 w/50K on rebuilt CIS passes smog with amazing emmision #'s..the Tech can't believe how clean this 25yr+ 911 registers... BUT I'm really itching to do an upgrade on the engine 3.0-3.2 and would love to chuck the CIS for numerous reason...

Any input is greatly appriciated...sorry don't mean to highjack the aweesome thread!

JTO · 03-13-2008, 01:21 PM

Hi Andrew,
You have done so many things to enhance that beautiful little car. The PMOs are the cherry on top. Congratulations.

I hope to be down next week so I can see and hear her run!

Troy

ael911 · 03-13-2008, 01:39 PM

Hey Troy,
The real truth is you are the one who has done so much work to this car to get it to this point. I am just trying to keep the tradition going...

I hope you can make it down next week too. I am going to shorten that accelarator rod with Steve's advice to cut and braze it back together with a brass sleeve. Hopefully you and I can tune this thing over a few Sierra Nevadas...

911 Freak: I personally don't know of anyone in this state that can pass smog with carbs. Luckily, my car is the last MY to be exempt from smog. That is one of the main reasons why I took the plunge with PMOs.

TWork · 03-13-2008, 02:12 PM

If the car you want to put them on is the one listed in your sig, then you're out of luck. Post-75 cars in CA are required to have the standard emissions equipment which were on the car as it was originally manufactured -- unless you upgrade the motor to that of a newer car. In that case, you have to have the smog equipment that is standard for that newer motor.

Quote:

Originally Posted by 911Freak

Steve, Andy or anyone else know if the PMO's can be set-up in order to pass Ca smog emissions parameters?

I've been drooling over this setup, but am apprehensive due to stringent emmision parameters...

I've read in many threads most people just flat out saying it is impossible to use Webbers or PMO's in a Ca smoged 911...but with such tech expertise I find it difficult to dismiss the probability of tweaking the AFR & CO2 etc to fall within the parameters..some the domestic cars that pass are freakin nasty! There's gotta be hope, no?

Maybe the PMO Fuel Inj setup instead?

I ask this b/c I notice Andy is in Ca...but may be exepmt due to the MY of his 911...

My current '81 w/50K on rebuilt CIS passes smog with amazing emmision #'s..the Tech can't believe how clean this 25yr+ 911 registers... BUT I'm really itching to do an upgrade on the engine 3.0-3.2 and would love to chuck the CIS for numerous reason...

Any input is greatly appriciated...sorry don't mean to highjack the aweesome thread!