52' Type 527 Comp Engine Carburetor Question

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Don Greenman
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52' Type 527 Comp Engine Carburetor Question

#1 Post by Don Greenman »

Hello,

I need the experts help on this one.

Does anyone know what the correct carburetors should have been (or should be) on a 1952 Porsche Pre A type 527 1.5 litre comp engine with a early Hirth roller bearing crankshaft?
Appreciate any clarity concerning this matter.

Thanks,

Don

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John Brooks
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Re: 52' Type 527 Comp Engine Carburetor Question

#2 Post by John Brooks »

John Brooks

62 Roadster
66 912
84 Cab
getting pushed around in porsches since 1965

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Alan Hall
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Re: 52' Type 527 Comp Engine Carburetor Question

#3 Post by Alan Hall »

It is my understanding that the 527 engine had 40pbic carbs up to engine number P-30250 and 32pbi carbs for engines P-30251 and later. I believe the jetting for the two version is as follows. The 32pbi used had a 26 mm venturi, 115 main jet, 55 idle jet, 1.0 idle air jet and 180 air correction jet. The 40pbic used had 26mm venturi, 115 main, 55 idle, 1.0 idle air and 160 air correction.

Don Greenman
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Re: 52' Type 527 Comp Engine Carburetor Question

#4 Post by Don Greenman »

Hello John,

The spec book helped a lot. I think these are the correct carburetors for my 52' 356.

Thank you for your help,
Don

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Re: 52' Type 527 Comp Engine Carburetor Question

#5 Post by Don Greenman »

Alan,

Thanks for your help on this carburetor question. What you have shared with me is excellent information. Our mechanic is going to check the engine # tomorrow.
Full discloser:
I purchased this 356 from a private party 2 months ago. The car has been static for over 2 years. So the owner is making sure the car is in tip top shape before he ships the 356 to me. One of the things that came up was that there was no push cable (choke cable) going to the carburetor from the dash. Let me clarify what is there currently. There still is a choke cable going from the dash to the engine compartment, but it has been cut. Or so they think it might be cut intentionally. The owner got the car this way.
He had the Porsche restored, and did attempt to addressed the choke cable concern. He found out that the 32 pbi carburetors
that are on the car had no choke parts on them. So there was no way to attach a new "longer" choke cable to the carb.
I just started talking to his Porsche mechanic recently. One of the questions that came up is... are these carbs the correct ones for this matching numbers 527 engine. With the existence of the shortened choke cable being there we are not sure now.
Here is a couple questions I have that I hope you can answer.
Is it possible that choke cables were installed on all 52' Pre A Porsche's from the factory? And used on specific carburetors?
Maybe the 1.3 Litre motor in 1952 used the choke cable mechanism, but not the other 1500 engine options. Just thinking out loud.
Should we even attempt to find choke parts for the drivers side 32 pbi carburetor, and hook it up?
I am concerned that if we don't connect the choke cable to the carb it might be a deduction at concours events.
Any advice at this point would be greatly appreciated.
*I included a photo of the choke cable knob on the dash.
Thanks,
Don
Attachments
Porsche 356 Choke Cable Knob.jpg

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Alan Hall
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Re: 52' Type 527 Comp Engine Carburetor Question

#6 Post by Alan Hall »

Don, The choke cable would have been installed in all cars in '52. Both carbs would have had the choke mechanism installed but the right side would have had a stiff wire installed to hold the choke in the off position while the left side would have had the choke cable hooked up. The choke was really not needed and so it was not uncommon for folks to delete the choke hookup and wire both sides off. Also the choke fitting on the carb is a casting and was often broken and replaced with a cover plate as was used on later 32pbic carbs. I don't know how this all affects judging but the original would have had the choke fittings on both carbs.
Attachments
DSCN5599.JPG

Don Greenman
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Re: 52' Type 527 Comp Engine Carburetor Question

#7 Post by Don Greenman »

Alan,

You are wealth of knowlegde on these carburetors. I am so glad you replied to my questions on the Pre A Corner forum. Can't thank you enough for taking the time to help me out on what's been an unsolved mystery on our end, We only thought we needed to put the choke mechanism on the right side carburetor. My next question would be.... do you know a source where I could buy the choke mechanism set up for the Type 527 32 pbi carbs?
Thanks!
Don

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Alan Hall
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Re: 52' Type 527 Comp Engine Carburetor Question

#8 Post by Alan Hall »

Don, The choke casting is being reproduced by a fellow in Italy who sells parts on ebay under the user name alfa1750 as I recall. Not sure of a source for the other bits, but you might ask carb rescue. I just checked Alfa1750 listings on ebay and it looks like he now sells the complete choke assy. Don't know anything about the quality or correctness of it but the ebay item number is 266028746073 if you want to check it out.

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Rick Albro
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Re: 52' Type 527 Comp Engine Carburetor Question

#9 Post by Rick Albro »

Alan is right that in most of these early cars the fuel enrichment mechanism has been deleted. The choke knob and cable are not what you show in your image within the green circle (I have reread the post and decided your circle is red not green) but the "S" knob is connected to the enrichment mechanism. Your image shows the "H" knob the lighter knob, and the third knob. A lot of the mechanisms become warped and leak. The cable is only hooked up to one side as shown in the below images. The operation of the choke cable also takes a considerable effort to have the knob operate the mechanism. The cable is long and the travel of the dash end is relatively short. Even if you have the enrichment mechanism most people would use a gasket to block off the internal pathway and simply add an external cable for show... Making the system work is more a matter of principal than of function... Some would insist on making the system work but the return for the effort is usually not there... this becomes a matter of choice... If your goal is to get every possible point in a judged contest then that is different from enjoying and having a functional car... Many people may disagree with my opinions, I like to balance my enjoyment with efforts and balance my passions with reasonable expectations... I would certainly try to make the system work but also realize when a point of diminishing returns has been met... I think you will find many people will support your passion and drive as long as your enthusiasm carries the day...
S knob routing part 1.jpg
S knob routing part 2.jpg
IMG_0100.JPG
Many people sell various parts of this mechanism. I have in the past made complete sets that are exact duplicates of originals. I would check to see what is available on the shelf first.

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Re: 52' Type 527 Comp Engine Carburetor Question

#10 Post by Don Greenman »

Alan,

Good call. We contacted Jim at 356 Carburetor Rescue. He suggested the same thing. Buy the parts from alfa1750 on ebay. Jim only has bits, and pieces of the original choke parts for the 32 pbj carbs. We are contemplating this reproduced choke parts option.

Once again thanks for your solid information.

Thanks,

Don

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Re: 52' Type 527 Comp Engine Carburetor Question

#11 Post by Don Greenman »

Rick,

Once I started this quest a couple days ago I had no idea what information & comments I would be receiving concerning
re-attaching the choke cable "enrichment mechanism" to the carbs on my 52' 356. All of you who have pitched in with your great
advice has given me a lot to consider. You have brought up a lot of great points. From what I keep hearing from you, and everyone else is that the factory installed enrichment system is not "ALL" that. As you put it.... the return on the effort is usually not there. Having the cable in place for "show" seems to be a smart option. As long as the cable is hooked up to the correct choke parts on the 32 pbj carburetors.I would be happy with that. Jim at 356 Carburetor Rescue said the reproduction choke mechanism from Italy is not a factory match at all. I won't be happy putting something on our 356 that doesn't match the factory original enrichment mechanism parts. So I better start hunting now for factory choke parts. Any help would be greatly appreciated. My wife & I live in So. Cal. We want to drive our 356 to So.Cal Porsche & 356 events here on the west coast. We also own a 1975 Porsche Targa 911S. Currently going through the 2.7 motor. Another fun Porsche to drive. We have talked about entering the 356 in the Porsche Parade event in Palm Springs next year. The car has been beautifully restored. This is the only item that we are trying to reconcile.

Appreciate your help, wisdom, and great advice.

Don

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Rick Albro
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Re: 52' Type 527 Comp Engine Carburetor Question

#12 Post by Rick Albro »

There is an enrichment valve on both sides but only one is hooked up. The passenger side assembly has a short length of wire and is in a fixed position.
enrichment.jpg
IMG_7026.JPG
60631.jpg

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Re: 52' Type 527 Comp Engine Carburetor Question

#13 Post by Albert Haefner »

We put a plain paper gasket under the lid. So the choke is out of order. We do it for all carbs 32 and 40 on 356es.
Need no choke ( see from 356 A on ) and is a source of difficulties and problems also due to a 3 meters long Bowden.
 

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Re: 52' Type 527 Comp Engine Carburetor Question

#14 Post by Vic Skirmants »

Rick; why is the passenger side "choke" upside down?

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Alan Hall
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Re: 52' Type 527 Comp Engine Carburetor Question

#15 Post by Alan Hall »

Vic Skirmants wrote: Sat Dec 31, 2022 8:29 am Rick; why is the passenger side "choke" upside down?
That picture show a carb that is not a 356 carb ( I believe it is a 32picb, probably from a Borgward or Mercedes)

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