52' Type 527 Comp Engine Carburetor Question

For Pre A discussions and questions
Message
Author
Don Greenman
356 Fan
Posts: 13
Joined: Thu May 12, 2022 4:43 pm
Tag: Luft 356
Location: California

Re: 52' Type 527 Comp Engine Carburetor Question

#16 Post by Don Greenman »

Thanks gentlemen. I am learning a hell of a lot on enrichment mechanism parts for my Solex 32 pbj carbs.
Trying to stay factory correct on the choke system is becoming quite the challenge.

User avatar
Rick Albro
356 Fan
Posts: 330
Joined: Thu Mar 27, 2008 12:57 am

Re: 52' Type 527 Comp Engine Carburetor Question

#17 Post by Rick Albro »

A quick response to Vic's question is simply that as Alan has pointed out it is not a 356 item but fits some other vehicle of the era. There is a partial off line discussion that suggests using one of the other enrichment valves from one of these other applications. I did not keep the responses totally isolated... Perhaps I have started to show my age...

User avatar
James Davies
356Talk Moderator
Posts: 2951
Joined: Thu Aug 15, 2013 9:15 am
Location: Heidelberg, DE

Re: 52' Type 527 Comp Engine Carburetor Question

#18 Post by James Davies »

All great info supplied here. A further note, the type 527 engine is not a "comp" engine. It is Porsche's first 1500 motor (ignoring the type 502).

People assume because the type 527 has a Hirth crankshaft that it must be "competition" or "super" or similar, but this is not the case. The Hirth crankshaft was Porsche's solution to using a 72 mm stroke in the VW case. And only that. In fact, Porsche competition engines of 1951-52, the type 514, used VW crankshaft/rods on the 1100 and Hirth on the 1500 - so competition was not the driving force behind the Hirth.

So no, 527 motors were not competition and were not supers. As you can see from Alan's jetting info, the venturis for the 40 PBIC and 32 PBI versions of the motor are the same size, leading to roughly similar performance at the same RPM. 60hp.

User avatar
Vic Skirmants
Registry Hall of Fame
Posts: 9279
Joined: Tue Oct 27, 2009 5:02 pm
Location: SE Michigan
Contact:

Re: 52' Type 527 Comp Engine Carburetor Question

#19 Post by Vic Skirmants »

James Davies wrote: Tue Jan 03, 2023 6:15 am All great info supplied here. A further note, the type 527 engine is not a "comp" engine. It is Porsche's first 1500 motor (ignoring the type 502).

People assume because the type 527 has a Hirth crankshaft that it must be "competition" or "super" or similar, but this is not the case. The Hirth crankshaft was Porsche's solution to using a 72 mm stroke in the VW case. And only that. In fact, Porsche competition engines of 1951-52, the type 514, used VW crankshaft/rods on the 1100 and Hirth on the 1500 - so competition was not the driving force behind the Hirth.

So no, 527 motors were not competition and were not supers. As you can see from Alan's jetting info, the venturis for the 40 PBIC and 32 PBI versions of the motor are the same size, leading to roughly similar performance at the same RPM. 60hp.
74mm stroke.

User avatar
Albert Haefner
356 Fan
Posts: 121
Joined: Fri Aug 20, 2010 9:10 am
Location: sw Germany
Contact:

Re: 52' Type 527 Comp Engine Carburetor Question

#20 Post by Albert Haefner »

James is right. Hirth was necessery to get the stroke of 74 in a VW split case, only possible with a closed connection rod crankshaft bearing.
With a longer stroke, the bearing half shell nuts would touch the engine case - only until when an intelligent Porsche engineer invented studs
on the lower half shell which allowed to have the nuts at the upside of the rod. This was the solution!
And then, the Hirth roller crank disappeared even for the later 528 engines. The roller crank always caused problems when used in cruising cars.
Not enough oil with the small pump at lower revs. Same reason is valuable for later carrera engines.
 

User avatar
James Davies
356Talk Moderator
Posts: 2951
Joined: Thu Aug 15, 2013 9:15 am
Location: Heidelberg, DE

Re: 52' Type 527 Comp Engine Carburetor Question

#21 Post by James Davies »

Vic Skirmants wrote: Tue Jan 03, 2023 8:40 am 74mm stroke.
*foreheadslap* Thanks for the correction Vic. =)

I'll add that all this development happened very, very quickly at Porsche. At the beginning of 1951 they developed the 1100 race engine (Type 514) using 40 PBIC and a new Fuhrmann-designed camshaft. And almost concurrently developed this into a 1500 engine for Liège-Rome-Liège using the same race components, and almost simultaneously started putting the road version of this 1500 into customer cars, all by the fall of 1951.

So while some engines in the P-30xxx series were race engines, most were street engines in customer cars. Similarly, not all engines in the P-40xxx series were type 528 (1500 Super); some were 1100 race engines.

User avatar
Albert Haefner
356 Fan
Posts: 121
Joined: Fri Aug 20, 2010 9:10 am
Location: sw Germany
Contact:

Re: 52' Type 527 Comp Engine Carburetor Question

#22 Post by Albert Haefner »

But longevity was not a strength of roller bearings.
They all died early - unless raced with high revs and a lot of oil.
 

User avatar
Albert Haefner
356 Fan
Posts: 121
Joined: Fri Aug 20, 2010 9:10 am
Location: sw Germany
Contact:

Re: 52' Type 527 Comp Engine Carburetor Question

#23 Post by Albert Haefner »

My Suggestion: Never restore a roller crank to re-use it in a car. But keep it as a Beautiful doorstop or deco object in a glass cabinet. Just take a plain bearing one. Much cheaper and no difference in performance.
 

Olivier Auvray
356 Fan
Posts: 326
Joined: Thu Apr 10, 2008 2:19 pm
Location: Porscheville France
Contact:

Re: 52' Type 527 Comp Engine Carburetor Question

#24 Post by Olivier Auvray »

Details about carburetor change:
003.jpg
004.jpg
In German, a drawing is added:
25-04-52.pdf
(4.61 MiB) Downloaded 29 times

User avatar
James Davies
356Talk Moderator
Posts: 2951
Joined: Thu Aug 15, 2013 9:15 am
Location: Heidelberg, DE

Re: 52' Type 527 Comp Engine Carburetor Question

#25 Post by James Davies »

Thanks for sharing Olivier. I had not seen this version of this document.

Olivier Auvray
356 Fan
Posts: 326
Joined: Thu Apr 10, 2008 2:19 pm
Location: Porscheville France
Contact:

Re: 52' Type 527 Comp Engine Carburetor Question

#26 Post by Olivier Auvray »

James Davies wrote: Fri Jan 06, 2023 10:52 am Thanks for sharing Olivier. I had not seen this version of this document.
In 51/52 Each owner of a 356 fitted with a 1500 cc engine received this document. It's a complement of the "glove-box" manual.

I know two versions:

-the first one has one side in Emglish, the other side is in French.

-The second one is in German and has one more page.

Tony Proasi
Classifieds Moderator
Posts: 326
Joined: Thu Mar 27, 2008 12:40 pm
Location: Louisville KY
Contact:

Re: 52' Type 527 Comp Engine Carburetor Question

#27 Post by Tony Proasi »

Does anyone have more detailed info on what they are referring to in this paragraph? In the process of dialing in my engine and I have it about 85% I assume it has to do with the transition between the idle and main circuit.
Attachments
IMG_0484.jpeg

User avatar
Alan Hall
356 Fan
Posts: 1453
Joined: Wed Mar 26, 2008 12:06 pm
Location: Orinda, CA

Re: 52' Type 527 Comp Engine Carburetor Question

#28 Post by Alan Hall »

The stabilizing hole is the hole in the butterfly plate as seen in attached photo.
Attachments
DSCN0520.JPG

Tony Proasi
Classifieds Moderator
Posts: 326
Joined: Thu Mar 27, 2008 12:40 pm
Location: Louisville KY
Contact:

Re: 52' Type 527 Comp Engine Carburetor Question

#29 Post by Tony Proasi »

Thanks Alan I appreciate it.

Alan Klingen 2
356 Fan
Posts: 427
Joined: Fri Sep 15, 2023 8:20 pm

Re: 52' Type 527 Comp Engine Carburetor Question

#30 Post by Alan Klingen 2 »

I think the carbs would be a 32 mm single barrel Solex Alan The Stable.

Post Reply