WTB Solex 40PI parts

[mybd911]

I'm interested in purchasing something to fix some play in my throttle shaft (that the butterfly valve attaches to, not the throttle linkage) in my 1965 Porsche 911 6 cylinder Solex 40p1

Basically my left hand bank has a lot of play in all three carbs that seems to be sucking air in making it hard to adjust the idle... Is there bushings or washers that I can buy?

Attached is a picture of my car. It's a 1968 912 (with a 1965 911 engine) made into a 1973 RS tribute car:


Merle

[1QuickS]

Hi Merle,

The Solex carbs (like most of the Webers) use teflon "bearings" in the journals that support the throttle shafts. These journals do not support the shafts well and quickly allow the shafts to rub the throttle body housings. This rubbing grooves the shafts allowing them to become loose in the journals which allows uncontrolled air to enter the intake manifold which then causes erratic running and tuning. Solexes were noted for this issue which was the primary reason why they were replaced by the Webers...at least this is what I believe.

There is nothing that I know of that is an easy solution. I am in the business of rebushing these carbs as well as the Webers and the Zeniths. The rebushing routinely corrects the issue but the process requires machine work beyond that of the typical enthusiast. Check out this page from my web site for a picture of the Teflon bushing/shaft wear issue in Webers: Weber Carbs Technical

Will send PM.

[mybd911]

Thanks for your reply Paul. You seem very knowledgable about this problem. I have
reviewed your web page and most info is on Weber carbs. Can I assume the solex
is similar and the price to repair is the same. I am brand new to this whole business
so I apologize for my lack of knowledge. Is it possible to simply buy and change the teflon bushing's.
Thanks Merle

[1QuickS]

Merle,

I typically perform a full restoration and re-manufacturing effort on the Solexes including the intake manifolds. Since you are looking to the throttle body service only then I would price in accordance to that. I think it better to discuss my service off line, so please send an email to: info@PerformanceOriented.com and we can discuss your topic more thoroughly there.

Teflon bushings are not available for Solexes but can be made, they are captive between inner and outer bushings in each journal. However, the use of Teflon bushings is the fundamental design flaw of the Solexes and the Webers made after 1966. The Teflon easily deforms under loading due to intake vacuum and mechanical operational forces; I posted a technical article regarding Solex issues on the Early 911S Registry:

http://www.early911sregistry.org/forums/showthread.php?69263-Solex-40PI-service&highlight=Solex

This posting should help explain why replacement would be a temporary solution, the shafts are worn where the Teflon was not "supporting" the shaft so new Teflon will deform rapidly and return you to your current issue.

It might be advantageous for you to consider selling your engine with Solexes to a restorer of these increasingly valuable cars and upgrade engine and carbs. You might even get lucky and get a no-cost swap-out...these early parts are desirable!

[mybd911]

Thanks Paul, very informative info will contact direct.

[chris_seven]

Solexes are notorious for not sealing well and this is only one of the defects that they suffer from but the good news is that they can be cured.

The Tefoln supports were never effective as seals and for years O rings have been added but again O Rings are a very poor means of sealing a throttle shaft. O rings are not really designed as a rotary seal and suffer from varying friction and this makes idle speed very inconsistent.

The only real way to solve the shaft leakage issue is to fit a new shaft and a PTFE Rotary Shaft Seal



While the body of the carb is being machined is also wortwhile to fit a high quality bush to properly support the shaft and reduce future wear. We use a GBB Bush which is lead free and suitable for use in a gasoline environment.



There are also issues concerning the vacuum enrichment device and the pump mechanism which are often blocked and need careful re-work and lower ball valve seat and replacement of the ball which is made from brass and has often corroded.

The upper ball valve is manufactured from glass in a brass housing and these are normally in reasonable condition but clogged. Removal from the carb allows them to be ultrasonically cleaned and replaced in good working order.

The gasket and repair kits that are commercially available are IMHO very poor quality in terms of both materials and fit.

The lower gasket that is installed below the jet carrier is oversize and too thick.
It prevents the jet carrier from seating correclty and this upsets fuel metering.

We have remanufactured these and other gaskets in high quality Klinger materials of the correct thickness and sizes.




The pump diaphragms used in these kits are a material that seems to have issues with modern high ethanol content fuel and they can leak after a relatively short time. We have ahd diaphragms made that are resistant to modern fuel.




The O rings for seating the jst carrier that are supplied in the repair kits are also very poor. They are a very hard NBR and it can be difficult to correctly seat the jet carrier. if we add to this the fact that it is common to find jet carriers with bent 'ears' the problem can become serious.

The bend on the ears cannot safely be straightened by re-bending as the Mazak casting will break. It is als difficult to re-machie the carrier as the bend can sometimes be so severe that the carrier jams on the captive screws that hold it in place.

To solve this problem we have sourced captive screws with a smaller diameter shank which allow more misalignment and made a 55 Shore A O ring that is softer then normal so alignment and sealing can be achieved with a lower force.







When combined with a few other detailed modifications to the carburettors progression circuit it is possible to restore these carbs successfully and make them run evenly and eliminate most of the 'horrors stories' that abound.

[1QuickS]

Chris has identified many of the areas needing attention to get these Solexes working well; subtle but all important.

[mybd911]

Thanks Cris, all you guys are very knowledgeable I wish I knew a few of the tech aspects.
I am considering all options
Thanks Merle

[kenikh]

Super detail, gentlemen.