Back on the topic of Rebushing Solex 40PII Split Shaft carburetors. This week I am starting on a 40PII rebuilding project. At least a decade ago I bought a bunch of 40PII cores, that have been sitting. Finally finished some other projects so I am back on them. The cores were mostly throttle bodies, not complete carburetors, and they were split half and half between split and solid shaft. My thinking then was to rebush and bore the lot of bodies, then sell them to people who wanted to rebuild 40PII's, but did not have the capability to do the machine work. I will get to the details later.
The split shaft 40PII strictly speaking is not a 356 part. They were a redesign of the solid shaft 40PII that was introduced for the 912. A number of changes were incorporated when the split shaft was introduced. The major changes included A) the split shaft B) dependent idle circuit C) New design mixture adjustment screw D) Additional drillings in the idle circuit E) transition vacuum port for the vacuum retard distributor on the 912 F) Improved throttle shaft bushings G) change in location of the accelerator pump bleeder H) changed jetting (mostly as a result of B). Probably other things, please add anything I have missed. There were a lot of claims when split shaft carbs came out that they improved the idle and transition circuits, and owners were happy about that. However, the split shafts proved problematic, so that over-shadowed the improved running, and gave the 40PII's a bad reputation.
So today was spent rebushing. First task was to remove the bushings, second was to pull the actual bushing out of the outer carrier, then install new bushings and re-install in the carburetor.
A ⅜-16 tap was used:
However, these carbs are 60+ years old. at least half of the bushings started spinning when the tap was in about 2 threads. After pulling them it was clear that the retaining compound had failed. The bushings are two piece, with an outer carrier and an inner bushing. The inner bushing is pressed in place, but the carrier is a loose fit, held in place with a retaining compound that is '60's technology. So it is even easier to remove the bushings by driving them out with a punch and hammer. I made a small driver that was 7.75 mm in diameter with an 11 mm shoulder, so it would fit in the bushing and clear the carb body.
That made the job of removing the bushings easy. But, for those bushings that I was able to tap without spinning the outer carrier, I made a puller to extract the inner sleeve. For the bushings that were driven out whole, I needed a way to hold the outer carrier, so that I could tap it and extract the sleeve. I could have put them in the lathe and drilled out the sleeve, but that proved to be unnecessary. I used a 5C collet block to hold the bushing, and it worked fine. However, if you don't have a collet block, drilling the sleeve with a drill just under the sleeve diameter would make it easy to remove.
The puller body was just a piece of scrap. It had an i.d. large enough for the sleeve to go through and small enough to block the carrier.
Only 2-3 threads are needed to pull the sleeve.
This shows the 4 carriers after extracting the sleeves:
A ball hone was used to clean the bores in the carburetor and inside the carrier: