AC ACE RPM Drive
The AC 2 litre car that donated our AC Works engine was not fitted with an RPM drive like the later AC ACE. As such we are on a mission to resolve this. We have located a drive thanks to Robin Woolmer but due to the rarity they are not cheap coming in at £291 each including postage. At the time of writing this (August 2017) Robin only has a couple left. The pictures below show our engine and you can clearly see the plate where the take-off goes. Next to it is a picture of the drive. Many thanks to Will Mahany for supplying those images.
The AC Angle Drive supplied by Robin Woolmer
Our Fabricated RPM drive threaded plates
Here are the threaded plates we made to take the RPM drive. They are a phosphor bronze. Note in the pictures the drive was offered up to res thread and is on the wrong side of the plate. The alloy plate in the pictures below is the cover plate that was on our 2 litre engine. We used this as the template. If you look at the alloy plate you could technically lathe it out and thread it. However, the phosphor bronze makes a better job of it.
Could this be the part?
The angle drive for the AC ACE is a tough part to find. However it looks like the drive and bracket could have been fitted to 1940s/50s motorcycles as a speedo drive. It appears to have a round drive and not the square drive but this could machined. I am getting the dimensions to see if it will fit the AC engine. If so, it will give restorers another source to find one.
VINTAGE SMITHS CHRONOMETRIC ANGLE SPEEDO DRIVE BSA AJS PANTHER NORTON TRIUMPH
VINTAGE SMITHS CHRONOMETRIC ANGLE SPEEDO DRIVE BSA AJS PANTHER NORTON TRIUMPH
On close inspection the angle drive looks correct but the plate is a different size. It has to be the right size to locate in the engine block. So you could get away with altering the drive a tad. By my reckoning the plate is one centimetre too big and the bolt holes are slightly located in the wrong place.
Driveshaft for the square drive of an AC taco drive
The horizontal drive shaft from the crankshaft gear to the distributor spindle, located at the base of the distributor, (on engines with a tacho drive) has a female square socket to take a square spindle to the angle drive. Rod Briggs has some of the shafts with the socket at £88.88 each. Here's mine below for reference. You will need to make this conversion as the AC litre engine was not set u to take a rev counter.
