Needle Bearing Crankshaft
Hi again,
On first disassembling this engine, I was rather surprised to find that it was equipped with one of the optional needle bearing-type crankshafts. I don't think that the previous owner was aware that his engine contained one of these rare upgrade items, otherwise he would have been asking a higher price (The needle crank seems to be a desirable item among Whizzer enthusiasts.)
In the early fifties, Whizzer contracted with a German manufacturer to produce a multi-piece crankshaft incorporating a captive needle or roller-type bearing for the crank journal. Presumably, the optional crank offered increased performance potential over the standard one-piece, insert-type crank (and perhaps a measure of
cachet.
) The needle crank required the use of a special connecting rod, designed to clamp around the needle bearing's outer race. Metric cap screws are used (M6 x 20MM long,) the heads being cross-drilled for a retaining wire.
Removing the crank from my engine, I found it to be in good shape visually, but the needle bearing race seemed to have an excessive amount of clearance, indicating a good deal of wear. Checking it with a dial indicator showed a clearance of about .005", which I deemed as excessive for re-using in an engine that was being rebuilt. In order to return this crank to factory specs, I would need to acquire the tools and expertise needed, or hire the work out to someone else. What to do...
As I was trying to make up my mind, fortune intervened: An original Whizzer needle-crank service tool came up for sale on eBay. This was more than a tool-lover like myself could resist! Even though I could have had someone else rebuild my crank for much less than the cost of the service tool, my hunger for the experience of doing it myself carried the day. I know enough about myself to realize that this is a major driving force in why I do this kind of work. It's not just the prospect of achieving an end result, but the joy in mastering the challenges of the experience itself.
Anyway, I did wind up purchasing the Whizzer needle crank service tool. It was not in the best of shape, but looked to be mostly intact. There were some parts missing that would have to be replaced or re-made. The pressing screw turned out to be seized up. Missing parts included the indicator bracket assembly (and of course, the indicator itself), the "tommy bar" (the long sliding handle for tightening the screw), the centering pin, and the spreading wedge. Here's a "before" picture of the tool:
As I pondered possible approaches for restoring the tool to usable condition, fortune intervened once again. As it turns out, I had already purchased numerous parts for this project from a gentleman by the name of Chuck Gatto. It seems that he noticed that I was the one who had bought the crank service tool on eBay, recognized my user name from our parts transactions, and contacted me to offer information and advice (the story is actually a little more complicated than that, but not really worth going into here.) Chuck has a lot of experience with the Whizzer in general, and with needle crank servicing in particular. In addition, he has a helpful nature, and offered to provide any information I would need to reproduce the missing crank service tool parts, as he owned one himself.
Chuck carefully measured the indicator bracket components from his crank service tool, and mailed me some dimensioned sketches -- at his own expense. He also included dimensions for the tommy bar, and... A COPY OF THE ORIGINAL WHIZZER SERVICE BULLETIN for the "Crankshaft Disassembly and Concentricity Checking Tool" (Bulletin #42, June 1, 1954). Talk about a helpful guy! (I should mention that Chuck gave me permission to use his name in relating this story.)
The major components of the Whizzer needle crank are held together by medium-to-heavy press fit joints. While assembly of these components can be readily handled with conventional pressing machinery,
disassembly requires special provisions. The needle crank tool provides this capability, and in a fairly simple manner. One side of the tool is equipped with a slotted plate to support either of the crank webs whilst the pin is pressed out with the screw. An additional feature provides a means to for checking the alignment of the two crank halves.
The tool I purchased was well-packed for shipment, and arrived in good shape. Soon after, I set about disessembling the tool for refurbishment. As mentioned, the pressing screw was seized in the threaded body hole, and it took a good bit of effort to extract. The threads on the screw were ok, but some galling of the female thread was evident. Fortunately, the machine shop at the company where I work had a M16x1.5 tap, and I was generously allowed to borrow it for cleaning up the galled threads.
After receiving the dimensions from Chuck, I set about making the parts for the missing indicator bracket. I also ordered a new dial indicator. The indicator bracket is not a difficult or complicated assembly, but I wanted to reproduce it as close as possible to the original, to help preserve the value of the tool. Here is what the finished indicator bracket assembly looked like before black oxide:
The original tommy bar had a metric diameter, so I had to turn the replacement from a larger diameter piece of cold-rolled steel. The body casting itself was bead blasted to remove rust and old paint, as were some of the other parts. Some parts only required moderate wire brushing. The body was painted with several coats of a grey oil-based enamel, while some of the other parts would be sent out for black oxide treatment. The centering pin was made from a "G" size high-speed steel drill blank (.261" dia.), which just happens to be the right size for a close slip fit in the crank journal through-hole. All I had to do was grind a 60 degree point on one end -- same method as used earlier to reface valves. Here's a picture of the finished tool:
(
to be continued...)