Fellow AC'ers
I thought for the benefit of all, that I would write a brief (not really) report on my recent acquisition of a set of newly manufactured stub axle's purchased from Winchester Motorsport. I know that several of you have recently bough them as well.
A bit of background - BE603 is a race car, so all bets are off in terms of normal usage. After having sheared two sets of key's on my original channel and key configured axles, I was desperate to find a more reliable solution. This known "Achilles heel" has vexed AC owners for decades and Nigel's offering looked to be a Godsend.
Found on the inside back cover of each ACtion Magazine for the last few months, the Winchester Motorsport advert boasted "No more taper drive shaft failures! 1" 10-Spline conversion for Ace/Acea (sic). Call for details"
Firstly, let me say that dealing with Nigel as a vendor was a pleasure. Although he is quite the dinosaur in terms of technology - no email, no voice mail, when I did connect with him, he was a great chap to speak to.
After discussing my current dilemma, Nigel assured me that he had what I needed to make my problem disappear. So, betting on his British honor, I wired the better part of $2,000 to him for the privilege of having his cure to what ailed me.
After about a week of shipping, they finally arrived and were eagerly unpacked. At first glance, they looked fantastic. All shiny and robust looking, along with those 10...no wait...8 splines(?) to drive the mighty 140 BHP Bristol power to the rear end. All was right in the world.
After a thorough inspection, these new axle's looked like they were just the thing to bring my Aceca back to life. However, there were a few design flaws that were worth noting in terms of potential areas for failure as well as one area in particular that should definitely be redesigned.
Fast forward to the installation. Anyone who has worked on the rear end of an ACECA/Ace know it is not for the faint of heart. Clearances designed for elves and specialty tools for sure. I was assured that the new axle's would be a "direct replacement" for the original...How many times have we heard THAT?
Well, damned if it wasn't true! Although the swap out took the better part of a full day, it was indeed a straight swap out with minimal headache. True, getting the hub to fit right did take some heating etc., but the key thing is that I did not have to do any reshaping or modifications to get the parts to eventually fit.
Now here is where it gets interesting. Both axle's were put in and the bolts were assembled with Loctite and set at 80ft/lbs of torque for safe measure and off we went to the races. The Rolex Monterey Motorsports Pre-Reunion.
With her newly installed power transformers, the ACECA performed as expected and we completed 10 laps of practice at Laguna Seca with no incident. The rear end seemed to be firm and true and there were no noises or extraneous issues to deal with. Delight!
The same results were delivered throughout the weekend with another practice session, a qualifying session and the the final race. Well done!
The following weekend came and I took BE603 out on the track for another practice session at Laguna Seca for the much anticipated Rolex Monterey Motorsports Reunion. All went well and my times were looking better than the previous tune up sessions.
My next practice session came the following day and out we went. 2 and a half laps in, after coming out of turn 4 and heading down the straight for turn 5 I shifted into 4th gear and the tach hit the rev limiter almost immediately! I clutched in again and put the gearshift perfectly into place and ZOOM the revs spiked again.
Was this deja vu? Was it happening again? How is it possible? Those axles looked blood bullet proof! I was furious.
So, I limped off the track and was eventually towed back to the paddock. My weekend was now shot to hell. I put the car on jacks and while in gear was able to spin the left rear tire...busted stub axle - AGAIN!?[
!] Really unhappy.
So, I decided to have a look. After removing the knock-off of the left rear, I was shocked to find the bolt lying unattached inside. Upon removal, I was able to look into the hub and see light on the other side. WTF? The bolt had backed out and the shaft had pulled itself out!
Now, at least I had something to work with. The shaft had indeed not sheared, but just fallen out. Unfortunately, due to the mechanical dynamic of a half shaft spinning freely inside the edges of a hug, the splines were now pranged up a bit and so was the inside of the hub. Due to the tight tolerances, they would not go together for love nor money.
After spending 90 minutes getting the shaft off, I hand filed the spline ends flat again and also did so with the hub. Bingo...they went together. Weekend saved! Or was it?
I reassembled the axle/stub combo this time with super duper Loctite (supposed to require a torch to release the glue)and I torqued to 100lbs. to be safe. She sat overnight while I headed to the bar for an overdue bottle of tequila with my name on it.
The next morning, the practice session was completed without incident and all was well. I decided to pull the spinner to see if everything was tidy. Unfortunately, it was far from it. The bolt had broken the Loctite seal and had spun 6 FULL REVOLUTIONS! Incredible! We were well on our way to repeating what happened the prior weekend. Not good.
So, I re-glued and re-torqued the bolt AGAIN so that I could finish out the weekend. After the morning qualifying session, I repeated the process yet again so that I could make sure that my axle was not going to drop again...or worse. I also decided to check the right axle. It had rotated 4 revolutions! This was nuts...literally
So, what does this ALL mean? Due to a couple of design flaws, I feel that these axle's really must not be used for racing without some form of modification...which I am working on as we speak. It is simply not tenable to re-torque your stub axle's after every 30 miles of hard driving. It is insanity.
The left axle should have had a reverse thread bolt to offset the natural loosening effects of the left hand rear wheel. I am currently fabricating a fix that will hopefully stop this nonsense and make my investment worth while.
Don't get me wrong, I do believe that these are indeed nice replacements for a standard road going car...maybe. However, I still believe the mechanical forces are far too strong even in a mild driving condition to not naturally unscrew the left hand bolt. I will defer to others who may have bought them for that purpose.
In the end, the actual design is far superior to stock and will no doubt be 100% more reliable, but unless you want to re-tighten them after every short drive, you may want to be wary.
Once I have completed the design of the bolt "keepers" I will try to post the pictures in hopes they may provide help to others.
Sorry for the lonnnnnnggggg post. But I felt the background and true experience might be helpful.
Cheers,
Rob
