ET: Engine (Twin) Advice on fitting new cam spindles

Phil Arundel

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VOC Member
I am about to fit new cam spindles to a twin (I have none to remove) and was wondering if anyone has any advice on doing this.
Thanks
Phil
 

ClassicBiker

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VOC Member
I was lucky when I replaced mine a few years back, one of our section members had made up a set of gauges to insure all the spindles he replaced were set to the same height. He let me borrow them. Check to see if someone in your section has done this. Also a heat gun is a real boon to the job. Warms the cases gently and locally to get spindles in and out. I also chilled the spindles in the freezer for a couple of days before installing. One spindle was a tight sliding fit. Loctite bearing lock can be your friend. I cleaned both the hole and spindle thoroughly with acetone, applied a generous smear on both and installed. Checked the next day and it was rock solid.
Steven
 

davidd

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VOC Member
Phil,

The cam spindles are available with oversize ends if you run into a small problem with the fit. I often use some Loctite if the spindle hole is bell mouthed slightly.

The spindle heights are difficult to do correctly, but Vincents do not seem overly sensitive to running spindles at incorrect heights. That said, decide what height you want to shoot for with the two cam spindles by comparing them to the other spindles. The datum is usually the big idler because it cannot be adjusted lower. If you put all of the under the steady plate washers on the spindles that remain in the case, they should all measure the same distance from the mating surface of the timing chest. You can use a 1" tall by 9" plus long ground bar to measure down to the spindles.

I use a slide hammer to remove and install spindles. Once I have decided the height that I want I cut a piece of conduit or scrap tube that fits over the spindle and inside the machined portion of the crankcase where the spindle is installed. (For some of the smaller spindles you need smaller tubing). I install a large washer on the tool and screw the spindle into the tool. I slide the conduit over the spindle and install the spindle. The conduit hits the washer and the spindle will stop at the chosen height.
DSCN2772.jpg

This is a 500 case, but the theory applies to both. I am not checking the heights to the mating surface, but just to each other. I have done the math and calculated the difference in height to the idler. The idler receives the large washer (two are seen here lying in the case, one for the large ider and one for the small idler not shown and for the 500 only).
DSCN2774.jpg

Here is the 500 case with all the tubes and under steady plate washers in place. When I measure down to these all the figures are exactly the same height. Thus, the steady plate is held flat. (I don't use a breather spindle in the racer.)

You can do it another way. I did it this way because I feel it is worth getting the steady plate flat and although the prep time is higher, I do all the bearings and spindles at once when the cases are hot. So, it saves me time when installing all these items. But, for two spindles it is not a lot of work. You can run the spindles at different heights, but they will be pulled or pushed slightly by the steady plate. Engines often run this way for years.

If you use a new Simmonds nuts on the cams, run a tap through them or turn them on and off a scrap spindle until the nyloc is not gripping. It is the shape of the nut that is important and it does not need to lock tightly onto the spindle. Owners often turn brand new nuts onto the cam spindle and end up rotating the cam spindle in the case due to the turning resistance presented by the nut.

Good luck!

David
 

Phil Arundel

Well Known and Active Forum User
VOC Member
Phil,

The cam spindles are available with oversize ends if you run into a small problem with the fit. I often use some Loctite if the spindle hole is bell mouthed slightly.

The spindle heights are difficult to do correctly, but Vincents do not seem overly sensitive to running spindles at incorrect heights. That said, decide what height you want to shoot for with the two cam spindles by comparing them to the other spindles. The datum is usually the big idler because it cannot be adjusted lower. If you put all of the under the steady plate washers on the spindles that remain in the case, they should all measure the same distance from the mating surface of the timing chest. You can use a 1" tall by 9" plus long ground bar to measure down to the spindles.

I use a slide hammer to remove and install spindles. Once I have decided the height that I want I cut a piece of conduit or scrap tube that fits over the spindle and inside the machined portion of the crankcase where the spindle is installed. (For some of the smaller spindles you need smaller tubing). I install a large washer on the tool and screw the spindle into the tool. I slide the conduit over the spindle and install the spindle. The conduit hits the washer and the spindle will stop at the chosen height.
View attachment 27314
This is a 500 case, but the theory applies to both. I am not checking the heights to the mating surface, but just to each other. I have done the math and calculated the difference in height to the idler. The idler receives the large washer (two are seen here lying in the case, one for the large ider and one for the small idler not shown and for the 500 only).
View attachment 27315
Here is the 500 case with all the tubes and under steady plate washers in place. When I measure down to these all the figures are exactly the same height. Thus, the steady plate is held flat. (I don't use a breather spindle in the racer.)

You can do it another way. I did it this way because I feel it is worth getting the steady plate flat and although the prep time is higher, I do all the bearings and spindles at once when the cases are hot. So, it saves me time when installing all these items. But, for two spindles it is not a lot of work. You can run the spindles at different heights, but they will be pulled or pushed slightly by the steady plate. Engines often run this way for years.

If you use a new Simmonds nuts on the cams, run a tap through them or turn them on and off a scrap spindle until the nyloc is not gripping. It is the shape of the nut that is important and it does not need to lock tightly onto the spindle. Owners often turn brand new nuts onto the cam spindle and end up rotating the cam spindle in the case due to the turning resistance presented by the nut.

Good luck!

David
Thank you David for your expert advice.
Regards
Phil
 
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