E: Engine ET162 dimensions

greg brillus

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I've had cams that were out by miles......the lengths all over the place.......i'm sure there is a spec on the proper lengths. I generally customize what ever I have to to get the timing chest contents up to par. You can shave a whisker off the inner end of a cam if it seems too long, but like you say, you need to get the followers as central over each lobe as you can........This can also be difficult if the followers are wider than the lobes........The shim washers are great, but far from what is really needed.......Main problem is their thickness is often either too much or not enough......This is where you need to improvise.......using whatever washers it takes to do the job.......They need to be hard ones as well.......A lot of the supplied ones are stainless and way too soft. On the smaller spindles they become cup shaped and this makes the shimming of the steady plate a right pain. Often I will trim down the length of the long steel tube spacers and simply shim up the difference generally on the inner end of said tube, even linish down the width of the follower if this helps, it pays to add shims to the inner side or else they will fowl on the cam pinion.......Get the steady plate as flat as possible to avoid any strain on the spindles, they are only a mild interference fit, the cam spindles not more than 0.001" and the smaller ones less again.......these will shift when the engine is at full temp on a hot day, the cases can get up 130 plus degrees Celsius when checked with a temp gun between the cylinders. Using loctite on spindles and the like is ok, but be very careful to clean up any left over that surrounds the spindle bore, if you slip a follower over the spindle, the loctite will quickly anchor it to the spindle and can be a right bitch to remove. Good idea to set up the cams and their pinions meshing with the large idler adjusted up to both cam pinions and rotate the large idler several times and make sure there are no tight spots.......this will cause a "Hunting sound" within the timing chest when running, so adjust the idler to run freely at this tight spot if needed, the small amount of backlash between the gears when turned will do no harm or create too much noise when it is running. If the timing chest is set up well and the rocker gear in the heads has the ET 100/1 mod carried out, plus no excessive side play in the rockers/bearings the engine will run nice and mechanically quiet........Good luck with it all.
 

Bill Thomas

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I also free off a bit the nylon end bit of the nuts, I have found them much too tight ,
And it shifts the spindles if your not lucky.
 

davidd

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I guess we should not be surprised that Greg has had to deal with all sorts of problems, including variable camshaft lengths. He has no way of controlling what shows up at his door for fixing.

I build with all new gears and spindles. It may seem excessive, but the reliability of these engines is incredible with a new timing chest and I feel that is a very important requirement for a racer. I use only Megacycle cams because of the quality. I use all the Maughan parts for the timing chest, including the big idler boss. I use the shoulder of the large idler boss as the datum, but I have never had a cam that exceeded the height of that datum. In fact, the datum from the idler boss is quite a bit higher than the instruction sheets anticipated, so those stated dimensions are often of little use to someone assembling a new timing chest.

There is no washer called for behind the camshaft between the shaft and the case, but when lining up the followers with the cam lobes I am always forced to install one in that position. This means that I have to install the same size shim under the other gears to keep the steady plate level. Fortunately, the Arbor shims from McMaster Carr are up to the job and I have never found any cupping or softness when using them.

I suppose the answer is that you need an initial datum location when setting up a new timing chest and the shoulder of the large idler boss is quite tall and easy to install in place. If you have to shim behind the cam to align the followers to the lobes then the top plane of the cam gear becomes the new datum that requires the remaining gears to be adjusted to this new dimension with the object of keeping the steady plate flat.

Bill is spot on about the Simmonds nuts on the cam spindle. I run a tap through the nut to score the nylon. I also run them on and off an old cam spindle held in a vice. There is nothing worse than tightening up this nut and having the 5/16" threaded stem break off due to the high friction fit provided by the nylon insert.

David
 

Cyborg

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I also free off a bit the nylon end bit of the nuts, I have found them much too tight ,
And it shifts the spindles if your not lucky.
In the bin of parts that I received there was a spindle that suggests it could shift the threaded part away from the rest of the shaft. It looked like a new spindle so don’t think it was broken any other way??
 

Cyborg

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Good read David. I’m guessing that one of the silver linings to Greg’s operation is that he is continually learning about new undiscovered Vincent quirks along with the wondrous things you see when the timing cover is popped off. At least I think it’s a silver lining...
Fortunately with this engine, the cases are NOS, and everything that has gone into or is going into the timing chest is new except for the followers which are getting refaced with stelite.
Further to the simmonds nuts, (now that I know what they are called). I wonder if the sometimes the spindles are partly to blame..... the way they are threaded and heat treated? Some of them look like they might be a source of drama.
The cams I’m using already have the pinions installed, so just for fun I will see if my cheap endoscope will give me a little better view of the follower alignment. Not sure if that makes sense, but will give it a try and find out.
Wish I could order stuff from McMaster Carr.

Ps.. A recent “quirk” that I became aware of is the ridiculousness runout on some of the C20/1 . In speaking with others it turns out it’s not all that unusual. You just have to know to look for it and treat them all with suspicion. Sorry for the sidebar to the sidebar over to the clutch department.
 

Bill Thomas

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This is why we call it the " Horror Chamber ", I say stay out of there if you can,
Once you see something, You can't Un see it :D .
The spindles are a bit brittle, I have seen the threaded bit broken off,
Put a few normal nuts on there if you want to hit it, So you are hitting the nut , Not the end of the spindle.
 

greg brillus

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If the cams and pinions are pressed together, you can align the followers by looking down the pushrod tube spigots atop the crankcase. Spindle sizes can be all over the place, so double check them........The follower spindles are usually a nominal 0.375" diameter give or take, but the cam spindles should be 0.501" and these can be more or less depending on who made them......It is nice to have some as "Go.......No go" guages where possible.........where a spindle will just enter the case without any great force will need about another 0.001" to be a good fit into the heated case.......if it was say another 0.002" larger in diameter it will almost certainly be too tight......... I think Bill pointed out that too tight a cam spindles will actually cause a bump in the cylinder base area immediately above the spindle, and I have found he is absolutely correct. I found this out with my own engine when rebuilding it back in 2016........Upon removal the old cam spindles had been plated up with copper to about 0.5035" roughly, so I duplicated these figures using over sized spindles, but my final size was slightly more than this, the spindles went it with the case nice and hot, but the spindles were very tight going in. After they cooled off I noticed the raised bump from the alloy "Jacked up" from the larger spindle........It was simply a matter of dressing the small amount off with a broad file, but it taught me another lesson that the size required and what you might think it should have can be too much.
 

Bill Thomas

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For years I never gave it a thought, I am a Mechanic, Not as clever as I should be,
When I hear of people skimming the face the barrel sits on !!,
I can't think why that spindle hole is SOO close to the top, Not a good idea.
Some bits of the Vincent are so strong and other Bits you just wonder, Why !,
When other makes don't have that trouble.

like when people skim the C/case halves, Which upsets the gears in the gearbox and the flywheels,
Barrels etc
 

Cyborg

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I did the last twin and the Comet Mongrel by just peering down the tube holes and it seemed to work fine. I don’t currently have any followers ( dead or not) to see if the camera will be of any assistance. I bought the thing, so would be nice to use it somehow. Quality of the camera is iffy, but would be good enough for shimming followers. I don’t know the exact specs on the spindles other that they fit properly. I took the cases over to the local guru because I wanted to confirm that my plan of attack for some surgery had merit. Didn’t get to explain my plan... just instructed to leave the cases and he’d have a look. Next day, I received an email stating they were done. I’m not sure why and I’m not sure he knows why either, but when I picked them up, he said to bring them back when I had the bearings, spindles, etc. Given his experience and equipment, it was a pretty easy choice. The cases turned out to be quite a lot of work. NOS die cast cases and the some of the bearing bores were actually undersize, etc, Anyway....long story short, I have them back. Decked, mains installed and then lapped to size, spindles installed and assurance that “ you have a nice set of case there”. So consider myself fortunate. I would be tempted to say that other than maybe adjusting spindle depths, assembling the timing chest should be straight forward, but I don’t want to jinx myself.
 

Cyborg

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When I hear of people skimming the face the barrel sits on !!,
I can't think why that spindle hole is SOO close to the top, Not a good idea.

Certainly no room for error. Mine just took the slightest skim cut to square them up. On the area by the spindle you can tell the cutter wasn’t doing much. I was happy to loose a tiny bit just to make sure everything was square. Then you can get away with a little less piston clearance and the piston pin is probably a little happier staying where it is. All a trade off I guess.
 
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