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Dynamo/Alternator

pifinch

Well Known and Active Website User
VOC Member
#1
Lady and me have been together for over 30 years, Lucas dynamo on a series C, I fitted a JG unit in 1974, it has been fine until now, the dynamo has finally spilled its guts & I have bought a Alton - Looks great but the Lucas 'mo had a tapered spacer, the parts list shows a shim for the miller unit, the Alton fits too snug to the primary chain, I have no knowledge of miller dynamos, do I need PD19 or am I better of using a large dia. o ring to effect a seal? any help welcome. THANKS.
 

bcc99

New Website User
Non-VOC Member
#2
Alton

I recently fitted an Alton alternator to my Series C. I fitted only the oil thrower (PD28) and sprocket (PD15/1), as per the instructions, and found alignment was quite straightforward. I was able to slide the alternator from left to right in the clamp, to position the sprocket in the middle of the central chain run, then rotate the alternator body to achieve clearance, which I checked with the clamp fully tightened and the chain in various positions, and under tension from the kick-start. The instructions state the gap should be 10 thou, but I couldn't think of an easy way to measure this. I just checked that the sprocket could be moved slightly, independently of the primary chain, in all positions. All seems fine (after only 57 miles!).
 

Glenliman

Well Known and Active Website User
VOC Member
#3
You can purchase sheet cork in various thicknesses and this can be used to make a seal/spacer for the Alton. To do this, cut a ring of cork to fit between the Alton and the flange on the engine casting. This cork seal will be a narrow ring laying right at the outside dia. of the Alton. If you look at the Alton and look at the engine casting the dimension for the dia and width of the cork will be obvious.
You may have to do some trial and error with different cork thicknesses in order to get the appropriate thickness such that when the Alton with cork fitted is pushed up tight to the engine casting, making a seal, the sprocket is centered on the width of the primary chain rollers.

It has been suggested to me that it would be a good plan to put a tiny groove across the face at the top side of the cork seal in order to allow primary case air pressure to escape as things heat up. Otherwise it is possible that positive pressure could be created in the primary, and this could cause the primary case to leak oil.
I did not put the groove in and I have had no problem with primary leakage, however.
In fact, I used the cork seal described above on my Miller to cure leakage I had around that unit. When I switched to the Alton, there wasn't room for the cork since in the case of the Alton, the sprocket sat nicely in center with unit pushed up tight, metal to metal. I used a heavy bodied anerobic sealer on the flange instead.

It sounds like your situation with the Alton is similar to the way my Miller lined up, so some thickness of cork should fit the bill.
 
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bcc99

New Website User
Non-VOC Member
#4
Alton part 2

In light of the posting by wormtorn I looked again at my Alton installation. There is clearly a gap of 1/8" between the alternator and inner chaincase. I had assumed that the combination of oil thrower PD28 and oil ring ET164 were sufficient to prevent significant loss of oil - neither the parts list or Know Thy Beast mention the use of cork gaskets. Reading further in KTB, in a section referring to series D, there is mention of an alloy adaptor, PD32, which fits in the gap between Lucas E3L and inner chaincase, and which may be skimmed if necessary to obtain the correct sprocket alignment (implying that the dynamo should sit right up against this). The use of silicone sealant / strategic drilling is also mentioned as a means of preventing oil seepage. Although there is no sign of leakage, and my primary chaincase still contains the right amount of oil (I just checked), I have only ridden 57 miles since the conversion so perhaps should reconsider. In which case, cork seems like the way to go (as the gap is too big for sealant).
 
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Glenliman

Well Known and Active Website User
VOC Member
#5
The cork fix was suggested to me by John McDougall.

The first time I took my top-end apart and removed the Miller i noticed some oil laying on the crankcase under the dynamo. I asked John about this and he informed me that most of the countless Vincent twins he has rebuilt have had oil under the dynamo, found upon teardown. This appears to be oil which finds it's way past the flinger. The cork takes care of it quite nicely.
 

Pete Appleton

Well Known and Active Website User
VOC Forum Administrator
VOC Member
#6
Alton Oil leaks

I tried 'O' rings and cork gaskets with little success. In the end I put a 1/4 " bead of ordinary silicone sealant around the end of my Alton and pushed it inwards until the sprocket was in the middle of the primary chain and did the clamp up. 7000 miles later - still no leaks.
The obvious worry when using copious quantities of silicone is the danger of any excess finding its way in to the oil system. This is not a worry in the primary case as there are no oil ways to block.
The other comment that I would make is please dont smother it in that horrible orange muck. Buy some clear stuff from a builders merchant, it works just as well and looks nicer.

Pete
 

mick the vin

Well Known and Active Website User
Non-VOC Member
#7
Just Been Reading All The Comments Regarding Altons As I Have Been Having Probs With My Lights - See Lights Thread
So You Spend £300 Odd Quid On A Piece Of Kit That Solves All Your Problems And You Still Have To Bugger Around Making It Fit And Oil Tight
I Was On The Point Of Ordering One But Bi Am Now Having Second Thoughts
Am I Being Unrealistic In Expecting Something To Just Bolt On

Mick
 

nkt267

Well Known and Active Website User
VOC Member
#8
On a Comet you do away with the seal and use silicone sealant and you may even have to shim it for pinion clearance. If mine ever comes back I might be able to try it again.
 

Glenliman

Well Known and Active Website User
VOC Member
#10
Really there is no difficulty in fitting the Alton.
The oil getting past the flinger is a problem with the Vincent, not the Alton. As I mentioned earlier, nearly every engine John has stripped has had a little oil laying under the dynamo, and most of these probably had their factory Miller or Lucas in place.

Vincents do tend to leak a lot of oil ,there is no doubt. Factory workers from the 40s and 50s talk about the ever present oil leakage problems, so we know that they leaked when new. My Rider's Handbook lists the "oil mileage" as one imperial gallon in 1500 miles! I wonder how much of this number was to allow for the inevitable leakage?

Over the years various people have found ways to cure most of these leaks such that today it is possible to have a dry Vincent. Possible but extremely rare! I was just at the IOM and had a look at all of the bikes after the lap. The vast majority had oil streaming down the crankcases and laying in pools underneath the engine/transmission.

If one keeps at it and uses all of the collective wisdom on the subject, most of these leaks, including the dynamo leak, can be fixed.
 

Len Matthews

Well Known and Active Website User
VOC Member
#11
There is a risk in making the joint between dynamo/alternator and crankcase oiltight because the pri. chaincase can't breath, bearing in mind that there's usually some blow past the driveside mains. A while ago Hugo Myatt wrote in MPH stating that his twin gearbox was getting pressurised and mentioned he'd recently sealed the dynamo with RTV. He adopted a rather amusing method of detecting this pressure build-up!
 

andygbsmith

Website User
Non-VOC Member
#12
Just use a small amount of silicone on the face of the Alton and that sort's any problems.
I don't agree with the coment's about oil leaks.
If you build them properly they are oil tight with the exception of a small amount from the breather.
 

Glenliman

Well Known and Active Website User
VOC Member
#13
Just use a small amount of silicone on the face of the Alton and that sort's any problems.
I don't agree with the coment's about oil leaks.
If you build them properly they are oil tight with the exception of a small amount from the breather.
In my comment on oil leaks I stated that it is possible to build a dry Vincent today, but they are a rare item. A walk past the 192 Vins that went around the Isle of Man course last month amazed me as to how bad the leakage problems are. Nearly every bike showed oil leakage, quite a number with what I would call quite severe leakage. For me, severe leakage is when oil has found it's way onto the rear tire, as this is a pretty dangerous situation. I saw a number of Vincents with oily rear tires.

So I'm not sure if it is my comment or someone else's you don't agree with as we seem to have both said the same thing, that a dry Vincent can be built today.

The reality however is that most are far from dry , nor were they oil tight when they left the factory according to information from Vincent factory workers of the day.

Which, if any, of these comments do you disagree with?
 
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#14
Dribbling Vincents.

A walk past the 192 Vins that went around the Isle of Man course last month amazed me as to how bad the leakage problems are. Nearly every bike showed oil leakage, quite a number with what I would call quite severe leakage. 'Quote'

Could this be because they had just had the pants thrashed off them?
Bikes with VERY bad oil leaks were not let out onto the track.

Russ
 

Glenliman

Well Known and Active Website User
VOC Member
#15
I'm sure the high speed run contributed, but this is something that you should be able to do without having oil end up all over the place.

My point is being taken the wrong way, It was not intended as criticism of the brand, I think they are fabulous bikes.
My point is that there are a lot of clever fixes for the common oil leaks on the Vincent, and that a lot of Vincents are in need of these fixes. I happen to own one that needs help in a big way!
I also own one that is nearly oil tight, and I took it around the IOM course.
I touched 110 MPH twice on the course and generally ran the hell out of it, but it showed no sign of oil leakage afterward.
And yes, it did have oil in the tank!
 
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andygbsmith

Website User
Non-VOC Member
#16
Hi Worntorn, My coment wasn't aimed at you but more of a general coment.
I think that the way you ride the bike should't change anything, I normaly cruise at 80mph and on the IOM I spent the week thrashing the bike everywhere. Still no oil leak.
I think one of the the biggest problems is engine breathers you have to have a one way valve in line and the aim is to try to keep a slight vac in the cases.
I have built lots of big Harley engines (over 2 litre) and its the only way to keep the oil in.
Andy
 

pifinch

Well Known and Active Website User
VOC Member
#17
I thought everyone was ignoring my question, thankfully I was wrong! My main problem was, Alton butted to chaincase, Alton sprocket adaptor, oil thrower and co. the sprocket wants to kiss the chain sideplates-not good, it never did with uncle Joes, However, the thick silicone bead either side of a nylon shim sounds good, I will give it a go! ( old age/paranoia, I bought the Alton on special delivery 4 weeks ago because I needed to go on some runs, delivered next day! needless to say it is still not permanently mounted & I have not yet converted from+ Earth to - Earth!) Tomorrow! then Copdock Len.
 

john998

Well Known and Active Website User
VOC Member
#19
Dynamo

Hello.
To say that the Vincent is bad for leaking oil is a little OTT.
Compared to other British bikes of the era it is probably the best in that respect.
On both my Rapide's there is no , or very little oil leakage around the dynamo, with no silicone or cork gaskets. The standard oil thrower works fine.
As for the rest of the engine use gaskets only on the cylinder base, all other joints are Loctite plastic gasket, or silicone used with great care.
The only small drip is from the gear change cover after each run.
I have done all the mods to the shafts in there but it has so far defeated me. John S.
 

Rapide998

Active Website User
Non-VOC Member
#20
Only blood loss from my Animal is from the chain oiler pipe when I stop, or from the valve lifter cable entry point on the timing side if I've let her off the leash for a bit :D
As for the all over Satin Black Honey Badger.....she's muzzled at the moment while Master bring her back to life :cool:
 
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