Started work on my VCH

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Brian_Walker
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Re: Started work on my VCH

Postby Brian_Walker » Tue Jun 05, 2018 3:03 pm

Thanks for the great information David, I have 3 different cams Jack gave me one he said was for Mount Druitt (I think it was what Johnny Shanks was running ) One was an Art Senior cam that he gave me a fancy fuel recipe for to use with that piston I showed with the hole in it (I was running straight methanol as half the ingredients in Arts magic mix were not available so that may have been the reason the inlet leaned off and froze solid with ice) Jack wasn't that close to Claude so the other may have been one of his own grinds as it also has a series of two holes either side of the keyway which I am not sure may have been an attempt to mimic the adjustable timing they had on the Manx's or just for balance.
When I reassemble the engine I will clock all the cams to find out their timings.
The timing cover with the external pump I called a rotary is indeed a gear pump I just called it rotary to differentiate it from a piston pump.
The head does have an offset spark plug I have attached a photo.
When you say through bolted do you mean the cylinder base studs are replaced with bolts?
Again thanks for the info, I hope my engine isn't the one that was in Johnny's bike that was involved in a fatal, I should try and trace the serial number as there weren't that many that came to Australia.

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1951-52 VCH under restoration

david.anderson
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Re: Started work on my VCH

Postby david.anderson » Wed Jun 06, 2018 8:29 am

Brian
John Shanks was known as the King of Mt Druit during the mid 50s as he was almost unbeatable on his Ariel at that track during that period. John used either Vic Lyons cams (or later factory HS cams). During the 70’s Vic Lyons ran a Yamaha dealership in Lidcome. He ground a cam for me at that time. I subsequently broke a cam follower foot and did some cam damage and the cam was reground to hopefully Lyons specs by Claude Cartledge. The Lyons cam has a retarded valve timing and performs better if advanced one tooth to a near straight up timing. Vic Lyons passed away possibly 10 years ago and was living in the Batemans Bay area at the time. A lot of Lyons equipment ended up with Stan Corish’s widow who sold it off. The cam master blank is possibly in Nowra with the wife of another deceased Ariel owner.
The holes that you are referring to may be the balance holes in the gear wheel that were standard on all later single lobe cams.
To my knowledge Senior generally only provided one cam grind to the public, so the cam you have should be the same as mine. The Senior cam that I have is almost a straight up valve timing (2 degree advance) and is a very good performer on unleaded. Years ago I spoke to someone who had a collection of 7 or 8 Senior cams that went from mild to wild. They had been a present from Senior to a very close friend.
Many Senior cams have a map of Australia on the outer cam face with Senior inscribed within the map, but not all Senior cams (including mine) have that. Does your Senior cam have the map.
Through bolting means the head bolts go through to the crankcase where they engage into an offset crankcase stud/nut, as in the attached photo. That way there is no tension on the base flange by the engine on compression stroke, however the disadvantage is the differential expansion of the alloy head and cylinder to a steel bolt to contend with which can result in pulled crankcase threads. I have used studs that have reduced shanks to make them a bit more stretchy.
I have created valve lift tables for Senior, Cartledge, Lyons and Corish cams. Measured at .050 lift the cams should give the following valve timing
Senior 35 57 64 31 overlap 66, LSA 103.73
Lyons 10 63 42 34 or if advanced one tooth 24 49 56 20 overlap 44, LSA105.25
Corish 23 55 64 14 overlap 37 LSA110.5
Cartledge advanced one tooth 21 62 63 34 overlap 55 LSA 107.5
Standard VH twin lobe cam 2 49 51 2 overlap 4 LSA 114
David

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Brian_Walker
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Re: Started work on my VCH

Postby Brian_Walker » Mon Jun 18, 2018 11:24 am

Well, I threw away the paint stripper and razor blade and spent $150 dollars and got my frame sand blasted, it was back the next day sprayed with some phosphorous containing finish. Ariel works must have spent a small fortune on brazing rods looking at the amount of spelter all over the frame after blasting.
In the photo attached you can see the joints where each section of the frame is joined.
I have now painted the frame with etch primer to keep it happy till I return from my annual wandering north with the caravan till Sydney weather warms up again.
Image
1951-52 VCH under restoration

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Brian_Walker
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Re: Started work on my VCH

Postby Brian_Walker » Thu Jun 21, 2018 8:43 am

Last Day before my trip, should be packing the caravan but just checking compression volume of old piston and measuring valve timing and inlet length.
Haven't found the formula for adjusted pipe length and megaphone reverse cone diameter and length, straight pipe would be about 20" and inlet length from carb to inlet valve is 8.5".
I have attached the shot of my old piston ~12.5:1 bit hard to an accurate volume when the plug hole is offset and at an angle (between 40 to 45 ml. This piston was tested with plasticine and ran ok to 7900 rpm without closing the plug gap so I think it would be about as high as you could go.

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1951-52 VCH under restoration

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Brian_Walker
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Re: Started work on my VCH

Postby Brian_Walker » Sat Jun 23, 2018 10:39 am

Here is a picture of the JP 9:1 piston haven't weighed it but it looks ver low compression next to my normal piston.

New JP 9:!
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Old High Comp Pistons Current and holey one from running too lean.
Image[/URL]
1951-52 VCH under restoration

nevhunter
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Re: Started work on my VCH

Postby nevhunter » Sat Jun 23, 2018 12:51 pm

Looking at it I would reckon about 9:1 would be close.. Plenty of valve relief there. Nev


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