VH 500 top end

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Norm Emerson
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VH 500 top end

Post by Norm Emerson »

Hi,
I have striped my 1954 VH 500 top end to check it over before it goes into the frame and I found that the alloy head has a chip in the recess (see attached photo). To my way of thinking the best thing to do would be to fit a cylinder head gasket. I have tryed Dragonfly but they don't stock anything to fit soI wondered if anyone had any idias what might fit. The inside dia. would have to clear the lip on the cast barrel (79.5mm.) And the 4 -3/8"dia. studs are on a 94.5mm. PCD.
If nothing is avalabel does anyone know where I could get some sutable copper to make one?
Also I noticed that the inlet rocker has a small spring on the oil seal screw end of the spindle but the exhaust rocker does not. There is about 1mm. end play on the exhause rocker. There is no room to put a spring onto the exhaust spindle as the "barrel" shaped bit on the oil seal screw end is longer than the inlet spindle.... Maybe it's the wrong spindle? Any ideas.
And finallyI, see in the parts list, 2 pieces called valve stem end caps which are missing on my valves. Do I need them?
Thanks for any advice.
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charvey
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Re: VH 500 top end

Post by charvey »

Hi Norm, I have an iron head prewar VH and both rocker shafts have a spring on them I take it so stop end float, and I always fit valve stem caps as I have noted on an old head I had the valve stem top had been hammered by the rocker and I had to grind the valve to get it to slide out of the valve guide.
I make copper gaskets out of old water tanks You have to anneal them but I just made some for my 29 Ariel SV, valve covers which seem fine after not being able to get any the right size, head gaskets would be a would be a bit thin perhaps not sure you could always double it up ? Regards Clive.
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Re: VH 500 top end

Post by JohnnyBeckett »

hi you can get copper sheet from model engineering supplies or off Ebay
Norm Emerson
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Re: VH 500 top end

Post by Norm Emerson »

Thanks to you both
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Vincent.vanGinneke
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Re: VH 500 top end

Post by Vincent.vanGinneke »

Yes, do use valve stem caps.
Valve stem end caps are also known as lash caps.
But if you search 'valve stem cap' on Drags site it gives this : https://draganfly.co.uk/shop/62804/valv ... h/#31-0103
check the size you need.
succes.
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Re: VH 500 top end

Post by Simon.Gardiner »

Norm
That head looks a little poorly!
When the faces are ground/lapped with a slight gap between the wider two, the gas seal should be on the very outside edge of the spigot (as I understand it when fully tightened down the head distorts slightly across the spigot which actually makes this seal). Looking at your pic, with a bit of work you might just be able to get a continuous surface around the inside corner of the head and that might be enough to seal without a gasket.
As others have noted elsewhere, you can use the head gasket from the iron head '52-'53 VH if you put a nick in it for the stud between the push rods.
However, I'm going to be a bit radical and suggest that stud could possibly be taken out completely - the iron heads only use 4 bolts (and the alloy head 350 never had the extra fixing either).
The alloy Rover (ex-Buick etc) 3.5 V8 engine engine was found to have a long-term issue with head gasket reliability; it used 5 bolts around each cylinder in a pattern very similar to Ariel (ie 4 almost equi-distant spaced and a 5th between 2 of them) and it was found the extra bolts - which were all effectively in a line along the outside of the heads - were causing the heads to tilt very very slightly. Later - and most powerful - versions of the engine went back to using just 4 bolts and it strikes me that the alloy head VH might not gain anything from the 5th stud either.

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Re: VH 500 top end

Post by david.anderson »

The head cannot be used as it is even with a copper head gasket. It will leak. The head can be resurfaced on a lathe bolted to a faceplate and centred. 1mm (.040”) can be removed from the inner and outer surface without a problem, even with high lift cams such as the HS. You will get a small increase in compression ratio. If you do not want the extra compression then a suitable thickness head gasket can be fitted. If more than 1mm has to be removed a copper gasket can be used to reduce the effective shave back to 1mm. If you are running a 7.5 compression ratio then it will increase to 8.0 to 1 after 1mm is removed from the head. Alternately you can have the head repaired with weld and then re machine.
If you do not to use valve caps you can have the valve stems stellite coated. The stellite coating should be the thickness of the valve cap to return the rocker geometry to standard after taking into account how much is removed from the head and pushrods.
Earlier rocker boxes did not have a spring on the end of the shaft. End float was controlled with hardened steel washers.
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Re: VH 500 top end

Post by nevhunter »

That Head needs repairing where the piece is missing by TIG welding and also the exhaust insert is very wide. Before you spend effort on these heads check the Valve guide fit in the alloy. They are hard to get good replacements so repair it well. The fifth stud is probably to the load caused by the push rod with the VH strong valve springs nev
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