Alloy head

[Dean Mitchell]

I have just bought an alloy head for my Ariel 350 ng, what I would like to know , would I require longer push rods due to the head being slightly taller. I am also going to fit a single lobe cam at the same time. The other question I have is, will I require longer head bolts to fit the head to my cast iron barrel with seperate push rod tubes, the year for the barrel is 1946.
I would appreciate any answers, Dean.

[will_curry]

As far as I'm aware there was only ever one sort of alloy head for the 350 singles and that was
fitted to the last series of engines fitted into the swinging arm frames.

There will be two challenges: fitting the pushrod tubes - the later engines had them cast into the cylinder -
and sorting an exhaust pipe.

The pushrods for the later engines 1856-56 are I think slightly longer than the earlier types.

https://draganfly.co.uk/product-categor ... ottom-end/
Will give you some idea.

[Simon.Gardiner]

Dean
As Will says, this isn't an straightforward exchange of one head for another.
On a pre-1952 cylinder barrel, the barrel spigot won't fit the head (not without being ground to reduce the size anyway).
A '52-'55 350 barrel will have the right sized spigot (I think, it's definitely smaller, does the alloy head share the '52-on head gasket?) but you'll still have to deal with the need for very much shorter push-rod covers.
I'd suggest it'll be easier if you find a later cylinder barrel with enclosed push-rods that will match the head!
That'll only leave the matter of the exhaust pipe (but the alloy-head pipe might adapt to the earlier frame easier than the other way round) and the push rods. The push-rods for the alloy head are also alloy, to allow for the extra expansion I imagine but the later ones are a straight swap-in if you're also going for a single lobe cam.

HTH

SG

[Dean Mitchell]

Many thanks for your answers Simon and Will , seems it is not as straight forward to do . I will have to take a look at the spigot on my barrel to see if it can fit. The exhaust I think I can deal with .
Dean.

[Simon.Gardiner]

Dean - if you're still after getting a bit more 'go' changing the cam will make more difference than changing the cylinder head!

SG