Ariel Owners Motorcycle Club

I have had huge issues trying to fit a new exhaust valve guide to a '57 alloy head.

Got the old one out no worries but the new one just will not go in! It gets half way then won't budge.

Is there something i am doing wrong or are they usually awkward?

I have heated the head up in the oven, gas mark 9 for 25 minutes, but it has been on a baking tray (for ease of getting it out), will the bottom of the head have been shielded from the heat to some extent and therefore not have expanded as much as the top half?

Hope someone can help,

Rob

Although I'm no expert I have managed to put in new valve guides on non Ariel alloy heads using the same technique as you've described and have never had a problem and I'd be surprised if the baking tray was a problem. You could try leaving it in for longer to be sure.

So, clutching at straws...
Is it possible that the hole in the head might have a ridge which might be catching the guide? Maybe the guide is not going in at the right angle? It might be worth measuring the internal diameter of the hole just in case something strange has happened in the past such as a repair. It the guide the correct diameter?

That's all I can think of. I hope that a proper expert comes along soon with something better. Good luck - Dave.

Hello Rob have you tried to cool the valve guide in the fridge ? the ice department of course for a longer time( few hours), it works both ways then, smaller guide and bigger hole.
regards chris