Xflow Clearances and Plugs

[Mat Norris]

I have a non-caterham sourced xflow fitted to my 7, with an apparently big valve head and a Piper 'Blueprinted' cam. Unfortunately I don't have any more info on the cam and I would like to findout ideally what valve clearance I should be running at. The guy I purchased the engine from (a respected motorsport engine builder) thought 8 and 10 thou when cold, which seemed to me to be a bit tight. However, when hot, the clearance seem to open enough to give some tappet noise or maybe its just a noisy cam?? Thoughts and suggestions would be appreciated. Also, what's a good spark plug to go for if replacing the standard NGK one?

Cheers, Mat.

 

[Anthony Micallef]

Hello Mat, hows the car going? I sent you an e mail a while ago saying hello, not sure if you received it though.Drop me a line and tell me how things are going.

[Roger King]

I'm afraid that it is impossible to say what the valve clearances should be without knowing the cam profile. As a last resort, you could remove the camshaft and measure the profile of the ramp (the bit of the cam lobe that gradually takes up the valve clearance) and work the clearances out from this. But if you've removed the cam, you can just look for the profile number stamped on it anyway.

[John]

For plugs use NGK B8ECS set to 25 thou. For tappet clearances, ring piper and get a X-Flow cam spec sheet. This will list all the cams, some of which can be discounted straight away eg Forumla Ford etc. Measure your valve lift with a DTI and try to match it up with one from the list, then use the clearances recommended for it.

 

John