More Cam Questions

[chris_seven]

As we are making steel cam cores I have been looking at adding an MFI pump drive as an option and have come to realise the extent of my ignorance about MFI Fuel Pumps. All of the engines we have been working on have been either carburetted or CIS and our MFI experience is limited.

The above photographs show the ends of a pair of 3 bearing 'E' Cams and I don't think that the orientation of the 'Thru Holes' has any significance.

I am more concerned about the position of the holes for the pump drive and if the need to oriented relevant to the timing of the cam and hence the key way.

I realise that the pump gear is adjustable but I am not sure if the 4 holes need to be positioned accurately relative to each other or also to the 'cam'.

Any ideas?

[Flieger]

I would think not, since the timing is adjustable when you install the belt. If the hole pattern did matter then it would have to have a feature so you could only put the pulley on in one orientation.

[prschmn]

Through holes-I think just pressure relief for oil so doesn't matter but the sprocket mounting?
I'd wonder how many teeth the sprocket has-does it relate to the timing? I.E. if that number isn't divisible by four then-----

[chris_seven]

Originally Posted by prschmn

Through holes-I think just pressure relief for oil so doesn't matter but the sprocket mounting?

I agree about the through holes but do worry about the others.

I will by the cams on a CMM and see what I can learn.

[racing97]

Chris I have made several adapters for people who want to put cores without the mechanical drives in mechanical injected projects and I put the holes where ever I feel and it makes no difference. There is plenty of adjustment to compensate for the belt drive timing no matter what you do.

regards

[chris_seven]

Originally Posted by racing97

Chris I have made several adapters for people who want to put cores without the mechanical drives in mechanical injected projects and I put the holes where ever I feel and it makes no difference. There is plenty of adjustment to compensate for the belt drive timing no matter what you do.

regards

Thank you