jimmerp

How much reduction in base circle can the stock lifter handle before you need make additional changes in the head setup? is 30 thou ok?
thanks Jim

jimmerp

What, not even a single opinion??

333pg333

There might be opinions but you want an answer. Not that many on here that have physically done this.
Someone will turn up.

TurboTommy

I could not give you a definitive answer on the 16 valve configuration.
But on an 8 valve, the stock lift is 0.474". Jon Milledge made me a cam with 0.503" by reducing base circle and he said the lifters will take up the slack (but not too much more). So, that's almost 30 thou.
However, on a 16 valver, there's less lift to work with so 30 thou would be a greater percentage of the base circle. My guess is it might be be too much.

jimmerp

I was talking to LR and he mentioned that the preload on the 8v was 40 thou, with a total lifter travel of .120 he had no specs for the 16. I feel that Its related to having suitible preload remaining of the hydraulic lifter. I have heard of sbc guys adjusting preload down to keep the lifter from keeping the valve off the seat if it pumps up and cant bleed down at high rpm. If what JM says and the 40 thou is what you were working with to start sounds like you have about .010 on that base circle.. My cams will arrive this week coming and we are going to try it. If I can get .010 I will run it as is.

Paulyy

You know working in MM is so much easier to understand.. and would make more sense on a german car

But for some reason, cam timing and cam specs get very secretive for these cars. Don't know why.

67King

Most folks that do this are 'Murican Yank Tank drivers, and most of the equipment that the older guys who have that artistic know-how are in standard units. Not that I disagree with you, I much prefer the metric system.

That said, what we used to do with the old Turbo Fords I played with was either shim the lash adjusters, or put caps on the valves. Those were followers, rather than buckets, but I'd guess one could make a shim or cap to go between the valve stem in the button on the bucket?

jimmerp

haha...I am Metric raised but all the spec I have for the cams are imperial. My grinder is one of those old guys..