valve adjustment - zero lash

Carlo, if you have chromoly pushrods, you want to set your valve lash at zero, you should be able to rotate the pushrods, don't make it tight, but "loose-zero" is perfect for chromoly because as the engine grows wider as it warms up, the lash will increase to around .004-.006 as the chromoly doesn't grow in length proportionately to the engine growth (in width).

If, however, you have aluminum pushrods, you need .006 lash/clearance as the aluminum pushrods grow with the warming engine which keeps the lash/clearance correct at all temperatures (in theory).

Thanks Will, that is what Pat says too.

Will, I wanted to add. That was a great explanation of why the zero lash works with steel push rods. I read quite a bit about it, but no one explained how the steel vs aluminum expansion rate is different allow us to (carefully) pull this off. Thaks

I second that; it took a while, but after 4 different sources sounding the horn on how great chrome-moly push rods are, I began to unnerstan...

Also in my case, I have thee odd little rollers with a flat spot on the rocker adjustment .

So zero lash helps me sleep at night not worrying about that roller rolling off teh flat spot... And it is easier to do than the feeler gauge...

I'll drank to that...and it's really fun when it rolls off the flat spot onto the round spot...and you can't get it to swivel back to the flat spot...

Just so you know- Chromoly is great for pushrod material when valve spring pressure is so great (bigger than VW diameter double or triple springs) that even aftermarket heavy duty aluminum pushrods won't stand up, but for most street cars (and that includes just about everyone I know's engine here) chromoly is overkill. They add unnecessary weight which is harder for the springs to control, and this translates into slightly less peak rpm than the engine would be capable otherwise, and shorter spring life. They are popular because they are just over half the price of aluminum pushrods of the proper material and heat treat, but aluminum is the proper material this part.

One advantage chromoly pushrods do have over aluminum in a street engine- while aluminum pushrods will continue to expand and keep the valve lash reasonable no matter how hot the engine gets, the engine will get noisy with the chromoly (due to it's lower expansion rate) if temps get beyond normal operating parameters (the engine overheats).

The adjusters with the flat on the ball are Ford Courier/Mazda and yeah, they can be a pain in the a**. I find the  swivel/elephant's foot design easier to work with, although a genuine oem set (they're Porsche parts) are expensive these days. IIrc the flat ball design isn't capable of quite as much valve lift as the Porsche designed adjusters, but again, for most of us that's not a concern. As usual, the aftermarket makes poor, cheaper copies of both, so (as always) you get what you pay for. Al

I also prefer teh elephant foot heads. I have a set , but did not installon the engine because - the push rods are hollow for a little oil feed. They fit into the rockers also hollow and onto the adjustable feet also hollow. So I did not want to mess up teh marginal amount of oil feed this was designed to do. The Porsche elephant feet are not hollow and do not have that little pin hole aligned to the rockers - aligned to the push rods - etc...

Did I explain that clearly? What do y'all think of that? Is there really an significant oil moving through there? I hate the little swivel ball heads.

Photos of engine finally ready to install.

Then there are the push rods (forgot what they are called) that have additional hole in the them for better oil flow...