Pushrod hole & Pushrods
Turbo Mini Forums

Can anyone shed light as to why No 1 & 8 pushrod holes are a larger Dia at the top 40mm ?
As I was considering opening the other 6 to the same size.
Also has anyone used MED's latest 1 piece uprated pushrods, if so any views / comments.

http://i28.photobucket.com/albums/c248/spe...er1/mini007.jpg

If it a'nt broke don't fix it !!!!!!!!!!!!!!!!!!!!!

Leave well a loan, is my advice......... STD pushrods are well up to the job....... no unnessasary money spent in the wrong department. IMO........

Why do you say that Benross? With the high lifts that we are using in N/A with high revs surely a stiffer pushrod is an advantage but they do necessitate a larger pushrod hole

I seriously doubt it!

For what it's worth, the answer to the original question - why are the casting holes different sizes - is probably because the designer could make the outer ones bigger without challenging other voids in the casting (waterways/ports).

The designer would have wanted the largest possible size for mold release etc.

So, if you enlarge the smaller ones, just like porting, you risk a breakthrough into another void.

As many have found out, enlarging the ports risks hitting the pushrod holes. Your scenario is just the opposite.

But if you only enlarge the top part (and taper it nicely) it may not be a problem.

Just my thoughts.

Schrödinger's cat - so which one am I ???

what is the spacing between the outermost valve centres and the outermost pushrod centres? Perhaps the valves are further apart and the pushrods are angled ever so slightly? If not, then it is as Rod suggested - just to keep consistency with wall thickness, which from a design perspective is a personal preference thing...

or maybe those the are for locating dowels during block machining .

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