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Tue Apr 07, 2009 7:20 am

Eaallred wrote: I've been toying around with the idea of the dual tapered aluminum in my race car. It see's 9000rpm with K-800's and heavy 48mm intake valves. It's tempting to try, but i'll probably wait until I go Ti valves at least.

Eric,

Your probably better off using ultra light ti valves with tapered chromoly for added clearance in the pushrod tube.

At 8500rpms or so you dont need k800's with ti. The "regular" chevy springs should be enough.

Tue Apr 07, 2009 7:43 am

Does anybody know what is the typical pressure of VW dual springs? Thanks.

Tue Apr 07, 2009 7:46 am

1961bluebug wrote: Does anybody know what is the typical pressure of VW dual springs? Thanks.

Different variations out there. Length of valve stems will change seat pressure and cam lift and ratio rockers will effect pressure at the nose of the cam at full lift.

Tue Apr 07, 2009 8:55 am

Alan_U wrote: Eaallred wrote: I've been toying around with the idea of the dual tapered aluminum in my race car. It see's 9000rpm with K-800's and heavy 48mm intake valves. It's tempting to try, but i'll probably wait until I go Ti valves at least.

Eric,

Your probably better off using ultra light ti valves with tapered chromoly for added clearance in the pushrod tube.

At 8500rpms or so you dont need k800's with ti. The "regular" chevy springs should be enough.

Yea, my plan (eventually if money issues don't keep getting in the way) is to send my heads down to Jeff Denham and have him install Ti and re-do the valve springs to what he feels they should be. I'll need to decide between alum and chromo pushrods at that time. Alum is big diameter. I've switched to waterboxer tubes for more clearance, I don't know how close the alum will be though. Might have to buy a single and check it out at that time.

If I don't sell the car that is. I just finished a major project on it that is making me want to keep it now, hahaha

Tue Apr 07, 2009 9:52 am

Eric, would you also be factoring in the pushrod weight difference in spring selection?

Max

Tue Apr 07, 2009 10:53 am

I have the aircooled.net alu pushrods on my 112hp 1800, very happy, much quieter that the horrible cr-mo's i had before.
Cant say a bad thing about them.

Tue Apr 07, 2009 12:37 pm

Max Welton wrote: Eric, would you also be factoring in the pushrod weight difference in spring selection?

Max

I would have Jeff do that. That's why I would need to decide if I were going to switch to alum or keep my chromo before I were to send him my heads. I could get quite a few more rpm's out of this motor with Ti valves and alum pushrods.

Wed Jun 10, 2009 11:39 pm

On a related topic, would HD aluminum pushrods be set with the same valve clearance as a stock pushrod ?

Wed Jun 10, 2009 11:42 pm

I'm running my with stock lash, no problems.

Thu Jun 11, 2009 8:14 am

The rule w/ pushrods is they have to be as stiff as possible...especially the exhaust side.

I only WISH the aluminum pushrods available are as stout as the stock Type IV size. I wonder if they can be had w/ wall thickness as Bus pushrods.

I like the BERG chromoly and use them exclusively for large strokers w/ heavy springs.

I have machined/ sized AC.NET aluminums for strokers. I wish they are much fatter.

Thu Jun 11, 2009 8:37 am

our Dual Tapered are much stronger, if you are worried about that. They are also more $.

John
Aircooled.Net Inc.

Thu Jun 11, 2009 9:22 am

John,

Can the heavier aluminum pushrods be ordered without the tapers?

I really like them just consistent diameter along its entirety. That will also be something if they come the size of Bus pushrods.

Thu Jun 11, 2009 9:24 am

I don't know. In ME classes you learn that the additional diameter is NOT NEEDED at the ends, since the ends do not flex.

John
Aircooled.Net Inc.

Thu Jun 11, 2009 9:33 am

[email protected] wrote: I don't know. In ME classes you learn that the additional diameter is NOT NEEDED at the ends, since the ends do not flex.

John
Aircooled.Net Inc.

I know but it is just easier to chuck and cut the darn thing on the lathe to size. So you do not have a work stick-out of 6 inches! :D

Thu Jun 11, 2009 9:38 am

THAT IS TRUE!

Thu Jun 11, 2009 11:11 pm

[email protected] wrote: ... the additional diameter is NOT NEEDED at the ends, since the ends do not flex.
I concur. The extra diameter to the ends just adds weight and no strength since there's no bending happening at the tips.

Fri Jun 12, 2009 6:52 am

BTW, this is also why factory pushrods are straight and not tapered.

John
Aircooled.Net Inc.

nsracing wrote:

I know but it is just easier to chuck and cut the darn thing on the lathe to size. So you do not have a work stick-out of 6 inches! :D

Fri Jun 12, 2009 7:11 am

What about heat transfer, would non tapered be a more even distribution of material accounting for this?

Can someone post a picture of a stock vs bus vs fancypants (aircooled) pushrod next to each other in the same pic? ...for visual contrast of scale.

Fri Jun 12, 2009 1:26 pm

I run AC.NET ones on my 2165 [94x78] CB 044's w/duals and dual 44mm idf's . I also spent the time to do the valve train geometry properly at the same time at my last rebuild. The days of valve train noise and constant adjustments seem to be over. I don't usually pull more than 6500 rpms; and am now very happy.

Sat Jun 13, 2009 10:47 pm

youngstah wrote: What about heat transfer, would non tapered be a more even distribution of material accounting for this?
Heat transfer? From where to where?