The Cal-look Lounge

just wondering if anyone has had a go with the BP4054 aluminium push rods.

(http://www.vwparts.net/mm5/graphics/00000001/4054.jpg)

i wonder if they're as good as the heavy duty ali push rods aircooled.net sells and if they'd stand up to some good dual springs (BP4046)
bugpack claim that they're lightweight and very strong, a choice for the discerning engine builder.

I used those a few years ago and the ends wore using single HD springs.

I have used the aircooled.net ones and the Smith Brothers ones and they work great with dual springs.

I just got another set of Smith Bros alum pushrods in the mail this week cut and assembled.  They do good work and have a great product.  Joel Mohr used them a lot.
Part number is NA39B-BB.

Here is some info for you to read:
http://www.thesamba.com/vw/forum/viewtopic.php?t=337492

http://www.cal-look.com/forum/index.php/topic,27153.0.html

Here is another link to check.

Rick, what spring pressure/rpm are these designed to take?

thanks for the replies, i didn't get much out of the links though.

the 4054 pushrods would be for a 1679cc, vz-14 cam and 4046 dual springs.
i could also get the chromoly BP pushrods, but the lightness appeals to me.

what are the opinions about the weight difference in ALU and CHROMOLY pushrods?

are these ALU pushrods strong enough for dual springs and fast lift of the VZ14?

in this topic someone also mentioned that ALU expands more easily, which can lead to loss of lift and more slamming against the valvestem.
i checked the expansion coefficients and ALU has about 24, steel about 12 and for as far as i can figure out chromoly also has about 12.

am i being too pretentious and scientific about this?

just curious what the opinions are.

Chris,

As always, it just depends upon what you are trying to accomplish with your motor, rpm range, lift, etc.  I have run aluminum pushrods for years in some of my  milder street or mouse motors.  I generally build motors that are drivers (even if large displacement) and don't hammer them much above 5500 rpms.  I run HD single springs for street motors and really mild, detuned cams that are primarly motors just for a driver.  I run chromoly if planning above 5500 rpms, dual sprinds and a lot of aggressive driving habits.  I like being able to run little or no lash on chromoly rods as they develop some clearance as the motor warms up.

I bent a lot of aluminum push rods in the early days until I figured out they would not survive my dual spring heads and drag race driving habits and moved to chromoly ones for aggressive driving.

Everyone has a different story here but I have always liked the aluminum ones in driver motors where I am just building a cruiser motor. I always run the HD thicker wall aluminum pushrods when using them.

JMO 

Rick M

never run Bugpacks, but I have run John Connollly's aluminum pushrods in my car since 2001-02.
Driven 4 days a week, dual 4046 springs shimmed .100 from bind, .526" @ valve, normal shift rpm to and from work, once up to temp, 4800rpm. In the canyon, there's a corner I exit and nudge 6500 every trip home. I stopped looking for problems with these years ago. Would I run them in a race motor? probably not. Would I run them against triple VW's or K Motions? No.
Sorry no info on Bugpack.

That's backwards.  Al expands at a faster rate than steel, so you don't lose as much lift as you do with steel pushrods.  If you set an engine to .006" of lash cold, when warm the steel pushrod engine will have much more lash than the Al pushrod engine.  IOW, you lose more lift with steel pushrods than Al.  It is also why it is 100% safe to set your lash with steel pushrods to zero.

steel including chromoly i suppose. we went with mantons...
thanks for the replies!

Bruce,

I agree. When I run steel (chromoly) I set my lash at zero with the push rods snug but still able to rotate with my fingers.  This has never been a problem and usually ends up with the normal lash when warm. The motor never has a lot of valve train lashing noise either.

Rick M