Good thoughts, Mindgame. That's where I thought the thread was going.

I agree, folks don't always read things the way we intend them to be read. The good thing is we can clarify what we said, or should have said. Maybe "This might be a good time and place for this discusson." would have been more appropriate. That was my intent.

Yep, in all the example you cited, especially BBC and offset pushrod SBC it makes lots of sense to use solids. The LSx valvetrain achitecture is a vast improvement over previous generations and does allow the more elegant solution of lower mass parts and straight line load paths so that HRs can work well.

When you get to OHC with hydraulic lash adjusters which don't reciprocate, rpm limits rise, of course.

Back to dynamic "cam twist". I haven't seen any data from Spintron testing that compares LS to SBC or BBC in that area. Has anyone here? There's more to gun drilling camshafts (an expensive operation for an OEM) than weight reduction.

I believe the Northstar cams may be hollow also. I seem to recall that the whole bank of gundrills at the GM Powertrain plant that produces Northstar cams went down due to a fire or something, and they had to subcontract the drilling for weeks. It took something like 4 or 6 gundrills runing 24/7 to keep up, and that was when Northstars were only in 3 or 4 Cadillac models. True, that's 4 cams per, but think of the number of LSx engines produced. That's a lot of busy gundrills!

 

I was impressed with the 7900 HR motor myself. Mustang guys have been forced to do some high RPM HR drag racing and from what I heard from Ron Iskenderian in the limited conversation I had with him they go 7800rpm or more. The LS1 really seems like a good platform to do this on. I have recieved some requests for a high RPM street/strip HR cam for a LS1, I think it's doable but I don't know if either the driveablity or the RPM is going to be the limiting factor. A 7500rpm max street car could do very well on the track, it's just not the easiest thing to do when you want to drive the thing down the street on weekends and such. The lifters are obviously important here too, but the rest of the valvetrain is paramount to making power and making it work without issues up in the 6500-7500 range.

Bret

 

With these high RPM Hr cam's what kind of parts are they using.
What dose weight do to the v train..from the heavy to the light
sorry if i am not asking this ? right but i would just like to no how much diff there is in HP/TQ with the lighter to heavy stuff

 

the mustang guys are using pushrods that have a different size hole in it and a titan oil pump.

 

They're ALL running Titan pumps 94guy? I stand guilty... I'd use my x-ray vision for other things.

I agree on the gundrilling OS. I haven't seen any examples but know of a few companies that offer the service... "Reed Cams" being one. Don't know that I'd opt for that on the standard sbc core for reasons stated. I've tried to dig up some info over the last year or so on the "why" behind the drilled cam core but couldn't really find a lot. I know GM aimed to lower valvetrain noise with the LS1 engine design, but I don't know if that played a part in it or not. I did read about one of the production Infinity engines which uses titanium valves. Not only because they reduce stress on the valvetrain but "they reduce valvetrain noise" as well. So maybe the camshaft serves the same purpose in the LSx, or perhaps "helps" the situation?

Bret,
If you really want to make a revver with a hydraulic lifter just do the same thing the SE guys do with theirs and modify the lifter. Joe Schubeck offers the service by the way. Can't see anything wrong with that for a street build as it doesn't compromise the integrity of the lifter... just keeps it from traveling/pumping-up as much. But yeah, with an rpm ceiling like that... it's bound to be a real fender shaker. Then again if everything's lighter (valvetrain) then it should rev higher on less camshaft duration. Which ties into what Schurters asking.

They're using the lightest components they can get within reasons of durability. If not titanium valves, then definitely lightweight SS. Titanium retainers and maybe titanium locks, not to mention the low mass spring.

-Mindgame