IInteresting read for the Pushrod vs OHC debaters :)

[hemi265turbo]

V8 / Pushrod

Just a comment to about the vvti, other tech to make a small engine
perform.

V8's dont exactly need VVTi from my experience.

With a 5.0 litre holden engine in a kingswood, with a 3.08:1 DIFF ratio and even lower at one stage (2.78:1) big hydraulic cam (range 3k-6k)
I was still having traction problems from 1200rpm, so 'extra' low end torque
from variable valve timing doesn't matter at all. Also i think it helps with
economy by comprimising cylinder filling (bad VE at low rpm's would be degrading cylinder filling (by a guess) to about 60% (3 litres). Which is perfect
in my book... at 3k when the cam is happy, that's my vvti!
Economy was great, as well as performance.


The introduction of D/OHC often went hand in hand with other radical head design changes etc, which makes a false belief that that is where the extra
perfromanace comes from.

Ie, compare a VN v8 (injected 5.0) to a kingswood 308 (5.0)..
What's the difference? EFI?? no... heads that flow 450hp standard.
Most people credit the EFI for the increase in power, it's just the
massivly improved head design.


I've said it before, to sum up one of these arguements:

There is no substitute for cubic inches for making power.
(Boost isn't, since you just boost the bigger engine too)
Bigger isn't always better though, the engines must suit the requirements of the car. Ie, 550cu in a mini might be a bit overkill..

We are all running on the internal combustion engine that was invented in
the 18'th century. UNTIL SOMEONE CREATES A CAMLESS ENGINE, EVERYONE IS JUST AGRUEING ABOUT THE SAME THING!! CAMS OPEN VALVES!! HOW
THEY DO IT IS IRREVELENT!!!!!! HONESTLY IT IS!!!

go nuts rotor boys

[Billzilla]

J CAMS OPEN VALVES!! HOW
THEY DO IT IS IRREVELENT!!!!!! HONESTLY IT IS!!!

Not it's not.
I explain it quite clearly on my site.
There are very distinct advantages to multi-valve twin-cam engines over any other type.

[banshee]

As there are advantages of using larger capacity engines to certain applications.

I doubt the world could run off multi-valve twin-cam engines.

[Nick]

the thing is, once peumatic valves with infinate variation with no cams and therefore can be made smaller and take up half the room than current multicam engines do while making the engine more efficient come to the modern car, the narrow minded pushrod fans will still like only their pushrod engines.

[Bomber2k]

the thing is, once peumatic valves with infinate variation with no cams and therefore can be made smaller and take up half the room than current multicam engines do while making the engine more efficient come to the modern car, the narrow minded pushrod fans will still like only their pushrod engines.

You know whats the appealing part about old push engines to me? The fact that it came standard as a factory option to my car and I can put it in without any engineering and hassle. Secondly, I can work on it myself, fairly easily. I'm going to attempt to rebuild it myself next year. Not to mension the price of parts and how easy they are to get. Lets see you get head bolts for a ferrari over the counter at Repco. They are realitivly easy to supercharge, piss easy to hook nitrous up to. Yeh sure, it might not be as high tech as if I other things out there, but it will still be very competitive.

I'd rather be arm deep in grease building my own shit than handing a mechanic my cheque book and bending over. I can build my own engine, build my own carbies, tune it myself, service it myself ect. My cars never left my garage for any work before. I'm not a mechanic, I'm just a software programmer looking for an escape from computers on the weekend. This old stuff is in reach for me, both technically and financially.

[Jim]

Thank you Mr Stereotype for dropping in to show us the extreme polarised and generic end of the spectrum! :D

[Billzilla]

I'd rather be arm deep in grease building my own shit than handing a mechanic my cheque book and bending over. I can build my own engine, build my own carbies, tune it myself, service it myself ect. My cars never left my garage for any work before. I'm not a mechanic, I'm just a software programmer looking for an escape from computers on the weekend. This old stuff is in reach for me, both technically and financially.

Me too, 'cept EFI is a lot easier than carbies to tune, I too do most of my own stuff, and I'm a pilot.

[Jim]

I'm a pilot.

so...when does the series start then? :D

*runs away*

[Bulgogi]

the thing is, once peumatic valves with infinate variation with no cams and therefore can be made smaller and take up half the room than current multicam engines do while making the engine more efficient come to the modern car, the narrow minded pushrod fans will still like only their pushrod engines.

Not to mention cost a lot less than what it does at the moment.

[banshee]

I'm a fan of V8's, does that make me a pushrod fan?

[Billzilla]

I'm a fan of V8's, does that make me a pushrod fan?

Not enough info.
I own two v8's, but both are quad-cam & have 32 valves each.

[Bulgogi]

http://www.jack-brabham-engines.com/

I think the 6-stroke design will rule over both OHC and pushrod. :D

[hemi265turbo]

Pushrod Adv

There are also advantages to pushrods over other types too.
Ie, the physical dimension, simplicity, cost, etc. And I don't belive
v8's that only chug to 4k need a valve train that is optimised
for higher revving engines.

Again, applications are the key. Whatever's cheapest and does the job best will be chosen. You'd be stupid to run a complex 5 valve per cylinder quad cam setup on a chugga v8. It doesn't require it, nor would it benefit from
it. Also the money saved on both design and production, (and later on servicing (imagine 40 valve seats to regrind!) could be put to better use on
other desgin aspects of the engine.

When they do make pneumatic or solonoid operated vavles, I hope they
name the little stick thing that actuates them pushrods , but I bet it will
take a while for the OHC boys to let go of their cams!

[banshee]

Its like the Beatles and Elvis, you can be an Elvis man and like the Beatles, or you can be a Beatles man, and like Elvis, but you can never like both equally.

Edit - Bill, I gave you enough info..

[Sturmovik]

Rotory valves are where its at....