Non Rotor: Tech
08-12-2003, 06:51 PM
#11
Senior Member
Join Date: May 2002
Location: California
Posts: 22,465
Originally Posted by Eric Happy Meal' date='Aug 12 2003, 03:38 PM
[quote name='j9fd3s' date='Aug 12 2003, 02:12 PM'] [quote name='phinsup' date='Aug 12 2003, 01:50 PM'] This is a fairly arguable point, many would claim that the engergy lost from the cam to the lifter, through the pushrod to the valve is more then any disadvantage of the having the cams overhead.
And the fact is less moving parts is less room for something to break, that's the general theory behind the overhead cam as far as I know. Not to mention the potential of multiple valve heads and cams. This is very hard to do with a pushrod engine as you would have to increase the width of an already larger block.
And the fact is less moving parts is less room for something to break, that's the general theory behind the overhead cam as far as I know. Not to mention the potential of multiple valve heads and cams. This is very hard to do with a pushrod engine as you would have to increase the width of an already larger block.
mike [/quote]
well all pushrod engines are overhead valve. [/quote]
not so. flathead ford v8's are pushrod (i think) and not overhead valve
mike
08-12-2003, 07:02 PM
#12
Senior Member
Join Date: Feb 2002
Location: Close enough to annoy you.
Posts: 1,381
Not true flat heads have valves in the block itself, some models had the cam up high but Ford and Studebaker I know for sure did not.
Citroen had a variable valve timing system based upon hyrdaulics opening up at the correct time and filling the lifters giving a higher open time with a push rod engine. Bizzzaarreee.
Otherwise mechanically simple is the best bet plus the aforementioned compact size...although they've gotten pretty good about sinking the cams down into the head further.
There was also the loophole the in old Indy rules that allowed a pushrod engine more boost to make up for the lack of valving/intake. Penske/Mercedes took advantage of said rule and blew the rest of the field away.
They of course changed that rule shortly after.
The problems with pushrods include plugged pushrods if they transfer oil, lifter noise, misseated pushrods, bad valve adjustments with solid lifters and flex at high speeds. Mostly fixed of course
Citroen had a variable valve timing system based upon hyrdaulics opening up at the correct time and filling the lifters giving a higher open time with a push rod engine. Bizzzaarreee.
Otherwise mechanically simple is the best bet plus the aforementioned compact size...although they've gotten pretty good about sinking the cams down into the head further.
There was also the loophole the in old Indy rules that allowed a pushrod engine more boost to make up for the lack of valving/intake. Penske/Mercedes took advantage of said rule and blew the rest of the field away.
They of course changed that rule shortly after.
The problems with pushrods include plugged pushrods if they transfer oil, lifter noise, misseated pushrods, bad valve adjustments with solid lifters and flex at high speeds. Mostly fixed of course
08-12-2003, 07:09 PM
#13
Junior Member
Join Date: Jun 2003
Location: COLORADO
Posts: 18
yea push rod engines are cool and make alot of power, but like they said over head cams were done for less moving parts............ then came the rotary engine and the world was like... " What no pistons, pushrods, valves, hell not even a block of some sort?" so every one ran from the idea and here we are pioneering the rotary engine with 1000 + horspower with 1.3 liters!!! who would of ever thought?
08-12-2003, 07:23 PM
#14
Senior Member
Join Date: May 2002
Location: California
Posts: 22,465
Originally Posted by rotarydoc' date='Aug 12 2003, 04:09 PM
yea push rod engines are cool and make alot of power, but like they said over head cams were done for less moving parts............ then came the rotary engine and the world was like... " What no pistons, pushrods, valves, hell not even a block of some sort?" so every one ran from the idea and here we are pioneering the rotary engine with 1000 + horspower with 1.3 liters!!! who would of ever thought?
mike
Thread
Thread Starter
Forum
Replies
Last Post
-xlr8planet-
Rotary Engine Building, Porting & Swaps
9
01-25-2010 10:29 PM
Bastard
Rotary Engine Building, Porting & Swaps
21
09-01-2008 12:19 AM
Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)