PONTIAC ZONE TECH FORUMS
 

Go Back   PONTIAC ZONE TECH FORUMS >
Engine Tech
> Engine Buildups in progress
User Name
Password

Engine Buildups in progress Tell us what your latest project is, and post a few pics.

sponser links

Reply
 
Thread Tools
Old 06-11-19, 09:15PM   #16
Gach
Administrator
 
Gach's Avatar
 
Join Date: May 2003
Location: ....
Posts: 19,285
Default

Yup, the shorter roller lifters take a much longer push rod. The Jessel lifters took a 9.300 push rod.
__________________
The things they hide, the way they spin things, the excuses that they make and the things they omit.
Gach is offline   Reply With Quote
Old 06-11-19, 11:34PM   #17
Steve C
Verified User
 
Join Date: Dec 2002
Location: .
Posts: 1,091
Default

Pushrods can deflect under high loads because of differences in angularity between the lifters and the rocker arms. Oblique angles contribute to side-loading that leads to deflection of the pushrod. If the pushrod deflects, it reduces net lift at the valve, which hurts breathing and the engineís power potential. It also shortens valve duration and retards valve timing.

Scenario ..... with a set of CNC wide port Edelbrock heads. They will require offset rockers and generally use lifters with a offset pushrod cup. The result, pushrod angularity between the lifter and rocker arm. Or in short... the pushrods will be 'skewed', or placed at an angle.

Rhetorical question... Knowing one should not be overly concerned about pushrod weight because it's on the slow moving side of the valve train. What would reduce the angularity relationship in the above scenario, longer pushrods or slightly shorter pushrods used in conjunction with "Hi-Seat" style roller lifters.


.
Steve C is online now   Reply With Quote
Old 06-11-19, 11:53PM   #18
Gach
Administrator
 
Gach's Avatar
 
Join Date: May 2003
Location: ....
Posts: 19,285
Default

Off set rockers and off set lifters, ( cups ) on intake only. Thereís different degrees off sets. 500 off set Rocker shaft and 700 degrees rocker shaft.
A Wide Port with only a 500 off set rocker shaft with a 180 off set lifter ( cup ) there is absolutely no angle. The later would have off set lifter bores.
__________________
The things they hide, the way they spin things, the excuses that they make and the things they omit.
Gach is offline   Reply With Quote
Old 06-12-19, 12:02AM   #19
Steve C
Verified User
 
Join Date: Dec 2002
Location: .
Posts: 1,091
Default

"there is absolutely no angle"

Wait what, how do you figure no angle with a .500" off set rocker arm used with a typical .180" offset pushrod cup. The pushrods will be 'skewed', or placed at an angle.

And with a Crower product. The difference between the Hi-Seat lifter and a "regular" lifter would be a 0.170" longer pushrod in theory. In the scheme of things not a lot of difference.

Now back to my question above.
Steve C is online now   Reply With Quote
Old 06-12-19, 12:27AM   #20
Steve C
Verified User
 
Join Date: Dec 2002
Location: .
Posts: 1,091
Default

"Offset lifters are used when a cylinder head company moves the pushrod location to make room for larger intake ports. This offset can put the pushrod in an angle which can cause clearance issues and higher chances of deflection. Lifters with .150", .180", and .200" offset seat either Right or Left correct the angle problem."

Chris Straub
Mfg Performance Parts
Straub Technologies

" Often an offset rocker can be combined with an offset lifter to move the pushrod out of the way of a wide intake port. Many engine builders would rather include as much offset in the rocker as possible since they feel that the tradeoff of increased lifter bore loading from the offset lifter can be excessive, while others are willing to accept increased lifter bore wear in favor of less angle on the pushrod. Lifter offset also reduces the amount of offset required from the rocker arm. It’s always a good idea to operate a pushrod as close to vertical as possible, since pushrod angle also imparts a bending moment into the pushrod that is not an issue in pure vertical motion."

https://www.chevydiy.com/shaft-rocke...-block-chevys/


And the answer to my question..... the longer pushrod would reduce the angularity relationship.

Last edited by Steve C : 06-12-19 at 12:51AM.
Steve C is online now   Reply With Quote
Old 06-12-19, 01:05AM   #21
Gach
Administrator
 
Gach's Avatar
 
Join Date: May 2003
Location: ....
Posts: 19,285
Default

A longer push rod yes, but not with a shorter push rod. Push rod Hole on a 375 CFM head isnít moved as much as a 420 CFM head. Plus the intake is mover over. Itís not like the early Wide Ports.
__________________
The things they hide, the way they spin things, the excuses that they make and the things they omit.
Gach is offline   Reply With Quote
Reply


Currently Active Users Viewing This Thread: 2 (0 members and 2 guests)
 
Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
valley pan Bad67Bird Parts & Cars For Sale & Wanted 8 02-03-13 09:38AM
list of failing banks by state- is yours on the list ? Zedo Grape Vine - General Discussion 13 08-03-10 09:26AM
Who makes Tomahawk Valley Covers? Bnick166 Aftermarket News & Products 5 06-18-10 03:06PM
NEW Tomahawk Original Valley Pan!!! Ace-PPR Aftermarket News & Products 17 05-30-09 10:07PM
valley pan install t-bar Engine Tech Discussion - Street or Strip 9 07-11-08 09:26PM


All times are GMT -3. The time now is 05:59PM.

Featured Ads
Ken's Speed & Machine
Mayhem Turbocharging

Carter Cryogenics.  What can we freeze for you?

Pacific Performance Racing

Central Virginia Machine Service.  Home of the Injun Engine!

All Pontiac Engine Kits

Larry's Auto Machine.  Full serivce auto, marine machine shop, domestic and foreign.

Powered by vBulletin® Version 3.6.8
Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.
2001 - 2007 PontiacZone.com
Page generated in 0.08947 seconds with 27 queries