Club Cobra Gas-N Exhaust  

Go Back   Club Cobra > Engine Building, Tuning, and Induction > Small Block Talk

Keith Craft Racing
Nevada Classics
MMG Superformance
Main Menu
Module Jump:
Nevada Classics
Nevada Classics
MMG Superformance
MMG Superformance
Advertise at CC
Banner Ad Rates
Keith Craft Racing
MMG Superformance
Keith Craft Racing
MMG Superformance
November 2025
S M T W T F S
            1
2 3 4 5 6 7 8
9 10 11 12 13 14 15
16 17 18 19 20 21 22
23 24 25 26 27 28 29
30            

Kirkham Motorsports

Like Tree2Likes
  • 1 Post By DD (CA)
  • 1 Post By

 
 
LinkBack Thread Tools Rate Thread Display Modes
Prev Previous Post   Next Post Next
  #1 (permalink)  
Old 05-16-2017, 05:33 PM
CC Member
Visit my Photo Gallery

 
Join Date: Feb 2016
Cobra Make, Engine:
Posts: 4
Not Ranked     
Default Pushrod damage or more...? 289 mild

Hello and sorry for the LONG, vague post (for builders) or too tech post (for those like myself).

Subject motor:
289 hid flat tappet
Stock heads: ported, machined deck*
Cam: Comp: 256XE+Ni treatment
Springs: Standard, single coil
Rockers: Comp Mag.Plus roller tip

Longer story behind motor, but should be NOS, stock and virgin cylinders.

This week is the third time I've had my guru go back into it. First time, after 20min, car would idle extremely rough, any throttle and clutch out would die; would not get underway. Motor pulled. gone through. Machinist "no damage, see nothing wrong here." Motor back in. 2-3 drives; 10mins long, clatter-clatter.

Pull VC, few arms noticeably loose, by hand. Lock nuts on screw down studs. Ran motor, adjusted. Full loose > turn to quiet > 1/2 turn and polylock. Motor quieter, but after 20min drive becomes louder clacking again.

So back we go....

Pull VC, 3 arms really really loose, polylocks not loose. hmm. Remove arms. Galling at ends of pushrods (light, standard, non hardened(?). Most arms clean 100%, some very light marking. Going to reuse.

IM removed, new lifters being placed in and hardened pushrods (TFS 6750*). My guy did note the wear on valve pin was slightly toward exhaust (outboard), so moved from now measured 6.785" (was 6.8") rod to shorter 6.75 rods to center wear.

The lifters were not noticeably gouged or worn flat/concave. Therefore, the assumption is that cam is still OK. There were a couple lifters with linear marks barely, but the thought is this likely occurred when rods did not turn freely due galling. (All but 2-3 rods had damage...) Rods not bent or at least not easily noticeable with table test.

Lifters not considered to have collapsed.

Called Comp to ask "is it possible to have excessive pushrod wear, but not be due to damage from a cam?" Answer: yes, sure.

My question is... I'm not so totally sure this is all we should be doing.... I've seen some posts on here with 'lucky' folks having bent rods and suggestions were largely to replace and try again. Which is what we are doing. Anyone else care to chime in for what else I might wish to look for while IM is off...?

Thanks very much,

DD (CA)
Attached Images
 
Reply With Quote
 


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

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On



All times are GMT -7. The time now is 06:21 PM.


Powered by vBulletin® Version 3.8.0
Copyright ©2000 - 2025, Jelsoft Enterprises Ltd.
Search Engine Friendly URLs by vBSEO 3.6.0
The representations expressed are the representations and opinions of the clubcobra.com forum members and do not necessarily reflect the opinions and viewpoints of the site owners, moderators, Shelby American, any other replica manufacturer, Ford Motor Company. This website has been planned and developed by clubcobra.com and its forum members and should not be construed as being endorsed by Ford Motor Company, or Shelby American or any other manufacturer unless expressly noted by that entity. "Cobra" and the Cobra logo are registered trademarks for Ford Motor Co., Inc. clubcobra.com forum members agree not to post any copyrighted material unless the copyrighted material is owned by you. Although we do not and cannot review the messages posted and are not responsible for the content of any of these messages, we reserve the right to delete any message for any reason whatsoever. You remain solely responsible for the content of your messages, and you agree to indemnify and hold us harmless with respect to any claim based upon transmission of your message(s). Thank you for visiting clubcobra.com. For full policy documentation refer to the following link: CC Policy
Links monetized by VigLink