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Cooked Pushrod #666349 04/10/10 08:11 PM 04/10/10 08:11 PM
Joined: Dec 2008 Posts: 184 Central Coast P Plumcrazyracing OP member
Plumcrazyracing OP member P Joined: Dec 2008 Posts: 184 Central Coast	Was running the valves and found #3 intake pushrod was quite burnt from the cup to about 3/4 of an inch down. Lash was right where it was supposed to be. Pulled the rack out and discovered that maybe my clearancing between the rocker and the pedestal was too tight. Maybe the heat transfer could have done this? The pushrod does not show any signs of rubbing the head, the rocker did not show any signs of a plugged oil hole, shafts were installed correctly and i have about 95 passes on the motor. Any thoughts, or suggestions on what to inspect are welcome. 493, indy ez cnc'd heads, indy rocker set up, comp solid roller lifters, smith brothers pushrods. Steve

Re: Cooked Pushrod [Re: Plumcrazyracing] #666350 04/10/10 09:58 PM 04/10/10 09:58 PM
Joined: Apr 2005 Posts: 936 Deland, Florida B biff426 super stock
biff426 super stock B Joined: Apr 2005 Posts: 936 Deland, Florida	How many threads are showing under the rocker arm on the adjusting screw? pushrod could be too short

Re: Cooked Pushrod [Re: biff426] #666351 04/10/10 11:05 PM 04/10/10 11:05 PM
Joined: Dec 2008 Posts: 184 Central Coast P Plumcrazyracing OP member
Plumcrazyracing OP member P Joined: Dec 2008 Posts: 184 Central Coast	Quote: How many threads are showing under the rocker arm on the adjusting screw? pushrod could be too short Funny you should ask that! I figure I might be about .060 too short. I have about 1.5 threads if not two below the rocker on the adjuster. Sounds good but Indy recomends that the threads not show. So I might have measured wrong. But would this really cause a heat issue in the pushrod like that?

Re: Cooked Pushrod [Re: Plumcrazyracing] #666352 04/10/10 11:25 PM 04/10/10 11:25 PM
Joined: Dec 2008 Posts: 415 Peru cbarracuda mopar
cbarracuda mopar Joined: Dec 2008 Posts: 415 Peru	yes

Re: Cooked Pushrod [Re: Plumcrazyracing] #666353 04/10/10 11:30 PM 04/10/10 11:30 PM
Joined: Nov 2003 Posts: 6,293 Rock Springs Bob_Coomer master
Bob_Coomer master Joined: Nov 2003 Posts: 6,293 Rock Springs	Quote: Quote: How many threads are showing under the rocker arm on the adjusting screw? pushrod could be too short Funny you should ask that! I figure I might be about .060 too short. I have about 1.5 threads if not two below the rocker on the adjuster. Sounds good but Indy recomends that the threads not show. So I might have measured wrong. But would this really cause a heat issue in the pushrod like that? shouldnt have caused the problem...ask your self why that one pushrod was burnt? If the adjuster and pushrod length was to blame they would be others know? It might be a simple as lack of oiling. I would inspect the rocker arm and shaft assembly closely before just replacing the push rods. Champfer the oil hole, and banana grooving the rocker arms can make a big difference. [color:"red"]65 Hemi Belvedere coming soon [/color] [color:"#00FF00"]557" Indy engine 1.07 60ft 144mph in the 8th 2100 lbs package [/color]

Re: Cooked Pushrod [Re: Plumcrazyracing] #666354 04/11/10 12:43 AM 04/11/10 12:43 AM
Joined: Dec 2008 Posts: 415 Peru cbarracuda mopar
cbarracuda mopar Joined: Dec 2008 Posts: 415 Peru	banana grooves are usually added to gear shafts to improve oiling of the rocker itselt in kase you have bushed rockers,the ideal for the rocker adjusting screw is to have only one thread showing below the rocker arm with valve lash set,if you smoked your pushrods more oil to valve gear womt fix the problen only longer pushrods

Re: Cooked Pushrod [Re: cbarracuda] #666355 04/11/10 01:05 AM 04/11/10 01:05 AM
Joined: Jun 2005 Posts: 6,257 gulfport, ms, west mi rowin4 master
rowin4 master Joined: Jun 2005 Posts: 6,257 gulfport, ms, west mi	I guess I don't understand what the push rod length would have to do with the burning of the cup. If the adjuster is to short it will hit the rocker [ not good ] or if the adjuster is to far out it will possibly break the adjuster ball off. But at 1 1/2 threads out , that's within normal adjustment. I'd look for lack of oil as you said the adjustment was correct. it's ok to butt heads, just don't do it with a butthead

Re: Cooked Pushrod [Re: rowin4] #666356 04/11/10 01:49 AM 04/11/10 01:49 AM
Joined: Aug 2003 Posts: 43,232 Bend,OR USA C Cab_Burge I Win
Cab_Burge I Win C Joined: Aug 2003 Posts: 43,232 Bend,OR USA	I have cooked some pushrod cups do to the pushrods not being able to seperate from the adjusters balls long enough to allow oil to get in there The pushrod and rocker arm adjusters needs to be free enough for the two to have clearances from each other when the valve is closed If the other fithteen are doing okay I would look closely at the hurt one Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)

Re: Cooked Pushrod [Re: Cab_Burge] #666357 04/11/10 08:39 AM 04/11/10 08:39 AM
Joined: Dec 2008 Posts: 1,200 UK 6 602heavy pro stock
602heavy pro stock 6 Joined: Dec 2008 Posts: 1,200 UK	I'm glad this came up , was checking lash & found 5 pusrods burn't , i have pr oiling along with spray bars , plenty oil up to the cup as i checked again yesterday , all these burnt pushrods are exhuast , these are brand new from Smith Bros , one thing i did'nt do was to lube the cups before fire up , did'nt think this necesary due to oiling direct to cup , funny the ex have taken the hit , all adjusters are within spec of Jessel (adjuster nut flush with top of adjuster) , i just don't know why this happened? , had four spare to which i lubed before intall , will pull the covers & check again after a good run.

Re: Cooked Pushrod [Re: rowin4] #666358 04/11/10 09:12 AM 04/11/10 09:12 AM
Joined: Dec 2008 Posts: 415 Peru cbarracuda mopar
cbarracuda mopar Joined: Dec 2008 Posts: 415 Peru	Quote: I guess I don't understand what the push rod length would have to do with the burning of the cup. If the adjuster is to short it will hit the rocker [ not good ] or if the adjuster is to far out it will possibly break the adjuster ball off. But at 1 1/2 threads out , that's within normal adjustment. I'd look for lack of oil as you said the adjustment was correct. lengh affects the geometry

Re: Cooked Pushrod [Re: cbarracuda] #666359 04/11/10 12:25 PM 04/11/10 12:25 PM
Joined: Dec 2008 Posts: 184 Central Coast P Plumcrazyracing OP member
Plumcrazyracing OP member P Joined: Dec 2008 Posts: 184 Central Coast	As far as the length goes, my pushrods are all about .060 too short. All of my pushrods are the same length and this measurement is constant throughout. I have three pushrods that have discolored and one of which i refer too as "cooked". The only anomoly i have found is the clearance between the thin spacer and the pedestal on all three! This makes me believe the tight tolerance generated too much heat and transferred through the rocker and adjuster. Add the pushrod theory and just maybe this is the problem. Oil feed appears to be fine, no obstructions and no galling of the rockers (yet anyway). Does anyone have any comments on the rocker/spacer/pedestal tolerances and my suspicion of the heat transfer? Thank you for the help.

Re: Cooked Pushrod [Re: Plumcrazyracing] #666360 04/11/10 01:05 PM 04/11/10 01:05 PM
Joined: Aug 2003 Posts: 43,232 Bend,OR USA C Cab_Burge I Win
Cab_Burge I Win C Joined: Aug 2003 Posts: 43,232 Bend,OR USA	Do the hurt pushrods slide up and down easily or is the rocker tightness help bind them up a littel? As far as rocker side clearances my opinion is like every other part in a race motor "looser is better than a tiny bit to tight" Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)

Re: Cooked Pushrod [Re: Plumcrazyracing] #666361 04/11/10 01:19 PM 04/11/10 01:19 PM
Joined: Dec 2008 Posts: 415 Peru cbarracuda mopar
cbarracuda mopar Joined: Dec 2008 Posts: 415 Peru	.060 too short is ok in a low tension spring,spring load play a part.Also aluminum roller rokers like no thread showing below the rocker arm

Re: Cooked Pushrod [Re: Cab_Burge] #666362 04/11/10 01:19 PM 04/11/10 01:19 PM
Joined: Dec 2008 Posts: 184 Central Coast P Plumcrazyracing OP member
Plumcrazyracing OP member P Joined: Dec 2008 Posts: 184 Central Coast	Quote: Do the hurt pushrods slide up and down easily or is the rocker tightness help bind them up a littel? As far as rocker side clearances my opinion is like every other part in a race motor "looser is better than a tiny bit to tight" Don't quite understand what you mean by slide up and down. As i adjusted/checked lash the pushrods were not jammed or obstructed. The pushrod clearance through the heads was normal with no signs of interference. On the other hand, some select rockers were not quite that 'free'. Looking at it that way, i guess the rocker may have bound a little and caused more of an impact on the pushrod.

Re: Cooked Pushrod [Re: cbarracuda] #666363 04/11/10 01:22 PM 04/11/10 01:22 PM
Joined: Dec 2008 Posts: 184 Central Coast P Plumcrazyracing OP member
Plumcrazyracing OP member P Joined: Dec 2008 Posts: 184 Central Coast	Quote: .060 too short is ok in a low tension spring,spring load play a part.Also aluminum roller rokers like no thread showing below the rocker arm 240 on the seat and 495 open. 1.86'sh installed height. I need to check my build notes on the exact installed height.

Re: Cooked Pushrod [Re: Plumcrazyracing] #666364 04/11/10 01:27 PM 04/11/10 01:27 PM
Joined: Dec 2008 Posts: 415 Peru cbarracuda mopar
cbarracuda mopar Joined: Dec 2008 Posts: 415 Peru	Quote: Quote: .060 too short is ok in a low tension spring,spring load play a part.Also aluminum roller rokers like no thread showing below the rocker arm 240 on the seat and 495 open. 1.86'sh installed height. I need to check my build notes on the exact installed height. That's a High tension spring for a roller cam. I'm sure a longer push rod will fix your problem.

Re: Cooked Pushrod [Re: Plumcrazyracing] #666365 04/29/10 07:02 PM 04/29/10 07:02 PM
Joined: Nov 2009 Posts: 191 WI mopar873 member
mopar873 member Joined: Nov 2009 Posts: 191 WI	I'm feelin' your pain. I installed a new set of Indy rockers on my Iron block with 440-1s. I had two intake pushrods that not only cooked, but also had their cups deform outward. These are the same pushrods used on the last set of 1.5 rockers. I took the shafts off and saw the witness marks on the rocker from compressing the pushrod cup. Curiously enough this only happened on two cylinders. After having checked everything, and "clearancing" the rocker arms a bit, I tried original length again. Another burned/deformed pushrod. Then I went to two pushrods that were about .040 shorter. Now they are getting warm the first inch down from the cup and it appears they don't get as much oil as the others. I can't understand why on only two cylinders, but if this thing keeps pi$$ing me off, I am going to thru-pushrod oiling and the proper roller lifters. What I don't know is how tolerant these pushrods are to heat. I dont want to have a cup pop off and play tag with my rotating assembly!! BTW, the adjusters showing are consistent with all the other rockers. any comments would be great

Re: Cooked Pushrod [Re: mopar873] #666366 04/29/10 07:29 PM 04/29/10 07:29 PM
Joined: Jun 2003 Posts: 52,972 Romeo MI MR_P_BODY Master
MR_P_BODY Master Joined: Jun 2003 Posts: 52,972 Romeo MI	There are a couple different styles of rocker arms, one will have a squirter hole that squirts oil towards the cup.... if the push rod length is wrong the oil doesnt squirt INTO the cup(may miss the whole area and if thats the case all its doing is spraying oil on to the head... check what style you have... the other style has the oil come across the arm(internally in the arm) and comes out right at the cup area also some of the cheaper arms I've seen the squirter hole was aimed wrong and missed

Re: Cooked Pushrod [Re: cbarracuda] #666367 04/29/10 08:50 PM 04/29/10 08:50 PM
Joined: Nov 2003 Posts: 6,293 Rock Springs Bob_Coomer master
Bob_Coomer master Joined: Nov 2003 Posts: 6,293 Rock Springs	Quote: Quote: I guess I don't understand what the push rod length would have to do with the burning of the cup. If the adjuster is to short it will hit the rocker [ not good ] or if the adjuster is to far out it will possibly break the adjuster ball off. But at 1 1/2 threads out , that's within normal adjustment. I'd look for lack of oil as you said the adjustment was correct. lengh affects the geometry Wrong push rod length does NOT effect it... [color:"red"]65 Hemi Belvedere coming soon [/color] [color:"#00FF00"]557" Indy engine 1.07 60ft 144mph in the 8th 2100 lbs package [/color]

Re: Cooked Pushrod [Re: Plumcrazyracing] #666368 04/29/10 09:58 PM 04/29/10 09:58 PM
Joined: Aug 2003 Posts: 43,232 Bend,OR USA C Cab_Burge I Win
Cab_Burge I Win C Joined: Aug 2003 Posts: 43,232 Bend,OR USA	I have seen (on a 426 Hemi motor) exhaust pushrods rubbing on the head cause those ones to burn the pushrod ends(rocker arm end tips) up What I'm trying to say is if the pushrod is rubbing on the heads and the rocker arm adjusters are prying on the tips of the pushrods not allowing them to have enough free play to allow the pushrod to drop down away from the adjusters no oil will get in there so they burn up from a lack of oil IHTMS Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)

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