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#1
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Pushrod rubbing guide plate/head
I bought a new engine with dyno time only on it.
I pulled it apart to change the cam and noticed the pushrods are rubbing against the guide plates/ head. In the pics, you can see the dark marks on the pushrods. I can feel a slight ridge in the pushrod with my finger nail where the dark marks are. Do I just clearance the area, replace the pushrods, and check for interference? I'm thinking of using a hand file (fine rat tail) and sand rolls to clearance the area. Is there a better way? |
#2
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that a 3/8'' push rod in a guide for 5/16''? check the pushrod hardness, it should not be harmed with a light file or knife contact, if it does, it may be part of the problem
that style rocker is going to have some side to side movement as designed.
__________________
1969 carousel red firebird 455, richmond 5 speed 1964 540 gto 1971 lemans sport convertible 1972 Maverick under slow construction |
#3
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I'm not sure about the guide plates. There is .026 clearance total between the pushrod and the guide plate. So .013 on each side of the pushrod.
The pushrods are 3/8. I was told they are Smith Bros pushrods. And a cheap China Swiss army type does nick the pushrods with moderate force. I also have some Manley pushrods here for a different engine. The same knife with the same force, does not nick the Manley pushrods. So the pushrods are most likely the problem? |
#4
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From what you say the push rod maybe softer than it should be BUT they should not be making any contact.
Stan PS - What ratio are the rocker arms?
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Stan Weiss/World Wide Enterprises Offering Performance Software Since 1987 http://www.magneticlynx.com/carfor/carfor.htm David Vizard & Stan Weiss' IOP / Flow / Induction Optimization - Cam Selection Software http://www.magneticlynx.com/DV Download FREE 14 Trial IOP / Flow Software http://www.magneticlynx.com/DV/Flow_..._Day_Trial.php Pontiac Pump Gas List http://www.magneticlynx.com/carfor/pont_gas.htm Using PMD Block and Heads List http://www.magneticlynx.com/carfor/pont_pmd.htm Last edited by Stan Weiss; 02-24-2020 at 02:51 PM. |
#5
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they are going to move around with a normal stud, NON SHAFT MOUNTED (BOLD FOR STAN), roller rocker arm. If there was no side movement why would you run a run a push rod guide?
I think you are on the right track with the pushrods. Maybe a bad batch or a parts selection from previous owner what heads are those with offset rockers and no shafts?
__________________
1969 carousel red firebird 455, richmond 5 speed 1964 540 gto 1971 lemans sport convertible 1972 Maverick under slow construction |
#6
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Quote:
Looking at the picture I do not see contact from side movement. Stan
__________________
Stan Weiss/World Wide Enterprises Offering Performance Software Since 1987 http://www.magneticlynx.com/carfor/carfor.htm David Vizard & Stan Weiss' IOP / Flow / Induction Optimization - Cam Selection Software http://www.magneticlynx.com/DV Download FREE 14 Trial IOP / Flow Software http://www.magneticlynx.com/DV/Flow_..._Day_Trial.php Pontiac Pump Gas List http://www.magneticlynx.com/carfor/pont_gas.htm Using PMD Block and Heads List http://www.magneticlynx.com/carfor/pont_pmd.htm |
#7
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The rocker arms are Harland Sharp 1.65 ratio with .250 offset.
Isky lifters with .180 offset The heads are KRE high ports. It does look like the head and guide plate have been ground on for clearance. |
#8
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actaully those look like isky sbc guide plates, that may be part of the issue. the U in the guide plate may not be deep enought to your point. the hole in the head looks like its been clearanced for 1.65 or more ratio rockers but hard to say, not knowing the history.
but why did pontiac install millions of guide plates on heads if the rockers would have stayed straight the whole time without them?
__________________
1969 carousel red firebird 455, richmond 5 speed 1964 540 gto 1971 lemans sport convertible 1972 Maverick under slow construction |
The Following User Says Thank You to mysticmissle For This Useful Post: | ||
#9
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Quote:
Stan
__________________
Stan Weiss/World Wide Enterprises Offering Performance Software Since 1987 http://www.magneticlynx.com/carfor/carfor.htm David Vizard & Stan Weiss' IOP / Flow / Induction Optimization - Cam Selection Software http://www.magneticlynx.com/DV Download FREE 14 Trial IOP / Flow Software http://www.magneticlynx.com/DV/Flow_..._Day_Trial.php Pontiac Pump Gas List http://www.magneticlynx.com/carfor/pont_gas.htm Using PMD Block and Heads List http://www.magneticlynx.com/carfor/pont_pmd.htm |
#10
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I had the same issue, needed the Isky 2 piece guideplates due to an offset intake lifter, pushrod tube and rocker on an iron D port. 1.65 rocker and roller cam and 3/8" pushrod hit the back of the U in the guide plate slightly. Just ground out the rear of the U slightly (engine assembled with new heads and valve train days before a UIM World series event). Ran flawlessly so never bothered to change things out.
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Working on going faster (and now staying dry at the same time !!) |
#11
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"actaully those look like isky sbc guide plates, that may be part of the issue. the U in the guide plate may not be deep enought to your point. "
I found that on their 2 piece 3/8 guideplates when I used 3/8 on my RAIV head.
__________________
Skip Fix 1978 Trans Am original owner 10.99 @ 124 pump gas 455 E heads, NO Bird ever! 1981 Black SE Trans Am stockish 6X 400ci, turbo 301 on a stand 1965 GTO 4 barrel 3 speed project 2004 GTO Pulse Red stock motor computer tune 13.43@103.4 1964 Impala SS 409/470ci 600 HP stroker project 1979 Camaro IAII Edelbrock head 500" 695 HP 10.33@132 3595lbs |
#12
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They are Isky 2 piece guide plates that have been tacked together.
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#13
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Better picture attached.
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#14
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Hole in guide plate does not look like it is centered exactly over pushrod hole.
So, most likely the previous owner/builder tacked them in the wrong spot. The 2 piece guide plates and human error are the variable here. |
#15
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you can see in the head where the push rod has been rubbing. theres is couple schools of thought there.
if it was mine, i think i would clearance the guide plate a little more and swap out the pushrods and inspect it in a short time period. Is it only the intakes? if so is your cam a liitle bigger on the intake side?
__________________
1969 carousel red firebird 455, richmond 5 speed 1964 540 gto 1971 lemans sport convertible 1972 Maverick under slow construction |
#16
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If this were mine what I would do is put some machinist dye on the push rods and turn the engine over by hand to see where they make contact.
Stan
__________________
Stan Weiss/World Wide Enterprises Offering Performance Software Since 1987 http://www.magneticlynx.com/carfor/carfor.htm David Vizard & Stan Weiss' IOP / Flow / Induction Optimization - Cam Selection Software http://www.magneticlynx.com/DV Download FREE 14 Trial IOP / Flow Software http://www.magneticlynx.com/DV/Flow_..._Day_Trial.php Pontiac Pump Gas List http://www.magneticlynx.com/carfor/pont_gas.htm Using PMD Block and Heads List http://www.magneticlynx.com/carfor/pont_pmd.htm |
#17
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Mystic Missile, I will do just as you suggest. And yes, it is just the intake pushrods and the cam has .015 more lift on the intake.
Stan, will do. Thanks everyone for all the help. I really appreciate it. |
#18
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That first shot with the rocker plate looks off from hole and pushrod. Looks like hits guide on one side aluminum head hole on the other.
__________________
Skip Fix 1978 Trans Am original owner 10.99 @ 124 pump gas 455 E heads, NO Bird ever! 1981 Black SE Trans Am stockish 6X 400ci, turbo 301 on a stand 1965 GTO 4 barrel 3 speed project 2004 GTO Pulse Red stock motor computer tune 13.43@103.4 1964 Impala SS 409/470ci 600 HP stroker project 1979 Camaro IAII Edelbrock head 500" 695 HP 10.33@132 3595lbs |
#19
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The pushrods have to touch the guide plates-otherwise they are not being 'guided'. . The pushrods must be hard enough so that the light rubbing doesn't wear them. And smoothing off all the sharp corners on the guide plates will help .
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#20
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Those guide plates where ground, but never polished out to remove the sharp edged left from the grinding on the top and or bottom side.
__________________
Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs! And he was not talking about 1/8 or 1/4 mile ETs! 1) 1940s 100% silver 4 cup tea server set. Two dry rotted 14 x 10 Micky Thompson slicks. 1) un-mailed in gift coupon from a 1972 box of corn flakes. Two pairs of brown leather flip flops, never seen more then 2 mph. Education is what your left with once you forget things! |
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