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#1 |
Registered User
Join Date: Mar 2022
Location: Havelock
Posts: 6
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fellas,
I have a 67 283 and cylinder 7 the intake valve rocker slips off and bends the pushrod. I installed a new lifter/pushrod then put the original rocker back on and when adjusting it if I barely tightened it it would want to slip off. I changed out another rocker and the same thing happened. I tightened it just enough to take the tick away and took it for about a 15 mile spin, about 10 miles in I gave it a good shot and bam I got the lifter tick, came home pulled the cover and found the rocker off the valve with a bent pushrod. The post on the head doesn’t seam bent Any ideas? Cheers Brant |
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#2 |
Senior Member
![]() Join Date: Mar 2003
Location: Colfax-California
Posts: 8,526
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Re: 67 283 keeps bending pushrod
When you adjust the valve how many turns does it take to take up the lash? I'm thinking a possible broken spring. Check the tip of the valve for squareness also
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#3 |
Registered User
Join Date: Mar 2022
Location: Havelock
Posts: 6
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Re: 67 283 keeps bending pushrod
After the lash was taken up if I tightened it up a typical 1/2 turn it would want to slip right off , if I took it 1/4 it wasn’t really square on the valve but enough to not slide off… until I hit about 4000 rpm
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#4 |
Senior Member
![]() Join Date: Oct 2010
Location: Cadiz, Ky
Posts: 512
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Re: 67 283 keeps bending pushrod
Is the top of the valve worn? It looks like it in the pic.
__________________
1972 Chevy LWB Roadster 1999 Chevy Silverado 2wd 2015 Chevy High Country 4x4 Crew Cab |
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#5 |
Senior Member
![]() Join Date: Mar 2003
Location: Colfax-California
Posts: 8,526
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Re: 67 283 keeps bending pushrod
Looks like it to me also.
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#6 |
Registered User
Join Date: Sep 2011
Location: Ark City, Kansas
Posts: 3,333
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Re: 67 283 keeps bending pushrod
Things that can bend a push rod.
1. Spring coil binds 2. Valve retainer hits top of valve guide 3. Slot in rocker arm not long enough to allow full lift. (Rocker stops moving. Against rocker stud, not likely your problem) 4. Bent valve. That hole in the head where the push rod goes, should be flat on each side. It is a guide for the Push rod to ride against. To keep the rocker on the top/ center of the valve stem tip. It could face or into your problem..... Something is hitting something solid and stopping free valve train movement. If your pickup is needed as a daily driver, you know that the 1/4 turn adjustment works at Lowe engine speeds, this would allow you to limp it around for a while, BUT could cause more damage... |
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#7 |
Registered User
Join Date: Oct 2020
Location: Albuquerque, New Mexico
Posts: 474
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Re: 67 283 keeps bending pushrod
Is the fuel fresh? Old gas can varnish the valve stems causing them to stick in the guides which in turn bends the pushrods.
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#8 |
Registered User
Join Date: May 2021
Location: SoCal
Posts: 121
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Re: 67 283 keeps bending pushrod
A close-up pic of the top of the valve stem would be helpful. Push rod guide looks enlarged also. Possible worn cam lobe creating slop in rocker, damaging top of valve stem and misaligning push rod to wear guide.
My .02 |
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#9 |
Senior Member
![]() Join Date: Oct 2014
Location: New Palestine In
Posts: 931
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Re: 67 283 keeps bending pushrod
Check to see if there's a slot worn in the side of the rocker arm stud. That will let the rocker to move sideways and slip off the pushrod. The mushroom look of the top of the valve indicates loose adjustment also.
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Phil "Money is only a tool to create and achieve what you want most in life" PayPal: rodnrudy@comcast.net |
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#10 |
Registered User
Join Date: Feb 2021
Location: Kernersville, NC
Posts: 88
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Re: 67 283 keeps bending pushrod
Just a thought. Is it possible the press in stud is starting to back out of the head? Of course, it would start making a racket as it loosened up.
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#11 |
Registered User
Join Date: May 2016
Location: Oklahoma
Posts: 189
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Re: 67 283 keeps bending pushrod
Good advice. Take a rubber mallet and bounce it on the valve stem. Make sure the stem is free to slide.
__________________
1971 C20 Custom Deluxe, HT383, 4L80E, 3.73 Locker, 4 Wheel Discs |
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#12 |
Registered User
Join Date: Apr 2010
Location: So Cal
Posts: 1,437
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Re: 67 283 keeps bending pushrod
If the studs are all the same height and the valves are all adjusted the same, you should have approximately the same number of exposed threads above all the adjuster nuts.
If the exposed threads are different, this should help you find the problem. Why did you change the lifter? Was this problem there before?
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'67 GMC 2500, 292, 4spd, AC |
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#13 |
Registered User
Join Date: Mar 2022
Location: Havelock
Posts: 6
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Re: 67 283 keeps bending pushrod
Hey guys thanks for all the input, turns out the valve was worn on a angle I guess due to a loose rocker? Wore over time ? Enough to make it slip off eventually . Had a couple options grind the valve stem flat again or slap on a newer vortec 350 style rocker with guides on either side… it’s a 289, not planning on breaking any land speed records. We will see how it holds up. Down the road it may be due for an overhaul, 61 000 original miles and it’s just a Sunday driver for now , the patina looks nice , I installed a tach, temp and oil pressure sensor
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#14 |
Registered User
Join Date: Mar 2022
Location: Havelock
Posts: 6
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Re: 67 283 keeps bending pushrod
Should be a couple pictures
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#15 |
Senior Member
![]() ![]() Join Date: Mar 2016
Location: Near Canon City ,Colorado
Posts: 3,970
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Re: 67 283 keeps bending pushrod
Welcome aboard .I'm glad you may have fixed it for now .(flipped pic)
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__________________
'35 1/2 ton Pickup (bought 2020) '68 C10 Suburban (bought 2021) '72 K5 Blazer (bought 2013) '67 Stepside (bought 1997-sold 2021) '96 Bronco Eddie Bauer (inherited 2010) My 1st day here-'67 C10(sold)and '72 K5 Blazer http://67-72chevytrucks.com/vboard/s...d.php?t=702056 "Another Blue Chevy"(1935) http://67-72chevytrucks.com/vboard/s...d.php?t=799203 ![]() ![]() |
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#16 |
Registered User
Join Date: May 2016
Location: Oklahoma
Posts: 189
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Re: 67 283 keeps bending pushrod
That's a good, low buck and practical idea. Let us know how it works out.
__________________
1971 C20 Custom Deluxe, HT383, 4L80E, 3.73 Locker, 4 Wheel Discs |
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#17 |
Registered User
Join Date: Jul 2008
Location: Eastern Oregon
Posts: 2,336
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Re: 67 283 keeps bending pushrod
Can’t help with the rocker issue but I love your color and the 3 on the tree ! I miss my 68 GMC with it…
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71 C-20 07 Magnum RT AWD |
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#18 |
70+ ( Old Skool Club )
![]() Join Date: Nov 2003
Location: Saskatoon, Saskatchewan ,Canada
Posts: 9,119
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Re: 67 283 keeps bending pushrod
Welcome to the Boards. Nice truck and looks vaguely familiar. Sorry for the valve grief so soon.
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1972 C10 Custom/Deluxe 613 Highlander 406/700R4 1999 White Tahoe LS 4x2 with Z56 Police Package 1992 K1500 GMC Suburban Members I have personally met: MusicMan70 - HeavyD - ChewyChevy67 - StingRay -71SWB4x4 - 67 Burb - DeadheadNM - too much stuff - bc65 - das601 " Circumsatances Do Not Change Responsibility " " The Sky is not the Limit, Your Mind is." Marilyn Monroe .. RIP Charlie Watts 1941 - 2021 |
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#19 |
Registered User
Join Date: Apr 2016
Location: Kirkland,WA
Posts: 65
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Re: 67 283 keeps bending pushrod
I had a 67 El Camino with a 327. It had 200,000 miles on it. The holes in the head that act as pushrod guides were worn and it started bending pushrods. The fix is getting steel pushrod guides like these:
https://www.amazon.com/Small-Block-C.../dp/B075NPHNPZ |
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Tags |
283, pushrod, valve adjustment |
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