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#1 |
Junior Member
Join Date: Feb 2005
Location: topeka, kansas
Posts: 258
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SBC Rocker arm tick
Ok, I'm stumped. I can't get a rocker arm to stop ticking. 1970, 350 chevy engine. Stock cam, hydraulic lifters. Engine was rebuilt I believe about 12 years ago, but has sat for years at a time since then. Oil pressure is normal. I've been using as daily driver for past couple of months, and this ticking I just can't figure out.
Issue: Exhaust rocker on #7 cylinder ticks nearly constantly. Not when first starting, but maybe a minute or two after startup, then almost all of the time. Sometimes at around 1600 RPM it will rhythmically tick for 5 seconds, stop ticking for 5 seconds, and repeat. I've used a hose as a stethoscope - It's not exhaust leak. The ticking is definately coming from the #7 exhaust rocker. I've adjusted using standard methods, engine off, tdc #1, then tdc#6 per http://berlinetta.info/Lash.htm Then also with engine running, loosen until clack, then tighten down until ticking stops, then 1/2 turn more. In fact, it will continue to tick even when tightened so far that cylinder starts missing. Looked at and measured the stud - it is not pulling out. Checked for weak/broken valve spring by pressing with hammer handle. It compresses same as other valves. Looked at rocker, washer and nut. all look good, but swapped the rocker, nut, washer and pushrod with another cylinder. Still no luck. Ok, so it has to be a bad lifter right? Nope, just put in all new lifters, adjusted rockers using both methods and Exhaust #7 is still ticking. Can't adjust it away. I followed this thread with a lot of interest because I'm having similar issues: http://67-72chevytrucks.com/vboard/s...d.php?t=733510 Any other ideas? I'm thinking about just getting earmuffs....
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_______________________________________ 62 SWB BBW (under construction) 86 Vette Convertible |
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#2 |
Moderator
![]() Join Date: Dec 2012
Location: ON, Canada
Posts: 2,158
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Re: SBC Rocker arm tick
I had the same problem with my 65 C10. One would clatter. It would go away when properly lashed, but would loosen up. It was solved by a new rocker arm nut, a freebie from my local machine shop. Installed, lashed, two years of no clatter. I've read that you can re-squish them into an oval with a vise, but they are cheap, so why bother? However... seeing that you tried swapping over the rocker and the nut, I'm at a loss.
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#3 |
Registered User
Join Date: Apr 2016
Location: san diego ça
Posts: 121
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Re: SBC Rocker arm tick
Did you have a good look at the valve stem tip? Look for uneven wearing or pitting. If not my best guess is the lifter.
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#4 |
Registered User
Join Date: Apr 2016
Location: san diego ça
Posts: 121
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Re: SBC Rocker arm tick
Sorry , you replaced the lifters...
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#5 | |
Junior Member
Join Date: Feb 2005
Location: topeka, kansas
Posts: 258
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Re: SBC Rocker arm tick
Forgot to mention - all new rocker arm nuts also. But that gives me an idea - what if the threads on that stud are bad? All this work and I don't recall inspecting them that closely. I'll take a closer look today.
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_______________________________________ 62 SWB BBW (under construction) 86 Vette Convertible |
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#6 |
1962 C-10
Join Date: Apr 2005
Location: Las Vegas, New Mexico
Posts: 4,978
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Re: SBC Rocker arm tick
I've gone up to 3/4 turn past on my rockers.
Maybe a cam issue?
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Joseph Chavez ![]() "See the USA in a Chevrolet!!" ......................_____ .........________//__{\_____ ,,,,,,,/__(O)___//___/__(O)_/ 1962 C10 Shortbed Fleetside 327/th350 GV overdrive 1974 C10 Longbed Fleetside 350/th350 "The Trash Truck" 1999 Chevy 2500 OBS, Longbed 5.7/4L80E 4x4 2015 GMC Sierra SLE 1500 4x4 |
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#7 |
Registered User
Join Date: Aug 2016
Location: Brunswick, Ohio
Posts: 49
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Re: SBC Rocker arm tick
What about the pushrod? Could it have a slight bend to it?
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#8 |
driving is in my blood
Join Date: Dec 1999
Location: Mesa AZ
Posts: 5,725
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Re: SBC Rocker arm tick
Cam starting to flatten?
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-78 c10 short/step: 388cid, M20, 5/5 drop, lots more. Playtoy and first vehicle. -98 c1500 x-cab: 5.7L, 17" rims, 5/6 drop, flowmaster, helper bags,NBS rear disk brakes. -02 Suburban 4x4: leveled front -CBR600F4i, CBR600RR, CBR1000RR, and standup skis DISCLAIMER: I cant spell for the life of me. |
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#9 | ||
"I ain't nobody, dork."
Join Date: Sep 2007
Location: Whidbey Island, Washington
Posts: 8,940
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Re: SBC Rocker arm tick
Old cam and new lifters... possible cam lobe wiping out and eating the bottom of the lifter too.
Check your oil for fine metal particles in it. Will look like fine glitter. Gary
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'cuz chicks dig scars... My 1972 GMC 1500 Super Custom (Creeping Death) "long term" build thread. The Rebuild of Creeping Death after the wreck Quote:
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#10 |
Registered User
Join Date: Jul 2010
Location: MD
Posts: 1,937
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Re: SBC Rocker arm tick
In situations like this I start moving parts. Switch rocker & ball assembly from the ticking cylinder with another. If still #7 you know the problem is deeper.
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1969 c-10 Step Side Long Bed. I-6 250cid = ![]() |
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#11 | |
Registered User
Join Date: Feb 2009
Location: southeasternfoothillsofusa
Posts: 1,557
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I would still remove and swap spring and any shims. Ask me how I know? Hint: too many hours to admit it. HTH; and please let us know; then you and I will compare hours spent. ![]() Sam |
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