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Author
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Topic: broken, 4 rocker arm studs, where to go from here?
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MDF99
Gearhead Posts: 234
From: Hamilton, Ohio, USA
Registered: May 2001
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posted 05-18-2003 11:59 PM
   
Bummer, while remounting my intake manifold trying to correct what I hoped was a vacuum leak, I discovered a lifter leaning up out of its bore in the valley. I removed both valve covers and found 4 cleanly snapped rocker arm studs, two on each side, cylinders 1,4,6,8 all were intake. The poly locks still have the broken stud tips locked in them. What could have caused this? What should I check out for damage from here? Engine is a 289 w/AFR 185 heads, cam is a Comp solid. Thanks.Matt
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Butch Jennings
Gearhead Posts: 632
From: No. California
Registered: Apr 2000
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posted 05-19-2003 12:13 AM
Sounds like a piston to valve clearance problem to me, you said you were looking to fix a vacuum leak. Had you not mentioned a vacuum leak, I'd say look for coil bind or just cheap studs.
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Butch
460 powered 1967 Comet Cyclone (Broken)
10.271 @ 130.231
Butcher's Home Page
"Friends don't let friends drive Chevys"
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MDF99
Gearhead Posts: 234
From: Hamilton, Ohio, USA
Registered: May 2001
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posted 05-19-2003 12:35 AM
I'm hoping cheap studs, I had a reputable shop build this engine for me and they should have checked the clearance, but who knows?? The studs came with the heads from AFR.
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Butch Jennings
Gearhead Posts: 632
From: No. California
Registered: Apr 2000
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posted 05-19-2003 01:39 AM
Did you find a vacuum leak when you pulled the intake? If it were my deal, I'd be leaking it down to see if the valves are bad before I went much further.------------------
Butch
460 powered 1967 Comet Cyclone (Broken)
10.271 @ 130.231
Butcher's Home Page
"Friends don't let friends drive Chevys"
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bluestreek
Gearhead Posts: 1724
From: Athens,GA
Registered: Jul 2001
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posted 05-19-2003 02:24 AM
That many studs breaking off ussually happens when the rocker hits against the stud. Turn the motor over by hand and see if the rocker slots are bumping against the polylocks at full lift. Over revving the springs (floating the valves) can also cause it.------------------
1966 Mustang Coupe: Custom glass hood and BIG scoop sits atop a 289 stroked to 331 c.i., Steel crank and girdle, 5.4 H-beams, Forged slugs, TFS alum. heads, ported Stealth 8020 intake, Xtreme 274 Solid Roller, Holley 750 HP, long tubes, 4speed, 9" 3.50 posi.
So far: 12.11 @ 114 mph (7.68 @ 93 mph)
DanH
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MDF99
Gearhead Posts: 234
From: Hamilton, Ohio, USA
Registered: May 2001
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posted 05-19-2003 07:57 AM
I didn't positively find a vacuum leak. The intake gaskets appeared to be in good shape, they were however installed by the shop w/RTV around the water ports only. I'm not ruling out a vacuum leak.
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Moneymaker
Administrator Posts: 26813
From: Lyons, IL, USA
Registered: May 99
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posted 05-19-2003 10:14 AM
Piston to valve is fine.
AFR buys studs in bulk and they offer several qualities.
A new set of premium studs and possibly even a stud girdle may be in order.
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Alex Denysenko
Co-Administrator and Moderator NHRA/IHRA/SRA member and licensed Superstock driver
MCA member# 53321
NHRA and IHRA SS/LA National Record Holder '00,'01,'02,&'03
First SS/MA in the TENS!
Fleet of FoMoCo products including 88 ASC McLaren Mustang #28
Professional Manwhore
The Barry of BarrysGrrl Quote #1: "I never met a magazine mechanic I liked."
Quote #2: "Make sure brain is in gear before engaging mouth!"
Quote #3: "If you can't run with the big dogs, stay on the porch!"
www.moneymakerracing.com
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MDF99
Gearhead Posts: 234
From: Hamilton, Ohio, USA
Registered: May 2001
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posted 05-19-2003 12:27 PM
Thanks guys, Alex do you have some rocker studs in stock? Right now I'm leaving on a job, be gone at least through this Friday, I'll send you an email perhaps as late as next Monday. Thanks again.
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