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Author
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Topic: How much spring pressure before a press in stud might pull out?
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Dubz
Gearhead Posts: 1888
From: Manitoba Canada
Registered: Oct 2002
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posted 12-04-2004 05:03 PM
   
Just wondering for cam sake, i'm gonna get the rocker adjustment kit from comp for the press ins, as the washer trick didn't work, i'd need the special nuts that come in the kit, as the stock ones arn't crimped to hold the preload setting, and a jamb nut doesn't work.Anyway, what would be the most spring pressure you would run with a 1.7 ratio rocker arm?? would 339lbs/inch on a .531 (taking into account the 1.7) cam be too much?
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bluestreek
Gearhead Posts: 1724
From: Athens,GA
Registered: Jul 2001
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posted 12-04-2004 06:03 PM
I honestly have never had a ford stud pull out but also never used more than 300lbs at full lift with any pressed in studs. It happens on chevy's a lot though. Had a few break becuase of stock rockers.
One thing about it, if you go ahead and try it and a stud starts to pull up, all that happens is you get a very noisy rocker.  ------------------
1966 Mustang Coupe: Custom glass hood and BIG scoop sits atop a 289 stroked to 331 c.i., Steel crank, rods and girdle, TFS alum. heads, Stealth 8020 intake, Xtreme 268 Solid Roller, Holley 750 HP, long tubes, 4speed, 9" 3.50 posi.
11.86 @ 116 mph (7.62 @ 93 mph)daily driver!
DanH
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Dubz
Gearhead Posts: 1888
From: Manitoba Canada
Registered: Oct 2002
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posted 12-04-2004 06:29 PM
just wondering if i could get away with a 270H and the reccomended springs or if i'd need to go smallerspring listed is 942 seat load [email protected]
open load [email protected] so if my calculations are correct that would be [email protected] [This message has been edited by Dubz (edited 12-04-2004).]
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steve'66
Gearhead Posts: 9476
From: Sonoma,CA,USA
Registered: Mar 2000
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posted 12-04-2004 08:27 PM
Dubz,I think the 270 with those springs is safe with press in studs. 
The crane kit is suspect though. I never adjusted valves as much as when we ran those things on a pair of '68 351w heads on Melissa's 289. Screw in studs with polylocks are better.  SteveW
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bluestreek
Gearhead Posts: 1724
From: Athens,GA
Registered: Jul 2001
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posted 12-05-2004 01:57 AM
Should be ok. I've used the 280H kit before on stockers. I always like to see the tops of the studs to be even all the way across the head. If one stud is higher than the others then it is suspect. If you lived closer I have one of those adjuster kits you could have. ------------------
1966 Mustang Coupe: Custom glass hood and BIG scoop sits atop a 289 stroked to 331 c.i., Steel crank, rods and girdle, TFS alum. heads, Stealth 8020 intake, Xtreme 268 Solid Roller, Holley 750 HP, long tubes, 4speed, 9" 3.50 posi.
11.50 @ 116 mph (7.33 @ 93 mph)daily driver!
DanH
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jeffstar
Gearhead Posts: 123
From: Toronto, Ontario, Canada
Registered: Feb 2003
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posted 12-05-2004 10:25 AM
Perhaps I was unlucky on a 289, but I had a studs come loose.When I first put the cam in with the original 289 springs, I had valve float at about 5700 rpm. I changed the springs to slightly stiffer factory Ford springs from a (390 I think?) I was only reving it to about 6000Rpm with this very mild cam and several studs started to pull out.
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Dubz
Gearhead Posts: 1888
From: Manitoba Canada
Registered: Oct 2002
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posted 12-05-2004 04:41 PM
darn, that would have been swell. I would guess shipping would be about as much as they are worth too...[This message has been edited by Dubz (edited 12-05-2004).]
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Ryan Wilke
Gearhead Posts: 2265
From: Stanton, Michigan 49707
Registered: Oct 2000
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posted 12-06-2004 10:13 AM
I recall reading about some folks "pinning their rocker studs" rather than going to screw-in studs.... Does anyone still do that?Ryan
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Moneymaker
Administrator Posts: 26811
From: Lyons, IL, USA
Registered: May 99
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posted 12-06-2004 11:40 AM
quote:
Originally posted by Ryan Wilke:
I recall reading about some folks "pinning their rocker studs" rather than going to screw-in studs.... Does anyone still do that?Ryan
Yes they do. ------------------
Alex Denysenko
Co-Administrator and Moderator NHRA/IHRA/SRA member and licensed Superstock driver
MCA member# 53321
NHRA and IHRA SS/LA & SS/MA National Record Holder '00,'01,'02,'03,& '04
First SS/MA in the TENS!
IHRA division 5 Superstock Champion
Fleet of FoMoCo products including 88 ASC McLaren Mustang #28 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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Ryan Wilke
Gearhead Posts: 2265
From: Stanton, Michigan 49707
Registered: Oct 2000
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posted 12-06-2004 11:59 AM
Alex,
Other than the physical differences in the necessary machining needs, what are the Pros & Cons to pinning vs. screw-in style studs - are they comparable in RPM limits, durability, cost, etc. ? Ryan
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Moneymaker
Administrator Posts: 26811
From: Lyons, IL, USA
Registered: May 99
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posted 12-06-2004 12:09 PM
It is strictly a economical alternative that most do it yourselfers can hadle on their own.
These days most machine shops will charge you as much to pin studs as to machine for screw in.
Only an old time rural shop will still do it fairly cheap.Only pro's are stud can't pull out.
Con's are that you still have a OEM quality stud and are faced with it's limitations.
On a budget street build I would do it every time as the procedure and stock studs will stand 100 lbs of pressure. ------------------
Alex Denysenko
Co-Administrator and Moderator NHRA/IHRA/SRA member and licensed Superstock driver
MCA member# 53321
NHRA and IHRA SS/LA & SS/MA National Record Holder '00,'01,'02,'03,& '04
First SS/MA in the TENS!
IHRA division 5 Superstock Champion
Fleet of FoMoCo products including 88 ASC McLaren Mustang #28 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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Ryan Wilke
Gearhead Posts: 2265
From: Stanton, Michigan 49707
Registered: Oct 2000
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posted 12-06-2004 12:15 PM
 Thanks again for sharing your wealth of knowledge, Alex!! Now I can say I learned something new today! Ryan
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n2oMike
Gearhead Posts: 2680
From: Spencer, WV
Registered: Jan 2001
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posted 12-06-2004 01:55 PM
Plus, if you happen to break a stud that has been pinned in place, it's an extra bit of a PITA to get out.I've broken 3/8" screw-in studs, but at least the fix was an easy one. Unscrew the old ones, put in the new. Actually, if a person converts to screw-in studs, there is no reason not to use 7/16" studs. They are WAY stronger, flex less, and break less. The only other modification required for their use, is rocker arms with 7/16" holes for those larger studs. Good Luck! ------------------
Mike Burch
66 mustang real street
302 4-speed 289 heads
10.63 @ 129.3
http://www.geocities.com/carbedstangs/cmml_mburch.html
http://www.fortunecity.com/silverstone/healey/367
http://www.mustangworks.com/cgi-bin/moi-display.cgi?220
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mustangboy
Gearhead Posts: 1091
From: Ont, Canada
Registered: Mar 2002
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posted 12-06-2004 03:56 PM
How exactly are the studs "pinned"? Also I didn't quite understand Alex's reply saying the studs would only withstand 100lbs of pressure.Is this at full lift? Doesn't sound like much pressure.If this is with the valve closed then how much pressure open?I am also considering a cam swap in a very mild 289 on a tight budget.------------------
1968 mustang j-code sprint.13.69@101 306cu.in, stock ported heads,weiand exellerator,650 holley DP,hedman hedders,comp 292 Magnum cam,4-speed,8 inch 4.11 detroit locker http://mustangsandmore.50megs.com/MembersPics/mustangboy.html
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