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Author
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Topic: Do I need different rocker studs for my 351C?
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69Cat
Journeyman Posts: 97
From: Sask., Canada
Registered: Apr 2002
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posted 07-27-2006 09:12 PM
 
Heads are on and am installing my valvetrain. Everything is new: Ferrea 5000 valves, all other stuff is Comp Cams: 7502 push rods, 1130 Stainless rocker and matching locks, 4501 7/16" studs. Comp Cams XE-274 cam and lifters.Problem is, on my intake valves I get the rocker arm lock on 2 1/4 turns before I start preloading the lifter. The exhaust is about 3 turns. Each head came from very different places and had been previously machined for studs before I got my hands on them so I can rule out the possibility of machining the pedestals too low. My pushrod geometry looks like a text book example in the Comp Cam catalogue. So, should I be using the longer stud offered by Comp Cams #4512 on a 351C? It has a 1.90" stud vs the 1.75" I have now. The threads that go into the head are 0.75" vs 0.68" long but shouldn't be a problem. This change should get my locks on 1/4" before preloading the lifter. Is this common? Did I simply order the wrong stud or is something out to lunch? Installed height of the intake springs was 1.96" before shiming (1.850 shimmed), exhaust was 1.86" but that shouldn't matter for this situation according to how I reason it. Thanks a bunch,
Ken ------------------
69 Cougar XR-7
351C 4V
T-5
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Mark T 7724
Gearhead Posts: 334
From: Palmdale, CA
Registered: Nov 2000
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posted 07-27-2006 09:23 PM
Ken; The "Rule of Thumb" for any bolt is whatever the size of the bolt (O.D.) is that will be the minimum thread engagement, 7/16" Stud requires 7/16" thread engagement. Since you will only be Pre-Loading the lifter 1/4 turn it looks like you will need a longer stud.------------------
1964-1/2 Mustang SS/L 289 4-Speed, 10.537 @ 124.83. West Coast Money Maker Racing Team Member, http//www.tallentracing.com, Marketing Director for Calvert Racing Products
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kid vishus
Gearhead Posts: 7251
From: middle of NC
Registered: Oct 2000
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posted 07-27-2006 09:54 PM
What I have found is the ~textbook~ method for machining the pedastals puts the rocker studs too low. In the past, when I was in a hurry and couldnt wait for longer studs, I have put thick head washers under them to raise the threads up higher for more engagement. The last set of heads I had machined for screw in studs, we literally took just enough material off the tops of them to make them flat. That left a lot more thread available, and even then, I had to use the longer studs.
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clevelandstyle
Gearhead Posts: 1558
From: central Indiana
Registered: Jul 2001
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posted 07-27-2006 09:57 PM
Same here. I have used washers under the studs, but now I am using the longer studs.
If you try to run them without enough thread engagement, it is likely to pull the threads out of the nut. Ask me how I know.  ------------------
Ben
Grabber Green '70 Mach I 351C 4V
Robbin Egg Blue '79 Fairmont 408C 4V, 10.50 127 MPH
Prowler Purple '87 T'bird Turbo Coupe [This message has been edited by clevelandstyle (edited 07-27-2006).]
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69Cat
Journeyman Posts: 97
From: Sask., Canada
Registered: Apr 2002
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posted 07-27-2006 10:02 PM
Mark, you are right there. Its good to confirm the basics of what is acceptable.There is no doubt that a couple of turns isn't going to cut it. But, am I masking another problem by simply changing the studs? With a longer stud I can also shim under it with a washer to get it further out of the head and get a little more than 1/4" of engagement which still isn't alot. But, is that mickey mouse? Seems a longer stud is the only answer, looking for someone who has 'been there and done that' to confirm.
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69Cat
Journeyman Posts: 97
From: Sask., Canada
Registered: Apr 2002
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posted 07-27-2006 10:05 PM
Thanks guys, I was typing my reply while you guys answered!Good to know my experience is the same as others.
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kid vishus
Gearhead Posts: 7251
From: middle of NC
Registered: Oct 2000
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posted 07-27-2006 10:06 PM
Yeah, and try having minimum thread engagement with a .700 lift cam and 280 lbs of seat pressure. 
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Moneymaker
Administrator Posts: 29200
From: Lyons, IL, USA
Registered: May 99
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posted 07-27-2006 10:15 PM
I am almost afraid to say that possibly your machinest sunk the valves a bit too far which would create the problem you are having Ken.
I am assembling a 351C as we speak (actually just finished it about two hours ago) and am using DOOE N 4V cc heads that our shop machined for screw in studs and installed new stainlesss valves.
Using virtually all the same parts that you are Ken (and I obviously know what they are) I just set the valve lash with about 6-8 threads of engagment on the stud.
Just an FYI.------------------
Alex Denysenko
Co-Administrator and Moderator NHRA/SRA member and licensed Superstock driver
NHRA and IHRA SS/LA & SS/MA National Record Holder '00,'01,'02,'03,'04 &'05
First NHRA & IHRA 289 automatic Superstock Mustang in the TENS 06-99
First SS/MA in the TENS 04-03
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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Mark T 7724
Gearhead Posts: 334
From: Palmdale, CA
Registered: Nov 2000
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posted 07-27-2006 10:57 PM
Ken; You're probably going to have to raise the stud 0.125" with a washer which you'll loose in thread engagement on the bottom side. Alex is right the valves are probably sunk too much, The studs were machined too low, To correct the valve issue you'd have to machine the top of the valve, Then to get the geometry correct you need shorter pushrods. The best out for this is longer studs.------------------
1964-1/2 Mustang SS/L 289 4-Speed, 10.537 @ 124.83. West Coast Money Maker Racing Team Member, http//www.tallentracing.com, Marketing Director for Calvert Racing Products
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69Cat
Journeyman Posts: 97
From: Sask., Canada
Registered: Apr 2002
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posted 07-27-2006 11:59 PM
I dunno Alex, the valves would need to be sunk close to 1/4" to account for the difference. You know the one head you sent me, the one with the untouched seats, well the other head to make the pair looked very close to that one. Just a quick cut with a three angle cutter is all they got and hardened seats on the exhaust. I can see how this can account for the 0.110" difference in the height of the spring retainers. As noted, my exhaust goes on 3 turns vs 2 for the intake.No problem though, I'll get the longer studs like KV and Ben have experienced and maybe throw a shim under the stud to get even more bite with my locks. Alex (or others), what do you think of installing the Comp 972 springs with a 1.850" height which should net 109lbs on the seat? 1.800" would run into the coil bind spec of 1.195" when 0.565" lift and 0.060" safety clearance is included - or am I misunderstanding something? It seems I have tons of clearance between the coils at max lift right now. Ken
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Mpcoluv
Gearhead Posts: 1421
From: Charlotte NC usa
Registered: Apr 2001
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posted 07-28-2006 04:53 PM
FWIW I found that the ARP catalog listed 351C studs are too short.
I used BBC studs with 2" above the guide plate.
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69Cat
Journeyman Posts: 97
From: Sask., Canada
Registered: Apr 2002
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posted 07-28-2006 08:17 PM
I ordered some studs this morning with the requirement of 2" long which I beleive is a BBC. Not much for speed shops here but the one we have can get them in for the morning (Saturday). Overall my valvetrain geometry looks fine so that should do it. Keep in mind all I know about this custom stuff is from mags  Still would like to know about 109lbs of seat pressure. I don't intend to rev this engine to the full potential of the cam at this point. Maybe in a year or two I'll go dual springs as I have the heads cut for them now.
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Moneymaker
Administrator Posts: 29200
From: Lyons, IL, USA
Registered: May 99
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posted 07-28-2006 08:39 PM
90 lbs is good for 6000 RPM all day long.------------------
Alex Denysenko
Co-Administrator and Moderator NHRA/SRA member and licensed Superstock driver
NHRA and IHRA SS/LA & SS/MA National Record Holder '00,'01,'02,'03,'04 &'05
First NHRA & IHRA 289 automatic Superstock Mustang in the TENS 06-99
First SS/MA in the TENS 04-03
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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Dad Vishus
Gearhead Posts: 1153
From: Moscow, Iowa, USA
Registered: Dec 2001
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posted 07-28-2006 10:09 PM
Don't guide plates raise the studs some also?I didn't see anything about them in the list of components. ------------------
63 Falcon 377 Cleveland stroker Flying Toilet alchohol injection. 6.19 @ 110 MPH 1/8 mile
2002 Ranger FX4 daily driver
2000 F350 PSD Crew cab dually - Like commuting in a B52!!
98 US Cargo Phantom II 28' [This message has been edited by Dad Vishus (edited 07-28-2006).]
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69Cat
Journeyman Posts: 97
From: Sask., Canada
Registered: Apr 2002
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posted 07-29-2006 11:54 AM
DV-I do have the Comp guideplates installed, thanks for looking for the obvious as I do miss the obvious sometimes.Alex-thats good to know. We never talked about that detail.. Anyway, there are no ARP studs in Canada (these are apparently the only 2" long option) according to my local shop and I'm sure they didn't look for the Comp Cams 1.9" long ones either so no joy this weekend. Next week its back on the phone to see who can get what and when. Man, I wish I had a good local shop in the area that would put in the extra effort to find this stuff so that when I'm working out of town things still move forward.
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Hans olsson
Gearhead Posts: 936
From: Sweden
Registered: Apr 2000
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posted 07-29-2006 05:04 PM
ARP 100-7101 are 1.9 inch long.------------------
- VIN 1F05M139343
- 71 Mach 1 Ram-Air
- 351C 4V 285 HP
- E-F-G/SA
- Stockers are way cool!
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Mpcoluv
Gearhead Posts: 1421
From: Charlotte NC usa
Registered: Apr 2001
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posted 07-29-2006 05:50 PM
Why not just order the ARP ones from Summit or somebody?
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69Cat
Journeyman Posts: 97
From: Sask., Canada
Registered: Apr 2002
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posted 07-30-2006 10:34 PM
I put washers under them for now and got 5-7 turns on the nuts. Will order some longer ones this week, it may take some time to get what I need but won't be waiting on them.Ordering from the US is costly for one item and takes about 5-7 days at best so need to find something local. Got the engine fired up tonight but was getting hot (reached 210F) after 5 minutes so had to shut it down. Try again tomorrow with a fan on the front to get more air. It was about 95F today.
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