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Author
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Topic: Advice to Avoid Breaking Pins in roller cams
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Fordwiser
Gearhead Posts: 390
From: Metamora, Illinois
Registered: Dec 2000
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posted 12-10-2001 07:08 PM
   
Make sure your cam bolt is not bottoming out in the cam, so when you torque the bolt it's actally tighting the timing gear to the cam and not just tighting the bolt into the bottom of the hole. I used the factory bolt, washer, and even the fuel pump eccentric and it still bottomed, the cam was not drilled and tapped as deep as a stock cam! I asked a local Ford racer/engine builder who runs Pro/Mod what he used for a timing set when he ran his high 7 sec. Cleveland,
he said he used a factory type NYLON cam gear(double pinned) high quality stock type chain and a multi indexed crank gear for the stock type chain. He thought the nylon absorbed the harmonics from the steel roller cam and the super stiff valve springs, and in general was a lot easier on the valvetrain. I'll let you know how it works next season since I'm going to give it a try!
Roger
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kid vishus
Gearhead Posts: 6098
From: middle of NC
Registered: Oct 2000
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posted 12-10-2001 07:18 PM
Thanks for the info.I know mine wasnt bottoming out, I used a thick washer under the bolt. I bottomed the boolt out without the washer, measured the thickness and got a washer that was thicker than that measurement. I thought about double pinning it, but I couldnt find a spot where the gear was thick enuff that I would feel comfortable to have a pin sticking thru. I had one buddy who runs a rlloercammed 289 tell me he uses a special pin in his motors and has never broke one of them. I need to ask him what it is and where to get one. Maybe then I will consider going back to a roller cam. But for now, this solid makes as much power as the roller was, and costs alot less money to replace parts for.
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Fordwiser
Gearhead Posts: 390
From: Metamora, Illinois
Registered: Dec 2000
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posted 12-10-2001 09:32 PM
What sucks was this winter when I pulled the motor out, one of the main things I was going to do was double pin the cam. The last race I had planned for the year it let go! Bent all the Exhaust valves and push rods and cracked one of the roller lifters. At least it didn't hurt the cam or the pistons. Think the pin had been bending/breaking most of the season, since it ran its best early in the season and went down from there. Made changes that should of made it pickup but never quite got it back to where it had been.
Plus there were clues that something wasn't right but I guess I ignored them since I was bracket racing and it was still pretty consistant.
Roger
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clevelandstyle
Gearhead Posts: 1035
From: Connersville, IN
Registered: Jul 2001
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posted 12-10-2001 10:25 PM
I've broken the cam pin twice. The first time, I thought it was a fluke. I replaced it with another pin just like the first one. The second time, I put in an industial grade dowel pin. It is MUCH harder than the original pin. If this baby breaks, I've got more problems than worrying about the pin. 
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Moneymaker
Administrator Posts: 25883
From: Lyons, IL, USA
Registered: May 99
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posted 12-11-2001 11:26 AM
The only way you can guarantee that you won't break a cam pin ina SBF is to double pin it. That's what we do with all roller cam RACE applications. A little extra effort can save a lot of grief in the long run.  ------------------
Alex Denysenko
Co-Administrator and Moderator
NHRA/IHRA/SRA member
NHRA and IHRA SS/LA National Record Holder '00 & '01
Fleet of FoMoCo products
Moneymaker Bio
US Class Nationals link
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Fordwiser
Gearhead Posts: 390
From: Metamora, Illinois
Registered: Dec 2000
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posted 12-11-2001 05:33 PM
Any ideas what the best material is for the pins? I would think to hard and it would be brittle.
Roger
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Moneymaker
Administrator Posts: 25883
From: Lyons, IL, USA
Registered: May 99
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posted 12-11-2001 05:52 PM
Standard cam pins work just fine as long as you double them up. You can also buy hardened pin stock at any industrial hardware supply warehouse. You can find them in the yellow pages. ------------------
Alex Denysenko
Co-Administrator and Moderator
NHRA/IHRA/SRA member
NHRA and IHRA SS/LA National Record Holder '00 & '01
Fleet of FoMoCo products
Moneymaker Bio
US Class Nationals link
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clevelandstyle
Gearhead Posts: 1035
From: Connersville, IN
Registered: Jul 2001
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posted 12-11-2001 07:11 PM
I hear what your saying, Alex. If I have any more problems, I'll do the double pin thing. As of now my hard dowel pin has been working for three years.
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