Head bolts

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wrooper
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Head bolts

Post by wrooper » Wed 2. Jun 2010, 18:05

Hi all,
I have a 1965 Chris with the 430 Lincoln and am having difficulty with head bolts.

I attempted to reuse the original bolts and with oiled threads I broke a bolt trying to get to 140 ftlbs. I then attempted to use a Fastenal 41/2" 9/16" bolt that was supposed to be grade 8. I had figured out that the "oiled" bolt torque value s/b decreased to around 100 ftlbs and I broke one of the new bolts trying to get 100 ftlbs. In addition at least one bolt was seriously "necked"]stretched at 90 ftlbs.
Anyone have a source for head bolts somewhere south of $10 each? [ARP]

Am I right to assume the shorter of the two bolt sizes specified for the Ford 460 is the correct bolt size for my application?
Thanks in advance

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Theo
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Re: Head bolts

Post by Theo » Thu 3. Jun 2010, 03:51

Welcome to the board wrooper. As for the correct sizes of the bolts you might call a Tech Rep. at Arp. They are usually very friendly and happy to help. There might be other sources as well. I think arp has some good info about torque w. and w/o lube on their web site. Not sure.
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wrooper
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Re: Head bolts

Post by wrooper » Fri 4. Jun 2010, 05:51

Thanks for the attention Theo,
I have talked to ARP and they spec the shorter of the two 460 head bolts at 9/16,12 tpi and 4.475 inches long. I am pretty convinced these would be close enough to the 41/2 inch original bolts but they are >$10 each.

Has anyone else had experience with torquing these heads and trying to get 140 ftlbs? OIled? Dry?

I am now trying to use 100 ftlbs and wet with oil as an approximation of 140 ftlbs dry.

I am seeing the advantage of "tighten to yield" If you consider that friction accounts for around 20% of the torque value,actual torque values in the field must vary greatly. Bill

keithol
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Re: Head bolts

Post by keithol » Wed 9. Jun 2010, 08:34

A 9/16 grade 8 bolt should have no problem with 140 ft. lbs. When I was teaching auto mechanics, students sometimes read the wrench setting wrong, also torque wrenches are not infallible. I hope I am not offending any one here , just trying to be of help. I just had to put in my two cents worth. Happy wrenching!

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Theo
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Re: Head bolts

Post by Theo » Wed 9. Jun 2010, 13:29

keithol wrote:........wrenches are not infallible. I hope I am not offending any one here , just trying to be of help. I just had to put in my two cents worth. Happy wrenching!
Go ahead Keith, you're not offending anyone. We appreciate your input a lot.
As for torque wrenches I'd like to mention that one got to be aware of break points, lube and pull techniques. Those click wrenches need to be used w. care if you don't want them to click too early at the wrong time. I'm sure you guys know that anyway, just what springs into my mind.
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Chris Craft crazy
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Re: Head bolts

Post by Chris Craft crazy » Sat 3. Jul 2010, 18:30

I talked to Bill over on the woodenboat forum, and spoke to him on the phone too... sent him a few headbolts to replace his broken one etc.... ;)
MEL Marine division... and if you thought MEL car parts were scarce....

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Re: Head bolts

Post by halloran » Thu 16. Sep 2010, 09:25

140 lb/ft seems way high. I have a Chilton book for 60-68 430s and the proper torque sequences are 85/95/105 dry.

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