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manifold srew torque spec

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manifold srew torque spec


Post by chuck58pan » Thu Dec 02, 2010 3:43 am

Happy Holiday, what would an approximate torque spec be on the screws through phenolic spacer be? mine seem a little short and i don't want to over=tighten .my wrench is calibrated in inch lbs. also if i may piggyback posts would 5/16 copper tubing cause any problems if used for a fuel-line? thanks, chuck

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Re: manifold srew torque spec


Post by Cotten » Fri Dec 03, 2010 6:50 pm


Most sources cite 15 ft/lbs for a 5/16" fastener, but we know that the manifold and carb flanges distort easily upon the spacer and gaskets. (All three should be ground flat religiously, as this is the one interface that cannot be bubble-tested.)

So I prefer to just watch the dial as I snug them up alternately, and them use the wrench to make them all even when they are firm.

If my wrench doesn't have a dial, I don't have a torque wrench.

And didn't you mean 1/4" tubing?
Copper works for the later rubber-grommet fittings, but tends to eventually work-harden and crack with the early flared fits.

Good luck!


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Re: manifold srew torque spec


Post by chuck58pan » Fri Dec 03, 2010 10:04 pm

Thank's, Cotten my shut-off/reserve has a fitting to allow use of rubber hose which leads to the fuel strainer that has a stub of 1/4 with a compression fitting. My plan is to run solid tubing to a valve then solid to the strainer . the threads on the plunger-rod assembly and the fuel strainewr seem to be 5/16 that is why i thought 5/16. I am definately npt, AN , and any other designation challenged. I guess i will look for a more suitable tubing material and throw a lawn-mower shut-off in line with my existing set-up.

john HD
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Re: manifold srew torque spec


Post by john HD » Sat Dec 04, 2010 12:23 am


napa and most other decent auto parts stores sell sections of cad plated steel brake line.

you can cut off the ends and bend to your fit your needs. then flare as needed.

the last oil line i made this way cost about 7 or 11 bucks.


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Re: manifold srew torque spec


Post by chuck58pan » Sat Dec 04, 2010 12:57 am

Thanks John, that finish along with hoding-up to the vibration will look more natural also. I may have to tackle my cut-down rubber spliced oil lines to my S.S. oil pump. really want the filter back on.If the grit i cleaned from the fuel filter is evidence.
fresh stock(well pretty stock) motor and i feel better with a filter. Thanks,Chuck

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