# Lock washers on carburetor hold down nuts



## ragtopgoat (Sep 26, 2019)

I have my tri-power carbs off for rebuilds (‘66 389) and I noticed there were no lock washers on the hold down nuts. Seems like there should be. Any reason not to use split or wavy washer?


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## Old Man Taylor (May 9, 2011)

Not that I know of. I use the split washers myself.


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## PontiacJim (Dec 29, 2012)

This has come up before and the answer was that no washers were used. However, like others, I think lock washers would not hurt. Just make sure you have enough thread left on the studs as you don't want the nut to be at the top of the stud and strip the threads. The other thing to check would be to make sure the lock washer is not contacting anything so it will snug down flat -many are larger in diameter than the nut and the carb may have a casting where just the nut itself has enough clearance. I don't believe this is an issue, but check.

Then after you run the engine and it heat cycles as few times, I like to go back and check to make sure all the carb nuts are still tight - and check your intake bolts while you are at it as well.


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## Jetzster (Jan 18, 2020)

Have a Question on split vs star or other type lock washers, 
does not hi-heat Affect the torsion within split washers in a hot location ?
I’ve heard they sometimes repeatedly loosen depending on what their made of, as the push torsion doesn’t stay in them when they get hot...
Are Especially Exhaust manifolds an issue with them?


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## Old Man Taylor (May 9, 2011)

I only know of that being an issue on exhaust manifolds, and that’s because they experience such large and fast temperature swings.


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## Jetzster (Jan 18, 2020)

Roger that OMT, thx ,so a large temp change like on an exhaust then will affect em , but an intake area is ok..I knew I had read something about that


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## theamcguy (Jan 14, 2005)

I beleive the reason why lock washers were not used is because they will dig into the soft aluminum and leave a burr. This burr will be there and if not removed will cause problems the next time the carb is tightened down.


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## Old Man Taylor (May 9, 2011)

Tripower carb bases are not soft aluminum, they are cast iron.


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## ragtopgoat (Sep 26, 2019)

Thanks for the feedback, this is good info. I think it will be a good idea to ensure the nuts stay tensioned. I have some wavy washers that should work. And as mentioned above the tripower carbs have cast iron throttle plates with room to accommodate them.


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## nick rice (Nov 10, 2014)

I just go around all of them once in awhile and make sure their tight just like everything under the hood and interior screws as well. Never had a carb nut feel loose but sure have on the interior.

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## Montreux (Mar 8, 2009)

The good news is they don’t need to be “tight” tight. Not much more than 1/4 turn past finger tight. Don’t remember the shop manual spec, but it’s in the range of “not much”. Flanges on the carburetor are almost as delicate as the ears on a thermostat housing. And the spring back in the gasket helps keep tension on the nut.


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