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Engine basics => Engine set up tips => Topic started by: Allen Eshleman on November 25, 2023, 10:34:27 AM

Title: Clunk size
Post by: Allen Eshleman on November 25, 2023, 10:34:27 AM

I have a tank, Pylong brand which seems to have come without a clunk or more likely, I lost it. Does it matter the size of a clunk and the clunk hole.  I have some smaller tanks that come with a clunk with a smaller hole and for smaller tubing. Can that be used for a larger tank and LA 46? I have one from a Kraft (Hayes) that has the larger hole like Dubro and Sulliivan. 

I also have the Dubro tank filter. Can that be used in place of the clunk?

Title: Re: Clunk size
Post by: Dennis Toth on November 25, 2023, 01:20:53 PM

Allen.
For larger engines say anything bigger than a 15 large tubing is better, particularly for 4 strokes. The small tubing reduces the fuel draw of the engine which makes the needle touchy to set and can cause funky engine runs. As for the clunk, you want something with some weight to it with a 1/8" - 5/32" hole.

You can make a clunk from a piece of copper tube then wrap with ~1/2" of copper wire and solder.

Best,    DennisT

Title: Re: Clunk size
Post by: Allen Eshleman on November 27, 2023, 11:35:19 AM

Thanks Dennis.

Title: Re: Clunk size
Post by: Allen Eshleman on November 27, 2023, 11:37:14 AM

What about the use of the in Dubro sintered bronze tank filter?  Would they be too restrictive?

Title: Re: Clunk size
Post by: Dennis Toth on November 27, 2023, 03:29:14 PM

Allen,
I have seen several very good flyers use the sintered filter in the tank as the pickup clunk, works ok but can give sputtery engine cut off at the end of the fight as some air gets sucked in with the last drops of fuel.

Best,  DennisT

Title: Re: Clunk size
Post by: Ken Culbertson on November 28, 2023, 03:09:39 PM

I have made some nice clunks by drilling an 1/8" hole in a brass teardrop fishing weight like the one at this link and pushing 1/8" brass tubing into the fat end.

https://www.ant-supplies.uk/fishing-products/fishing-sinker-weights.html

Ken

Title: Re: Clunk size
Post by: Allen Eshleman on November 28, 2023, 07:54:39 PM

Thanks guys.  I found the original but I have learned a lot from your suggestions.  I also saw the proflex tubing in the recent post on uniflow tanks.