Reed valves

[Homemade]

Looking for some knowledges on reed valves.

Can reeds be hand made out of this stainless or aluminum? Does anyone here have more expertise with it then me? (I have little to no experience with reeds). Are thy sized for the specific displacement for that motor? Will a set of reeds from a small engine work?

This is for a power products ah-80 on a Lombard model 5. Will a set from a. Ore common ah-47 work. The ah- 80 is 130cc and the ah47 is only 77cc.


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[67L36Driver]

I would start my search in the outdoor power equipment category of evilbay. First with 'Power Products' and then with 'Tecumseh'.

AH-47 were as common as dirt at one time. AH-80 some less.

 

[67L36Driver]

A reed is made from thin high carbon 'spring' steel. Not easy to work with.

 

[Homemade]

AH-47 were as common as dirt at one time. AH-80 some less.

That's why I'm hoping they will be the same part between the two.


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[RandyMac]

phenolic, McCulloch used it.

 

[Homemade]

phenolic, McCulloch used it.

Would those work? Do you have the parts? Will reeds from saw fit another of different displacement?


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[RandyMac]

https://www.interstateplastics.com/...enolic sheet&gclid=COrAzp7NvdMCFYMDaQod1S4Meg

 

[67L36Driver]

Westinghouse Micarta will work I bet.

 

[Wagnerwerks]

You used to be able to buy bulk fiber Reed material in different thicknesses.

 

[Al Smith]

I made a set for an AH-58 engine on a Sears gear drive from steel shim stock.

 

[Al Smith]

A thought: You might be able to buy sheets of thin composite material from Mc Master-Carr.With a steady hand perhaps cut the material with a die grinder.

 

[Homemade]

I made a set for an AH-58 engine on a Sears gear drive from steel shim stock.

That kinda what I was thinking. A have a few friends who are machinists. I think I can get some feeler gauge sets and narrow down the correct thickness to achieve the correct flex.

The saw it's going on is only a "one tank of gas per year for memory sake" kind of saw. It was my grandpa's and I don't want to take it into the woods with me ever, but I like to see the old iron run every once in a while.


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[Al Smith]

Another thing to consider is the area of the reeds .In the pic they don't have much area so it would take a really limber reed to be able to open up which I doubt carbon fiber or fiberglass would work properly . In case you did not know you can buy feeler gauge stock which comes in thin strips ,which would work .

 

[Homemade]

Yep I've used feeler gauge stock for other things. Shim stock will do the same. I'm hoping that the thickness will match the flexibility. I'm sure the rigidity of the reed will make a difference.


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[bikemike]

Thin carbon fiber. If it does break it usually won't score a motor. It has been done in the past and fairly easy to work with

 

[Al Smith]

Perhaps but that is a very small window in that picture .Unlike for example a reed valve McCulloch reed which has a large window in comparison .PSI differential times area .
There is probably a table of info on this but I have no idea where it might be found .MC sites or outboard motor sites perhaps.Maybe RC sites that deal with multiple cylinder engines .Boylston reeds might have some info .

 

[Homemade]

it's alive! I got a reed made new with some .005" shim stock. I very carefully cleaned the carb, making sure not to tare the diaphragm. Poured some gas in the cylinder and pull and pull and she fired. It seamed like it had very low compression. Made a few test cuts and really couldn't get the carb to dial in real well. Not a lot of power when 4 stroking. So I'm guessing either bad crank seals or the piston rings are fried.

Either way. It's going to get a paint job and retire on a shelf in my shop.


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[67L36Driver]

Compression on the old PP engines run 80-100 for normal.

I had one Lombard 34(?) that pumped 70.

Ran like a champ.[emoji106]

 

[Al Smith]

FWIW those old Power Products engines did not run that fast .PP engines were used at one time like Briggs engines .Just a generic engine used on just about anything you could think of .I doubt they'd rev much more than 4000 4500 RPM if that fast .They were about like old Evinrudes you can't hardy wear one out except to straight gas them .

 

[Homemade]

Well it bogged down to the point of stalling in a 14 utility pole. I'll get a compression test on it. While trying to drain the gas,it barely trickled out. Slower then expected. I am thing a clogged fuel filter has something to do with that.


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