URAYASUTTARO

We have no experience for metal reed ,but my friend said maybe ok. He is expert that making original small glow engine .
so confidence his advice.
I understanding damage of inside and also reson of FRP ,it's the resault. i will take on responsibility of all.[:@]

Tired Old Man

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Sorry to see that you experienced this. Metal reeds have worked in many engines for many years but there's always that moment one fails. Unfortunately when they fail they are injested into the engine. I'm one of the lucky ones that has had a reed split, but it did not fragment as yours did. I've seen a few that have come apart like yours and none ultimately worked out well.

For any manufacturers reading this thread there are numerous examples out there for not using metal reeds. Failure is one reason, poor seating is another, reducing engine performance. Yes, they work and they are inexpensive to produce, but the only people that benefit from them are the manufacturers. Everyone using them in their engines is at risk of severe engine damage should a metal reed fail.

For everyone else. please again note that the metal reeds noted here were not produced by DA. DA uses a fiber reed, and although they too can fail, they do not damage an engine when they do so.

gofly2000

My Feedback: (41)

ZDZ super 80 claimed using rotary valve. Does it mean no reed valve sheet?
How often should I check the reed valve sheet on my old DA-100?

thanks

Tired Old Man

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You really don't need to check them at all unless it suddenly starts running like crap. I think DA would prefer that you don't tear into them as well. Tony will likely have some input in this area.

A rotary valve is a completely different animal.

jack1933

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Hi Pat,,., As you know, I have been using Homelite Spring steel reeds for 30 years now, and have never had any type of failure. The thickness of the Homelite reed is .006, so being thinner than the plastic, will give you a 200-300 rpm. increase, so if some would happen to flake off, it may or may not cause engine damage, my opinion is that it would not. What would happen If a carb, or choke, butterfly screw, or a small rock were ingested, Im thinking damage would occur. Why don't you try a set of metal reeds, and see for yourself how they perform.
Regards
Jack

rajul

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Jack, where do you get Homelite Spring steel reeds from? How do you cut them? Any pics of this stuff? Thx

RTK

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I think I still have an old out-board that uses steel reeds, must be 40 years old.

jack1933

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Hi Rajul, The Homelite reed sets came from Homelite dealers. I have made some spring steel reeds for an EVO 150, and the rpm was increased by 200. I think one must be very careful that the edges must be at least 1500 grit polished, at least thats what I did. The .006 spring steel in M.S.C.'s catalog is of high quality, per an engineer I spoke with about this matter. If you need any further info, please let me know. My phone number is- 580-276-5322.
Jack

jack1933

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Hi Rtk, That is still true today, as far as I know the outboard mfgs. still use steel reeds, at least they are in my 135 horse Mercury outboard.

Tired Old Man

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Jack,

I currently have two engines running steel reeds. One of them split early in it's life cycle. IMO, once you see that you have had a metal part break away inside an engine the only prudent thing to do is perform a teardown and inspect everything.

If a steel reed was to "flake" away very gradually I agree that it would not likely cause other damage. Screws and rocks and other large body hard materials can be a big problem if they get the opportunity to get under the crank and/or up the side of a piston. Bearing parts are a good example of what happens when things get loose inside the carnkcase.

jack1933

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Pat, AllIm trying to do is relate 30 years of experence in these forums, and as you know its just my opinions, based on experence. If this does not count for anything, then Im wasting my time.
Jack

URAYASUTTARO

I have 3W 106B2 so opened reed, 3W is wide inlet port and reed frame made from alumi and coverd rubber loocks like strong.
DA is made from just plastic.simple and small.
Now running 6000rpm, If suction efficiency 60% .Airmass is about 6L/sec. It 's may deformation reed frame caused by severe condition,
and as resoult will get some trouble for reed seat. It will damage for reed sheet. I think need reinforcemet for fame.
What do you think ,I want ask Tired old man.

rajul

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Uraya, did you compare the reed and reed block design and materials of the old DA100? If you could post some photos, that will be great

rajul

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What is the function of the curved plates on both sides of the reed block? They seem to have different curvatures.

RTK

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To my limited knowledge, it helps direct flow and keep the reed from over extending so to speak.

rajul

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How do carbon fiber reeds compare to metal and frp reeds? Who supplies CF reeds?

Tired Old Man

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Jack,

I'm with you on all of this, really. We're just sharing both sides of the experience fence is all.

Tired Old Man

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Carbon reeds can be among the best of the best-if- they were cut correctly. If they were cut from a sheet with something like scissors they will fray the edges every time. McMaster sells some pretty good reed material but I can't remember the name of it. Not carbon.

The reed housing from the 3w in the pics has that curved plate to limit the reeds from opening too far and really screwing up fuel induction, while returning the reed to the closed position a bit faster. I won't go into the whys and hows of that discovery. The DA housing is actually just as robust as the 3w massive unit and handles the load just fine. If you wanted to do some experimenting you might want to try adding a .005" cross piece over the reeds that extends about 1/4 of the way down the reed. Stiffens the reed, which may have been the original problem. Opening to far and slamming back into the housing. Or it could have just simply been a fluke caused by a materila defect in the fiber that nobody could have forseen.

jack1933

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I doubt very much thaty the stiff plastic reeds open much more than about .10-.20 thousands inch, just my opinion on this, have no real factual data. Anyone out there know how much they open?

jack1933

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Hi Pat, As you know, we are decendant from apes, and therefore like to throw poo once in a while. Hope this helps explain these forums a little better. LMAO
Jack

Tired Old Man

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No worries Jack.

I really agree with you on the amount reeds generally open. A particular manufacturer had some pretty serious induction issues some years back and they came up with a wierd plate for an answer. Probably used more for stiffeners and directing the mix but the crank still gets in the way.

The metal reed failures may well be caused by the type of material used in the reeds. I know yours work out very well but some others do not. The problem is we don't know what we're getting in some engines, and I doubt we ever will.

jack1933

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Can we not just forget about the reeds?

EddieDean

My Feedback: (3)

I've got a 3W-50i that since new blows reeds every 3 to 4 gallons of fuel. I had installed 3 sets of reeds. Finally on Gerhard's (Aircraft International) recommendation, I cut about 1/3 of the top off of a bad reed and doubled a new reed. The new reed was placed against the reed holder and the modified reed was placed over it facing the piston. The idea is to limit the distance traveled by the reed during each cycle. I've only run about a gallon since the upgrade, so I'm waiting to see if this is a cure.. The reeds were actually seperating the fiberglass layers at the tips and then fraying and being eaten away.

Tired Old Man

My Feedback: (1)

Precisely the reason I suggested a metal doubler extending about 25% of the reed length.

URAYASUTTARO

I received improvement reed sheets from da distributor.
same naterial(frp) and thickness. but it will use double sheets.
Immediately tried 3 flts . It keeping normal condition and no damage.
so we don't need talk about reed .I will close this thread.
!! DA need notice like this information on your home page for user.
do not put screen!! I will still use da too.