captinjohn

I now own A used (about 5 -10 hours on it) Desert Aircraft 50cc engine. It has a real quiet canister on it. The engine seems to run real good, but has a "ticking" sound on Idle. I removed the exhaust and it seems the ring groove in the piston allows the piston too travel a bit before the ring moves, thus making this sound. Is this normal for a 50cc DA engine. Thanks Capt,n

mrbigg

My Feedback: (21)

Sure it isn't the rod? They've been known to have problems.

Tired Old Man

My Feedback: (1)

I believe you'll eventually discover the tick is caused by the stack up of bearing tolerances and nothing to be concerned about.

If the engine had been involved in a single point landing I would pull it apart and check the condition of the needle bearings at each end of the rod, but I suspect the tick is as previously noted.

w8ye

My Feedback: (16)

Many brands engines of this size often have the "tick". But it generally is most noticable when just playing with the engine and it not running under its own power.

Truckracer

My Feedback: (19)

My DA50 has always had that click at idle .... even after one trip back to DA for their famous service. A year or so ago, I replaced the wrist pin and needle bearing with no improvement. It runs great with no signs of excessive wear anywhere so its just a sound you learn to live with! A classic example of "if it ain't broke, don't fix it".

captinjohn

Well I do not know what to think for sure. It seem like when viewing the piston and moving the prop just the slightest..the piston moves(right then) ...but not the ring untill the top or bottom edge of ring land comes in contact with ring.That click iskinda right in time with the ring slop in piston...which may not hurt anything. How about other DA 50 engines...how is this ring movement in the ring grove. Is it more than on other engines? Thanks Capt,n

w8ye

My Feedback: (16)

This is the same as my observations

pe reivers

Rings should have decent play in the grooves. This allows gas pressure to reach the space behind the ring and press the ring to the bore.
Nothing to worry about. It should be that way.

Jezmo

Mine does it. Both the click and the ring moving slightly in the groove. Runs great, lasts a long time, don't **** with it.

captinjohn

I think I will pull the DA50 apart and check things out more. Is there any photos on-line to show what I should be looking for? Looks like more flying time lost....fall is close here in Mich....weather can get not so good for flying. I am guesing that bearings are easy to find in the USA. I hope the rod bearings can be pressed out and back in easy. May need to make a pushing tool on a lathe???? Anyone know the procedure on that? Thanks Capt,n

captinjohn

Jesmo, when you wiggle the prop back and forth it feels like the prop has no resistance for about .080 ! Is yours the same on that also???? Thanks Capt,n PS I can measre that with a dial indicator for more comparison.

a1pcfixer

My Feedback: (7)

A friend of mine had the exact same issue on his 2 years ago, and DA told him it was OK & acceptable.
Basically just a bit of slop in the top end of the wrist pin/piston, not critical.

Still, it worried him so he sent it in and DA installed a new piston & wrist pin.
Don't remember what they charged him though.

Tired Old Man

My Feedback: (1)

Unless the ring ends were riding over a port I would just go out and fly it. I do not recall any DA engine having a ring end/port alignment issue.

a1pcfixer

My Feedback: (7)

My friend's DA 50 ran fine, and had 5 seasons of light - to- moderate flying on it, maybe 10 gallons of fuel through it?

We compared the play at TDC on his to mine, and his had a tiny bit more slop so to speak.
Mine has a little less run time than his but close.

But like I said, DA told him it wasn't anything worth worrying about.
Still, he decided to have them replace the piston & wrist pin.

I'd have run it a few more years as is, but to each their own.

pe reivers

Play should be checked with the crank about midway. Not in top or bottom dead center.
Indeed, to each his own to make up problems where there are none.

Tired Old Man

My Feedback: (1)

Precisely!

a1pcfixer

My Feedback: (7)

CaptJohn,

I see DA themselves finally replied to your 3rd thread on this over on F-G.
Do ya believe them that it's not a problem?

Jezmo

John, I did not pull out any measuring tools but about midway through stroke, by eyeballing it, it looks to be about 40 to 50 thou or so at the tip of a 23 inch prop. My multi hundred hour DL has much more play and also makes more noise (clicking) but on inspection the pins, bearings, rod and piston look good. When you move the tip of your prop say .060" the crank pin moved significantly less because of the difference in arm length. You are looking at a ratio of about 16.5:1. My math may be wrong but I came out with .060" movement at the prop tip being .0036" total bearing clearance. That's the crank pin clearance and wrist pin clearance added together so it looks like you have just over 1-1/2 thou clearance on each end. You can see the total bearing slop is not really very much when looked at with that in mind.

I'd take it out, fly it and have fun. That's just me though. My DA50 came to me second hand and had been broken in on Lawn-Girl for a couple of gallons. The original owner was having problems with it quitting in flight so he sent it back to DA. They found nothing wrong and sent it back. He tried it a few more times having the same problems and so sold it to me for a heck of a deal. When I first received it, I looked in through the exhaust port and the piston was totally black from top to bottom. It had excellent compression though so I bolted it on my plane, fired it up and proceeded to set the needles. The idle needle required almost a half turn in to lean it enough for a decent idle. The high needle required more than a half turn in. It has never died a single time on me in over 50 flights. A few months back I changed mufflers to a different type and had the chance to see the piston again. It is now shiny and new looking from the ring to the bottom with absolutely NO carbon on top. Moral of this rant is, two things, the good oils WILL clean up a Lawn-Girl mess and DA's are good tough engines. One last time, go out, fly and have fun with your DA. They're good stuff even though they may make a bit of noise at idle.

captinjohn

I have been kinda busy on getting my place ready to sell and things for the wife. I will go and read the thread you talk about. I will then get back. I just never in all my engines and others have never run ito this noise so prominate. I just checked 2 Echos, 2 Zenoahs, a Homelite 25cc, a Ryobi, a Toro, and a SPE26. The 2 Zenoahs have the least amount of "freeplay" tested with piston up 1/2 way in cyl to avoid top dead center rock. I think I will get a Pitts style exhaust to cover up the noise...that should keep the embarasment down. I take pride in the way my engines run and sound. Best Regards Capt,n

Tired Old Man

My Feedback: (1)

None of them are a DA. Just go fly.

mbinkley

Just do a one piont landing it take the tick away every time.

captinjohn

I think that was done allready for me.

Tired Old Man

My Feedback: (1)

Just go run it. Worst case, take it off whatever, pack it in a box and send to DA for customer service, and get back a near new engine. As we can all tell, DA likes working on engines, else all their customers would not be so eager to send tham back.

captinjohn

Well I took the 4 bolts out and pulled the cylinder assembly / jug. I wiped the piston off with a paper towel. The first photo of piston is how it looked with a wipe...no cleaning fluid used. The last photo of piston is a light wipe with acetone on a paper towel. The looks of a high quality engine inside is worth pulling the jug....a simple job. I could feel not one tincy bit of play by pulling or pushingon the piston...in the normal up and down travel. Looks like this thing is built too last a lifetime!!! Very nice inside. How it makes a click running on Idle, I will never know??? By the way, people was telling me too just fly it. I do not have the airplane yet I want to put it on. So doing what i did was simple to do and sure worth it. Got to get a plane and FLY FLY FLY !!!!

Best Regards Capt,n

captinjohn

Well now the stupid photos will not upload??? Get a 500 error?????.....................