AMB

Well group after many years the poor OS 10 is worn poor compression, need a new p/l chances of finding one not good, may be able to find a new ttgp10 and just put the Davis head on it (same one) the head of course is fine , have a TT10 with Davis head runs like a striped ape, compression excellent in mu nuovo 1300 VMAR
electric conversion. I do have a NIB OS10 LA davis head but thats for an other plane martin

Recycled Flyer

Martin, try this guy -
http://www.rayaracing.com/

But Idon't know if a worn piston can be corrected by this guys technique.

AMB

hmm worth a check if 20 bucks gives us a fix well worth it, never knew such a service was out there, thanks martin

1QwkSport2.5r

I'm not sure if he works with engines as small as a .10.. I know the car guys use Rayaracing to re-pinch ABC sleeves. The piston is usually not touched, merely giving the sleeve a squeeze is all it takes to bring back like-new performance. Worth a shot IMO.

Edit: I didn't think about lapped engines. I would think a linear pinch would work for saving a lapped engine. Maybe.

RocketRob

My Feedback: (1)

Martin,
If you watch fleabay you can pick up these engines pretty cheap - cheaper than a new PL.
Might be easier to find another complete engine - with the added benefit to get another carb/NV

aspeed

A collet on a lathe would work well for pinching a cyl.  if done carefully.  just tighten it down a bit at a time and rotate  and keep tightening  a bit more ... It may be wise to keep the piston near the bottom of the sleeve while doing this so it doesn't collapse too far. They are not rare, you could likely find something useable as has been mentioned.

DeviousDave

AndyW did this on the 1/2A forum with a tired Norvel .074, it worked.

AMB

Well maybe fleabay , pulled engine out of plane I have a Sharma 09 with exhaust ring drop in fit, just get piece pf flex tubing to hook up to exhaust pipe which is aluminum tubing running to rear all lines up, mounting holes, throttle linkage simple way out and quick martin
I will find an other OS or TT10 not letting the Davis head go to waste away
life just got better tho MVVS 09 and 12 drop in fit too and the OS 10LA Davis head hmmm too many engines martin

for my mini- telemaster

Dennis the MVVS 12 came from you latest add to my small ones

Recycled Flyer

Well his feed back tells me that he does work on 0.12ci engines so I guess that size of engine holds no fear for him.

AMB

Well all the little OS 10 had a lot of blowby when I pulled it and removed backplate inside loaded with soot and carbon lots op top of piston too. The Davis head was quite clean almost nothing on contra, my clue should have been had to keep lowering the contra via compression screw to keep running and no mid range or idle, will look into the squeeze thing . Recyled Flyer thx for the info- martin

greggles47

If it can't be replaced or refreshed, the AP .09 Hornet is a good little job. I have two, 1 original (goes like stink) and 1 diesel conversion ( goes like stink too).

Fairly inexpensive from some Chinese suppliers.

Greg

Kiteflyer

My Feedback: (17)

Martin, i have a new piston & liner set for the OS 10 FP. I don't see myself using it anytime soon, so you can have it. PM me your mailing address.

gerryndennis

I agree, but I wonder if he could pinch a steel liner a opposed to a brass one? It would be good if he could.

Dave H

AMB

well "eagle eye" Bob Davis called me after seeing the post, the subject of the stuck in case liner came up Rather then doing the oven bit he suggested put in a pot of boiling water with detergent on the stove that is 212F, after about 10 minutes I fished it out and holding the engine with a pot holder gave it a sharp rap on the counter out it came
I am also getting a de-varnishing brush from him to knock off the glaze this might give us a better seal , worth as try but we do have a new p/l on the way
so looks like all the bases covered martin

Max_Power

I have actually tried the collet method by putting a liner in a 5c collet in a collet block (to supply the taper to squeeze the collect) and then put the whole deal in a small arbor press to apply pressure. This was a ABC liner and actually it worked pretty well although it takes less force than you think, and I overdid it and had a too tight of fit. 5c collets can be had in most sizes for about 5 bucks, so if you already have access to a press..... the collet block is about 40$ , but a round hole might be sufficient to squeeze a collet. I'm planning on trying again when I get another worn engine. Todd

aspeed

I just did it in the lathe. (Hardinge Chucker) The piston on the bottom half of the sleeve prevents it from collapsing way too far at least.  Most sleeve walls are pretty thin.  I think it is better with a collet than the collars that are sold for the buggy motors because the collet is more even if it is sized right.  I find the ABC motors don't wear out as fast for me, and I haven't had to do it for a long time. 

AMB

Ok OS10 folks several issues when I took the engine apart i noticed a slight bend at the upper end of the rod, put in the vice between wood cushions and got it straight when on a flat surface it is parallel now flipped it over looks the same wrist pin and crank holes fine none in crank end very little in top slop)
the issue is the teflon pads that go over the wrist pin in the piston, they have a little projection that goes in a hole in the wrist pin (snaps in) they are shot.
I do not know if the la10 uses the same procedure and are they they same size if they do?
I picked this one up in the used box a few year back in a local hobby shop and put the Davis diesel head on it
I am getting an other one (engine from Dennis but want this one up and running Bob Davis gave me some hints remove the glaze from the liner with steel wool rotate it in a figure 8 and it will make very small scores in the liner at the edges it will raise a bit making it a little tighter I am also getting a de-varnishing brush from him which will do a better job, think I will wait and do the brush thing more effective
big issue the teflon pads martin

controlliner

From experience, the TT .10 parts are interchangeable with the OS .10 FP and the TT .10 is still manufactured. I have interchanged parts between my TT .10 and FP .10 sucessfully. The .10 LA has the piston pin pressed into the to end of the rod. Also the wrist pin has rounded ends which are highly polished. There are no teflon pads. The LA has no parts interchangeability with FP or Thunder Tiger engines.

AMB

Controlliner THX for the info I picked up a new in the box off flea bay for $40 will still do the devarnish brush thing, will have to see if Davis has any 10 heads in stock if yes will pick one up then we have an other FP10 diesel. The bent rod (now straight) certainly reduced the stroke which did not help the compression either
my other 10s OS LA10 an other OS FP10 and several TT10s with Davis heads flawless runners martin

dennis

My Feedback: (90)

Martin,

I believe I have a head for both the FSR and the FP if Bob doesn't have what you need.


Dennis

AMB

Dennis do not know if they made the FSR as a 10, bigger ones yes martin
I just sent you a PM on 10FP head

controlliner

Yes they made an OS .10 FSR I have two.

Mr Cox

The .10 FSR is iron/steel construction while the FP ones are ABN. The FSR might make nice diesels too and last longer. Scary with the bent rod on the FP though...

AMB

Mr Cox the rod is now ok , straight real issue is the teflon pads that go over the wrist pin need new ones martin

controlliner

The ones for the thunder tiger .10 will work