Notices
Glow Engines Discuss RC glow engines

OS engines users Club

Old 09-06-2017, 08:20 AM
  #701  
Hobbsy
My Feedback: (102)
 
Hobbsy's Avatar
 
Join Date: Dec 2001
Location: Colonial Beach, VA
Posts: 20,370
Likes: 0
Received 22 Likes on 22 Posts
Default

The aforementioned OS LA 25 on the LT 25, it's angled to the right because I originally flew it with an Enya .25 Diesel and the muffler wouldn't clear the fuse side with the engine straight up. LT 25's build fast and accurate and I use only Super Phatic glue, no epoxy or CA.
Attached Thumbnails Click image for larger version

Name:	HPIM1245.JPG
Views:	144
Size:	2.01 MB
ID:	2230862  
Old 09-06-2017, 03:56 PM
  #702  
N1EDM
My Feedback: (2)
 
Join Date: Jul 2002
Location: Brockton, MA
Posts: 4,283
Received 6 Likes on 6 Posts
Default

Hi guys,

I need help with another engine question. I purchased a OS FS-91 Surpass (not Surpass II, etc., it's an early one). It needed bearings but that seemed about all. I fired the engine up on 10% fuel (just cracked the jug last week) and it smoked like a banshee. She got 9400 RPM with a 14x6 prop (pretty respectable for a vintage 4-stroke, eh wot??) but still smoked badly. I was able to get a nice idle out of it, too. Plug is an OS Type F.

I realize that the LSN also tunes the midrange but this seemed to have little to no effect. The HSN is on the verge of being lean. The carb is clean, the valves are set to about 0.4mm, and the piston is clean, as are the valves.

I had originally suspected a stuck ring but the ring is clean, unstuck, and has plenty of expansion left in it.

Any thought? The engine seems almost perfect except for the great gobs of smoke (no exaggeration) coming from it. I haven't checked the timing, but would I get those good an RPM number if the engine was mis-timed?

Thanks,

Bob

Last edited by N1EDM; 09-06-2017 at 04:04 PM.
Old 09-06-2017, 09:38 PM
  #703  
Broken Wings
My Feedback: (20)
 
Broken Wings's Avatar
 
Join Date: Jan 2003
Location: Cocoa, FL
Posts: 2,087
Likes: 0
Received 4 Likes on 3 Posts
Talking

Originally Posted by 1QwkSport2.5r View Post
Yes, I'll cut a Boost channel into the crankcase. The crankcase is cast as if they intended to have a boost port, but never machined it in.

Sure, why wouldn't you want to modify an OS Engine.......the Fox stuff worked out so well......(Smiles) If only (you know who) was here to show you the way.......
Old 09-06-2017, 10:14 PM
  #704  
Broken Wings
My Feedback: (20)
 
Broken Wings's Avatar
 
Join Date: Jan 2003
Location: Cocoa, FL
Posts: 2,087
Likes: 0
Received 4 Likes on 3 Posts
Default

Originally Posted by Hobbsy View Post
The aforementioned OS LA 25 on the LT 25, it's angled to the right because I originally flew it with an Enya .25 Diesel and the muffler wouldn't clear the fuse side with the engine straight up. LT 25's build fast and accurate and I use only Super Phatic glue, no epoxy or CA.
Have you found any advantage in running an engine on diesel prior to using it with glow fuel?
Old 09-07-2017, 02:42 AM
  #705  
Hobbsy
My Feedback: (102)
 
Hobbsy's Avatar
 
Join Date: Dec 2001
Location: Colonial Beach, VA
Posts: 20,370
Likes: 0
Received 22 Likes on 22 Posts
Default

John, not many engines will run on Diesel fuel without changing the head, a few will though. I have an OS LA .46 that I bolted a Davis Diesel head on to without breaking it in first on glow. Mr. Davis recommended breaking converted engines in on glow first. My Saito .80, (15.5 to 1 compression ratio) will fire up and run on Davis fuel with the coil removed from the plug. It will turn a Bolly 13.5x8 at 8,760 rpm and idle below 1.400 rpm.

Bob, it sounds like the .91 is in good shape and timed correctly. My guess is that the LS needle is too rich. I'd personally would screw it in until the engine hesitates when opening the throttle then back it out 1/8th to 1/4 turn, you should find the sweet spot close to that setting. Let us know how it goes, Thanks, Dave
Old 09-07-2017, 08:03 AM
  #706  
1QwkSport2.5r
 
1QwkSport2.5r's Avatar
 
Join Date: Oct 2006
Location: Cottage Grove, MN
Posts: 10,252
Received 60 Likes on 57 Posts
Default

Originally Posted by Broken Wings View Post
Sure, why wouldn't you want to modify an OS Engine.......the Fox stuff worked out so well......(Smiles) If only (you know who) was here to show you the way.......
I've done a Picco and Novarossi engine too. They run damn hard compared to stock. Buggy/truck engines often gain double their horsepower output and 30-60% more torque by making modifications to the internals. Boring the crank and changing the inlet timing alone can have a dramatic effect on power - often increasing fuel efficiency enough to gain 20-30% more runtime per tank of fuel as well.

I don't care what brand of engine it is - if there is a purpose to change the powerband or change the overall behavior of the engine, then I will make changes to get the result I want. So far I haven't had an engine fail except one and that was due in large part to a defective engine from the get-go.

Last edited by 1QwkSport2.5r; 09-07-2017 at 08:10 AM.
Old 09-07-2017, 11:27 AM
  #707  
sarpet
Senior Member
 
Join Date: Feb 2007
Location: joutseno, FINLAND
Posts: 244
Likes: 0
Received 1 Like on 1 Post
Default

Imade boost port cva engine and it rews 1000rpm more with apc 8x4 prop.
icopy it from cvr engine.
Old 09-07-2017, 11:44 AM
  #708  
1QwkSport2.5r
 
1QwkSport2.5r's Avatar
 
Join Date: Oct 2006
Location: Cottage Grove, MN
Posts: 10,252
Received 60 Likes on 57 Posts
Default

The CVA didn't have a Boost port either? I thought the LA was the only series like that.
Old 09-10-2017, 10:02 AM
  #709  
Broken Wings
My Feedback: (20)
 
Broken Wings's Avatar
 
Join Date: Jan 2003
Location: Cocoa, FL
Posts: 2,087
Likes: 0
Received 4 Likes on 3 Posts
Default

Originally Posted by Hobbsy View Post
John, not many engines will run on Diesel fuel without changing the head, a few will though. I have an OS LA .46 that I bolted a Davis Diesel head on to without breaking it in first on glow. Mr. Davis recommended breaking converted engines in on glow first. My Saito .80, (15.5 to 1 compression ratio) will fire up and run on Davis fuel with the coil removed from the plug. It will turn a Bolly 13.5x8 at 8,760 rpm and idle below 1.400 rpm.

Bob, it sounds like the .91 is in good shape and timed correctly. My guess is that the LS needle is too rich. I'd personally would screw it in until the engine hesitates when opening the throttle then back it out 1/8th to 1/4 turn, you should find the sweet spot close to that setting. Let us know how it goes, Thanks, Dave
I understand that, I was just wondering about a relatively cold break in. What is the reasoning for breaking in the engine on glow fuel first? Because it's a conversion?
Old 09-10-2017, 11:22 AM
  #710  
Hobbsy
My Feedback: (102)
 
Hobbsy's Avatar
 
Join Date: Dec 2001
Location: Colonial Beach, VA
Posts: 20,370
Likes: 0
Received 22 Likes on 22 Posts
Default

Mr. Davis says that the reason is to get the carb settings right and of course to limber up the moving parts although the Davis Diesel fuel being more "luby" I don't see how a break in on the Diesel fuel would hurt. I didn't break in my SuperTigrre .51 or my LA .46, they ran fine.
Old 09-10-2017, 05:57 PM
  #711  
1QwkSport2.5r
 
1QwkSport2.5r's Avatar
 
Join Date: Oct 2006
Location: Cottage Grove, MN
Posts: 10,252
Received 60 Likes on 57 Posts
Default

Generally, diesels run cooler than glow engines do, so for the engines that take a long time to break in, it takes a lot longer to break the in as a diesel. In general, diesel fuel is about twice the cost of glow fuel, so I can see why Bob Davis recommends breaking in conversion engines on glow fuel first. I would surmise that ringless tapered bore engines wouldn't be a big deal to break in as a diesel conversion, but a ferrous engine would undoubtedly benefit from a glow fuel break-in due to the need for heat cycling the ferrous parts for the right fit.

When I broke in my .25FSR with a new piston and liner, I followed the process outlined by Adriansmodelengines.com to heat cycle over 8-10 runs. The engine ran beautifully as I'd expect it to (remember that gold standard? ), but even after an hour of heat cycling, it still wouldn't hold a needle setting without sagging. A few more runs should have it ready for diesel duty. I got a NIP Davis head for the .25 for $5 from my LHS. Quite the bargain considering the engine was a freebie and the piston/liner was "only" $40.
Old 11-14-2017, 05:38 AM
  #712  
Linkan2
Senior Member
 
Join Date: Oct 2010
Location: Öland/ Kalmar/ sweden
Posts: 224
Received 1 Like on 1 Post
Default

Hello
I have bought an OS 200fs.
There is much written about this engine here in Sweden.
About how to get the engine going a lot better.
It is so that the valve springs have different hardness.
Then replace the soft valve spring with exhaust gas.
For harder harder valve spring number 45560210
so now I'm waiting for my valve spring
Lars
Old 11-14-2017, 06:13 AM
  #713  
Hobbsy
My Feedback: (102)
 
Hobbsy's Avatar
 
Join Date: Dec 2001
Location: Colonial Beach, VA
Posts: 20,370
Likes: 0
Received 22 Likes on 22 Posts
Default

OSMG924745560220 Exhaust 18mm length

OSMG924645560210 Intake 20 mm length

Last edited by Hobbsy; 11-14-2017 at 06:16 AM.
Old 11-14-2017, 02:54 PM
  #714  
Hobbsy
My Feedback: (102)
 
Hobbsy's Avatar
 
Join Date: Dec 2001
Location: Colonial Beach, VA
Posts: 20,370
Likes: 0
Received 22 Likes on 22 Posts
Default

Two years or so ago I bought a new OS 56 Alpha, moved the vent to the back plate because it would nearly stall every couple of minutes during a flight. Now looky here.
**Additional Technical Info Will Be Added When It Becomes Available.**
This is the O.S. Engines FSA-56II Four Stroke Engine with the F-4040 Silencer.




FEATURES
Blow-by oil exits through the breather nipple on back plate for more
stable operation
Black rocker covers
40NA carburetor
Power Box designed muffler for quiet operation is fully positionable
for tight fitting applications
Two-year limited warranty through Hobby Services beginning at date of
purchase

It wasn't my imagination.
Old 11-14-2017, 05:55 PM
  #715  
extra300crazy
 
extra300crazy's Avatar
 
Join Date: Apr 2015
Location: Clinton Twp. MI.
Posts: 164
Likes: 0
Received 0 Likes on 0 Posts
Default

Hobbsy,
Perhaps so, but i've been running the 72a, 81a, and the 110a for several years without such a problem. I can't believe it was just my luck. I believe that O.S. simply wanted to skip the machining process involved with the rebreathing design to save money and keep their price point and profit. They raised the price as well. I have 9 of the Alphas that have been trouble free.
Karl
Old 11-14-2017, 06:04 PM
  #716  
Hobbsy
My Feedback: (102)
 
Hobbsy's Avatar
 
Join Date: Dec 2001
Location: Colonial Beach, VA
Posts: 20,370
Likes: 0
Received 22 Likes on 22 Posts
Default

I'm genuinely glad your's work well, mine didn't, I'm thankful that the .95v and the .62v I just bought have front vents. But our "speriences" are different for most of us. Variety is good. Thanks
Old 11-14-2017, 06:19 PM
  #717  
extra300crazy
 
extra300crazy's Avatar
 
Join Date: Apr 2015
Location: Clinton Twp. MI.
Posts: 164
Likes: 0
Received 0 Likes on 0 Posts
Default

Hobbsy,
My club has a few of the 95v's running and they seem like fantastic engines. I have to wonder why O.S. didn't see fit to incorporate that design in the rest of their 4 strokes, because their cost is more in line to normal pricing that people would be willing to pay. I just can't see the cost justification in their new line of series ll alphas.
Karl
Old 11-15-2017, 03:50 AM
  #718  
Hobbsy
My Feedback: (102)
 
Hobbsy's Avatar
 
Join Date: Dec 2001
Location: Colonial Beach, VA
Posts: 20,370
Likes: 0
Received 22 Likes on 22 Posts
Default

The V series are mfd. in China, that might explain the better price. Here's a shot of the .95v interior I took when it arrived. It is a smoothy. This was taken after a 50 minute run on Wildcat 10% full synthetic. The only fuel I use now.
Attached Thumbnails Click image for larger version

Name:	OS 95v 1.JPG
Views:	126
Size:	1.71 MB
ID:	2245132  
Old 12-03-2017, 04:59 AM
  #719  
Hobbsy
My Feedback: (102)
 
Hobbsy's Avatar
 
Join Date: Dec 2001
Location: Colonial Beach, VA
Posts: 20,370
Likes: 0
Received 22 Likes on 22 Posts
Default

I Have been ciphering on and examining this OS 1.20 Surpass for a couple of months. I have effectively disabled the stock regulator by removing it's spring, so I haven't ruined it. By choking it I got fuel to carb easily through the IronBay regulator. I'll run it tomorrow, the prop is a Graupner SuperNylon 15x8. When the prop is moved either direction the fuel moves back and forth in the return line indicating that the gear pumps works well.. The recirc line is disconnected because it breathes so freely it negates the intake stroke, no kiddin, it needs to be restricted some way.
Attached Thumbnails Click image for larger version

Name:	OS 1.20 with IronBay regulator..JPG
Views:	70
Size:	2.31 MB
ID:	2246735   Click image for larger version

Name:	HPIM1299.JPG
Views:	60
Size:	2.29 MB
ID:	2246750   Click image for larger version

Name:	HPIM1300.JPG
Views:	47
Size:	2.23 MB
ID:	2246751  
Old 12-03-2017, 06:54 AM
  #720  
extra300crazy
 
extra300crazy's Avatar
 
Join Date: Apr 2015
Location: Clinton Twp. MI.
Posts: 164
Likes: 0
Received 0 Likes on 0 Posts
Default

Let us know how it runs. Did you attach the header to the exhaust port with teflon tape?
Karl
Old 12-03-2017, 08:16 AM
  #721  
RACE 66
 
Join Date: Jun 2005
Location: BELLINGHAM, WA
Posts: 251
Likes: 0
Received 1 Like on 1 Post
Thumbs up Enlighten on Boost Port Addition

Originally Posted by särpet View Post
Imade boost port cva engine and it rews 1000rpm more with apc 8x4 prop.
icopy it from cvr engine.
..
sarpet: Enlighten me about the boost port on the cvr with the transition to the cva. I have a couple of articles on modifying liners/cases for boost port additions. I to have a cva I would like to 'rev up' the little cva up some. Thanks

RACE66
Old 12-03-2017, 10:54 AM
  #722  
Hobbsy
My Feedback: (102)
 
Hobbsy's Avatar
 
Join Date: Dec 2001
Location: Colonial Beach, VA
Posts: 20,370
Likes: 0
Received 22 Likes on 22 Posts
Default

Originally Posted by extra300crazy View Post
Let us know how it runs. Did you attach the header to the exhaust port with teflon tape?
Karl

Yes sir, that is standard practice for me on four strokes, I've never had one come loose since doing that, no matter the brand. I pulled the head and the engine appears to never have been run. I'll go easy on it because of that and the fact that I am not sure how well the fuel system will pass fuel in it's new configuration.
Old 12-03-2017, 03:24 PM
  #723  
extra300crazy
 
extra300crazy's Avatar
 
Join Date: Apr 2015
Location: Clinton Twp. MI.
Posts: 164
Likes: 0
Received 0 Likes on 0 Posts
Default

Hobbsy,
I'll give the teflon tip a try, thanks.
Karl

Last edited by extra300crazy; 12-11-2017 at 12:43 PM.
Old 12-03-2017, 05:41 PM
  #724  
Hobbsy
My Feedback: (102)
 
Hobbsy's Avatar
 
Join Date: Dec 2001
Location: Colonial Beach, VA
Posts: 20,370
Likes: 0
Received 22 Likes on 22 Posts
Default

I don't have any Teflon tape on the adapter because I never removed it.
Old 12-11-2017, 10:00 AM
  #725  
blw
My Feedback: (3)
 
blw's Avatar
 
Join Date: Mar 2004
Location: Opelika, AL
Posts: 9,447
Likes: 0
Received 2 Likes on 2 Posts
Default

I've never had to use Teflon tape, but I know it works well. I always have a roll in my tool box when I fly.

Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell or Share My Personal Information -

Copyright © 2023 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.