90 Degree Muffler Adapter Seller:RC Specialties Details:
$17.95
| 7/13/2008
| Classified Ad
We will rotate YOUR AD in this spot if you select "Forum Featured" when placing or editing your ad!
Posts: 7524
Joined: 6/11/2003 From: Northridge,
CA, USA Status: offline
It was one year ago that I ran my ASP FS400AR radial (hereafter known as FS400) engine on a test stand to begin the break-in process. Over three days, I ran the engine a total of 62 minutes. Then I added after-run oil and left it attached to my engine test stand, put a cover over it, and put it in my shed. Where it has sat untouched for a year.
I decided I wanted to run it again on its one year anniversary. But over the preceeding year I have read some reports of various problems other owners have had. So I decided to pull the back off to have a look inside, and also I was going to adjust the valves before running. Upon first look inside the engine, I was pleased. It looked good. No rust, or evidence of severe metal shavings and such. But there was some grayish residue on the diffuser backplate. And in there I did notice a couple of pepper size specks of something. Then, laying in the ARO, I saw a piece of metal. I removed it, looked at it, and wondered where it came from. Then looking inside the engine I saw it. One of the articulating rods linkpins had broken off in two spots where the circlip attaches. Bummer!
The good news is that I discovered it before serious mechanical damage had occured. So now, it is time for a 1 hour TBO overhaul.
This thread will illustrate what the process is about, as well as give everyone a look at how the FS400 was manufactured and any goofs the factory may have made in machining and assembling the engine.
My initial impressions of this engine are that it is nicely made. Machined well, and uses decent metallurgy. My concerns are in the area of final assembly, and perhaps a lack of quality control oversight.
The following pictures are not my engine, but those of another owner who had an articulating rod linkpin let go. My engine was very nearly at this stage!
To be continued...
< Message edited by Kmot -- 12/17/2007 5:02:15 AM >
Specified adjustment: .04mm-.10mm for both In and Ex.
6) One head bolt on #5 cylinder head was not torqued down.
7) One shim on #5 cylinder is warped slightly. Probably due to non-torqued head bolt.
As you can see from the figures above, the valve adjustments were wildy out of specification. All the nuts were tight, so this is how it came from the factory. Perhaps there was some loosening of the tolerances as the parts wore in.
Here is where the engine spent the past year. You can see the fuel tank on the floor, as the rubber bands holding it rotted and broke.
The engine was under this canvas cover to protect it and keep it clean.
The following pictures are as the motor was removed and torn down. You see it just as I saw it.
Up to this point I thought all was fine. Then I found this:
The linkpin at top is the broke one.
Other than that, it looked OK inside!
The rocker boxes all looked good.
It's important to keep all the valvetrain in order as removed, so it can be put back where it came from.
Removing the cylinder heads.
This is another factory goof. It appears the first headbolt someone attempted to install was when the head was not lined up.
And finally down to the main power section and cylinders.
Here are the assorted parts so far.
Again, keeping the valvetrain in order, this is how I stored the tappets.
I am at the point where I need to disassemble the nose from the power section. I tried using heat on the area around the bearing to loosen the case. No luck so far.
Since I do not have a manual, I am guessing at how to tear down this engine. My guess is that the front bearing needs to come out before I can remove the nose piece. Next I will put the whole thing in the oven and see if that will get it to loosen up.
Posts: 13306
Joined: 3/20/2002 From: San Bernardino County,
CA, USA Status: offline
....there isn't very much meat on those big end pins.
Big end pins/lower-end pins/crank pins/bottom-end pins. "Link pins", OK too.
FBD.
_____________________________
An engineer says.... "That won''t work". A mechanic says..."Oh yeah, watch this". "Old Age, and Treachery will overcome youth and skill". Revver Bro #4.
Posts: 7524
Joined: 6/11/2003 From: Northridge,
CA, USA Status: offline
Link pins, Dave. Maybe on those little girly engines in the motos you worked on they were called big end pins (making up for other shortages, lol) but on the manly P&W radials I used to overhaul the correct nomenclature is link pins.
Motorman, max rpm never exceeded 7400 and the engine is rated much higher.
Posts: 13306
Joined: 3/20/2002 From: San Bernardino County,
CA, USA Status: offline
....well, allrighty then.
FBD.
_____________________________
An engineer says.... "That won''t work". A mechanic says..."Oh yeah, watch this". "Old Age, and Treachery will overcome youth and skill". Revver Bro #4.
Posts: 1438
Joined: 6/24/2003 From: Crystal Lake,
IL, USA Status: offline
Is it a fit (lack or clearance) or material issue? It's pretty common to find the heat treated parts too hard or not tempered in the Chinese products. Does the snap ring groove have radii in the bottom? Is everything square? Theoretically the side loading on the link pins should be extremely small so the ring groove needs little strength.
Posts: 7524
Joined: 6/11/2003 From: Northridge,
CA, USA Status: offline
Greg, once I get the engine completely dismantled I will be able to answer your questions.
From what I can tell so far, the nose case must be removed to then allow the link pin to be removed. I am approaching this disassembly extremely cautiously, for I have no clue where spare parts can be obtained for this engine and I do not want to break anything else during disassembly. I already expect I will have to make my own link pins.
FWIW, after I had heated the nose case I then turned the engine upside down and sort of slammed the crankshaft against a wood 2x4. That was more side loading of those pins and everything else than the engine would ever see normally and no other pieces broke off.
I can't heat the engine in the oven while my wife is in the house. And I will be out of town for a few days starting tomorrow so it may be awhile till I get the engine completely torn down.
Posts: 7524
Joined: 6/11/2003 From: Northridge,
CA, USA Status: offline
Okay, the wife went out and I cooked the engine.
When I tried to shake the bearing out, the whole nose case actually seperated. Oops! There went my opportunity to see how the engine was timed.
Anyway, found a little more detritus inside the nose case. Some of it was metallic, the stuff around the tappet bores is just sludge. Seperating the spacer from the nose case was a tough job because of the pin used to align them. So the plastic gasket didn't survive this time.
I removed the damaged link pin and then the piston and connecting rod. I found the piston pin only has a teflon pad on one end. I don't know yet if this is by design or by mistake.
Bake uncovered in a 300°F oven for 10 minutes.
Then rap on a piece of wood and the bearing should fall out. Not!
Okay, so now we have come this far let's just tear down the nose case and cam gears, etc.
Here is what the rest of the engine looks like inside:
And finally, here is the link pin. No Greg, it doesn't look like it is radiused for the circlip.
To be continued in a few more days. In the meantime, if anyone knows how to time this engine..................
< Message edited by Kmot -- 12/18/2007 2:13:32 AM >
Posts: 13306
Joined: 3/20/2002 From: San Bernardino County,
CA, USA Status: offline
....the failure on that pin is really odd, when there is no side thrust on it. It should be dead bolt reliable.
FBD.
_____________________________
An engineer says.... "That won''t work". A mechanic says..."Oh yeah, watch this". "Old Age, and Treachery will overcome youth and skill". Revver Bro #4.
Posts: 7524
Joined: 6/11/2003 From: Northridge,
CA, USA Status: offline
quote:
Are those cracks in the crank?!
My first thought also. No, that is the crank pin that was pressed into the counterweight and then machined.
FBD: I agree. But take a look at something. Look close at the pins in the photo. See the discoloring? Is that heat treat? Could they have been improperly heat treated and the flanges are too brittle?
Posts: 1438
Joined: 6/24/2003 From: Crystal Lake,
IL, USA Status: offline
For some reason heat treating isn't taken seriously or maybe it is not well understood over there. When I was working with RC electric motors a few years ago it took over two years to get a semi-properly heat treated motor shaft. Mean while the product was released and shafts broke right and left. I extremely rarely saw a bent shaft, only broken. Prior to that my experience with electric motors showed only bent shafts, some weak, some strong but never broken, but these were not of Chinese origin.
Printable Version
All Forums >> Glow Engines, Gas Engines, Fuel & Mfg Support Forums >> Glow Engines >> ASP/MAGNUM FS400AR Rebuild/Overhaul 
ASP/MAGNUM FS400AR Rebuild/Overhaul - 
