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-   -   A&M 3.2 (https://www.rcuniverse.com/forum/gas-engines-142/5424927-m-3-2-a.html)

bdtsr 02-15-2007 08:58 PM

A&M 3.2
 
Good, bad or whatever, my "Auction Site" motor arrived today. It's an A&M 3.2 with the A&M rod. Crank appears to be a Sachs. At some point someone used castor oil to run or store the engine with. It was gummed up pretty bad. I may have to install new bearings. Some how the piston got scratched on both sides and pinched the rings in the groove. Got them out but one broke. Even with one ring and everything cleaned and lubed it has really good compression. I'll have to pick up new rings and base gasket to try it out. The timing ring was changed to fixed type as well (monkey bracket to hold it in place). After new rings and gasket I'll put one of Ralph's ignitions (have two here on the bench) on it and give a good run on the test bench. Anyone have any favorite brand of rings to use? I know Frank Bowman makes good ones.

Antique 02-15-2007 09:03 PM

RE: A&M 3.2
 
Not likely a Sachs crank would have an A&M rod on it....A&M rods had pressed in bearings, if your wrist pin bearing is not pressed in and the rod is copper colored the rod and crank are Sachs.,,,Look for a small centering hole in the end of the crank, no hole means A&M....

bdtsr 02-15-2007 09:11 PM

RE: A&M 3.2
 
OK it's an A&M crank then as it has no hole. The rod is not copper colored. Not looking to hot rod with it. It'll probably go in a Midwest Extra 300. Hopefully it will do the job ok.

Antique 02-15-2007 09:24 PM

RE: A&M 3.2
 
The A&M crank with 2 counterweights was an exact copy of the Sachs...If it's a 3.2 MKII cantilever there might be a replacement from Fox or Brison, don't know for sure...

bdtsr 02-15-2007 09:27 PM

RE: A&M 3.2
 
How prone to failure are the A&M cranks? This engine has the bearings in each half of the case.

Tired Old Man 02-15-2007 09:36 PM

RE: A&M 3.2
 
The broken cranks is why A&M is no longer in business. As to how prone, the word at one time was "very".

Antique 02-15-2007 09:47 PM

RE: A&M 3.2
 
The problem was not the case bearings, it was the big end rod bearing...It should be OK for a long time...It was made a little loose and got worse with age...There's more than a normal amount of play when you rotate the crank...The Sachs crank fits perfectly it it ever goes bad...I saw only one broken crank, it was on a big twin in a P51 race plane....The singles just got too loose to run right...I still a few 4.2 and a 5.8 crank here, no 3.2...

bdtsr 02-15-2007 10:10 PM

RE: A&M 3.2
 
What piece of equipment would be best to use for ordering parts? I have a couple of good small engine places around to get parts from.

TLH101 02-15-2007 11:06 PM

RE: A&M 3.2
 
Ive been told, Sachs Dolmer 111, & 115 saws will have the parts you need.

Antique 02-16-2007 12:08 AM

RE: A&M 3.2
 
:D

TLH101 02-16-2007 10:45 AM

RE: A&M 3.2
 
OK, ok, Ralph told me.:)

Antique 02-16-2007 11:14 AM

RE: A&M 3.2
 
And the chainsaw reference manual told me..
Intertec Publishing, 0-87288-521-6 :D

bdtsr 02-17-2007 08:27 PM

RE: A&M 3.2
 
Well here's some interesting news. Stopped by my local Stihl dealer today because a Stihl engine I have uses a Mahle cylinder (42mm bore). The Stihl 026 has a 44mm bore. But at $48 for two rings I just couldn't do it. After doing some "Auction Site" searching, I found a new pair of rings for $20.50. They look to be a "Pinned" type like the ones on the motor I have. I guess we'll see when they get here.

Tired Old Man 02-18-2007 12:27 AM

RE: A&M 3.2
 
Lucky you weren't trying to buy a new cylinder. Cheaper to get the whole saw.

sengli 02-26-2007 04:35 PM

RE: A&M 3.2
 
I also have a A&M 3.2. The thing I have noticed with mine was the crank had a ton of play in it. This caused excessive vibration in the model, especially at idle. The engine itself ran great, started easily etc. I found that the front crank snout does not protrude all the way thru the bearing inner race. Somehow the crank had started to spin in the bearing itself. So what happened was the crank was worn smaller that the I.D of the front bearing. I had to turn the crank shoulder down, and install a sleeve and then press the new front bearing on. It is nice and slop free now. Does your crankshaft have alot of side to side play in it?

bdtsr 02-26-2007 05:49 PM

RE: A&M 3.2
 
No, it actually seemes pretty tight. I'm still waiting on the new rings before I can run it. Some how it got loaded with castor oil and the piston had some scratched on it where someone try to hold it with a tool. I broke one of the rings trying to get it out of the groove to clean it. So now I wait.


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