freebird1

I have a friend that is selling some items for a friend. He has a new sack dolmar 69 cc gasser with cdi and pits muffler. I have never seen one, read or saw one in action. I know that the company has went out of Bus, but it seems like a nice engine. I need this engine for a kmp 85" edge. Does anyone know anything about these sack dolmar engines. Thanks!!!!!

Big_Bird

My Feedback: (1)

The correct name is Sachs Dolmar and the 69 cc engine is normally referred to as a 4.2 cu-in engine. It is a very high quality engine although a little heavy by today's standards. With the built in CDI ignition you can't start it by hand. You must either must use a spring starter or an external heavy duty electric starter. As I understand, the engine had a safety feature that required it to flipped at the equivalent of 600 rpm to start.

I have one on a 1/3 scale Bucker Jungmeister which has been converted to use a CH Electronics Syncrospark ignition. The engine runs great.

Sachs Dolmar is famous for making very rugged chain saw engines for the commercial logging industry. As far as I know they never made engines for the RC business or home owner chainsaws. The Sachs Dolmar engine for RC were converted from chainsaw engines and were orange in color. Many companies use Sachs pistons and cylinders for RC engines. Brison and Fox to name a couple.

Antique

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Sachs Dolmar engines are the basis for almost all the aftermarket engines sold...The 69cc could be an old 4.2 Sachs chainsaw conversion, or an engine made from the crank, cylinder, and piston from the chainsaw, with a machined crankcase..Use a 24-8 or 24-10prop and fly it forever, it will outlast anyting you put it on...
FWIW, Sachs was bought by Makita some years ago...
If the ignition is battery powered the engine will start with one little finger, if magneto equipped it takes a big glove and an aggressive slap of the prop...
The one in the picture looks like an old Elliot Sachs, named for the guy who did the conversions...He painted everything with silver paint, even got some inside the case...It has the chainsaw magnesium alloy crankcase and a very old C&H ignition with the Delrin plastic magnet holder on the prop hub...

rmh

there goes the neighborhood --------

Kweasel

My Feedback: (29)

An old style 24-8 Zinger will sound great with that pitts muffler.

freebird1

This is the engine. I love the timing. It advances as the throttle does. The engine does say Sachs dolmar. Does anyone know anything about the EL unit in the photo. I am now sure what volt it requires.

Big_Bird

My Feedback: (1)

The ignition requires 4.8 volts and is a much older but very popular CH Electronics Ignition. The engine uses throttle coupled spark advance. You can get timing information on the CH site. The engine looks like an early Brison but I'm not sure.

TLH101

My Feedback: (90)

Pretty sure that is an A&M Conversion of the Sachs, but RCIGN can say for sure.

Big_Bird

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Here is a photo of an old A&M 4.2 that I stopped using a long time ago. It really doesn't resemble the engine in question. Look at the crankcase.

freebird1

My friend is sell several of these engines. Some of them have a long can type muffler for warbirds. I think this engine was made by Byron Originals, and was modified version.

Rcpilot

My Feedback: (78)

Run that brown ignition unit on 4.8V.

If you run it on 6V or higher, you can damage it.

freebird1

Thanks for the info. I tested the unit and fires great with 4.8.

tkg

My Feedback: (1)

Its an OLD A&M, the timing ring and monkey motion throttle linkage are the clues. It is a very early one most likely with a sachs crank (very good). The CH ignition is 15 years old at least. If it works use it, if it quits its not repairable.

freebird1

OK, I think the engine was put out by Byron Original. I think it has been Mod from the orginal ones with the pur power muffler. Does anyone know how these engines run and last?

Tired Old Man

My Feedback: (1)

The engine in question will last and run longer than you will if you don't crash it and maintain a resonable oil mix. The ignition unit can be easily replaced by the original manufacturer of the currently installed ignition unit. TKG is Terry Grant at CH Ignitions. They make an extremely reliable ignition system. As he stated, if it works, use it. If not give him a call to obtain a newer version.

As RCIgn stated, Sachs is and was the basis for most of the engines in use today. The only big differences between then and now have been in the timing attachment methods and lightening of the engines in general. Others have changed the case design, some have shaved the cylinders to shave a little weight and look different, but ultimately a large percentage of today's engines are still Sachs Dolmar in design.

If you have a big plane that needs the nose weight that engine is an excellent choice for the power supply.

Antique

My Feedback: (4)

Bigbirds engine is an A&M 4.2 MKII..It has a different case because it has a cantilever crank, only 1 counterweight...
The first is most likely an earlier A&M..Take the prop stud off and look at the end of the crank..A flush end is an A&M crank, a small hole in the center is a Sachs crank, way better...
Byron didn't make engines, they bought from A&M first and then used Mustang 50s...
The first engine could have been used in a Byron airplane, but would have had a different prop hub.. The Byron hub was made for the scale looking plastic blades and could be 3 or 4 blades..They didn't work very well and most planes were flown with 2 blade props...
Most Byron 4.2s had a plastic cover that fit over a stamped piece on the front of the case...It covered the mechanical advance unit for a more scale appearance....

Tired Old Man

My Feedback: (1)

Ralph,

I'll be back early February. How's that Brison 6.4 comin' along?

Antique

My Feedback: (4)

Still in the box, It will be running long before February

freebird1

Ok, I found the name Mahle on the block. I though they only made cyl. There is a hole in the shaft.

freebird1

RCIGN1, you sure know your stuff. You are 100% right. My friend had several engines, most like you have stated. The black hub and the larger prop nut assem. The muffler and mounting was unlike anything I have ever seen.

abacro

RALPH is 100% correct on this engines make and model. I know this for a fact because i have the EXACT motor in my WH 300LX. I removed it from a byron p-47,removed the large plastic and aluminum timing cover ring and am happily flying the stew out of it on 50 to 1 mix and a 24/8 zinger prop. I will admit it is a bit of over kill on the 28% extra thought. Vertical at just over 1/4 throttle! lol

freebird1

How about a muffle for it. Does anyone know where I can get a muffler.

Big_Bird

My Feedback: (1)

Depending on what kind you want you can try:
http://bennettbuilt.com/index.html
http://bissonmufflers.com/en/index.html
http://www.slimlineproducts.com/

freebird1

Thanks Big Bird. I talked to bennette and he said the mounting screws are 6mm. I think mine are larger. What are your muffler mounting screws.

Thanks

Antique

My Feedback: (4)

Stock are 6mm...If they're larger someone tapped the cylinder for 1/4x20...Not much room around the holes to go larger...6mm heli coils are an option...