Pelle Gris

I´m considering fabricating an inline twin from a pair of G-62´s. They will be set up for 180 degree firing order. Am I correct in assuming that a single 60cc size canister will be sufficient if I fabricate a 2-in-1 header, making sure that the length is the same for both engines?
I have seen other engines built like that, using G-62 engines/cylinders, and combined with a good exhaust, and a gear drive, the power is comparable to that of a Moki 250 radial.

Looking at exhaust setups for the big quads, they should work like two inline twins, sharing one crankcase, and they seem to work fine with one canister for each half of the cylinders.

w8ye

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With a 180 degree firing order a single G62 muffler should work OK.

pe reivers

2 in one will work fine, but be sure the header branches have equal length.

Pelle Gris

Wow, that was quick. :-) Thanks for the replies guys.

spaceworm

For the inline twin how are you arranging their cranks? Are you using each engines crankcase separately and connecting the cranks externally? If using a common case and a single throw crankshaft, how are you insuring each cylinder has it's own base compression for fuel transfer? I am very interested and curious in this approach to multiple cylinder two stroke cycle engines. Thank you very much. Sincerely, Richard

Tony Hallo

Your initial question raised my curiosity. I found no reference on the DA site for the 200. For the DLE I found www.dlenginesaustralia.com/dlshop/mufflers-etc/canister-70mm-diameter.html. They recommend canister sized the sameas used on the 170 cc, not the 111. You might consider using a larger muffler. Making a close fitting manifold may prove to bean interesting build also, I assume this is going in a warbird? Keep us posted on your progress please.

Pelle Gris

I will connect the rear shaft of the front engine to the mag of the rear engine. In that case it´s actually two separate engines connected externally. I have seen others convert to a single carb using 1-in-2 tubes connecting to each cylinder, but as a start I will use the normal two carbs I think.

I found a few videos on youtube of Zenoah inline engines.

http://www.youtube.com/watch?v=EnDoDv9E4jo

http://www.youtube.com/watch?v=x3bwRlc40WY

This is what I´ll try to replicate, as it´s the simplest approach I think. The engine in first two links is more involved, as it seems that the cranks have been modified to be able to mount the two engines so close together.

http://www.youtube.com/watch?v=4Pg8vRE6rqU

Pelle Gris

If I can get a reliable engine from the project I may go into a 1:3 scale Yak 50 eventually. That´s about 122 in span and 97 in length, weighing in around 45 lb I guess.
I had considered getting a King 200 for such a project, but that´s not cheap, and since I already have two G-62´s on hand, it would make a fun project.

A guy in Germany has made something similar. An inline twin using G-62 cylinders, but making a new crankcase, fitted with a gear drive. With two canisters the power is almost exactly that of a Moki 250 radial, spinning a Biela 32x18 at around 4300 rpm.

Pelle Gris

The header should not be too difficult to make using KS tubing.

pe reivers

here is my setup, which worked ok. Two reso tubes however give better power.

Pelle Gris

@Pe. Yeah, I´m sure that seperate exhausts work the best, but due to price/space I would like to stick to one singe silencer. I have however considered installing a tuned pipe instead of the canister, but still not sure. Depends on how well the engine runs if/when I make it.

I also assume, that the optimal header length for a single G-62 would be the same for an inline? So if it´s 22cm for the single, it´s also 22cm, from each cylinder, that works the best for the inline?

What engine(s) are you showing?

pe reivers

I am showing my Moki60 inline twin.
Reso tubes work about the same as canisters if on a 2-in-1 header, not much difference (some advantage for tuned pipe). Two canisters work better, and two reso's work better still.
If you want muffling only, please use the 2-in-1 header and use what you have available. As soon as the cylinders show different tune by spark plug reading, not being able to tune out with the carb, watch out. The header is wrong!