Does the 38cc 30DN cylinder fit the Zen G320 crankcase with a 30mm crankshaft?

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Mr. Marmot

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Hi. Can you put the 38cc cylinder from 30 degrees north (40mm piston, 30mm stroke) on top of a zenoah or rovan 32cc crankcase? Do the 4 bolt holes match? Thanks
 
I'd rather not touch my esp cylinders with a Dremel. The 38cc sounds like a better candidate, and the 40mm bore might make it easier, but I have never seen one in person. Does it have closed transfers?
 
Dunc2504 said:
Why would you need to touch the ESP head when it is made for the Zenoah crankcase already ?
My point is , An ESP set is probably not far off the power output of the 38.
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I think I just wanted to see how good the 38cc cylinders are as a cheaper option for power and that I'm also willing to modify (unlike an ESP head, which I know they are good already, but more expensive)
 
Dunc2504 said:
Why would you need to touch the ESP head when it is made for the Zenoah crankcase already ?
My point is , An ESP set is probably not far off the power output of the 38.
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I would guess that the stud spacing is the same , but no idea about the ports.
Try getting hold of a 30 DN base gasket and try it on your crankcase.
 
Indeed, it is a science experiment. I will try to get a base gasket, good idea, thanks. If anyone has done it, let me know
 
I know, its a late reply. I have been meaning to take a pic of this for a while. I had a Zenoah gasket I use for mock up at work and my 38cc cylinder at home. Finally got the gasket home to take the pic last week and only now had time to post it.

As far as timing numbers, IIRC when one adds a +2mm stroker crank with a Zen 320 cylinder compared to the 38cc engine, the Zen will have more duration numbers all around. With my 38cc reed build, the exhaust and transfer port numbers are close to where I want it.

If one goes the +2mm stroke crank to a stock Zen 32, one has to consider checking crankhsaft to crankcase clearance. One will need to get creative with a grinder and carbide bit and really pay attention to where both make contact. Or one could just purchase a case that has been already machined like the one DDM has.

Now the challenging question, does one build a 38cc from scratch or does one go with the ported 34cc cylinder kit? I already have a few engines from OBR and Taylor RC, along with cylinder kits from Bartolone, ESP and OBR. At this point, I like to experiment with my own porting and builds. At the end of the day, one can't go wrong a ported cylinder kit.
 

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one2boost said:
I know, its a late reply. I have been meaning to take a pic of this for a while. I had a Zenoah gasket I use for mock up at work and my 38cc cylinder at home. Finally got the gasket home to take the pic last week and only now had time to post it.

As far as timing numbers, IIRC when one adds a +2mm stroker crank with a Zen 320 cylinder compared to the 38cc engine, the Zen will have more duration numbers all around. With my 38cc reed build, the exhaust and transfer port numbers are close to where I want it.

If one goes the +2mm stroke crank to a stock Zen 32, one has to consider checking crankhsaft to crankcase clearance. One will need to get creative with a grinder and carbide bit and really pay attention to where both make contact. Or one could just purchase a case that has been already machined like the one DDM has.

Now the challenging question, does one build a 38cc from scratch or does one go with the ported 34cc cylinder kit? I already have a few engines from OBR and Taylor RC, along with cylinder kits from Bartolone, ESP and OBR. At this point, I like to experiment with my own porting and builds. At the end of the day, one can't go wrong a ported cylinder kit.
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I couldn't answer your question, i think u should go with what setup your most interested in finding out what it runs like. But I had a question for you, have you run the 30DN 38cc engine in stock form in a 4wd chassis? If so how is the power, bottom end snap, speed? I'm looking to upgrade from my bws 29cc that came in the 30DN DT. I am in process of installing new piston in the 29 with some home porting to see what I can get out of it, the first piston didn't last long, not quite 1 summer season. I have a feeling it won't be enough power even mildly ported especially cause I'd like to gear up for more speed. The stock 35mph'ish just isn't enough. I have an olimat silenced pipe already. So basically wondering what your thoughts are on that 38 vs the g320 or g340 zenoah. What's the best bang for buck? Thx!
 
romper4444 said:
I couldn't answer your question, i think u should go with what setup your most interested in finding out what it runs like. But I had a question for you, have you run the 30DN 38cc engine in stock form in a 4wd chassis? If so how is the power, bottom end snap, speed? I'm looking to upgrade from my bws 29cc that came in the 30DN DT. I am in process of installing new piston in the 29 with some home porting to see what I can get out of it, the first piston didn't last long, not quite 1 summer season. I have a feeling it won't be enough power even mildly ported especially cause I'd like to gear up for more speed. The stock 35mph'ish just isn't enough. I have an olimat silenced pipe already. So basically wondering what your thoughts are on that 38 vs the g320 or g340 zenoah. What's the best bang for buck? Thx!
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Okay, just to clear things up, I have never ran a stock 38cc engine on any of my rigs. I purchased the 38cc piston/cylinder kit to build my own reed case engine. It is currently still in the build stage. I still need to machine a 3rd and maybe a 4th transfer port and the corresponding window/s into the piston.

I would stay away from just trying to add a +2mm stoker crankshaft and stacking cylinder head gaskets to achieve the necessary piston to cylinder head clearance. IMO my race ported ESP g320 piston cylinder kit was more impressive than the cheap zen g340 engine combo previously mentioned.

As far as "best bang for the buck" is a trick question. If one is on a budget, the ESP race ported g320 piston/cylinder kit would be my first choice. If one has more money to spend, the ESP race ported g340 engine kit is a great choice. Keep in mind this kit comes with a zen case machined for a +2mm stroker crankshaft. But one still has to purchase a wrist pin bearing separately.
 
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