v-twin overheating?

jonnyr48 · Post by **jonnyr48** » Sun Jan 20, 2008 8:25 am

hi fellers, a general ignorance question (perhaps that should be the heading for a new section?). if the punsun v-twin(aircooled) is installed in-line, could the back cylinder have over-heating problems?

Andi · Post by **Andi** » Sun Jan 20, 2008 12:26 pm

I'm a newby here as well and in my part of the world we don't have the Punsun available. I have since checked them out on the web and from what I can see they are the V-Twin version of the YANMAR air cooled single L-Series engines, which gets cooled from the cooling fins of the flywheel and that said I don't think it should make a difference of how the engine is mounted once the opening to the flywheel fan is unobstructed.

These engines are used for Generators, Water Pumps, Pressure Washers, Plate Compactors etc in a mostly stationary position and shouldn't overheat. I can't speak for Punsun, but the YANMAR's are great little engines, they are bulletproof so to speak with regular maintenance.

I actually just started working for the local YANMAR Distributor/Dealer after having been an end user as Plant Manager for a Construction Company. I like the Punsun engine, to bad YANMAR doesn't offer it would be my choice, 20 hp (force) aircooled is just what I'm looking for.

Andi

jonnyr48 · Post by **jonnyr48** » Sat Feb 02, 2008 10:09 am

so, presumably if the engine's mounted transversely(as in punsun/dnepr) the blower becomes unnecessary because the normally stationary engine is now being cooled by the wind (albeit has smaller fins? than a bike-designed engine) tho could be a problem if you're stuck in traffic on a hot day. i'm just wondering how much horsepower and less frame mods can be gained? any thoughts?

TimppaX · Post by **TimppaX** » Sun Feb 03, 2008 11:40 am

Removing front cover & fan should give some more power, theoreticallay, but how much?

I´ve plans removing cover + adding pulley & install car altenator, if needed, for feeding rest of electrical system. No idea how powerfull Punsun´s own charging system is if any.

Post by **Fiddler** » Sun Feb 03, 2008 4:25 pm

Johnnyr,

Ive taken the round cover off to give you an idea of the blower size. Removal of the main cover and plastic finning will save you around 2 and a quarter inches in width although the crank bolt still protrudes.
Should release some hp but not sure how significant. As the engines designed to use forced air induction I'd be tempted to retain it if at all possible and factor it into your design although the engine has an oil cooler which helps. No harm with experimenting by ditching it later and keeping a close eye on oil temperature.

Timpax,

I measure 10 amps charge at max revs with the running lights on. Very little charge at tickover.

TimppaX · Post by **TimppaX** » Sun Feb 03, 2008 4:41 pm

OK. Charging should be no problem then. There is still space for pulley if needed.

I have already 80Amp battery in sicecar, just waiting for new system to be installed.

Just got news that container having my engine inside might be on ship someday after chinese new year around feb16th if snowing in China does not slow things any more.

jonnyr48 · Post by **jonnyr48** » Mon Feb 04, 2008 9:21 pm

thanks guys