Model Boat Mayhem

The Shipyard ( Dry Dock ): Builds & Questions => Pleasure boats, Sports, Race, Power and Leisure Boats: => Topic started by: fto mivec on August 20, 2021, 07:42:33 am

Title: 90 degree header on zenoah 300 pum
Post by: fto mivec on August 20, 2021, 07:42:33 am
morning everyone.can anyone tell me how to measure the distance for tuned pipe on a zenoah 300 pum with a 90 degree header.i know with a standard header its 13 1/2 inches cylinder head face to the taper on the tuned pipe.i just cant get my head around how you measure with a 90 degree header.can someone help thanks steve
Title: Re: 90 degree header on zenoah 300 pum
Post by: Andy M on August 20, 2021, 09:51:06 am
I would imagine that it has to be measured down the centre of the pipe.
Title: Re: 90 degree header on zenoah 300 pum
Post by: Andyn on August 21, 2021, 12:31:44 am
From the edge of the piston round the centreline of the header to the seam on the pipe :-))
Title: Re: 90 degree header on zenoah 300 pum
Post by: fto mivec on August 21, 2021, 08:28:55 am
sorry about this chaps.the header is a 90 degree space saver header.thanks steve
Title: Re: 90 degree header on zenoah 300 pum
Post by: Andyn on August 21, 2021, 10:19:54 am
Do you mean one of the ones that is essentially just a tube bolted at 90 degrees to the engine? I'd recommend against using o e unless you absolutely have to
Title: Re: 90 degree header on zenoah 300 pum
Post by: fto mivec on August 21, 2021, 10:34:30 am
thanks for that.the trouble is  i am trying to fit out a areomarine challenger 48" pro. i didnt want to have tuned pipe out of the back of the boat.so the only way is to put a space saver header on.so then it seems to be impossible to get the pipe at the right length.so i am a bit stuck.any ideas.cheers
Title: Re: 90 degree header on zenoah 300 pum
Post by: Andyn on August 21, 2021, 07:08:20 pm
Do you mean one of the Swan neck ones that goes forwards before it goes back? Again they're not great and are difficult to get a good pipe length with, but on a stock zen that won't matter too much anyway
Title: Re: 90 degree header on zenoah 300 pum
Post by: fto mivec on August 22, 2021, 06:53:32 am
yes it is that swan neck style that goes forward first.i am thinking of putting a bl7b electric motor and bl28 esc from prestwich in there instead.would be easier
Title: Re: 90 degree header on zenoah 300 pum
Post by: Andyn on August 22, 2021, 03:52:47 pm
The Swan neck should fit fine, it's been done before
The boat pictured below was converted by someone to electric. Can't say I understand why anyone would want to but still  %)
(https://forums.offshoreelectrics.com/cache.php?img=http%3A%2F%2Fi60.photobucket.com%2Falbums%2Fh9%2Fspotme2%2Fchallenger43-3_zpsb4e2f5a7.jpg)
Title: Re: 90 degree header on zenoah 300 pum
Post by: fto mivec on August 26, 2021, 07:03:00 pm
thanks for info andy.i am staying with the petrol.i had to cut down header and welded it back up as header was touching the side of the boat.i have now finished it and ready for the water.i would put some pictures on here for people to see but having trouble uploading some.thanks steve
Title: Re: 90 degree header on zenoah 300 pum
Post by: fto mivec on August 27, 2021, 10:31:29 pm
pictures
Title: Re: 90 degree header on zenoah 300 pum
Post by: Del-69 on August 28, 2021, 09:30:17 pm
Got the hang of pictures then. Nice looking boat. :-))
Title: Re: 90 degree header on zenoah 300 pum
Post by: fto mivec on August 28, 2021, 09:56:21 pm
the pictures are not quite right.seem distorted
Title: Re: 90 degree header on zenoah 300 pum
Post by: fto mivec on September 06, 2021, 08:29:56 am
updated pictures