1/2 VW Improvement Idea

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DaveK

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Apr 21, 2007
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Now this might be totally stupid, but why can't you have the exhaust point to the rear in the 1/2 VW conversions. I would think it would just take a custom grind cam that would flip the exhaust and intake profiles front to back. Would certainly help with making a proper pressure cowl for the engine. Any thoughts?:ponder:

Dave
 

DaveK

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Apr 21, 2007
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Oh, that is if you could also swap the heads left to right or make the half heads from the rear cylinders and have them bolt up.
 

Peter V

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May 24, 2006
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Heat.


Your exhaust valves will overheat and may likely decide to re-model your combustion chamber. :nervous:
 

PTAirco

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I doubt the exhaust valves would suffer much - on the stock 4 cylinder they are facing to the rear and seem quite happy there.
 

Peter V

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May 24, 2006
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Granted I haven't seen it happen on VW engines, but I do know of an attempt to do exactly this type of operation to Moto Guzzi air-cooled motorcycle engines (similar configuration to VW - cylinders out the sides) by a couple of endurance race teams in the early seventies, all the endurance racers that were equipped with reversed heads all failed early in the piece as their exhaust valves overheated and dropped their heads off.

I'm not saying you shouldn't do it, just be wary of extra heat issues. I'd want to make use of some extra cooling fins on the exhaust outlet and some ducting to ensure air gets back there. It is the hotest part of the whole engine. The cooler you can make it, the longer your engine will last.
 

DaveK

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My thoughts were that with proper baffling there shouldn't be a problem as the full VW heads have the rear cylinders exhaust valves facing the "rear." And in some ways it might help some as the air isn't heated going over the exhaust pipe before hitting the heads.

Dave
 

RacerCFIIDave

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Feb 8, 2008
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Asheville, NC
The other option are very expensive custom valves from Ferrera down in Florida...they will make what you want....any sizes...either just REALLY good stainless or sodium cooled...or even Inconel...but wow the price!

You still have to cool the head enough to make sure the seats dont distort...but this buys you quite alot of temp capacity...

Dave
 

piperpiper

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May 18, 2009
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Lot 8,Block 3,Dona Lourdes Subd.,Koronadal City,So
I think this would be a great idea and I see that it is doable.First ,use a full VW case then use the two rear cylinders instead of the two front.This set up however will force you to use a full length crankshaft and full camshaft.This way you can also use the two cut-off cylinders with their exhaust facing backwards.The whole idea will,however be a bit heavier.Has anyone tried this idea...any feedback please?:gig:

Jess Bechayda:ban::roll:
 

Dan Thomas

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Sep 17, 2008
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You still have to cool the head enough to make sure the seats dont distort...but this buys you quite alot of temp capacity...
Or the seats coming loose in the head. Aft ports would work if baffling was properly designed and constructed.

Dan
 
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