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cold air box, PCV  Rating:  Rating
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 Posted: 12-20-2009 09:04 pm
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jdenglish
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Has anyone put together a cold air box to outside air for Dellorto's?

In my Dellorto conversion with K&N filters I was going to rout the crankcase vent to an oil catch can but then into  __________?

What about a PCV valve?

Merry Christmas to all

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 Posted: 12-21-2009 02:27 pm
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Brett Gibson JH5 20497
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The GT's and late JH5's used a outside air box, that ran a 3" to 4" hose to the side of the radiator bulk head. US box's mated to Strom's. and EU box's to Dell's. and I think there is a Lotus box that is similiar. I can send you a pict. of my Strom one, or just check some GT engine pictures out there.

Brett 

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 Posted: 12-21-2009 08:53 pm
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John Finch
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You might try
 
Gerry Foley
8503  44th Street West
University Place,  WA  98466-7513

(253) 565-2175
gfoley@kendra.com

Two years ago, the airbox parts sold a la carte,  and each half was $45,  or $90 for a full airbox.   That was just the fiberglass bits.   You cut the holes,  sand,  and add your own filter, gasket and hardware.   I don't know current pricing,  or if he's still selling the parts.
 
You might also try Dave Bean to see if they have any of Gerry's air boxes left.
 
Thanks to T Engle for this info.

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 Posted: 12-21-2009 11:15 pm
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Jensen Healey
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The key to any airbox is to make sure there's room for the velocity stacks you are going to use. Add a minimum of 1" to the length of the stack for smooth air flow. 

Short stacks = more HP, long stacks = more torque. Any stack is better than no stack.

I made a extended fiberglass inner half so the 1 5/8" stacks would fit. The breather hose goes into it through a filter fitting I found at Kragen. The carbon canister tube also just connects to the airbox.

Kurt

Last edited on 12-22-2009 02:20 am by Jensen Healey

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 Posted: 12-22-2009 07:24 am
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James Sohl
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The Positive Crankcase Ventilation, pcv, valve goes in-line with the hose connecting the vapor separator to the air box.  The idea is that the pcv valve permits crankcase vapor to flow into the inlet air stream for combustion into less harmful emissions.  The pcv valve will close and block flow upon any overpressure in the air box due to popping, backfiring, etc. thus preventing any source of ignition (flame) from entering the crankcase ventilation plumbing.  Crankcase vapor is flammable, and a significant backfire could, at least in principle, cause a fire. 

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 Posted: 12-23-2009 07:31 pm
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Greg Fletcher
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Jensen Healeys did not have a PVC valve, I think that was added much later onto the MK III versions. A preformed hose from the crank case to the air box was all that it came with. I have actually never heard of a fire being started this way, but lots I don't know.

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 Posted: 12-28-2009 06:31 pm
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James Sohl
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Happy Holidays!
Greg is correct on both counts.  Jensen Healeys were not fitted with PCV valves in the early years, if ever.  As to the possibility of an oil fire, I have never heard of such an occurrence.  The emission regulators of the time apparently thought it made sense, and the oil fire theory persisted for many years.  In actual practice, the function of the PCV valve is widely adopted and so long as the valve does not stick closed, they generally cause no problems.  Crankcase emissions are far more chemically reactive than exhaust gasses and will react with uv-sunlight in the upper atmosphere to create far more 'brown cloud' than an equal mass of exhaust.

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 Posted: 05-03-2011 06:59 pm
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sjensen24
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John, I think you showed me your setup to catch oil from the breather tube a couple of years ago.  Can you send me a photo?

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 Posted: 05-06-2011 03:12 am
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John Finch
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Here is a pix showing the bottle and cam breather hose into it. The block breather hose is inserted below the red cam hose. The bottle is a bicycle water bottle with an oil breather filter on top that does a pretty good job of filtering oil out. Bottle is pretty easy to remove to empty. Although it never had more than 1/4" per season. Feel free to stop over and take a look. I'll post another pix too. Hope this helps

John

Attachment: Breather bottle sm.JPG (Downloaded 97 times)

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 Posted: 05-06-2011 03:13 am
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John Finch
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Another less cluttered view.

Attachment: Dellorto Passenger Side.JPG (Downloaded 92 times)

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