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Fresh air 4" hose installation tricks

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Michael Oritt

Michael Oritt

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I need to replace the paper 4" fresh air hose and in the past have had problems presenting it squarely to the metal vent fitting and getting it started.
I have a feeling I am not alone here and wonder if anyone has devised a trick to get the tubing started so that it will slip on without tearing up the inner liner and foil.
I am not up for removing the fender....
 
I usually make a small cut--1/2" or so--with snips or dikes lengthwise at the end to facilitate forcing the tube over the flange. It'll be behind the clamp, so no leakage, and if you make it at the bottom of the tube you won't have to see it often. Crude, to be sure, but I've never found a way to stretch the tubing so that it fits over the flange, and if you try too hard to force it on you'll mess up the tube anyway.
 
I am not up for removing the fender..

you can take the shroud off instead :encouragement:
 
I am not up for removing the fender..

you can take the shroud off instead :encouragement:
Click to expand...

I know I am misunderstanding your comment but, as I understand, the shroud is the aluminum section between the steel fenders. How are you removing the shroud without disturbing the fenders. Also, I would like to replace the 4" Cold Air and 3 1/2" Heater ducts and have put it off because of its difficulty compared to level of necessity.

Ray(64BJ8P1)
 
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Makes a good argument for removable side vents__leaves fender AND SHROUD in situ__during 4" hose replacements.

IMG_7239.jpg


Instead of buying the paper hose from Moss, I elected to use the__in my opinion, more durable__neoprene rubber hose from Pegasus https://www.pegasusautoracing.com/productselection.asp?Product=3620

3620.JPG
 
RAC68 said:
I know I am misunderstanding your comment but, as I understand, the shroud is the aluminum section between the steel fenders. How are you removing the shroud without disturbing the fenders. Also, I also would like to replace the 4" Cold Air and 3 1/2" Heater ducts and have put it off because of its difficulty compared to level of necessity.

Ray(64BJ8P1)
Click to expand...
I took it as a joke.

The heater side is easier than the fresh air side because the firewall fitting is at least visible, and the 4" hose doesn't have a fitting at the front bulkhead.

I've done the lengthwise slit in the fresh air side too, but I haven't been able to do the firewall fitting without taking off the fender.
 
Google Spectre 4" ducting. Accordion type with rubber ends that thread on. Joining two is easy - they also thread onto each other. They also have the 3" size - slightly smaller than the hole in the firewall, just add a collar.
 
Healey Nut/John,

Sorry, I obviously missed the sarcasm and took it too straight.

I had considered not using the paper ducts as Randy suggests but only saw alternatives, like drier ducts, to be too inconsistent with the look of the original. Randy's suggested alternative is much closer to the original look and a serious replacement candidate. Randy, would it be practical to spray the silver ribs with flat black to make is less obvious or would the neoprene reject adherence or, with engine compartment heat, cause pealing?

Ray(64BJ8P1)
 
I put mine in with the body in place. But I had the engine out...
i too cut about a 1/2” slit in the end to help it start over the front end piece. I slid the back on first. I struggled with it for a while and quit. Did the heater side. Was having issues with that side when I tried the slit. Worked fine so I did it on the fresh air side and it slid right on.
 
I just completed a job that is only slightly less difficult than the fresh air duct. I replaced the clutch master cylinder. What a bear. To make matters worse, I was replacing an almost new MC that had a manufacturing defect. The supplier sent me a new one without cost, but I still got the fun of installing it. I thought about the fresh air hose the entire time I had my head in the fender.
 
As is shown on page 96 of the Moss catalogue 4-cylinder cars have one length of the 4" hose which snakes along the right side of the engine compartment, behind the radiator bracket and shroud support, then gently curving to go over the nose of the fresh air valve and it is this last transition that is the bear. Six-cylinder cars have two trunks and the challenges of lining them up are probably just as difficult.

I am certainly not a slave to originality but the paper ducting is rather iconic and I am going to give it one try using the technique that Bob S. suggests and/or the adapter that Steve G. illustrates. If these fail and I shred the end of the tubing as I have in the past I will go for the Spectre 4" that BR linked to--it will probably make an easy job of what is just one more example of Austin-Healey torture.

Thanks to all my fellow victims.
 
RAC68 said:
Healey Nut/John,

Sorry, I obviously missed the sarcasm and took it too straight.

I had considered not using the paper ducts as Randy suggests but only saw alternatives, like drier ducts, to be too inconsistent with the look of the original. Randy's suggested alternative is much closer to the original look and a serious replacement candidate. Randy, would it be practical to spray the silver ribs with flat black to make is less obvious or would the neoprene reject adherence or, with engine compartment heat, cause pealing?

Ray(64BJ8P1)
Click to expand...
I wish I had an answer for you; for years I had a remnant of the hose, but after a couple of household moves, I haven't come across in recent memory. You could always order a sample of the smaller hose and do a paint/heat/flexibility test yourself.

To be honest, the hose is so hidden in the car, I can't even recall whether the ribs are visible or not! I suppose I'll have to go take a look...
 
I tend to struggle a bit then it slips on - eventually, but this is the English model and the clutch and brake masters are on the other side.

I have seen a metal reducer that Bill Rawles made ( a bit like the Steveg one but without the taper) and that fits into a smaller duct then that clamps over the stub on the fire wall - seems to work I suppose that you would have to do the same at the other end - I did not notice that bit.

:cheers:


Bob
 
Dayco makes a 4" duct hose #80175. It is a heavy black rubber hose, flexible, with a coiled wire support. A Parts store that sells Dayco should be able to order it for you.
Dayco 80175.jpg
 
I did both my cars with the body off during restoration. I used the original type material as I want the car to look like a car not an appliance using dryer venting .
 

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I also installed mine when I had the shroud and fenders off. Unfortunately I had to unattanch the hose to get the fender bolts on and then reattach afterwards. It was a bit easier the second time.
 
Try Tom's Import Toys for good rubber-based Fresh Air Intake Hose alternative to original paper one. In black with wire spiral as original, Tom said it's aircraft grade from smaller jets like Lear. Super durable, holds shape but compresses and contorts nicely. He even included instruction to ease installation. Still a bear of a job though - more difficult if you have bear-paw like hands. Gonzo
 
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