Air Injection Check Valves | FerrariChat

Air Injection Check Valves

Discussion in 'Mondial' started by moysiuan, Jan 10, 2022.

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  1. moysiuan

    moysiuan F1 Rookie
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    Nov 1, 2005
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    Canada
    #1 moysiuan, Jan 10, 2022
    Last edited: Jan 10, 2022
    I am doing some winter projects on my 1988 Mondial 3.2 cab, and decided it is time to renew the large braided hoses that handle the air injection, and the crankcase ventilation. Will do a larger post on the learnings from doing this but for now I have a question about the check valves.

    These are no longer available from the usual parts suppliers, other than some reproductions at very high cost. The replacement alternatives that are available are mostly the Standard Products, part AV7. Other brands out there like Moroso generally look like they they are likely made by Standard anyways, under private label.

    The hose nipple is 5/8 inch rather than 3/4 inch, but a bit of high heat silicon tape on the fitting and the 19mm (3/4 inch) hose will clamp down fine. These are probably the most typical replacements used on our cars these days, I understand previously there were some now discontinued GM and ACDelco parts that were used and had the correct 3/4 inch hose pipe fitting. I think a version in black painted colour GM one is still available, but they are all made in China and I doubt the quality is any different than the Standard one. Which is to say, not very good quality.

    I put a couple of these on my car two years ago, and was noticing a pronounced rattle on start up. I narrowed it down to the check valve, hence why I decided to go and do new hoses and such as well as I thought I might be getting some sort of air leak. The old original hoses have hardened up, so time to renew regardless.

    The two year old check valve had failed, probably after about 5,000km.

    I pulled one apart to see what is in there. A simple rubber check valve, with a cup on the exhaust side to protect the rubber. The rivit of the metal cup to a metal support web was loosened, and allowing the inside valve mechanism to rattle. The rubber was also hardened and not able to seal. Looks like the heat is hard on this part, but still I view this is a premature failure.

    Here is my question, the new ones that I bought as long term spares two years ago also rattles when I shake it by hand, less so than the failed one but still rattles. It does seal when I blow through it. Seems like the internal cup rivit is designed to have some loose movement?

    Is this normal for a new check valve? I don't want the stacatto noise on start-up again, although maybe that was from the rubber not sealing rather than the design itself. The rear bank one is easy to access, and I Use antio seize the last time so no trouble to remove. But the front bank check valve is not very fun to access and replace, so I would rather not put on some defective parts and have to repeat the project again.

    I enclose some photos of the old failed one. The first pic shows the rivit that is loose. The second shows the cup and deteriorated rubber seal.
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  2. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
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    Jan 11, 2001
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    Steve Magnusson
  3. 350HPMondial

    350HPMondial F1 Veteran
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    Feb 1, 2002
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    18 mi from the surf,, close to Pismo, CA
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    Edwardo
    I seem to recall, these are also MOPAR. 1988 Jeep
     

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