[TR] Triumphs Digest, Vol 5, Issue 25

[Ben Zwissler]

Guy,

There should be a spring, a steel diaphragm with a vertical pin and a 
rubber diaphragm inside the unit.  Modern PCV valves control flow to the 
intake manifold to some optimum amount.  Usually there's a spring/valve 
that only opens when there's pressure difference to pull it open and 
then if flow gets too high there's the other side of the valve closes 
when forced up all the way against the spring.  I'm not sure the TR4A 
has the flow limiting feature as if you use the vented cap so much air 
will flow through the PCV valve that you'll have trouble keeping idle low.

AFAIK the internal parts are available from the major vendors.

Ben.....


Ben Zwissler
bjzwissler at gmail.com
Columbus, IN
1966 Triumph TR4A
1973 MG Midget
1980 Triumph TR8
2007 Mazda RX8
2002 Yamaha FZ1
2003 Honda ST1300


On 1/19/2011 10:50 PM, triumphs-request at autox.team.net wrote:
> Message: 5
> Date: Wed, 19 Jan 2011 16:40:46 -0600
> From: "G.D. Huggins"<guy at genfiniti.com>
> Subject: [TR] TR4A - PCV Question
> To:redRiverTriumph at yahoogroups.com,triumphs at autox.team.net
> Message-ID:<5B28DE52-FDA7-415F-9DAE-A9A74C7FF7EC at genfiniti.com>
> Content-Type: text/plain; charset=us-ascii
>
> All,
>
> I've got a quick question regarding the PCV unit on the TR4A.
> Inside it has a diaphragm sitting atop a spring.
> It seems like something should be between these two parts.  Is that so?
>
> Also, how does this thing work?
> I know its purpose is to pull excess air from the crankcase and recycle it into the intake manifold.
> Is that flow supposed to create some sort of vacuum, actuating the spring, moving the diaphragm?
> Any explanation would help.
>
>
>
> Cheers,
>
> Guy D. Huggins
> 1965 Triumph TR4A
> CTC 63569LO
>