[TR] TR4 vacuum port

[Allen Hess]

Thanks for the photo. I do have the same manifold as your TR3B but it  
is not tapped and plugged as yours is. From what I've read, worn  
guides will cause a noticeable fluctuation of vacuum at idle.  
Compression in #1 is higher than 2, 3, 4 (172 lbs. / 165 lbs.) which  
may be due to carbon build up. I haven't tried but can you wiggle the  
stem with the spring in place??

Allen

On Jul 6, 2012, at 4:31 PM, <bill_beecher at flash.net> wrote:

> Maybe I'm all wet but what test would help you to isolate the #1  
> hole valve
> guides by tapping a fitting into the balance tube?  If I suspect  
> that I have
> a valve guide problem, a good wiggle test will usually show it with  
> out
> having to pull the head.
>
> Any reason not to suspect that you might have a broken or frozen ring?
>
> Bill
>
> -----Original Message-----
> From: triumphs-bounces at autox.team.net
> [mailto:triumphs-bounces at autox.team.net] On Behalf Of Allen Hess
> Sent: Friday, July 06, 2012 2:10 PM
> To: "triumphs list"
> Subject: [TR] TR4 vacuum port
>
> I've had occasional but persistent oil fouling of the #1 plug for a  
> few
> years and a hotter plug in that cylinder has helped. Symptoms point  
> to worn
> valve guides. I was going to get a vacuum gauge and try to do some  
> more
> diagnosis. However, I don't have any manifold vacuum port other than  
> the
> advance line in the carburetor. And I'm not sure that would work as  
> it lies
> beneath the throttle plate.
>
> The intake manifold has two bosses cast into the balance tube which
> certainly looks like Triumph was thinking about this but it would  
> have to be
> drilled and tapped. Anyone else been down this road?
>
> Allen