the Sanden air con is super, only drops 150 rpm when ticking over, 149 motorway miles and 21.7 av. but when I toe it at fifty in top I get a clunk from the a/c vac tank and the aircon goes off for the couple of second that my foots down, is this a problem with the one way valve would you think, the equivalent of a vacuum diode?

 

My thoughts are if you had placed some mention of air conditioning in your post title you may attract more responses.

I am less familiar with earlier models so not sure of vacuum tank you refer to.

Regards engine rpm dropping 150rpm at tickover when air conditioning on that's not meant to happen.

I believe extra air valve (right hand bank ) is meant to be switched by air conditioning to allow extra air bleed into right bank inlet to prevent engine revs dropping at idle due to extra load on engine.

 

I would say that the one-way check valve is a likely culprit, yes

Cheers
DD

 

I agree.


Cheers
DD

 

Thanks all. I will worry about the tickover drop when it suits to throw more money unnecessarily at it but I will say I wouldn't have known how much better the sanden was
(150 rpm less strain on the bottom pully etc) if the air valve was working correctly, and the fact it isn't working correctly must be economical.but thanks for pointing that out Paul.
DD I will source a new vac control. Asap

 

RGP
Very glad the Sanden worked out well. Mine was a huge improvement over the old OEM job. As for the one way valve, are you and Doug referring to the one-way valve that sits in the vac line between the manifold and the vac reservoir, and which is tucked up against the bulkhead in the engine bay?
If so, it is easily changed.
Greg

 

I don't know if the XJ-S does it too, but on all my Volvos so far, when you floor it, the AC would uncouple in order to free up power to use. Once easing off the gas, it would reengage. Most of the time it should barely noticeable.

 

yes Greg
its behind the washer bottle on the rhd car when I blow through it I can actually make it do a raspberry sound on the direction it should be sealed, if you know what I mean,

 

But Volvo's need all the help thay can get. Nasty that I am.

I reckon a Volvo motor is good as a starter motor for a V12, haha. About the same power.

I ditched that "Extra air valve" when I fitted the Sanden, as the drag was about 70% reduced as compared to the Monster.

 

I don't think mine has ever worked and iv owned it 23 years now, it almost stalled when the Henderson was switched on and I always thought it should have a method of avoiding this,


seen at Haynes museum

 

In my XJS V12 days I changed things a bit.

I ran the transmission kickdown from the of throttle enrichment switch. That left the original kickdown switch lonely and unused. I converted it to a an a/c compressor cut-out switch. So, at 100% throttle, the compressor would disengage.

The old A6 compressors are tough old dogs but really sap the power compared to newer designs....which is one reason GM ditched 'em back in the day

Cheers
DD

 

Now, thats an ENGINE.

 

grant there was no v12 engine jaguar in there at all!

 

That confirms the banter for years, "Haynes Manuals are next to useless".

They do need some educating, me thinks.

All and sundry keep going warm and fuzzy over the E Type, I never got that feeling.

 

My Jeep has a compressor in/out button, as did my weird 94 Olds Achieva. .The latter had a slick little DOHC 4.


That is the marvelous Duesenberg, circa 1930. Big OHV straight 8.
some with a centrifugal blower. Very fast, although rumoured to have
"weak" bottom ends. Easily a million dollar example....


I like the V12 powered T bucket. Must be a handful.


Back in the day, some MG TD owners tired of the little fours and installed Volvo "tractor" motors. Others went to "hottted" Ford V8 60's.


Carl

 

Gramt, the E-type hype is a bubble... No Jag can be worth so much... Not even that weirdly handling E-Type. The torsion bar front suspension, a halfmonocoque and a variety of awkward bpdy shapes... Worst being the Series 3 2+2 seater...

If you say to someone herr 'I've got a classic Jag' people say 'Oh you habe an E-Type?'

 

I get a lot of " oh, that's a Real JagUar... " because of all the jaguar X-types ford mondeo's! Some times I have to open the engine cover and give them a gander at the v12

 

Jez, just noticed my spelling. I am awfully sorry for my cruddy spelling in my last post...