Classic cars forum & vehicle restoration.

[ajb100]

Hi guys, what pressure cap would be needed for an e93a?

Thanks

[Penguin45]

Pretty sure it's 4 lbs.

P45.
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'67 Wolseley MkI 18/85, '70 Austin MkII 1800 The Landcrab Forum.

[Rick]

[ajb100]

From the limited knowledge I have, I don't think it did, but it must have had something to fill it. I know the later cars started with a 4lb cap, but didn't know if that went back that far.

[alanb]

The e93a had a thermo-syphon system so therefore it is not pressurised, later cars such as the 100e that were fitted with a water pump had a pressure cap.
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old tourer


Morris 8 two seater

[Rick]

Yep, all the E93A-engined cars I've had, from bog-standard engines in E83Ws to tuned jobs in Specials, have just had the plain original (non-pressurised) brass cap, with "Enfo" on it.

I may still have one or two about the place.

RJ
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[ajb100]

Thanks for the info, so the system is totally open?

[Rick]

[ajb100]

It has an electric water pump fitted instead of the crank driven one.

Looks like I'm going to have to re design my head take off to allow for an expansion tank as if been under the impression the system was sealed.

I've found this picture on this forum of a header tank design I'll have to emulate

[ka]

Spot on with the comments already posted. A water pump was available as an option, and also a top hose to take a thermostat, but I would imagine they have long been unavailable.
In standard trim the E93a was thermosyphon, which works quite well in normal temperatures, although there is always the hot spot around the exhaust valve side of the chest. These would not have a pressurised cap, but may have a catch/expansion tank from radiator. The optional, permanently driven water pump gave more efficient cooling around the entire engine, and the dependancy on the exhaust/inlet manifold hot spot even more important, as without a thermostat the engine would not reach operating temperature either as quickly as a stat allows, of even at all.
Using thermosyphon, the engine cooling was dependant a a larger amount of water in the system, therefore larger radiator and attributed weight.The water pump/thermostat system with either electric or engine driven fan allows less water, therefore weight and cost. The engine temperature became especially important with the introduction of heaters in cars, possibly accounting for the 100e running a stat, fan and pump, and a pressurised system, (an increase increase in pressure raises the boiling point of water/fluids by a few degrees).
It is also interesting when the recommended engine temperature is studied. Most thermostats run around 88 to 93 degrees, which would probably indicate the optimum running temperature of the engine, diesels used to run cooler then petrol, but with modern engines and fuels I am not so sure this is the rule now.
For interest my thermosyphon 10hp runs around 90/95 degrees, (I have a combined Smiths temp/oil pressure gauge), and yes I do run a water pump, an electric after market item on a separate switch/relay that I use when going up hills, sat in traffic, or the occasional warm day up here! I did have the optional electrical thermostatically controlled switch fitted, but trusted a manual switch and driver control more.
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KA

Better three than four.

[ajb100]

There's a cap on eBay:

http://pages.ebay.com/link/?nav=item.view&alt=web&id=331486357453

But it looks sealed to me, there's no were for it to vent through the cap.

[alanb]

It doesn't vent through the cap it vents via the overflow,
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old tourer


Morris 8 two seater

[ajb100]

Gotchya, thank you all