Davies Craig water pump

[dursleyman]

I have acquired a "Stage 2" Sprint motor which has a Davies Craig EWP pump conversion. I have the pump as well but I need some advice on how its plumbed in and how to retain the heater function.
Plan would probably be to use it with a dual controller to run the pump and my electric fan.
Anyone have any experience with this please?

Russ

1980 TR7 Sprint DHC
Dursley
UK

http://tr7russ.blogspot.co.uk/

[Cobber]

Generally, you just fit the pump 'inline' to the bottom radiator hose, it's recommended that you don't rigidly mount it, just let the hose support it.
Davies Craig makes ECUs that will control the pump, fans and auxiliary pump.
You'll need an auxiliary pump to circulate water through the heater core.
Important: Do not run the pump without water running through it (not even for a few seconds to test it) you'll bugger the seals! [xx(]
And nobody want's to bugger a seal, do they? [:0] [:D]

You should contact Davies Craig directly, here in Melbourne, I've found them to be good blokes, who know their stuff and extremely helpful. They'll be able to give you all the technical support you need.
Check their site too: http://www.daviescraig.com.au/


"Keep calm, relax, focus on the problem & PULL THE BLOODY TRIGGER"

80'Triumph TR7, 73'Land Rover (Ford 351. V8),
'89 Ford Fairlane
'98 MG-F, 69'Ford F250.
76' Ford F100

[Stag76]

With the TR7 mechanical pump, the heater return feeds into the pump cover, which is a low pressure point. With the EWP, the block is all high pressure, so the water will not flow through the heater. I silver-soldered a fitting to the plate on the rear of the head to feed the heater, and tee'd the return into the pipe connecting the header tank to the radiator, as this is on the low pressure side. You no longer need the bypass connection between the manifold and pump cover (this allows you to use manifold studs in place of bolts to attach the manifold), nor do you use a thermostat. I plugged the passages in the pump cover and manifold with welsh (core) plugs. The Davies Craig Controller will run an electric fan.

Hook it up, then forget about overheating, blown head gaskets, warped heads, stripped skew gears, slipping impellors, pump cover clearance, airlocks, leaks out of the slot in the block and whatever other evils the clockwork pump is responsible for.

There are some more pictures here :-
http://s991.photobucket.com/user/stag76 ... t=3&page=1







TR7 Convertible
Sprint Motor
MegaSquirt EFI

[dursleyman]

Bruce, thanks for the information, so can I just see if I understood correctly.

Use a take-off from the back of the head to feed the heater. Return can be to the header tank connection.
The small bypass pipe between inlet and pump cover is not required so can be blanked off.
Pump is connected into the bottom hose.
No thermostat - so just leave it out?

It will be really neat to be able to whip the inlet manifold off without having to worry about that blasted bypass pipe. I could easily swap between twin 45's and SU's to see what difference it makes.

I'll post some pictures when I get it all going.

Cheers

Russ

1980 TR7 Sprint DHC
Dursley
UK

http://tr7russ.blogspot.co.uk/

[Stag76]

Hi Russ,
That's correct.

You also have to blank off the hole in the pump cover where the heater normally returns. Mine was threaded so I made an alloy threaded plug, but you could cut and braze/solder the pipe.

An added bonus is that you are far less likely to strip the threads in the head by using studs instead of bolts as you don't disturb them. I heli-coiled all the doubtful threads in the head (which was most of them), then thread-locked the studs in.

Did the controller come with the pump? If not, there are two types...one with a fan control and one without. I removed the standard fan and use an electric fan switched by the controller, which only comes on after 10+ minutes idling, and then runs for 2-3 minutes on our 30+ celcius days.

http://www.daviescraig.com.au/Controlle ... tails.aspx


TR7 Convertible
Sprint Motor
MegaSquirt EFI

[moodyblue]

Interesting topic guys, I've been thinking about an electric pump conversion on a new sprint engine I'm rebuilding. There are a number of forum posts out there on the subject but I've yet to find clear details/sketches/pictures of the conversion. Some say the heater won't work and some say it will, while some say to remove the bypass tube and others say don't, etc, etc, confused
.
All that plumbing and wiring might not be my cup of tea, does anyone know of a compact external mechanical pump that can be fitted, like the Essex V6 as used by Stag owners?
Thanks.

[Stag76]

The heater will definitely work, so long as you feed the return line from the heater to a low pressure point,
not back to the original pump cover, which is a high pressure point when the pump is moved to its new
location at the base of the radiator. If the feed and return to the heater carry the same pressure, there will
not be any flow through the matrix.
The bypass tube should be removed...it can be blocked, but removal is easier.

It's one of the best modifications you can make to these engines.

This link explains the way the EWP works :-
http://daviescraig.com.au/electric-water-pumps

If you want any info etc. please PM me.

[Stag76]

[quote]does anyone know of a compact external mechanical pump that can be fitted, like the Essex V6 as used by Stag owners?[/quot

If you use an external mechanical pump, the problems with plumbing will probably be increased, as you will have to
plumb from the radiator to the pump, then to the inlet on the existing pump cover. You also have to mount the pump and
fit a belt to drive it.
With the EWP, you fit it into the bottom hose between the radiator and pump cover inlet.

An external mechanical pump won't have the temperature control and power saving benefits of an EWP.

The plumbing and wiring to fit an EWP are not really a problem when you consider the benefits.

[Cobber]

does anyone know of a compact external mechanical pump that can be fitted, like the Essex V6 as used by Stag owners?[/quot

If you use an external mechanical pump, the problems with plumbing will probably be increased, as you will have to
plumb from the radiator to the pump, then to the inlet on the existing pump cover. You also have to mount the pump and
fit a belt to drive it.
With the EWP, you fit it into the bottom hose between the radiator and pump cover inlet.

An external mechanical pump won't have the temperature control and power saving benefits of an EWP.

The plumbing and wiring to fit an EWP are not really a problem when you consider the benefits.

Add to the above, the need to fabricate the mounting brackets for the mechanical pump.

Seriously the Davies-Craig EWP is the simplest answer

[moodyblue]

Thanks. Yes it's something I'll have to think about. The pic I posted is from a dolomite site that tells us to leave a modified bypass tube in place with a small bleed hole. So I think what you guys are saying is that I should block the bypass holes completely in the pump cover and manifold, and also block off the heater return on the cover. I could TIG weld a little blanking plate on all three holes. Should I leave the steel return pipe connected to the manifold and instead of going to the pump cover, feed it to the header tank or somewhere? some more pictures of the set-up would be great as there aren't many online. If I do go for this option I could use the stainless manifold studs I've got instead of bolts which would be good.

[Stag76]

I blocked all holes, using Welsh (Core) Plugs.
I don't know what the value of the small bleed hole in the connecting tube is, as the pressure on either
side will be equal, so there will be no flow. Maybe it's for releasing air pockets, but they are not a problem
with the pressure source outside the block.
I felt it was better to remove the tube and therefore disconnect the manifold from the pump cover, allowing
the replacement of the bolts with manifold studs.
If you want the return pipe to heat the manifold you could do as you suggest and reroute the exit from the manifold.
I didn't do this as our climate doesn't require manifold heating.
There are some pictures of mine (not very good ones) here:-
http://s991.photobucket.com/user/stag76 ... t=3&page=1

I've sold this car, so can't take any more pictures, but, if you PM me any questions you have, I'll help where possible.

[moodyblue]

Thanks for the link and info. It looks like your return is going to the header tank. I do have a new original pump which I could fit, it would be the easiest, and neatest option of the three and I've not had any trouble with them in the past other than the early warning drip from the block due to impeller corrosion. I like the idea of manifold studs and ease of access to the external pumps though so I'll give myself a few weeks to think it over. At least I'm getting there.