Davies Craig water pump plumbing...

[shaunroche]

Hi chaps - I've had some good advice from a few fellas on here re the plumbing of the electric water pump....you know who you all are!....I'm getting close to fitting one now so would appreciate a few comments on the set up I am proposing in the image below.

I realise it may not be correct so am happy for you to put me right, as always!

I'll run it in conjunction with a controller and an electric fan and minus the thermostat, plus an electric cabin heater with simple in/out connections.

Am I correct in assuming that as I'm running Dellortos, I won't need a line in/out of the manifold....or will I?

Feel free to draw me a sketch as I'm not that bright remembering that a picture speaks a thousand words!

Image removed

I should add that I've fitted the Saab 9-3 radiator.....

[Carledo]

Dunno about the DC pump, i've never needed one, but you will need a proper header tank which fills the engine through the bottom hose and has an overflow pipe to it from the small bore fitting on the top right corner of the Saab rad. Top choice seems to be a Volvo one (740/850?) with a level sensor. It's mentioned in several threads on here but there is a "how to" thread by Ian (Sprint95m) I think he also uses the Saab rad and (along with me) was one of the first to do so.

Steve

Just been looking again at your diagram and I don't think the heater will work like that, I think you need to use the TR7 back of head outlet pipe to feed it and put the return to the W/P housing. No doubt someone who knows more about it will correct me if i'm wrong, but by my reckoning the pump draws cold(er) water from the bottom of the rad and pumps it into the block so your system would have it continuously circulating the coldest water in the engine bay through the heater, not the best idea!

[shaunroche]

Cheers Steve...it's a bit of a minefield, as Ian says something a bit different so still not sure....viewtopic.php?f=4&t=29334&p=275208&hili ... ig#p275208

[Carledo]

I think he may be correct and it would make more sense to put the return below the water pump. Leaving it on the pump cover would mean it was pressurized by the pump which will just stall the water in the heater cos the pressure would be the same at both ends. I was trying for a solution that didn't need any blanking off or extra fittings but that's obviously not possible. I guess the best compromise is to tee into the hose from the header bottle somewhere down near the bottom hos then tee the lot into the bottom hose, that would at least save having 2 rad hose to heater hose size tees in the bottom hose. I'd draw you a pic but my scanner is fubared!

Steve

[shaunroche]

So after having another look, a number of things are becoming apparent; I definitely need a header tank with a top and bottom hose, or can I retain the standard one?

If I need a double one, the dotted line would be needed?

Additionally, rather than have an outlet coming out of the back of the head, can I not just have one coming from the manifold? isn't this a shared gallery?

So, how does my revised layout look now then?

Image removed

[Carledo]

So after having another look, a number of things are becoming apparent; I definitely need a header tank with a top and bottom hose, or can I retain the standard one?

If I need a double one, the dotted line would be needed?

Additionally, rather than have an outlet coming out of the back of the head, can I not just have one coming from the manifold? isn't this a shared gallery?

So, how does my revised layout look now then?

Bin the stock header, yes the dotted line pipe is correct. The second pipe from the top of the header should go to the pipe outlet on the top right corner of the rad (not shown on your second drawing) and blank the tiny outlet on the stat housing. On standard SUed cars there is a water gallery in the head which enters the manifold ahead of No1 cylinder port and exits somewhere under the centre/rear of the manifold water is piped from there to the heater inlet via the so called "H" pipe. If your Dellorto manifold contains this gallery then by all means use it! If not then you'll have to put the TR7 takeoff on the back of the head.
Damn I wish my scanner was working, it's so much easier to draw it than explain it!

Steve

[shaunroche]

Brill Steve thank you! I understood all that so well done for explaining it all!

Upon inspection the manifold does not have a gallery so it'll have to be the back of the head thing.....I've looked on Rimmer's and I can't find anything immediately suitable (it might be there though....somewhere! )....what exactly is it off or do I have to make one?

BTW...for the header tank would something about 1.5 litres be suitable?

[Carledo]

Brill Steve thank you! I understood all that so well done for explaining it all!

Upon inspection the manifold does not have a gallery so it'll have to be the back of the head thing.....I've looked on Rimmer's and I can't find anything immediately suitable (it might be there though....somewhere! )....what exactly is it off or do I have to make one?

BTW...for the header tank would something about 1.5 litres be suitable?

I believe Ian made his own take off (its mentioned in that thread you quoted) but it is standard on all TR7 2.0 ltr engines so shouldn't be a problem getting one. I think the reason Ian made his is because the TR one is 5/8" bore and Dolly hoses are all 1/2" bore.

Viz the header, anything you can find that fits will do but it needs to be high up in the engine bay, such that the water level in the header is as high or higher than the filler plug on the stat housing. The favoured spots are between strut housing and bulkhead either side, but the fusebox needs relocating if fitting to O/S. 1.5ltr should be fine. I've done a quick search and the one most people fit is from a Volvo 850, fits in nicely and has a low level indicator sensor.

Steve

[sprint95m]

Sorry, haven't been following this.


Just to clarify and concur,

Volvo 850 header tank is good because its shape allows for all the coolant within to be above the engine if sited on the NS strut top.
It also comes with a (desirable) low level sensor.

Bottom connection from header tank is plumbed into the bottom radiator hose BEFORE the water pump.

RE. the heater supply, I used the hosetail from from an early 6 vane pump cover (these are also on some T2000/Vitesse engines). Early 1850s like mine
have plugs in the water transfer housing.... simply replace the plug with the hosetail. You cannot use a TR7 transfer housing on an early 1850.



Ian.

[shaunroche]

Cheers fellas!

It all depends on which way the water flows.....the set up below would suggest that the water is flowing anticlockwise....if it is flowing clockwise then the red line would be used?

Am I right in thinking that for the heater, I can use the hose tail that is on the engine water pump housing and also the threaded port that's in the side of the block?

Additionally, I only use one big hose of the three that are on the thermostat housing and blank the rest?

I realise that a volvo tank will fit but that would be a bit too modern....if someone would be kind enough to supply me with the dimensions for it I could get one made up.

Image removed

Rather than scan any diagrams in I just take a photo with my phone and put it in the thread in the usual way Steve!

Once again, thanks for all your help!

[sprint95m]

Cheers fellas!

It all depends on which way the water flows.....the set up below would suggest that the water is flowing anticlockwise....if it is flowing clockwise then the red line would be used?

Am I right in thinking that for the heater, I can use the hose tail that is on the engine water pump housing and also the threaded port that's in the side of the block?

Additionally, I only use one big hose of the three that are on the thermostat housing and blank the rest?

I realise that a volvo tank will fit but that would be a bit too modern....if someone would be kind enough to supply me with the dimensions for it I could get one made up.

The coolant flow is from radiator bottom spout to the engine.

No, you cannot use the hosetail on the old water pump cover as the heater supply (as this will result in no flow to the heater).
The best place is the water transfer housing at the back of the cylinder head.

No, you should retain the thermostat housing plumbing as it is. This is important because changing it will make it more difficult to bleed the cooling system.
Connecting the radiator vent directly to the header tank will allow only the radiator to bleed, not the engine. Mind the radiator is lower than the engine.



I can't understand how the Volvo header tank is too modern , since this conversion will be using an electric water pump.




Ian.

[shaunroche]

The coolant flow is from radiator bottom spout to the engine.

Good - so the bottom pipe from the nice header tank (not the minging plastic one) goes into a tee piece in between bottom the rad hose and EWP.

No, you cannot use the hose tail on the old water pump cover as the heater supply (as this will result in no flow to the heater).
The best place is the water transfer housing at the back of the cylinder head.

Good - is that this one from off a TR7 that Rimmer's are alluding to? http://www.rimmerbros.co.uk/Item--i-TKC1242U It will fit a Sprint head then?

No, you should retain the thermostat housing plumbing as it is. This is important because changing it will make it more difficult to bleed the cooling system.

Awesome.

So:

A - Heater piping: Hose tail in block and hose tail from back of head.

B - Header tank piping: top hose to Thermo housing, bottom hose to tee in between bottom rad hose and EWP.

C - EWP Piping: hose direct from EWP into old water pump housing on block.

D - Top hose: from thermo housing to rad top hose.

E - Thermo piping: Final hose tail on thermo housing is blanked off.

Fingers crossed then, it'll look a bit like this....

Image removed

I can't understand how the Volvo header tank is too modern , since this conversion will be using an electric water pump.
Ian.

We'll agree to disagree then

[Carledo]

I dare say one of the aftermarket performance part people will flog you a pretty aluminium header tank for only about 3 times the cost of a Volvo one...... but if that's what you want!
I think the latest diagram is almost right, the only error now is that the heater return should go to the same (or nearly the same) place as the lower header bottle pipe. Basically the heater needs to draw its water from the hottest part of the engine, ie the rear of the head and return it to the cold side of the water pump so the W/P can draw it from the heater and maintain circulation. Sorry for the bum steer on the overflow, my engine sits lower so it works a different way, I should have realized this!
I will try a photo of a drawing as you suggest, if I can get my ancient and palsied hands to stay still enough to make it legible, i'll post it!

Steve

[Carledo]

Camera flash error.... I think! Best I can do for now!



I've added flow arrows in the hope that it makes more sense!

Steve

[Carledo]

An add on, the hosetail from the waterpump housing WAS the original heater return but will no longer work because you have moved the water pump itself to the other side of the hosetail!

steve