It's Broke :(

[SaskStag]

Hi Steve,
The hose I'm waiting for goes from new pump to old water pump area where that big stainless steel pipe runs. The hose has apparently just arrived in Toronto! That's over 2 weeks just to leave the UK and get to Canada! Now it has to make it's way here (3 days drive/ 3 hour flight). I'll have to make it a cup of tea when it arrives, poor thing will be knackered with all this travelling.
Tanya

[Stagsongas]

Hi Steve,
The hose I'm waiting for goes from new pump to old water pump area where that big stainless steel pipe runs. The hose has apparently just arrived in Toronto! That's over 2 weeks just to leave the UK and get to Canada! Now it has to make it's way here (3 days drive/ 3 hour flight). I'll have to make it a cup of tea when it arrives, poor thing will be knackered with all this travelling.
Tanya

Tanya,

You made me smile! Fingers crossed!

Ah, just the one sugar please.....

Regards

Steve

[Stagsongas]

I blanked off the entrance to the water pump top cover using a brass plumbing fitting.

The water return from the heater and the bypass hose from the thermostat housing can be teed together and then need to be teed into the lower radiator hose before the pump.

Another way of doing it is to take a section of thick bolt the same diameter as the inside of the U shaped bypass hose and drill a little hole in it to act as an air bleed. This is pushed up inside the bypass hose and held in place with a hose clip. Very little water will pass through it but it gets rid of the airlock in the water pump housing and means only the heater return has to be plumbed in to the suction side of the pump.

Despite what the instructions for the EWP say, I would leave the thermostat in place but with a 3mm hole drilled in it. This gives sufficient back pressure to work the heater otherwise you may have to spend more on a heater circuit pump. I am using this system both on an RV8 and a TV8. Provided the thermostat is set to open before the electric pump steps up to its second setting it will work fine.

Neil

Thanks Neil,

This is beginning to make sense now. An airlock in the old pump housing is so much more likely to happen when there is no pump in there any more. Added to that, the return from the heater hose used to be on the low pressure (drawing) side of the original, high mounted pump, but now it isn't, so it follows that the return has to be moved down to a position behind the new, lower pump.

I did get the pump plumbed in today but left the control system out for now. I planned to run the pump direct initially, to keep things simple. I was pleased to see Davies Craig suggesting you do that for initial bleeding of the pump anyway. Pity they don't give wiring information for the pump alone, so I got the meter out. For the record, Blue is +12V and Black is Earth -. What you would have guessed, but best to make sure first.

First results were not as good as I'd hoped, I spent a long time checking pipe runs and looking for potenial airlocking in or past the heater return, but at this point it's worth mentioning that my car has more hoses than most. To run LPG, the vaporiser/reducer unit needs a constant supply of hot coolant, otherwise it will freeze very quickly, even in Summer. Although I have just added a new hot supply from the RH head coolant transfer housing to the vaporiser, I can't get the return feed (to the long metal return hose) to work at all. Essentially, this is a duplicated and mirrored system like the standard LH one that feeds the heater which also may not work (didn't check that yet) but there is a common factor there, the return hose position in relation to the new pump.

Now, you may have solved this problem with a few words. If there is an airlock in the old WP housing then not much is going to move up there, and extending the return (and bypass) hoses down to the low pressure side of the pump will tend to pull on the return feed, making the circuit run as it should.

I thought about the auxiliary pump but if I do need to fit one, I'm going to try using a Jaguar heater circ. pump to see if it cures any problem before buying anything. I might have to use that anyway to heat the LPG vaporiser, wiring it opposite to the EWP so it runs when the EWP is off and be off when the EWP is on. just to keep things flowing. That's easy with a changeover relay (from memory, SRB 501?)

Unfortunately I have a lot of other work tomorrow so the target for getting the car running is out of reach now (club meeting and Malvern won't be possible) but that's how it goes, I'm sure it'll get cured soon. It will give me time to think about and absorb what you have said, especially about the blanking, not sure I understand that yet although I do see how the restrictor in the bypass would work.

Anyhow, thanks a lot for the information, much appreciated.

Regards

Steve