The V8 Owners Forum -

On my inlet manifold the little water pipe on top and the one under the thermostat housing have been blocked off, Ideally i would like to open up the little one next to where the water temp sensor goes, on a normal manifold are these normally pressed in or what, as mine has threads in it and a plug has bees screwed in. Im going to have to drill it out thought as its seized in there.

Im thinking of just ting to find a bit of pipe and trying to get someone to braise / tig it into place,

What do you guys think?

Im also going to try and get the plug out of the larger one underneath and pipe it into somewhere, im using a electric pump and serpentine front end so it wont go into the back of the water pump like its ment to.



Do you think it would be ok if i just left them blocked up ?? or would i be gettin issues with air pockets, by the way there is NO thermostat in it.

Thankls Slatter

I am wondering why you want to remove the plug, is it leaking?? or do you want to use it to vent the manifold?? Take the thermostet housing off and see if it actually breaks into the water jacket, ot may be just a bracket fixture, venting something as close to the thermostat housing seems a bit of a wasted effort
why do you want to run without a thermostat, the engine will never properly get up to temp, or do you intend to run the pump under thermostatic control,
Ian

I wanted to use it to vent the manifold and have sowhere els too bleed it from, i dont have anywhere on the engine at the moment. and im puttin it into my new racer which had a pipe from the rad to here ( my old racer didnt have this pipe on the rad) .

Reguarding the thermostat, im sure it says im the electric pump instructions to remove the centre of the thermostat so the pump can flow the water freely, The only pipeing it has is header tank to top hose , top hose and bottom hose and rad back to header tank. With having a thermostat in there with the electric pump on constantly the water wouldnt be able to flow and knacker the pump im guessing ... It says in the pump instruction book, but i dont have it to hand.

Hope that makes sense !

The danger with this setup is that the water flow through the heads is limited to how much you need through the radiator - this will control the average temperature fine (as long as the pump and rad are big enough) but will usually leave you with far lower flow through the heads than normal, and this can cause problems with hotspots. If you're sure you want to use an EWP I'd suggest an external stat to control flow through the rad, and leave the pump running flat out all the time to ensure your head are protected. Rover do a very handy entry stat (PEM101020) which would enable you to convert to this setup very easily.

I do like the idea of the remote thermostat.... But when i removed the existing thermostat i was only doing what it says on the davis craig instructions........

3. Continuous Running.
Wire the pump direct to the ignition for maximum cooling - suitable for race vehicles, very hot climates and chronically over-heating engines. This option requires the removal of the engine thermostat and either the mechanical pump impeller from the pump shaft, or the bypass of the water pump pulley from the belt set-up, using a shorter belt.

If i was to put a thermostat in but srill a hole in it so some water can circulate, im just worried i will knacker the pump ?

Slatter wrote:Davis Craig instructions........

Oh dear, I'll say no more.

GreenV8S wrote:

Slatter wrote:Davis Craig instructions........

Oh dear, I'll say no more.

I dont know alot about cooling, hence first of all i followed the instructions, then i came on here to ask for advice.

The main reason for having an electric water pump is so that the engine can be turned off, and the water pump and fans can be left on.

Don't worry about it, GreenV8s hates EWPs lol!!!! only kidding

I have the same davis craig pump and plan to fit a remote thermostat at some point. Just going to dril a 5mm hole in the original for the time being through and run it constantly.

I have had the original water pump stripped bare on the outside, pulley removed, shorter belt for alternator and some metal weld to bung up the hole. Should work a treat. If not; new rad time! (mine is 30yrs old!)

Thanks chodjinn

Thats just what ive done, what u see of the waterpump is just the casing, it runs freely inside.

The problem with these solutions is that they give you very poor temperature control so the engine temperature is forever going up and down with load and road speed, and they give you woefully little water flow through the heads which compromises the durability. There's a good reason why the mechanical pumps consume thousands of Watts and these little EWPs consume hundreds. If you look at the flow versus back pressure characteristics of the EWP the flow falls off catastrophically as soon as you offer any back pressure. They can flow enough to control the average engine temperature but that isn't all you need.

I looked into the electric pump also a while back but eventually came to the opinion about the original mechanical ones that if it aint broke don't fix it!

Another option I someone use a few years back was to add the electric pump as an extra pump - leave the mechanical one in and feed water from the cylinder head to the rad via the electric one. When you shut off the engine the EWP keeps the circulation going, bypassing the thermostat. Presumably the EWP has some kind of non-return valve in line so that water doesn't back up through it when the engine (and therefore mechanical water pump) is running.

I think the guy had done something similar for the oil too.

Just my 2p!

WRT the issue of varying water temp using just the EWP and external/modified thermostat - I'm also going to be using a Laminova water/oil heat excahnger, which will definitely help to regulate engine water/oil temps. Just got to plumb it in correctly first