The V8 Owners Forum -

It could indeed be an airlock as its only been filled on the level.. When I originally filled the coolant I had the nose of the truck in the air. I will change the thermostat as I have it and need to rule it out anyhow, and also reverse down my drive hich will point the nose higher than the rest of the engine bay!

Cheers!

Darkspeed wrote:I would never advise anyone to run without a stat - this can in fact cause overheating.

Without the restriction of the stat the water flow can be too high and pass through the rad without giving up enough heat and return to the engine not cooled.

Race cars running without a stat fit an orifice plate in its place

Andrew

I agree, maybe its OK as a quick test but its not a good permanent solution. The stat or a restrictor plate create water pressure in the heads that is ABOVE the blow off pressure of the rad cap. This pressure prevents steam pockets and "packs" the coolant around the combustion chambers.

The Eddy performer manifold would benefit from the "drilling holes" mod to. EDIT...Why did I think you an an Eddy manifold? Doh!

have a read of this (halfway down the page). My mate nicked the info off this site, he had massive cooling problems before this mod. I also told him to fit a 74 degree stat. His car runs at 80-85 now I believe. (My holes are bigger than the "4mm" stated, more like 7mm)

http://how-to-build-a-pilgrim-sumo.wiki ... e-plumbing


Pete

What type of carbs/inlet manifold are you running?

harvey wrote:What type of carbs/inlet manifold are you running?

Twin SU HIF6's on the standard Manifold.

Fitted the new stat, and am going to see if the one I took out opens in a pan shortly. Have been out for a run and everything seems to be running ok.. Although I had taken it easy and its a cool night. Seems better, left it idling for a few mins and had no oil lights.. Although somethings making noise, either the alternator or the water pump. Spinning both seperatly made no noise but when they were both spinning and engine revd the was a bearing noise.. Ill try and find a spare alternator or idler to narrow it down!

So maybe the waterpumps not best!

In that case make sure that the bleed pipe that goes from the centre of the manifold to the top of the rad or expansion tank, is clear. The metal pipe in the manifold gets blocked and traps air in there causing the problem you are having.

Yeah i had that problem the first time I started her up after the rebuild. I know thats clear now..

Just warmed thermostat up in a pan and it opened up and closed quite normally, So I will try blocking off/restricting the heater matrix pipes tommorow

The thermostat that you warmed in the pan, that opened and closed quite normally. I assume this was the one removed from the engine?

If so, the behaviour that is displayed is by no means a guarantee that it is not the cause. Themostats once damaged by overheating can function fine on a number of occassions afterwards, and then fail,..closing during operation and resulting in a massive increase in engine temperature.

I know this from having experienced the very same some years ago with my 3.5. In my case I was lucky, replacing the thermostat always cured the problem.

Ron.

RoverP6B wrote:The thermostat that you warmed in the pan, that opened and closed quite normally. I assume this was the one removed from the engine?
Ron.

Yup. Well I am taking it down to my mates garage this morning and will run a infra red thermometer thingy over it for hot spots and do a compression test. Hopefully the new stat has cured it though

I'll let you know cheers

Well after lots of testing and running up and down the road and idling I have come to the conclusion I need a bigger radiator fan

I tweaked the mixture (it was rich) but probably had no bearing. It seems to run at around 90 degrees most of the time and maintained this temperateure at idle. However I knocked the fan off and it creeped up to 100c. Switched the fan back on and and it wouldn't pull the temp down..

Its a small fan so I need a bigger one anyhow! Hopefully that should sort it out. I'll post back once its done

It's a Series radiator isn't it?

The only situation that I've known them to be adequate is when the fan is the engine-driven fan. Even with a 16" electric fan, you will probably struggle.

Chris.

Not true

I run twin 11 inch units

When it gets hot the temp will come down in a minute or so!

But it is a £400 rad said to be suitable for 600hp
Size 30 *60 cm (approx) 4 core ali unit


Ian

ChrisJC wrote:It's a Series radiator isn't it?

The only situation that I've known them to be adequate is when the fan is the engine-driven fan. Even with a 16" electric fan, you will probably struggle.

Chris.

Yeah its a series. I have bought a bigger fan so will see how myc of a difference that makes. The existing fan is fairly small and I had been advised (by you i think) too change it anyhow. SO Maybe I should have taken that advice earlier on

ANyhow the radiator is the four core MOD model so should be man enough! If not I may try and shoe horn something else in there!

I tried a series 4-core rad on my 4.6. No good!

Now I have an LDV 300 series rad which is the full width between the wings, and with an extra core (3 I think).

Works great!

Chris.

What fan are you using with that radiator?

Im a big fan of engine driven cooling, but theres no space so must use an alectric!

Up until recently I was using a Pacet 16" with the LDV rad:



I found that to be just about OK.

Now I've got a GEMS timing cover, so I've got a massive engine driven fan too!

Chris.