OK I think I know what's happening. We have installed the header tank on the wrong side of the thermostat. So the thermostat opens when warm, traps the water in the header tank when it closes and doesn't let it back down after cooling as it has closed. Maybe?

Useful link that I'm still reading.

http://www.miata.net/garage/CoolingSystemProblems.html

I get air trapped in front of the thermostat as this is higher than the radiator. It is slightly lower than the expansion bottle.

I have a bleed screw here to help get the air out.

I was thinking about moving my header connection to just in front of the thermostat.

Paul: do you think it would be better to connect it to the bottom hose?

David

The radiator I'm using is a Polo rad which doesn't have a cap is this the rad overs are using?
I haven't started mine up yet I have mine connected the same as you Guy's so I expect mine is going to do the same.
Regards Mick

I have used the same radiator

David

That's good then I used a Polo expansion bottle with the bottom connection tee into heater hose connection and top connection taken to top of rad does that sound okay?
Regards Mick.

I think a bottle feed to the top hose that goes from the front of the engine to the rad would duplicate the factory system best.

Not sure what you mean if you are talking about the top pipe from the expansion bottle this joins the rad next to the top hose so taking it to the top hose would be the same, if you mean the bottom connection of the expansion bottle this would be going up hill to the top hose I think so it would not want to fill the system.
Regards Mick.

I hope this image makes it clearer. So rather than taking the bottom header tank feed to the heater hoses. Take it over to the top hose I have marked with a red line.

I will have a look and see if I can do that but I don't think that there is room to fit the tank higher than the rad
Regards Mick.

I am going to keep my header tank on the scuttle and run a pipe to the point marked on the diagram above

I have checked the heights and the header tank is 2 inches higher than the thermostat

David

The car I built for Teamtrain used all the old Ginetta parts for the cooling system,basically a Zetec engine,header tank feed to bottom hose and top hose to thermostat housing and return pipe in top hose to header tank above water level and no cooling fan at the time,ran hot but no problems as Zetec engines do run warm.

I think its just the way you have it routed David that could be the problem,cant remember exactly the way a thermo syphon system works but the idea is that it cools the water (obviously) as it goes through the rad from top to bottom or vice versa if you get what I mean and wrong routing will cause you grief.

I did my mods as described above. I ran the engine the allow it to warm up. I didn't put the cap on the coolant bottle. After about 5 minutes there was a surge of coolant that overflowed out of the top of the bottle. Is this from the thermostat opening expelling air ? Anyone got any ideas?

Thanks

David

Have you read the link Chris put up? there is a mentioning there about venting and overflowing.
Regards Mick.

The system is meant to run under pressure to hold the water against the cylinder walls otherwise the water will boil away from the hottest point's,cylinder walls and cyl head,so not having the cap on will allow it to boil.

Air will cause the same problem as there is no heat transfer to cool it.

Thanks

I think the best thing will be for me to take it our fun a spin this evening (with 10 jumpers on)

Ps have you been doing much flying lately? I went for a trip in a warrior the other week - stags shaw mast to Hexham the coast and back along the Tyne with my mate and son. Very very bumpy but good fun. It's gote thinking about selling the roadster to start a home build kit plane!

WHAT!:eek: You must be a serial project person like me.:cool:

Dual chk Friday morning 25 mins,Sunday 1hr 25 to Sherburn,1hr around Sherburn and 1hr 10 back to NCL in Warrior so Yes just a little.

Keep the car !!!!!

Was going to fly along the wall the other week but inversion had it covered and vis to low so flew up towards Otterburn then east and back down the coast.

Fly In at Eshott soon.

Are you two in the RAF?

No,I manage a garage in north east. :cool:

Cool, what do you fly? A picture would be useful. I've always wanted to get into microlights as there is a club and landing sight very near and I see them up there every weekend (weather permitting) in the summer. Have to wait till the kids have grown up though.:rolleyes:

Piper Warrior PA28/Cessna 152/172 Piper commanche twin engine,all good clean (expensive)fun.

Where abouts are you ?

Formby near southport seems people really like flying around here. There's Woodvale airbase too a lot of flight training goes on there and then every summer all the planes for the Southport air show fly over head and some land at wood vale so the air is pretty busy around here. Best thing is seeing a lancaster bomber fly over with a couple of spit fires accompanying. Got goosebumps just typing that. :D I'll take a look at your plane later.

Oh yes we see them a lot doing flight training from Woodvale, I think.

They do the sunderland air show,have been in the air behind Lanc,Spit and Hurriacane and landed after them,awsome sight.

The climb out from runway 25 is in view of my house and even the 4 year old granddaughter know the planes from there.

Get yourself up there.

One day, when I get bored of living! lol

Fly in
 

We should do a fly in. I fly Warriors out of Wellesbourne. They do a mean fry up if you're ever in the area. :)

They have a Vulcan that's pretty impressive too. They did a fast taxi at the weekend
http://www.xm655.com/about.php
http://evergreen.zenfolio.com/p862318446#h17f716a3

Looked into aircraft kits before I decided to go with my build and decided it was a too expensive. If you were closer, I'd say we could team up!

J

I took my car for a spin around the twisty roads next my my house and around Newcastle airport. Part way during my adventure I managed to tag along with 3 other sevens. After following them I now know how fasty car will go around bends!! I really still should check my suspension alignment soon !

David

More tweeks
 

Tonight I installed one of these to my build....

http://www.demon-tweeks.co.uk/perfor...hift-light-pro

I was finding it hard to look at the Rev counter in the middle of the car with all the wind, noise and being generally flung around. The omex is more accurate than the mx5 gauges as well.

Now I can look ahead and wait till I get flashed.

I didn't pay that much though. I won a second hand one on ebay for £15!!!

David

That's a nice price! I couldn't drive mine fast without hitting the Rev limiter constantly. They make a big difference when tackling the twisty bits at high revs. I'd say it's almost a must have bit of kit on such quick reving cars.

This is the one I got.

http://www.digital-speedos.co.uk/4-l...ight-129-p.asp