The 1957 Dope Dauphine

[Adey]

thermostat turned up about an hour ago, so i tested it a pan to make sure it worked then fitted it. When driving from cold the temp seemed to stay in check for longer but once the heat set in its definitely running above 92c all the time.

I did have a chat with a friend who makes aftermarket rads and intercoolers who said that my rad was pretty cheap but wasn't sure if in his opinion it was an airflow issue or radiator design issue. He has offered to sort me an aluminium rad but id rather deduce what the actual issue is before jumping in with something bigger that could just be masking another issue or might not help at all.

So on my list is a cooling issue/rad/airflow or an engine issue/hg/crack somewhere i guess? a few in the know have said i shouldn't have an issue running it the way i am as I'm running a near standard r8 engine. They did have mechanical fans though.

Still awaiting the temp probe and the temperature gauge so still just guessing currently.

 

[DaveL485]

engine issue/hg/crack somewhere i guess?

Would be pressurising though if that was the case?

 

[Adey]

Would be pressurising though if that was the case?

Id expect so. It gains pressure but its a pressurised system, i can squeeze the pipes though whilst melting my fingers. Im loosing no water or oil and have no mixing or running issues. Thing is not many people do this over here and most that did it on the continent did it so many years ago i cant find actual credible information on running temperatures. Reading old posts R8s regularly run 95/100ish though that can be improved on with better fan units. I might make a drastic change to timing and see if it has an effect. My oem gauge looks to be showing 100ish but as its old and just red or green and designed for a different engine, with the sensor in a different location i cant take that as gospel.

The infrared probe i ordered still hasn't turned up and the replacement sensor for a spare digital temp gauge i ordered has been cancelled so still unsure how hot it actually is. pissing in the wind really.

 

[DaveL485]

When I say pressurising I mean popping the safety blow-off in the expansion tank.

 

[Adey]

oh defo not. hasnt even on test drives with the oe temp gauge reading well over.

 

[Adey]

These were posted on facebook in a french group i follow, translated a little but was done for evacuating heat, getting better flow and looking cool.

So I've done similar to test it out.



I've also sorted a loose gearknob issue I've had for a while. The previous owner fitted an old small engine piston but it had come loose. I tapped an m12 hole put a bolt in then drilled and tapped that to m6 to suit my twig like gear stick.

 

[andybond]

Am I allowed to say that I think the boot lifters are just for aesthetics? I dont think they will offer any better cooling? Infact, I dare say a minor decrease?

If you want optimum cooling you need to create a high pressure area infront of the rad ( you have done this already ) and box off the area behind the rad as much as you can to create a low pressure area. The vents in the back are perfect to keep air gently moving in the low pressure area.

 

[Adey]

Yeah you can. Without correct measuring we will never know. You could also go with raising the boot lid in that manner creates a bigger low pressure area behind that then causes the air to be draw through more? Bigger high to low pressure difference would give more flow.

 

[andybond]

Yeah you can. Without correct measuring we will never know. You could also go with raising the boot lid in that manner creates a bigger low pressure area behind that then causes the air to be draw through more? Bigger high to low pressure difference would give more flow.

It doesnt always work that way with low pressure. I was basing my experience on front mounted engines.

From my understanding there should already be a freaking large low pressure area behind the car caused by the drag, but it then goes into very turbulent air. I would also expect there to be an influx of air and therefore increase of pressure in the area marked red here :



and the yellow area marked will have swirling turbulent air trying to get back in. The design , although at the arse end of the car just looks exactly the same as a bonnet raiser to me

 

[Adey]

Quite possibly, ill see how it effects the car and will report back. The bigger the rear wall of the car the bigger the vacuum created directly behind it. Air could get dragged in at the sides and pulled straight out with the rest of it. The easiest way to check would be to measure the pressure in there with some sort of diy manometer. Maybe in the future ill try something. Though for a 50bhp 60mph tops car all im worried about really is it staying cool. If it does that im happy.

 

[Brigsy]

Sniff test it if worried there may be exhaust gasses in the coolant.

Might just be sensor location, ive noticed 6 degrees difference in coolant on opposite side of the head on my Extra van. My hoses are absolutely scorching as per normal gtt and it quite happily cruises along at 75deg, so would hook up an accurate gauge as the original panic gauge might be way off.

 

[andybond]

original panic gauge

That made me laugh more than it should

 

[Adey]

I should just disconnect it and drive until the header tank pops. Getting annoyed waiting for things to turn up so i can check. Good shout on the sniff test

 

[binge]

Does the temp just keep climbing and climbing? Or is it just running a bit on the hot side?

As above, if you had a head gasket issue, or something of the kind. I'd expect it to be blowing the cap within no time. Or just using all it's water up.

Before I worked out what was wrong with mine, I very nearly fitted a hose mounted sensor before and after the rad, onto a pair of gauges (or one gauge on a DPDT switch) so I could see whether the water was just not cooling down through the rad, or whether it was, and the engine was just heating it back up to 100+ before it got back round to the stat housing where the sensor is.

 

[Adey]

Seems to level out on the gauge. Ive not traveled more than 10 miles in a trip yet though. You know what im going to go double check the fan direction........ Hopefully when this infrared probe turns up i can take it for a run and just point and check in and out of the rad and all over the rest and see if theres any hot spots or anything.

What will be really good is i take it for a drive point it and go "ahh thats actually all fine" but im rarely that lucky

 

[Adey]

fan definitely runs the correct way.

I quickly knocked up some proper small restrictors for both the feed and return on the header tank. The theory was looked at earlier but ive revisited it. The header tank on this is now very free flowing, no heater matrix and valves in the way, someone mentioned that a lot of water can head there instead of the rad with 25mm bore pipes and a normal setup would have a higher restriction. So now ive put restrictions in both pipes to promote flow to the radiator. Im yet to drive it and check but will do at some point this weekend.

 

[Adey]

Thought I'd chance it today and pop to a cars and coffee meet. Drove there well no issues bar looking hot on the gauge. Drove home just the same though when I pulled up on the drive there was a different noise. Pop goes the header tank cap. Still running sweet but I'm going to go with definitely running too hot. Now need to figure out why.....

 

[Adey]

So i pulled the plug to check them for lean running. Nothing to note there, actually look ok to me, not overly sooty even but definitely not showing signs of running lean. So i went a little further and whipped the head off. Easy job on these and it came off within 2 plays of the full length Donna Summers track i feel love (you tube in the background) And I'm sad to say i cant see a single issue with any of it. I cant see any sign of blow by, nothing enough to go past the fire ring. All the bores look great and piston tops pretty clean. No visible cracks or splits in the liners. Water came out clean and the oil still looks new. I need to give the head a clean to remove some of the old gaskets but i cant see any cracks there either. It would of been nice to see something wrong to be honest. The only thing to note that i can see is there are 2 different shape gaskets available, one with egg shape fire rings and one round ones. Though overlaying every thing i can see it as an issue. Ill get some pics for you all to look at when i go back out to the garage.

 

[andybond]

Your car looks great in the company there. That Porsche is such a pretty car.

 

[Adey]

Im not sure which one i liked more the 911 or the old spider. Got a cracking shot of it turning up too.