The Shark

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pacman
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Joined: July 5th, 2006, 9:12 am
Location: Katrineholm, Sweden
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The Shark

Post by pacman »

Hi all!

Who am i? I l’‚­ve in Sweden, and work at Siemens industrial steam turbines as a design and development engineer.
Previosly i worked at Scania Buses as a design engineer. During that time i worked with the powerful CAD-system CATIA. Since my dream was to design and build a seven-like sportscar, i used CATIA to make a 3-D model of "my" car. A few changes here and there until i was satisfied with the design, and then made drawing for the chassi and the body.
It took five years, and the result is seen on the pictures. It‚´s made as a one-off, but i still have the moulds in case a body part is damaged for some reason....

The powertrain is from a Fiat 124 sport coup’‚©. It‚´s a 1756 TC, turbo converted. I have installed 132 1800 pistons to get a proper CR for the turbo. During the winter i have installed a Megasquirt&Spark system along with a custommade intake and intercooler. The unit runs ok for now (street use) but later i want to fine tune it on a rolling road dyno before taking it to track. I run approx. 0.5 bar boost at the moment, but when cooling problem is solved it will be raised toabout 1.0 bar.

Cooling problem, it‚´s really gives me a headache.
I use a Volvo 460 radiator and fan, internal thermostat and an expansion tank. Problem is that i have to use the fan during low load driving at normal speeds, otherwise the temperature climbs beyond boiling point. It also build up a tremendous pressure. It blow the hoses off. Yesterday i tryed to run without the thermostat in case it might work as a restriction for the flow. But there was no improvement.
Tonight i will install a new water pump, check all hoses and connections so there is nothing stopping the flow, like a sock or a rat......
One other thing is that the oulet hose from the head could not be filled with water, because if i do there is to little free volume in the tank for expansion. If i fill the tank with so much water that the hose is filled, when engine warms up the water will pour from the tank cap. The tank is from a Volvo, and should be sufficient if filled to "MAX" level mark.
Any thoughts, anyone?
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Seven-clone builder
Guy Croft
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Joined: June 18th, 2006, 9:31 am
Location: Bedford, UK
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Post by Guy Croft »

Hi Peter

welcome _ I think we 'met' before?

Thank you for a post which is a model of excellence, just what I am looking for on my new site, a nice introduction, some backgound, history and good technical.
My Russian born wife Natalya works for Siemens Gas Turbines in Lincoln by the way.
What is the operating temperature of the engine (max) under load? My guess is 85-100 deg C, which is too high for that motor really, but not necessarily dangerous provided that the cooling system holds its pressure and the coolant does not boil.
I'm thinking at this stage that the head gasket is blowing - extreme pressure in the cooling system is always exhaust gas getting in there.

If the system is just getting extremely hot on its own it is because the heat cannot get out of the engine bay. This is very common - build up of high pressure hot air under the hood. The fan should not be needed ever over 20mph.

I would be a bit nervous of putting 1 bar boost on normally aspirated pistons, the ring lands on cast turbo pistons are always thicker, and in my exp, they need to be.

GC
Kev Rooney
Posts: 45
Joined: June 26th, 2006, 7:29 am
Location: Portsmouth

Post by Kev Rooney »

You may find some information on here that may help ?

http://www.uk-hotrods.co.uk/Technical/C ... ooting.htm

I forgot to mention that laying the radiator over, as many do in '7' type cars can cause all sort sof cooling problems. Do you have a picture of the rad installation viewed from the engine side ?
Fiatnut
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Joined: June 22nd, 2006, 11:06 pm
Location: Sydney, Australia
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Post by Fiatnut »

Hi,
I'd be venting the highest point, or points in the cooling system back to an expansion tank located slightly higher than the highest point in the system...for my money I'd say you have air trapped in the head...the air will always go to the highest point, and "airlock" the cooling system.
Hope this helps,
Karl
Kev Rooney
Posts: 45
Joined: June 26th, 2006, 7:29 am
Location: Portsmouth

Post by Kev Rooney »

Looking at your engine pictures again I've just seen that you aren't using the head heater hose outlet fitting. I think you are probably getting an airlock there .
I normally 'loop' the heater system on all my engines rather than just blank them off to ensure continuos flow of water.
On my twin cam I am having a custom made stainless header tank so that the heater outlet can feed into this as well.

As the very minimum I'd try bleeding the air from the engine at that point per the tech article link.

Unfortunately I didn't give my past history on this forum but I spent 14 years in the automotive radiator trade with Serck Marston, this countries leading supplier.
pacman
Posts: 23
Joined: July 5th, 2006, 9:12 am
Location: Katrineholm, Sweden
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Post by pacman »

Thanks for your replays.

Guy, yes we have had some conversation going a few years ago when i built the engine with a K-jetronic fuel system. Thanks for your commitment answering all the questions.

The heater outlet is loop back to the pump, no blanking.

If you look closely on the picture you‚´ll see my "cheap & dirty" solution of an air bleed valve; a screw on top of the outlet hose.

Blown head gasket? I‚´ve had exactly the same behaviour two years ago (before the rebuild) and thought the gasket was blown. But it wasn‚´t, so i don‚´t think it is now.
Yesterday i replaced the waterpump with a new one. I couldn‚´t see any defects on the old one, so that shouldn‚´t make any difference. Tonight i‚´ll try to raise the expansion tank and run the engine with the cap off to see if i can get all the air off.

thank you
Peter C
Seven-clone builder
dido
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Joined: August 10th, 2006, 8:41 am
Location: Plovdiv, BULGARIA
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Post by dido »

Hello, Peter!

I REALLY love your car. As a matter of fact, you are the first person in this forum I see using a MegaSquirt EFI. I have two questions for you:

1. Did you solve the problem with your cooling system? What caused it?
2. What ignition control do you use? The original distributor, Ford EDIS or something else?

Regards,
Deyan
pacman
Posts: 23
Joined: July 5th, 2006, 9:12 am
Location: Katrineholm, Sweden
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Post by pacman »

Hello, Deyan.

Glad you like the car. So far it‚´s up to my expectatins.

The cooling problems was probably due to air locks, and unsufficient airflow thru radiator.
After installation of air bleed valves at highest points (front of outlet elbow and on hose at rear outlet on head) i managed to get the air out.
I also realized that i have had to much water in the expansion tank.
It is actally a fine line between to much water (causing water to leak out from under the cap at high temp), and to little water (level of water below highest point in system causing air trap). Eventually i found the right level.
To increase airflow thru the radiator i made two baffle plates, one on each side of the rad, to force air that otherwise should have gone beside the radiator to actually pass through the rad. I also replaced the intercooler with a smaller one. The previous ic, mounted in front of the rad, was very effective blocking air to the rad. I prefer having proper cooling of the engine instead of a few degrees cooler inlet air....
I have just installed a new fan (from summit racing) and a in-head mounted thermo-switch (200F on, 180F off). Problem is that temperature rise fast at low speed, or stand still. The previous thermo switch was mounted in the radiator bottom and wouldn‚´t kick in until boiling temp. I have installed a manual switch to control the fan, but i don‚´t want to have to keep an eye on the temp gauge all the time.

Ignition is Ford EDIS 4 (Fiesta, Escort, Mondeo) from a Fiesta.
For triggering i use a 36 teeth motorcycle cog wheel. I removed one teeth and machined the tooth to flat top. Works perfect.


thank you
Peter
Seven-clone builder
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