This might sound silly but I forgot which coolant lines goes where on the radiator when using a flat-4 suby engine.
Is it bottom part on the engine to bottom part on the radiator or reversed?
Thanks
Bottom part of engine to bottom part of radiator.
Think of it this way.. the bottom water inlet on the engine is the draw side of the water pump so you want water there all the time, thus the bottom
of the radiator feeds it so it has the best chance of there being water there for it.
Thanks, figured it was that way but the place of the thermostat made me doubt and I don't have my old radiator anymore to check how things used to be hooked up.
For some reason Subaru put the thermostat on the inlet. I will be relocating it to the outlet as most other engines, that results in a more stable operating temperature and it is much easier to bleed the system among other benefits...
just to make sure, the spring that's on the thermostat goes towards the water pump side. correct?
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Hi
The cooling system also has a natural thermo siphon as well, the hot water goes to the top, cool water falls to the bottom, so even with the motor
stopped after running the water will still slowly circulate.
That's why its best to mount cooling fans near top of the radiator.
Steve
That's exactly why I will be relocating the thermostat, the stock bypass flow on its own struggles to maintain the stat bulb at the real operating
temperature which results in a delay of it opening, this is exaggerated when used in mid/rear conversions like these. With the stat on the outlet
there is never any worry of it seeing the correct temp as pretty much all the flow is forced past it. It's fairly easy to convert, just cut the
centre out of the stock stat and use an external one on the main engine outlet (I have used a BMW E30 4 cylinder one), also block the stock heater
supply pipe and use the new stat bypass for the heater supply. Depending on year of the engine you may have to restrict some original bypass lines.
In the UK the K series engine suffers badly from this problem, Land Rover even supply a factory kit to convert to external stat on the outlet! I also
did the conversion on my last kit car which used a K series mid-mounted like the Lotus Elise and it worked a dream. With that engine it was even worse
as the return was to the aluminium head which resulted in nasty thermal shocks as the thermostat cycled and one of the reasons for the engine's
apetite for head gaskets...
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Hi Ricola
Do you have a photo of the BMW thermostat?
Steve
Here you go:
Also here's a diagram I did for the Libra's conversion:
I'm guessing all this isn't such a problem for you guys but in cooler climates it is. A lot of the Canadian vanagon guys use a thermostat spacer,
that brings it further away from the cold return and lets the bypass work a bit better.
This has been discussed on and off and various reasons speculated for the oddness of the Subaru setup. The intent seems to be to get heat to the
heater core as rapidly as possible, since the heater core always sees full flow.
Various setups have been suggested for an outlet thermostat. the simplest was just a couple of Chevy thermostat covers placed together with a
thermostat between and placed in the upper hose. This setup must have a small (as in 1mm) hole in the thermostat to allow a little water to flow to
actuate the thermostat. Most old-style thermostats include this hole, often with a little rattle pin in it to prevent clogging.
IMO, the best setup is the Canadian Tom Shiels thermostat spacer with a dedicated bypass line. Keeps things the way Subaru intended and compensates
for the much larger cooling system volume of the bus conversion.
The bypass line connects to the small nipple while the heater flow is now far enough downstream of the thermostat that it does not affect the
thermostat action.
One thing that various people have pointed out is the need to use a genuine Subaru thermostat. Aftermarket thermostats may not protrude into the
bypass flow enough to work properly.
The thermostat on my V6 is on the inlet to the water pump too.
Well it was until I removed it to install the electric water pump.
Hi Wes
How do you find the electric water pump? I have one sitting in my cupboard.
Steve
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funny trawling thro ebay last night looking at Beema radiators i came across one of those thermostat assemblies brand new
mine isnt working.it fluctuates and doesnt get hot enough.
and when the stat is open the bypass closes so no heater flow.
why does it work on ricolas?and not mine
about 14litres of coolent?
exposed metal lines?
lines bolted aginst the pan?
i'd make a bet the extra long lenght of your lines as well as the heatercore being all the up front would be playing a part in it
that huge merc rad is plenty big enough and the rad feed line loses abit of heat along the way
how come your bypass is closing?
I've been talking offline to him about it and I'm sure it is his heater return not plumbed in to the normal cool side properly. A mate has his sti speedster replica plumbed in like this and it works great, bleeds easily too..
Hi everyone
I have a Toyota 3ct diesel in my syncro.
Its a great conversion, except I tend to have a problem with cooling when taking on steep inclines (like mountain pass's).
with 4x4'ing it's great, I can go anywhere with her.
some vid's on
http://www.bastilledeblignaut.co.za/4x4.htm
(at bottom of page)
can anyone help????