Duratec cooling again
neilp1 - 6/4/16 at 07:34 PM
Hi all,
I have a Tiger Avon kit car with a 2lt duratec installed. My problem is as soon as I hit traffic the temp goes up (steadily) to 120 odd degrees and
the oil pressure drops to single figures. Oil presure comes back up once I drive though and water temp comes down. water temp fine when driving.
I have a large alloy polo type radiator (I used to have standard polo rad) and kenlowe fan which I have recently changed to see if it would cure it
(it hasn't) I also fitted an oil cooler (for much the same reason as oil pressure was very low). I have added water wetter (which has done
nothing at all) I've also fitted a new water pump. I had a different engine fitted last year (2lt duratec) but this was swapped out due to
smoking and the temp problem was the same.
I beleive I have it plumed in correctly with water temp sender in top hose and Omex ECU set at 95deg for the fan. Stat is mechanical type from
raceline.
I have cut loads of vents in my bonnet but it has not helped much.
Is there anything I could have missed or anything else I could try? below is photos of my set up.
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britishtrident - 6/4/16 at 08:19 PM
My first port of call is to check the ignition timing, the ignition timing has to be conservative enough below idle to allow cranking but in the idle
range if it is too retarded it will cause excessive heat recject particularly to the lower end of the engine and exhaust.
I would check the ignition timing the old school way with a timing light against a valid mark on the bottom pulley, 13 to 15 degrees BTDC at 800 rpm
should be about right.
The other thing that occurs to me is the airflow through the engine bay the fan could be re-cycling hot air from the engine bay when the car is
stationary, some builders have had to add extra side vents to let the air out. The way to check if extra extracion vents are required is test it with
the bonnect removed.
Kdempsie - 6/4/16 at 09:48 PM
The pipe connections seem OK, the same as I have on my car. The only difference on mine is that my car is mid engined. I had trouble with cooling for
a while where the system wasn't flowing through the rad properly but I think that was caused by air locks and the longer run to my radiator. Is
your rad warming evenly once the stat opens?
Is the stat definitely opening properly?
I resorted to an electric pump in the end because my pipe runs just seemed to be too much for the standard pump, I also changed my rad but just for
another polo type but with a bleed pipe off the top. With hindsight I think that's where most of the improvement came from. With the standard
pump I used to need to speed the engine up to fast idle to cool it down when stationary (sometimes).
It's worth getting someone to start the car and rev the engine and check the bottom hose is not closing up under pump suction and as already
mentioned check what the ignition timing looks like. I'm currently 5 degrees at idle which seems OK and steady on temp and engine speed.
Keith.
melly-g - 6/4/16 at 10:08 PM
Is it possible to run without the stat for a while to see if that helps?
On my pinto the stat is on the pipe into the top of the rad, I know it's a different old school beast. Did they change things around to try and
heat the engines up quicker to help with emissions?
Kdempsie - 6/4/16 at 10:30 PM
If you do choose to run without the stat for a while then you will need to block the bypass line to make sure you flow through the radiator and not
just circulate round the head.
Worth trying to see the effect.
big-vee-twin - 6/4/16 at 10:40 PM
Optimum running temp for Duratec is 110 degrees according to Caterham, mine runs around 95-100.
Guage goes up to around 120 in traffic but stabilises with fan coming in/out.
Never seen oil less than 25psi goes higher when driving to about 40psi.
[Edited on 6/4/16 by big-vee-twin]
hkp57 - 7/4/16 at 06:44 AM
Second vote for an electric water pump here.
With static air flow over the car not sucking anything out your vents the fan might not be moving much.
At 800rpm idle speed the water pump wont be optimal either.
Different engine I know but I use no thermostat in the block and have an elctric water pump with an adjustable thermostatic controller.
Works great and some say gives you back the power taken to drive the mechanical pump.
Not the cheapest bit of kit but I find it very effective.
http://daviescraig.com.au/
http://www.kitcarparts-scotland.co.uk/ep80-water-kit-water-pump-control-unit-pre-wired-relay-kit/
http://www.carbuildersolutions.com/uk/electric-water-pump-115-lmin-and-controller-kit
Added bonus as the pump continues to run after you shut the engine off after a hard thrash, stops any hot spots in the head etc as she cools.
[Edited on 7/4/16 by hkp57]
britishtrident - 7/4/16 at 07:40 AM
Changing the pump won't help if the radiator can't dump the heat energy faster than the engine produces it.
The cooling system is coping when the vehicle is moving which sugests there is no problem with radiator size
Apart from the checks I have already sugested you could check the outlet temperture from the radiator -- best way to do this a a two channel K-Type
thermocouple with the thermocouplre junction tucked into the hoses on the rad inlet and outlet pipes.
I know this will be something you will have already checked but is the cooling fan roatating correctly.
neilp1 - 7/4/16 at 03:06 PM
Fan is correct way. I was toying around with changing to a pusher fan but not sure whether it would make a difference
adithorp - 7/4/16 at 08:24 PM
It's probably worth re-routing your radiator bleed pipe so it rises all the way from the rad to the header tank. As it is the rad can't self
bleed (top hose looks to slope down from the rad as well). Doesn't seem much but I've cured an overheating MNR Busa by just doing that and
an MK with that plus replacing convoluted hoses with smooth bore.
neilp1 - 8/4/16 at 12:41 PM
Cheers for all the replies there
britishtrident - I never new that about the timing and I have run it up to temp on my drive with bonnet removed and it seemed fine.
When I IVA'd car during emissions test I got 140deg and 2PSI oil pressure and that's when I turned off. It was that hot that it melted 2 of
the top front wishbone bushes. This is when I cut some vents in the bonnet.
Electric water pump - I think not as I'm spending nothing more on it. I spent money on new rad and fan £300 and oil cooler £220. I'll be
divored if I spend anymore!
adithorp - I will re-route bleed pipe. Top hose has bend at front to miss the chassis rail. Will this make much of a difference.
I will try running without a stat after stoneleigh unless it goes pop on the way down as I'm away with work and not due home until 29th.
[Edited on 8/4/16 by neilp1]
adithorp - 8/4/16 at 01:08 PM
quote:
Originally posted by neilp1
adithorp - I will re-route bleed pipe. Top hose has bend at front to miss the chassis rail. Will this make much of a difference.
Once you have the leed pipe re-routed that will allow any air in the rad to escape and the angle of the top hose won't matter. When the engine is
revving there's probably enough flow to overcome the issue but not at idle.
Is the rad/nose-cone baffled? If not when stationary it could be drawing the hot air from the rad around the sides and back through the rad, rather
than fresh cool air.
neilp1 - 8/4/16 at 02:07 PM
No baffle, thats something else I will do after stoneleigh!
davidimurray - 9/4/16 at 07:29 PM
Sounds like a strange issue you have as my Duratec runs cooler than my Pinto did. Rarely do I see more than 105C and the fan easily controls the
temp.
Your setup looks virtually the same as mine. The only difference I have is that the top of the expansion bottle is linked to the port you have blocked
on the water rail on the back of the head.
This may sound stupid, but I take it your thermostat is a mechanical one.
I am only running a clio rad so nothing special.
ali f27 - 9/4/16 at 09:13 PM
Mines a bu""er for air locking after i have had it drained take it for a ride it gets too hot let it cool down and it is ok for months
untill you have the water out of it again never solved the probs why just lived with it
neilp1 - 10/4/16 at 05:07 AM
quote:
Originally posted by davidimurray
Sounds like a strange issue you have as my Duratec runs cooler than my Pinto did. Rarely do I see more than 105C and the fan easily controls the
temp.
Your setup looks virtually the same as mine. The only difference I have is that the top of the expansion bottle is linked to the port you have blocked
on the water rail on the back of the head.
This may sound stupid, but I take it your thermostat is a mechanical one.
I am only running a clio rad so nothing special.
I do have the mechanical stat. Do you have a pic of the back of the engine to top of expansion bottle?
Cheers Neil
neilp1 - 9/5/16 at 03:47 PM
Just a quick update. It ended up being a bad Earth on engine. Now replaced and it's running spot on😀 Just in time for summer
