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Cold Engine Performance
brynhamlet - 10/4/08 at 05:29 AM

I have a tuned Ford 1600OHV with a pair of twin Dellortos
Run perfectly until radiator sprang a leak. Car has not been overheated.
Fitted new radiator and because top hose was not getting hot, suggesting air lock or dysfunctional thermostat, removed thermostat.
Top hose got hot, more water in overflow bottle and whilst idling engine temp came up to normal.
Took it out and temp wouldn’t come above about 40-45deg and engine performance gone, plus spitting from carbs. Took it home
I think that due to no thermostat and cold engine, replacing thermostat with new will cure.
Or should I be looking deeper

Thoughts please

nitram38 - 10/4/08 at 08:20 AM

Just stick a new thermostat in.
Otherwise it will be over cooled.

MikeRJ - 10/4/08 at 08:30 AM

quote:
Originally posted by brynhamlet
I think that due to no thermostat and cold engine, replacing thermostat with new will cure.


Exactly, the thermostat is there to regulate engine temperature. Without it your engine temperature will always be low and will vary with ambient temperature, something that many people don't seem to realise!

Removing the thermostat can also have undesirable effects on the flow of coolant through the engine, potentialy creating hot spots etc.

ditchlewis - 10/4/08 at 10:56 AM

similar set up 2.1 sohc, twin dell 45's. took it out for a run on saturday and with some high speed runs the temp only went above 70 deg when sitting at the traffic lights. the car was also spitting when on duel carriage way.

the only time it ran well was when it had been left standing for a couple of min's- eg at the petrol station.

thought it could be the carb set up (proberbly is)

BUT could it be carb iceing?

ditch

britishtrident - 10/4/08 at 06:35 PM

You need a thermostat, most likely reason why your previous thermostat wasn't opening was you don't have a bypass connection fitted.

A bypass connection is a smaller bore hose (usually 1/2" or 5/8" bore) that connects from the top of the engine just below the thermostat to the water pump inlet -- in effect it by-passes the radiator and thermostat. The purpose of this connection is keep warm water circulating within the cylinder head and block when the thermostat is closed which has two effects
(1) it keeps the engine at an even temperature througout ie you don't get the engine hot at the top and cool at the bottom.
(2) It allows hot coolant to circulate and get to the thermostat --- which in turn makes thermostat open.

On most tin top cars including Fords the bypass is taken care of by the heater plumbing.



[Edited on 10/4/08 by britishtrident]