Newby to spitfires - mk1 overheating, help!

[Pmatthews84]

Hi, I have recently purchased a mk1 spitfire with a 1300 engine from a later model. The problem is it overheats when at speed usually above 40mph. The temp gauge creeps up and up until I stop or slow down.

When idling it drops back down to normal.

The coolant system has been flushed, new thermostat, new radiator, new cap, new pump. I have replaced the voltage stabiliser.

The timing has been done and the carbs have been tuned.

Any ideas?

[drofgum]

Paul,

There should be air deflectors on either side ahead of the radiator. If they aren't installed the  air doesn't go through the rad as it should, but goes around it instead.

Also the temperature gauges are fairly well known for inaccuracy, their usual problem is reading too high because the sending units available often aren't suitable.

If the car has the 22" (full width) radiator with the remote header tank that was the original configuration Triumph built. It was changed because the cars ran too cool. It is often observed that if the radiator doesn't actually steam and blow out coolant the engine isn't actually overheating.

Regards,

Paul

[RobPearce]

When you flushed the system, did you drain the block using the tap behind the manifold? And did it flow freely from there? It's common for the block waterways to get really heavily clogged, to that point where nothing flows out of that tap, and a half-hearted flush will have no effect on that.

Did the new thermostat have the air bleed hole? About a 3mm hole in the flange part. Without that you get air locks and very poor cooling.

And as Paul says, even with a new voltage stabiliser the gauge may just be lying. I've had stabilisers faulty from new, and temperature senders go partial-short (reads high once warm).

[Pmatthews84]

Hi, thanks for your help, I’ve got the radiator air bits at the front to direct the air into the rad and I check the tap in the block and it flows freely.

ive ran the engine without a thermostat and it has made no difference. I’ve changed the rad cap from 13 to 7lb and that’s made no difference either.

Ive bought a temp gun to check the accuracy of the engine temp so I’ll check that tomorrow.

i can only think that the timing is still out or it’s the head gasket? I do have an oil leak at the back of the block, would this cause any issues?

[RobPearce]

If the timing was badly out you'd notice in how the car drives.

If the head gasket was your problem you'd be losing coolant.

Oil leaks are worth fixing but don't affect the cooling system.

Does it lose coolant (or fill the overflow bottle if you have one) if you take it for a spirited drive with the 7lbs radiator cap? If not, then it's not really "overheating" - and I suspect it's not even really running hot.

[ferny]

For background info, I've just replaced the radiator I was using with one from a Mini. It's increased the capacity by 600ml. It always ran at 82 degrees (checked with ecu).  I'm running over well three times the horsepower than a standard Herald...

 

Deffo check the real temperature as I suspect the sender or gauge is reading in a way you're not expecting.

 

Weren't mk1 non-stabalised? Is there a chance of mis-matched components?

[Velocita Rosso]

The original models did not have heaters as standard. Does yours have a heater?

[Pmatthews84]

I'll check the temp shortly with the temp gun, mine does have a heater, it was an optional extra at the factory

[Velocita Rosso]

Quoted from Pmatthews84-

I'll check the temp shortly with the temp gun, mine does have a heater, it was an optional extra at the factory

Sometimes a blocked heater can restrict flow therefore adding to extra heat. and or if the heater pipes have been connected the correct way. Hose pipe into heater pip at bulkhead(hoses off) to check on what comes out from the heater exit. If all what you say has been done , i would then say it was a dicky/wrong transmitter in the stat housing

[Pmatthews84]

So I've just come back from a run and the temp gauge gradually went up and sat just shy of the H, I checked the temp with the gun and its 75c running into the rad, 58c running out through bottom hose, 98c block.

On idle it cools down to 60c running into the rad, at 3500 revs it goes up to the above.

That seems like normal running temps to me?

[RobPearce]

Yes, 75C into the rad is, if anything, a tad on the cool side. The block temperature is probably normal, though the difference is quite high. Check your fan belt tension - a slipping belt will reduce water pump efficiency, which would account for that. But your issue with the high readings is most likely the sender or the gauge.