HKM400

HKM400's 1969 Lotus 7 Series 3

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my radiator was in good nick and cleaned, but was not good enough for my modified engine, temperature fluctuated all the time. You need to check the fan type too, as some are specified as being designed to blow, suck or both (both is usually the most common but worst type as it does neither job most efficiently)

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The fan won’t make a difference at track speeds, so it’s only an issue if you’re over heating in traffic. 

90 degrees is super safe though. It’s likely that you won’t start losing horsepower until 95+ and the engine will be safe until over 100. 

Just run it hard :D . A head gasket is only a 10 minute job on your car.

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Like the others said, 90 is not that hot.  One of the big issues cooling 7 type cars is getting the air to go THROUGH the radiator rather than AROUND the radiator.  An indicator of this problem is that you get higher temperatures at speed versus in traffic.  Both of the Fraser's I have had have run hot in traffic but fine on the open road and at the track.  If yours runs OK in traffic but not at speed then I think you have an air flow issue.  How hot does it run when in traffic on a hot day? (quite hard to test with our weather at the moment!)

I would:
a) Check that the temperature gauge is correct
b) Make sure the system is bleed with no air locks, you might need to jack the front of the car up to get make sure the cap is clearly the highest point
c) Block the air gaps around the radiator to ensure air is forced through it
d) If you are using an electric fan is it run the right way for the side it is mounted on?

Electric fans are more efficient pulling rather than pushing air through the radiator, but again on 7's packaging is often and issue, on the Fraser it pushes.

Nice MG too.

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On 20/11/2018 at 16:00, HKM400 said:

I did replace the sensor awhile back- and had trouble finding one that actually fitted so a good point and I will check- how does one know how to match the sensor to the gauge?

Tech info for matching sender here http://www.veethree.com/temperature-gauges.html

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Cheers, new sender is on the way. Thanks @locost_bryan

Thanks @FraserNZ there are a few gaps around the radiator which probably isn't assisting with airflow so may seal them up with some foam tape or something like that.

The temp does climb when in traffic, but remains relatively constant when driving at normal road speed. Does need a proper bleed I think, new cap on the block should assist with that. Electric fan is mounted to the back, and pulls air through the rad. 

MG is my dads- I store the Lotus in the same garage as I don't have one of my own currently.

Hopefully with a good bleed and a new temp sensor we will be underway again. 

 

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Just FYI, the Fraser radiator is quite 'square' in shape so that it is a good fit in the nose cone, you might need more than just some tape to close yours off.  I will keep an eye out for your Dad, I also have a Healey 3000 so go on a few 'old' car runs that sometimes have MG's

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You could also consider running water wetter to help make the most of what you've got. 

We used that stuff on the jetpacks as heat was a problem and so was weight, so big engines and small cooling systems ect. Seemed to work well. 

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I had a yuck time with that water wetter stuff, it didn't help temps at all really, but it was good for finding places to weep from like frost plugs and gaskets 

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interesting! what brand? (if there are multiple brands)

we used redline 

Image result for redline water wetter

 

to be fair, we never actually ran the engines without water wetter so i guess i cant comment on how good it actually works.

 

lingish post

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1 hour ago, BlownCorona said:

interesting! what brand? (if there are multiple brands)

we used redline 

Image result for redline water wetter

 

to be fair, we never actually ran the engines without water wetter so i guess i cant comment on how good it actually works.

 

lingish post

Same stuff, I tried it to try and help with overheating but I think the cooling system was just too borderline in my case 

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Cheers everyone, yep it is kent powered. Never heard of water wetter before, thought it might have been a "blinker fluid" scenario. Google has revealed otherwise

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Hi HKM400, 
 

Fuel/air mixture play a significant part in the Kent style engine's temperature, as does ignition timing

I think you have a carb mixture problem that may be contributing to hot running. One of your carb throats is running leaner than the other, which will elevate the combustion chamber temps of those two cylinders... but it could be that the other two cylinders are actually running too cold and you do have a cooling system issue as well (I say this as it looks like two of the exhaust valves have been hotter than the other two)

I ran Water Wetter in my 120E race motors, but TBH I don't know that it made much difference. It certainly didn't hurt.

For a race vehicle (which can spend quite a lot of time at a standstill waiting for a flag, and then the rest of the time at near red-line) I like the Davies Craig electric waterpumps. They deliver a constant flow of coolant (regardless of engine RPM), where the mechanical pump will deliver too little flow whilst you wait for the red flag to be lifted, or too much flow (not giving the coolant time to rob the cast iron of heat) when you're screaming at red-line in third gear

These are simple, reliable engines that respond well to experience. Most mechanics are unfamiliar with carburetors or distributors, so if you're seeking professional help you'll want to find someone old or who has experience with Formula Ford

I ran my race motors up  to 215F (about 101C), but I always tried to keep them below 200F. That level of heat didn't cause me any issues, but I did re-build every season (at least)

Regards,

UJ

 

 

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plus one for electric pumps. I've not used one but everything I have read about them makes so much sense. I have allowed for the fitting of one in the back of my Imp by making sure the pipes layout would suit plus added some wiring in place just in case the Datsun pump wasn't up to the job of pumping coolant to the front etc.  When I last looked up the prices the Davies Craig pumps, with the electronic controllers have really dropped in price. Certainly not at all excessive for what they do and the quality of product. 

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On 04/10/2019 at 08:14, yoeddynz said:

plus one for electric pumps. I've not used one but everything I have read about them makes so much sense. I have allowed for the fitting of one in the back of my Imp by making sure the pipes layout would suit plus added some wiring in place just in case the Datsun pump wasn't up to the job of pumping coolant to the front etc.  When I last looked up the prices the Davies Craig pumps, with the electronic controllers have really dropped in price. Certainly not at all excessive for what they do and the quality of product. 

I put my DC EWP in the front of the Imp and it was fine. I routed the radiator coolant pipes through the body of the imp where the heater lines went rather than over the floor. To this day the worst job I have ever completed on any car. 

In regards to the lotus 7 overheating I had the same problem on my old 4age PRB. Through a combo of angling the front number plate to channel airflow up (bottom of which was at sump height so if I scraped on a speed bump I reversed out of there), changing to a SPAL fan from the repco cheapie electric fan, and redline water wetter I got it down from 110 degrees in traffic to around 90. 

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