Twincam running to cold?

[chrishewett]

Hi
I have been using my +2 this week and have noticed it is not getting up to its usual running temp. During the summer it was at about 90 degrees but in this cold weather will not go above 80. I have adjusted the kenlow so that it doesn't come on at all when the car is moving.
Should I be looking at thermostats?
Chris

[Dag-Henning]

- I wouldn't worry abt. 80 deg, unless you feel that your heater does not deliver enough hot air........( - if so, go for a warmer thermostat , but watch out when spring comes..)

Dag

[Hamish Coutts]

Chris,

Which radiator is fitted? Is it the smaller one with the small 'wings' at the side?

If so, I think this is a symptom of the rad being pretty near it's limit in the summer time which is why the temp is up around 90deg. What happens in traffic or at junctions when you are stopped? Does the fan cut in quickly?
I have the smaller rad which I had recored last year (with a Triumph 2.5pi type core, as advised by the radiator repair chap) and the temp sounds very similar to yours. I have an 82 deg thermostat fitted but the temp rarely goes above 80 deg on the open road in Winter. Stopped in traffic? then 90 deg appears pretty quickly and the fan cuts in.
The heater is also nice and warm.

I'm still not convinced I have the right radiator and am eying one of these full width alloy jobs as I'm planing some longer trips this year in the Summer. I don't to be one of these people stopped by the side of the road emitting more steam than a good going traction engine!

Happy new year, by the way.

Regards,

Hamish.

[type26owner]

Hey Chris,
Your engine is just obeying the laws of thermodynamics. I have to add a panel onto the front grill to reduce the airflow on colder days. I velcro a 40sq/in aluminum sheet so it can be removed easily. It's still a pain when I forget to deal with it since I'm strapped in when I remember. My choke cable which has no purpose anymore and is going to be used to flip that panel up and down REAL soon from the cockpit. Brrrr... the damn heater does not put out much heat too. It's a blast furnace when things are corrected.

Since the search capability is working on this forum again you should go back and read the stuff I posted on the cooling system. Lotus did the minimum in this area. It can be corrected quite easily though. I have lots of experience in heatflow of x-ray optics devices. To fix and understand the issues of the Elan cooling is a not all that hard. Most people do exactly the wrong things to correct the problems due to ignorance. Most of the info posted by non-engineers on the web is simply flatout wrong.

[twincamman]

heaters??? in California ---my SUPER 7 doesn't even have one ----you So cal Dudes are getting soft --whats cold there 50 degrees f??? ED

[type26owner]

Hey Ed,
I admit it, I'm a wimp and hate to be cold. On the otherhand, I get to drive my Elan all the time. The highpoint of every working day is the drive to and from.

Back when I had little kiddies that had to be dropped off at school I could only afford a 56 VW bug with no heater and no headliner. My son would take great delight in directing the condensation which would form on the inside of the roof so it would drip on my head. Now that was a miseable car to drive in the winter.

[twincamman]

Iwish I could drive it all year but the Snow and ice high points the car and the salt dissolves the 18 guage steel chassis in about a week -and the cold makes the fiber glass so brittle it cracks or breaks ---I'M just jealous of your fine so cal weather --we have 11 months of winter and one month of poor snow shoeing here -ed

[type26owner]

I've got a cozy warm cockpit in just three miles now.

[twincamman]

i had a V.W. 59 bug-----i WAS NOT EVER WARM IN THE THING---- the condensation simply froze inside till spring --my sons mini had what he called ' English heat' ---one degree above ambient ----Oh Canada---why wasn't the border set at the 50th parallel ?---ED [ NOMEX ON ]

[type26owner]

Hey, now that I'm thinking about it here's a tip I bet most folks have not picked up on. The knob on the heater cable locks into that position when it's rotated oneway or the other by about 90 degrees.

I put a hunking big return spring on the shutoff valve now that I can expire from being overheated. The damn thing could not be throttled back enough without popping open the bonnet and forcing it closed by hand.

[type26owner]

It's the big aluminum head that overcools the engine with the amount of airflow swooshing by it in colder weather. Try this experiment and see for yourself. Wrap the head loosely with aluminum cooling foil being careful not to short out the spark plug wires. The idea is to slowdown the convection cooling rate. The engine will heat up another 10C at least.

This the first car I've ever seen that both overcools and overheats! Nice work Lotus.

Overcooling is fixed by reducing the airflow. Overheating is fixed by by operating the engine between 90-105C and installing dual fans on the radiator that will force at the very minimum 1000 cfm. Installing just one fan without a shroud will not do it. Every square inch of the core must have air force fed through it. When this is done correctly the stock radiator has enough cooling rate so it can be operated at WOT on the racetrack on a sweltering 45C day. It gets mighty hot at Thunderhill racetrack.

Don't install an oil cooler either because the Elan is known to overcool it's oilpan. All oil manufacturers recommend the oil heatup to at least 190F to drive off the blowby. The Elan only gets it to 150F typically. If your engine oil turns black quickly after an oil change, that's the reason why.

[chrishewett]

Would you suggest reducing the airflow at the grill by blanking a part off or covering part of the rad to reduce its effectiveness? I didn't notice any serious overheating in the summer, the single fan adjusted to come on early seemed to keep that under control.
Chris

[type26owner]

Chris,
Try a piece of paper on the front grill which 2" x 20" or = 40sq/in. If you put it on the radiator it will do no good. No water circuits through the radiator until the thermostat opens. The convection cooling directly from the head at partial throttle is so high that the thermostat is not even opening. Honest to gawd this is what is happening when the ambient temperature gets down to 10C or below. Blew me away when I realized this!

Too bad Mike Causer does not post here. He's the only other engineer that has confirmed my diagnosis. His situation is even worse because on his later Elite he also gets carburetor icing. That would really suck!

[john.p.clegg]

Keith
This cooling via the head is all well and good but what is the route for this cooling air stream?
Surely if it has a route it can be reduced?

John

[chrishewett]

I can now see that reducing airflow at the grill is what is needed but paper or card put over it will cover the number plate letters. I am thinking of making up a perspex sheet to completely fill the hole and then drilling large holes in it to allow the correct amount of airflow, I will experiment with this. I really think it is running under working temp which can't be good, especially as the oil already is to cool. ( Also my toes are not at working temp!).
I will post again when I have some results.
Chris