Lotus Elan

Engine bay temperature versus engine cooling

PostPost by: Bigbaldybloke » Sun Jun 10, 2018 8:28 pm

I?m at the stage of rebuilding everything in the nose of my Plus 2. I?ve converted the headlamp pods to electric, have fitted a new original type air filter and trunking so it?s nearly complete in this area. I?ve noted several threads around engine cooling and blanking off all the gaps around the radiator to ensure there is a full flow of air through it. There are also several threads around problems caused by heat radiated from stainless steel exhaust manifolds. I have a stainless exhaust system.
While sitting in front of the car working in the nose, it?s obvious that there is a large opening between the front cross member and the bottom of the radiator that loads of air will go through as it?s a much easier path than through the core of the radiator. So should I blank off this area under the radiator to force air through the radiator, or leave it open so air can pass under the radiator and around the engine and especially the exhaust manifold?
All comments and theories welcome, my car hasn?t run for over 30 years but is getting close to being a runner again. When it was running I never noticed cooling problems, but do know that the wiring harness on the exhaust side had been melted / burnt prior to me owning the car ( lots of chocolate block connectors and odd wires connected to stubs of wires on the main harness were a bit of a give away, along with the blackened wires!)
I should mention that I have fitted twin electric fans on the radiator in place of the old siezed single fan that was originally there when I got the car.
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PostPost by: MarkDa » Mon Jun 11, 2018 12:04 am

There's no guarantee that air going under the rad will go up to the manifold is there?
Arguably air streamed in at a higher level is more likely to pass over the manifold and back/down. It will be warm from the rad but still a lot cooler than the manifold and if full flow through radiator at a lower temp than partial?
It makes sense to keep wiring away from the manifold anyway and anything still too close for comfort could be 'foil' wrapped?
On my Sprint I managed to fit a heat shield to the footwell by the manifold after reading stories of cooked fibreglass. Obviously if engine is already installed this is not an easy retrofit!
Do Plus 2s have vents into wheel arch to help bleed some hot air away like 2 seater?

2 seaters had top bottom and side blanking factory fitted so that's the route I'd go.
More questions than answers I'm afraid but food for thought I hope.
Neat job on the fans - they should do the business in traffic.
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PostPost by: mbell » Mon Jun 11, 2018 12:30 am

Standard fitment has a board from lip on the body infront of the steering rack to under the radiator to block air flow through that hole. Also foam on the bonnet to seal air flow over the radiator.

Basically doing everything to force air thorough the radiator rather than around it is the standard practice.
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PostPost by: prezoom » Mon Jun 11, 2018 2:06 am

To reduce the chance that incoming air would go where I did not want it to go, I made a plate that utilizes the over length of the bolts that secure the steering rack. Four holes in the plate that match the rack bolts, and the plate tucks up under and between the rack mounting tabs. The plate runs forward to meet up with the bottom of the nose. While it will not prevent any air from by passing the radiator, it does block a fair amount air. The rack bellows also help in reducing the flow of air.
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PostPost by: Bigbaldybloke » Mon Jun 11, 2018 11:32 am

Ok, sounds like some more aluminium fabrication required!
I like the sound of the plate made by Prezoom, I was wondering how best to secure anything in that area.
I've also ordered some self adhesive ceramic heat shield material from Demon Tweeks to put on the areas of the passenger foot well near the exhaust, looks like a bit of a fiddle to fit but then nothing is easy about Lotus ownership!
To answer some other comments, no, the Plus 2 doesn't have holes to vent out hot air into the wheel arch area, it all has to make its way down and out underneath the car.
The gap above the radiator is minimal as are the gaps at the side so I'll leave them for now, don't like the look of bits of foam just stuck there which seems to be the only way of doing it. If I have a problem then I'll have to revisit it, but with the gap at the bottom closed off I think that should be enough.

Thanks for your feedback, other suggestions still welcome, its never too late to learn things.
I'll try to post pictures of the final solution in due course.

Simon
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PostPost by: rgh0 » Mon Jun 11, 2018 11:53 am

Bigbaldybloke wrote:Ok, sounds like some more aluminium fabrication required!
I like the sound of the plate made by Prezoom, I was wondering how best to secure anything in that area.
I've also ordered some self adhesive ceramic heat shield material from Demon Tweeks to put on the areas of the passenger foot well near the exhaust, looks like a bit of a fiddle to fit but then nothing is easy about Lotus ownership!
To answer some other comments, no, the Plus 2 doesn't have holes to vent out hot air into the wheel arch area, it all has to make its way down and out underneath the car.
The gap above the radiator is minimal as are the gaps at the side so I'll leave them for now, don't like the look of bits of foam just stuck there which seems to be the only way of doing it. If I have a problem then I'll have to revisit it, but with the gap at the bottom closed off I think that should be enough.

Thanks for your feedback, other suggestions still welcome, its never too late to learn things.
I'll try to post pictures of the final solution in due course.

Simon


I have found the self adhesive heat shield tends to peel off after a time. I use non adhesive heat shield ( woven kevlar fabric with aluminum reflective facing ) and stick it in place with high temperature silicone sealant. ( loctite red or copper) this last much better I have found. I have it on the fibreglass the faces the exhaust heads including the bonnet all of which get hot after a few laps racing at full throttle

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PostPost by: prezoom » Mon Jun 11, 2018 4:00 pm

I used the ends of the U bolts from the rack. Drilled 4 holes to match, and the plate fits up against the securing nuts of the rack with 4 new nylock nuts. It is .060" thick aluminum, and is trimmed to fit up against the bottom of the nose, but is not fastened at that end, just a very small amount of clearance to keep from rubbing. . It took longer for the paint to dry than it did to make it. I can't say just how much it helps, but the car runs at 85c under any condition, moving or stopped in traffic, cool or hot day. Disclaimer! The radiator is a custom aluminum kit I bought from Wizzard Cooling in New York. They sell DYI kits, that you can configure yourself. I was looking for something very large to go with the Zetec and our desert climate. I can weld aluminum and did the conversion myself, in crossflow double bypass configuration, as both inlet and outlet are on the same side. Rather a bargain at $200. Re-cores of my 2 Marsden radiators on my other cars were more than 4 times that cost.
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PostPost by: William2 » Mon Jun 18, 2018 3:45 pm

I think the majority of Elans are probably fine cooling wise when on the move but it is at standstill on a hot day that you will see if you have a problem. I would have thought with your wide rad/twin fan installation you should be ok. Having said all that, the only possible issue is having fans on the front face of the rad as they will have some affect on restricting incoming air reaching the cooling matrix whilst on the move.
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PostPost by: Bigbaldybloke » Mon Jun 18, 2018 9:06 pm

Thanks for all the feedback and advice. I ordered some 1.5mm aluminium sheet pre cut to 500 mm by 150 mm and bent it into a ?Z? section, fitted a u shaped rubber edging strip on the top edge and secured it using the front two rack mounting bolts. I have the solid rack mountings which have a flat top so ideal to secure to. This has blanked off the hole below the radiator nicely. Just needed the assistance of Mrs BBB as my arms weren?t long enough to hold a spanner on both ends of the rack bolts!
I?ve noted Rohan?s comments on adhesive, but as I had already ordered the self adhesive heat shield I went ahead and fitted it, but will keep an eye on it and if it starts to come unstuck will take his advice on how to fix it for sure.
While at it I made up a heat shield for the alternator to protect the electronics from the manifold heat. When the car was last in use it did get through alternators quite frequently, i had put it down to vibration, but listening to the comments on here it?s more likely heat problems causing the diode packs to fail.
A couple of pictures attached but not easy to show the final installation.

Nearly complete at the front now, so once I?ve finished testing out each electrical circuit in the front of the car it?s on to completing the dashboard wiring , bolting it back in and then it?s add fuel and start up for the first time in over 30 years!
Attachments
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View through the nose cone
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Looking down on the blanking plate
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PostPost by: tonyr27 » Mon Jun 18, 2018 9:46 pm

May I ask which way your radiator fans rotate as looking at the photographs.
We have a three fans supplied by a well known radiator supplier on two Elan's and are questioning their performance.
We need to check they are installed correctly as they seem to do very little when in traffic!

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PostPost by: MarkDa » Tue Jun 19, 2018 12:04 am

BBB whilst you're having fun with tin snips you may want to consider a clutch slave heat shield.
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PostPost by: Bigbaldybloke » Tue Jun 19, 2018 12:34 am

Regarding the fans, they were bought as push fans, but I?m just at the stage of powering up each electrical circuit one at a time so will test them and confirm rotation in the morning.
Regarding the clutch slave cylinder I have used a banjo fitting on it to get the pipe run as far away from the exhaust as possible, but no heat shield fitted. When the car was running many years ago even with the pipe run very close to the exhaust it didn?t give any problems, so at present I don?t want to fit little easily damaged bits of metal under the car in exposed positions, but in the meantime I?ll do a mental design in my head, just in case.
The other area I?ve fitted some shielding is around my transverse silencer. See pictures attached.
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PostPost by: Bigbaldybloke » Tue Jun 19, 2018 8:45 am

TonyR
The fans turn clockwise when viewed from the front and push a good blast of air through the radiator
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