Bonnet seal

PostPost by: alaric » Mon Mar 17, 2008 11:42 am

Hi all. I was looking at the engine bay of the +2 and wondering what happens when it rains. As far as I can tell all the water running down the windscreen will go down the gap between the body and the bonnet. Has anyone put a seal along the rear edge of the bonnet? Is this worth considering - do all the grommets and pedal box gasket keep the water out of the car? Any ideas on mods around the pedal box to avoid relying on a gasket at that point?

Sean.
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PostPost by: mikealdren » Mon Mar 17, 2008 12:23 pm

Hi Sean,

I've not seen a car with a seal here and I think it would be difficult to get is watertight. Modern cars usually have a bulkhead forward of the trailing edge of the bonnet and water drains away without entering the engine bay. The sides of the bonnet are above the join between the inner and outer wings and water is channelled away along the join.

With Plus 2s, the water runs into the engine bay and it?s important to get the bulkhead seals watertight, especially the pedal box ? a common culprit for leaks into the cabin. Make sure there are no blockages at the front end of the pedal box so water can drain freely.

Mike
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PostPost by: alaric » Mon Mar 17, 2008 1:45 pm

Thanks Mike. A fibreglass deflector around the front of the pedal box has been suggested to me as a way of avoiding the main source of leaks. Now that it's been suggested I'm trying to come up with a simple mod that'll avoid spreading messy fibreglass all over my freshly finished bulk head.

Sean.
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PostPost by: mikealdren » Mon Mar 17, 2008 3:28 pm

Sean,
I haven't had problems with the pedal box but I suspect that the main cause would be if the fibreglass is in poor condition where the box mounts. The stud holes easily get elongated and cracked and the flange itself is quite thin - I've strengthened mine and repaired each mounting hole. It's quite easy to seal if there are good surfaces to seal against and I think that's a better approach than trying to divert the water.

Mike
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PostPost by: alaric » Mon Mar 17, 2008 8:54 pm

Ok. I'll leave my pristine bulkhead in one piece and go back to plan A, which was to reinforce the area that the pedal box bolts to from within the car - it's got a bit of flex at the moment. Thanks for the advice.

Sean.
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PostPost by: mikealdren » Mon Mar 17, 2008 10:15 pm

Not sure if this helps, it's the only photo I have of the area. I took the photo while I was working on the underbonnet area after I had stripped of the paint and some awful old repairs.

I think the elongated and broken mounting holes are probably typical of older cars, apart from being much larger (more area to leak) they also weaken the mounting considerably.

I refinished the edges to strengthen the area (from the under and top sides) and competely filled in the mounting holes. I then recut the holes to suit the pedal box making the holes not much bigger than the mounting studs.

I ended up with a much stiffer mounting face and I feel much more confident bolting it all up.

It's just how I did it but I hope it helps.

Mike
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PostPost by: lotuselan2 » Tue Mar 18, 2008 12:11 am

I thought the Lotus was designed to wear Wellies when you drive in the rain.
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PostPost by: alaric » Tue Mar 18, 2008 10:33 pm

Yup, my little four year old lad certainly has his wellies ready, and is very keen to go out in the car.

Thanks for the pic Mike. My bulkhead is already painted up, but the holes look very similar to in your photo - needless to say I would have done a better job of it myself - hindsight is a wonderful thing. My plan is to reinforce from underneath and try to carefully scrape away paint round the flange area so that I can fold matting round from the underside - I'll have to pre-wet it which I've not tried before. I suspect it'll end up everywhere, so I'll see how it goes.

It appears that one of the guys in my local club has made a deflector to go around the pedal box. I'm going to try and get a photo.

I'm working on the idea of a rubber strip around the bonnet aperture that the bottom edge of the bonnet pushes onto when it closes. If I can find some really soft rubber or sponge that may help reduce the water ingress. I suspect I won't find anything, but thought it worth a think on at least. Another idea would be the equivalent of a gutter running round not in contact with the bonnet, even if it's only at the back to keep the water off the grommets that go through into the car.

Whehey, this weekend should be solid elan building - I hope to get the pedal box in, and get the clutch, brakes and fuel line hooked up so that I can run the engine and maybe even drive the car up and down the driveway. I should probably fit the steering column too. I don't see much point progressing much further until I've tested all the bits that are there...

All the best.

Sean.
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PostPost by: h20hamelan » Mon Jul 26, 2021 1:05 am

anyone added a drill hole (added benefit of lightening) at the lowest outer point in the pedal box? I will do as above suggests, some form of channel/diverter. I suspect there is the opportunity for fluid or water to still accumulate?

thoughts?
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PostPost by: mikealdren » Mon Jul 26, 2021 7:57 am

On RHD cars, the only external part of the pedal box would drain into the rear of the wheel arch, I suspect it would result in more water and muck going in the reverse direction from the wheel arch into the pedal box area.
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PostPost by: h20hamelan » Mon Jul 26, 2021 4:30 pm

suppose I am LHD, +2, and S4. Though I am not as sure the S4 is as bad off, but probably thou.
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PostPost by: david.g.chapman » Mon Jul 26, 2021 5:59 pm

One thing which may be altered if the bonnet is sealed at the back is engine bay temperature. Some hot air is exhausted through that gap, providing a flow of air over the exhaust. I have a gap of 5-6mm there - just the way the car was built originally!

It may be though that turbulent air lower down in the engine bay makes that effect insignificant at speed.

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PostPost by: h20hamelan » Mon Jul 26, 2021 6:03 pm

true
I am only attempting to stop water flow into the box, or adding a or some drain holes.
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PostPost by: Bigbaldybloke » Thu Aug 05, 2021 5:25 pm

One more area to check, when i bought my car the previous owner had removed the carpets and his heel had actually worn a hole through the floor allowing any water to drain out.
After a bit of investigation with a hosepipe the leak was traced to the heater intake box just in front of the bottom of the windscreen not being properly bonded to the bulkhead such that any water that ran down the screen into the box was funneled onto the floor. Simple if somewhat fiddly fix to properly fireglass the box to the bulkhead. I just removed the intake grills, masked of the paintwork around the area, cleaned out the inside of the intake box as well as possible and added a couple of layers for fibreglass tissue and resin. its been fine since then. Just ensure you don't get any actually inside the heater itself!
Regarding the pedal box, when i refitted mine I ran a bead of black silicon sealant around the flange on the pedal box to ensure it sealed. Several people supply a pedal box reinforcing ring that bolts on inside the car, but note that they are designed for the later narrower pedal box not the early wider type.
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