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1970 S4 DHC bonnet issues

PostPosted: Sun Aug 02, 2020 11:29 am
by roebuck
Hello,
I have just received my 1970 S4 Elan DHC back from the body works and I have a few issues I would like a bit of advice to resolve.
1. The bonnet sits flat when closed unlike my S3 which kicks up when you pull the bonnet releases.The spring only start to work when the bonnet is up about 100mm.
Springs on the S4 and S3 appear to be the same. This prevents the bonnet releasing. It is necessary to pull the release and at the same time have another person press down on the leading edge of the bonnet.

2. I purchased from Paul Matty 18 months ago apiece of foam rubber that is sold as a BONNET FOAM REAR. it's about 25mms x 25mms. I can not work out where this goes and if it will kick up the bonnet to clear of the 2 bonnet catch springs.

Having examined the bonnet release cable I decided to replace it with a new one which I purchased from SJ Sportscars. I also purchased 2x bonnet catch springs.

3 Both bonnet catch springs are attached to the firewall with self tappers and speed locks.
What happens if the cable malfunctions? it's impossible to open the bonnet.
Is there a remedy?
Hope you can assist,
Regards,
Rob

Re: 1970 S4 DHC bonnet issues

PostPosted: Sun Aug 02, 2020 11:44 am
by TBG

Re: 1970 S4 DHC bonnet issues

PostPosted: Sun Aug 02, 2020 12:18 pm
by oldelanman
Hi Rob,

1) Not sure I understand your description but I suspect the bonnet release cable just needs adjustment ... sounds like the cable is too slack so the catches don't quite release fully. The adjustment procedure is detailed in the workshop manual.

2) The foam strip fits on the narrow ledge at the top of the firewall between the two catches, it stops the bonnet rattling on the catches.

3) The screws securing the catches are supposed to be fitted from inside the car with the spire nuts in the engine bay .. not pretty but it does allow removal of the catches if the release cable fails.

Re: 1970 S4 DHC bonnet issues

PostPosted: Sun Aug 02, 2020 3:00 pm
by ericbushby
Hi Rob,
I agree with Roger above.
The other purpose of the foam strip is to reduce the amount of hot, possibly smelly, air from the engine bay entering the heater air intake.
Cheers
Eric in Burnley
1967 S3SE DHC

Re: 1970 S4 DHC bonnet issues

PostPosted: Mon Aug 03, 2020 2:29 am
by roebuck
Thank you for your assistance.
The issue with the bonnet is that it does not spring up to clear the catches.
I have adjusted both catches to release but the bonnet just sits there.
The foam may here but on my S3 the bonnet springs up about 100mm on releasing the catches.
thanks again
Rob

Re: 1970 S4 DHC bonnet issues

PostPosted: Mon Aug 03, 2020 8:33 am
by lotusfan
'The spring only start to work when the bonnet is up about 100mm.'

Hi Rob

No one seems to have commented on your statement above. I think there must be a problem either with the hook on the front of your bonnet or the spring. If it only starts to work when the bonnet is up 100 mm, that sounds very odd. When it is open 100 mm does it then open yet more?

Perhaps you should attach a photo of the bonnet hook and the spring. The spring is attached to the steering rack isn't it?

Re: 1970 S4 DHC bonnet issues

PostPosted: Mon Aug 03, 2020 8:39 am
by oldelanman
Hi Rob,
Mike makes a very good point.
Does the spring hold the bonnet open once you have released it manually ? If it does then it's not the spring causing your problem so try this....
With the bonnet open pull the release knob fully out and hold it there, you should now be able to fully close the bonnet without it touching the catches at all. If it does touch the catches then they are not moving far enough, either because the cable is incorrectly adjusted or because the bulkhead fittings that the cable passes through (manual refers to them as fairleads) are stopping them. They are adjustable with a large nut on either side of the bulkhead .. maybe they are too far forward into the engine bay. If you do have to adjust them the cable will need readjusting afterwards too.
If it's not the catches holding the bonnet closed, the only other thing I can think of is maybe the skid plates are too short and are catching on the head of the first nylon bolt that the bonnet runs on.
My money is still in the catches though.

bonnet catch.jpg and
Needs adjusting?
bonnet skid plate.jpg and
Too short?

Re: 1970 S4 DHC bonnet issues

PostPosted: Mon Aug 03, 2020 8:58 am
by 512BB
There are springs and there are SPRINGS. A mate of mine had a similar issue and commented on the fact that when I opened the bonnet on a car of mine, it sprang right open, but it barely did on his car.

When I had a look and feel of his spring :D , it pulled up about a foot with no effort. No wonder it would not raise his bonnet. When he had a feel of my SPRING, he could not believe the difference in non pull out ability. Obviously, the difference was in the coil thickness between the two springs. Changed his spring for a 'correct' item, and POP, up came his bonnet.

May, or may not be your issue.

LS

Re: 1970 S4 DHC bonnet issues

PostPosted: Mon Aug 03, 2020 12:03 pm
by sprintsoft
Hi Rob,

"... It is necessary to pull the release and at the same time have another person press down on the leading edge of the bonnet..."

If this method works then it's most likely your spring is old / weak / overstretched

Iain

Re: 1970 S4 DHC bonnet issues

PostPosted: Mon Aug 03, 2020 7:37 pm
by RichardHawkins
Rob & 512BB,

I had a very similar problem problem with my 1968 S4. Unfortunately I had lost the spring I removed and had to buy another. The spring was incapable of lifting the bonnet. I measured the force needed to lift the bonnet, and got a spring made by a local manufacturer. The idea that I had bought a weak spring did not occur to me, which is daft, because so many after market parts are poor.

Richard Hawkins

Re: 1970 S4 DHC bonnet issues

PostPosted: Mon Aug 03, 2020 9:06 pm
by collins_dan
If the bonnet is clear on all sides, then it must be the spring in the front or the nylon bolt heads and metal strip that are the problem. Maybe the last bolt head is worn down, so spring is not being stretched when the bonnet is fully down. Point is look at the front, not the back. It sounds like something is hanging up the pivot point. Good luck. Dan

Re: 1970 S4 DHC bonnet issues

PostPosted: Mon Aug 03, 2020 9:16 pm
by steve lyle
For the Oklahoma heat I installed a big aluminum radiator in my Sprint from DBE. I couldn't find a way to install the spring once the new radiator was in the the car - and I never liked the spring anyway because it made it so difficult to remove the hood completely.

So my solution is that I carry a plastic tool, which I got initially in an interior trim removal kit. The hood opening process is, I stand next to the driver's door with the window down, reach in and pull the release with my right hand, while I slip the plastic tool in between the hood and the cowl where the latch "catch" is on the hood with my left, and "lever" the hood up.

The tool also comes in handy when closing - for some reason the catch bar on the hood on the passenger side sometimes slips behind the catch 'spring' affixed to the body. The hood looks latched, but isn't, and lifts a bit at high speed. I know the hood isn't going anywhere, but it spooks the wife so if I need to I can use the tool to lever the spring back behind the hood catch.

I'm thinking the right solution for me is to go with one of the catches in TBG's thread.

Re: 1970 S4 DHC bonnet issues

PostPosted: Tue Aug 04, 2020 4:57 am
by roebuck
Thank you all for your advice.
I will now go through all steps to see if I can resolve the problem.

My car has the spring attached to the body about 100mm in front of the steering rack. I have a large radiator with electric fans. The radiator sits directly about the rack.

Thanks again,
Rob

Re: 1970 S4 DHC bonnet issues

PostPosted: Tue Aug 04, 2020 5:52 am
by oldelanman
roebuck wrote:My car has the spring attached to the body about 100mm in front of the steering rack. I have a large radiator with electric fans. The radiator sits directly about the rack.

That is your problem .. the spring is now at the wrong angle to lift the bonnet.

Re: 1970 S4 DHC bonnet issues

PostPosted: Tue Aug 04, 2020 10:00 am
by lotusfan
Rob

The obvious solution is to make the bonnet hook project forward by 100 mm more but I very much doubt that it would be as simple as that.

Post a picture so that we can fully understand. Good luck!!