Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Rattle behind bulkhead

Have just spent the best part of the day looking for an intermitant rattle, not body creak, that seems to be behind the bulkhead, engine side, or infront, dash area. It appears for the first few miles at any time, braking, cornering, normal driving, anytime. I think I have checked most nuts and bolts from front to back , (I think Meccano sets had less). I can see no evidence of anything rubbing or knocking. I know it's like looking for a needle in a haystack, but just wondering if anyone has had anything similar and found the cause.
Took it for it's last test run and it started snowing, do I put the hood up or not, leave it down, bad mistake, came home looking like a snowman driving, interesting to see where the air goes when driving, snow makes it just like a wind tunnel.

Brave man

We have found two sources of rattles in our car. A sound like a stick caught under the front of the car turned out to be the air cleaner box rubbing on the centre of the bonnet where the hinge is. There was also a rattle that sounded like a loose washer behind the dash. It started at about 2,500 rpm. That turned out to be the rearmost bonnet mount near the centre of the windscreen. There was something loose there that the mechanic fixed so I don't know exactly what it was.

Behind the dash there is a whole mass of potential rattle inducing stuff! There's the wiring loom and certainly on mine, a number of relays and terminal blocks. They are up against the stainless bulkhead which makes a wonderful sounding board!

I've zip tied and put foam (steady Dave!) behind them and am down to just one intermittent rattle.

I found a loose cable in the air intake box for the heater
Fixing this with bluetak solved the tapping noise
John

Ah Peter, you may have put your finger on it, there was a small white deposit on the air cleaner box, which I assumed to be dried polish from when I had a senior moment and polished the car, it just cleaned of with a wipe over, but have just had another close look and there is a small mark on the top of the box. When the bonnet is open there is clearance, but using the old bike trick of a bit of plasticine on the top and closing the bonnets there is probably only 0.020in clearance, enough when moving for slight movement to just tap the box. As it's been chucking it down all day I am resisting a test run after a little removal of plastic on the box, snow I can cope with but I don't do rain unless I have to.
Thanks Jay, think I bought all the tie raps in the local shop and added extra raps to everything just in case, anything that looked near anything that it could touch was wrapped in cut up old motorcycle tube.
One thing I did find some time ago was the top and bottom pipes to the radiator were horribly close to various brackets, so a few hours was spent modifying brackets and mountings to give clearance. All was probably just ok in a new car but when mountings etc start wearing I coule see hoses being chaffed and a sudden loss of coolant, which would probably happen in the worst place and time.

I more or less proved the aircleaner box was the source of the tapping noise by wedging a piece of foam rubber between the plastic box and the metal and the noise disappeared. The box would be very difficult to lower but I can't see why Morgan could not have reduced the edge of the bonnet a little in the same way as they have done over the heater box edge. We now have a section of metal without paint and a 1 mm deep groove in the top of the airbox.

The mechanic pressed the airbox clamps down tighter but ours still touches every so often. Ultimately I will probably try to modify the bracket.

Final instalment of the mystery rattle, thought I had found it with the airbox tapping the bonnet, so gentle filed of the bonnet edge to give better clearance, but alas after test run was still there, returned home, lifted the bonnet and it rattled, closed it and it rattled, head scratching time, the hinges had always been oiled, along with anything else on the car that moved. I noticed that the rear hinge was a bit jerky, so a squirt with more oil, no improvmemt, of with the bonnet after a houdini act getting at the rear hinge bolts, try it in the bonnet, it's tight, the bend on the bonnet that forms the female part of the hinge isn't round, quickly turned up a suitable brass drift, gently tap it in the hole, now nice and round and loose on the pin, assemble it all together, nice and free now.
test run of 220k and no rattle, (well the sun was shinning so I just followed it). Just out of interest I mounted a dial gauge on the bulkhead to see how much the bonnet moved when driving, that was frightening, looking at the gauge the needle flapped about as if it wasn't connected, I knew the body flexed, but there is serious movement there, hence the rattle only at certain times and luckily it was in the rattle position when I stopped.

Glad to hear you got it fixed. Makes me wonder exactly what was done to our rear bonnet hinge. The mechanic said he tightened ours in some way.