MGB Under-hood insulation on the MGB

[William]

So, attached to the underside of the hood of Dad's B is that silvery bubblewrap heat shielding stuff. It was never glued in or anything, just cut to fit and held in place by the underhood structure. The heat (ha!) and exhaust gases seem to have gotten to it, and it keeps falling off (right onto the carbs!). So Dad pulled it out the other day.

I'm pretty sure that it's not an original item for a '71 B. Does this stuff have any real benefit? I would think it's keeping the hot air in even more, even though it's "reflecting" the heat.

Should we go buy more and put it back in?

-William

 

[Stewart]

the original heat shielding should be a black cover with a burlap colored fiber under it. The main purpose of the stuff the best I can tell is to keep the paint on the hood from bubbling up. Moss or VB sells the original style pads and on eBay there are some very nice looking pads with a MG logo on them. They should be glued on.

 

[MtnDriver]

The underside of my bonnet was furry from that fibrous stuff. I pulled the bonnet off the car for other reasons, then spent several hours with a bottle of Goof Off and a plastic chisel de-furring. I found rust that could not be seen with the glue in place, likely saved more work down the road on the bonnet as I hadn't planned to touch it for quite a while. I'm almost ready to prime and paint, then I've a pair of those mylar bubble insulation panels that you describe (came with the car). May velcro them in or something. Heck, they're taking up space OUTSIDE the car at the moment; might as well do something with 'em. What I will NOT do is squirt glue around at random and squish the mylar in place.

It's amazing, by the way, what cleaning up the underside of the bonnet does for the aesthetics of the engine compartment.

Tim

 

[Steve_S]

The insulation will do a few things...

1. Reduces hood (bonnet) temperature, which protects paintwork and lowers temperature of air entering the fresh air vent.

2. Reduces hood vibration

3. Reduces engine noise heard from outside of vehicle.

 

[Shinsen774]

Original material replacement is pretty inexpensive. For about $10 more you can get this modern material that looks a little better. Use 3M adhesive #90 to attach. See below.

I got mine from Jeff Zorn at Little British Car Company. I also see them on e-bay from time to time.

 

[William]

Thanks for the replies! I think Dad actually stuffed the insulation in the trunk, so we can't even claim we removed it to reduce weight!

I'm quite sure that the orignal shielding disappeared when the car was repainted by the PO, as there's no sign of glue or fur on the underside of the hood. Don't think it did any good either cause the paint has a blister on it. We'll probably buy some more when the car gets repainted and re-install.

Good idea on the Velcro.

-William

 

[David_DuBois]

The other advantage to some kind of insulation on hte underside of the hood is that if some debris is kicked up to where the fan gets hold of it, it can be thrown against the under side of the hood hard enough to cause a reverse rock chip in the hood. I got several ugly stars on the front of the hood from just such encounters before I got smart and installed the insulating material.
Cheers,

 

[mowog]

I used rhino lining as an under bonnet insulator it has worked fine for several years and is no worse for wear the original insulation is known to sag and the replacement pieces do not seem to fit as the original did

 

[1965_MGB]

I know it would probably be overkill, but some Dynamat would serve the same purpose (albeit more expensive). I have some of the stuff on my firewall and the tops of the foot wells. I know it helped quite a bit with the heat transferred into the cockpit, but it is a bit expensive.