Quite so, Frank. Ideally I want a material that is non combustible, sound deadening, sound absorbing and thermally insulating. I guess I want the impossible and will have to compromise somewhere along the line…
Rigid fibreglass board of about 1/2" thickness would cover most, (I could paint it with matt black stove paint for appearance) but I haven’t found any yet.
Frankie
…and almost all car interiors today are just ABS plastic and fabric. How flammable is that…?
I think it would be extremely difficult, and mostly very expensive, to have a non flammable interior, (unless a Model T type with bare metal seats).
But it seems not to be a concern in real life, never heard of an interior just catch fire by itself.
But I too would feel better if that hood liner was not flammable.
For whoever maybe interested I took some more pics of the hood liner my PO installed in 2005. It never got cleaned during the last 15 ys. Yet, it still is black - poor lighting and a simple phone camera makes it look grey.
The liner is composed of a felt-like base and a black cover. It has stood the engine heat extremely well; only the glue has given in along the rearmost part. No issues about heat so far.
BTW, no cutouts were necessary for SII cars.
Good luck
Jochen
75 XJ6L 4.2 auto (UK spec)
That looks like Hardura, or very similar. The inner material is a type of sisal or natural fibre, by the look of it
Yes, that’s Hardura. Good to know it has stood the test of time in your engine bay, Jochen. It comes in more than one thickness - how thick is the material under your bonnet?
8 mm maybe - will check once I’m at the car again.
Best
Jochen
75 XJ6L 4.2 auto (UK spec)
Sorry it took so long.
The material is glass fiber, which means that it melts and forms a brittle glass droplet.
The part you show in the first two photos is not covered on mine.
I think hardura or pretty much anything heat resistant enough will do (the Volvo probably won’t get as hot under the hood anyways?).
You can see where the engine gets close and I left the upper radiator brace in for, um, reference in the last photo.
…which would bring us to the question of what glue to use that survives the conditions.
David
Thank you for doing these tests and reporting back on the results.
This looks like a manufactured pre-formed liner, so it will be necessary to find the specific product for retro-fitting. Dense fibreglass mat would be good, but I haven’t been able to find anything like that on line - probably NLA?
Frankie
I received a sample of “sound deadening” felt yesterday. The material on the RHS in the photo is this felt and on the LHS is Hardura.
I am inclined to go for the “sound deadening” felt because it gives the look I am after, is sold as suitable for engine bays, claims FMVSS compliance, is more easily worked than the stiffer Hardura, and can be supplied with a suitable contact adhesive.
All I need to do now is decide how best to remove the bonnet and hope re-aligment won’t be too much of an issue!
With a two-layer set-up; the ‘dense’ side goes to the bonnet (reducing bonnet vibration), Frankie - and the loose weave towards the engine (to absorb engine noise…
Frank
xj6 85 Sov Europe (UK/NZ)
**
Draw a line around the hinge, get a helper and from then on it is not even that bad 
The felt will look fine. Almost like my insulation!
Of course you can’t pre-mold anything and why bother, but it gives a good idea of what was done and where the clearances are tight… and with the oil that soaks into the material over time even glass fiber would make a good fuel should it catch fire. I‘d say don’t be worried if it can burn, only make sure it does not melt or ignite too early.
years ago, i decided the bonnett liner in my car detracted from the nice looking LT1 V8 ! Moth eaten bear rug.
Solved. Removed it and tossed it. Much like the “pad” that was over the transmission. Oil soaked in that case. trashed !!
I tried to polish the paint. No go. Still matte brown.
Planned to spray with truck bed liner, an under coat like material . Never happened.
Tis bare. I’ve grown to like it that well No paint issues, Noise is a “?” thong to me. About all I hear from under the bonnett is when the E fans kick in at idle, About 90 C !
Or, on crank, a quick start, no relay rattle…
Carl
