Hi all,

Im considering making an engine cover out of fibreglass.


Has anyone done this before? Is it strong enough and heat resistant enough? Is it a definite fire hazard?

Thoughts on a postcard please.

Sure I saw on ebay some heat resistant carbon fibre, think fibreglass/grp is too risky.

its not the fibre its made from thats the issue, its the resin.
If made with (if memory serves me correct) phenolic resin or additives into polyester resin, then it can withstand higher temps.
But it really depends what engine bay temps are and how close it is to hot components, you may find normal poly resin would be OK.
It would smell a fair bit for the first few miles though

As above, it is the resin that poses the problem, not really the fibre until you get mega hot...

Look for a high temperature epoxy (look for a resin where you can obtain a Tg value higher than you expect the panel to get to), and make sure the part is postcured to ensure you achieve that Tg value.... The problem is, high temperature epoxies tend to be rather unsuitable for processing with a bucket and brush!

Engine cover. I guess your engine is in the back, but why is this any different to a bonnet.

Bonnets on fury, phoenix, westfield, are all fibreglass. Most of these don't go up in flames.
You can help these with reflective heat barriers.

Perhaps I don't understand.

Matt

I think it much depends on what you want to cover, (engine is a bit vague), the bonnet on my car has a GRP bulge, (see <<< and that is roughly 3/8" to 1/2" above the plenum and lined with reflective heat shield stuff, (looks like thin ally on a self stick backing). It has retained its true shape, and hasn't caught fire yet, now about 3K miles. HTH Ray

In the past I have made fibreglass primary and magneto casings for my trials bike engines, in order to save the original alloy / magnesium ones getting smashed on rocks.
Heat never caused any problems with them. Have made them for modern jap motors and old brit stuff.

I don't think a postcard will be big enough but you could tape several together. Fire resistance could be a problem as could loss of stiffness if doused in cold water.

IIRC you're looking at significant softening around 60-70C and total breakdown >120 or so, unless you go with aircraft grade stuff, then you may get a little more. Easy enough to insulate though I suppose.

Thanks for the replies chaps.

I suppose it was a bit vague, and i should have said Cam Cover.

use high temp resin and gel coat and you should be ok.

The car in your avatar, is it the avelle? or the model previous to it done by Jeff Ashton?

why not use the standard engine cover? is it just a weight thing, or are you scared of finishing your project.

This isn't a "don't be stupid" question, it is an "I'm interested" question.

Matt

DRIVE THE BLOODY THING FIRST!

read this first http://tiny.cc/mdlqu

[Edited on 17-12-10 by mangogrooveworkshop]