Intake manifold construction

[Matt Cramer]

	I've seen intake manifolds made out of carbon fiber reinforced plastic
before.  So I don't see why you couldn't use fiberglass on some engines.
There are some designs where it would probably be a bad idea (for example,
on a Chrysler slant six and certain other engine designs, the intake
manifold is in direct contact with a red hot exhaust manifold).  But if
it's clear of any hot surfaces, it should probably work.
	Fatigue, both from vibration and from thermal expansion cycles, is the
biggest unknown.  I wouldn't expect thermal expansion to be a significant
problem except possibly at the bolt holes, where thermal expansion might
cause clamping forces to vary.  Vibration is likely to be the biggest
source of trouble, and I really haven't learned much about how composite
materials behave under cyclic loads.  It's probably governed by some
hideously complicated equation anyway. But I'm pretty sure that a
fiberglass manifold is a workable possiblility.  After all, boat hulls have
to deal with vibration too.

Matt Cramer
'66 Dodge Dart, no EFI work yet
http://drive.to/slantsix

At 12:21 PM 4/14/2000 +1000, Sean W Walsh wrote:
>
>
>Can anyone give me a reason why I shouldn't construct an intake manifold
using
>Glass Reinforced Plastics?
>
>I have an older 4 cyl lancia engine with a dual throat single carby and 4
branch
>manifold. I'm converting this to EFI and want to create a port injection
rampipe
>style intake with a small plenium etc. GRP lends itself to "backyard"
techniques
>and since I have a bit of experience with boat construction I thought I'd
give
>it a go myself rather than getting something fabricated.
>
>What are the problems I'm likely to face : different temperature expansion
rates
>of the inlet manifold (grp) and the head (alloy)?  fatigue from vibration?
high
>temperatures breaking down the epoxy?  I know there are epoxy resins
available
>that are rated to 150 degrees celsius so that should be enough (?) any other
>suggestions?
>

----------------------------------------------------------------------------
To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes)
in the body of a message (not the subject) to majordomo at lists.diy-efi.org