injector bosses

[Seth]

On Thu, 28 Aug 1997, James Weiler wrote:

> 
> 
> On Thu, 28 Aug 1997, Paul Witek wrote:
> 
> > Hey gang-
> 
> <snip> 
> 
> > Now I just need to figure
> > out how to modify the manifold for the injectors....
> > 
> Hi Paul.  You and I are at the same place.  I'm trying to figure out how 
> to mount injector bosses in an aluminum intake as well.  I've thought 
> about threading them in but large taps and dies are expensive, but if 
> this is the way to go then I'll just bite the bullet.  
> 
> Welding (I've been told) will distort the manifold too much.  What 
> about bolting it to a pair of heads prior to welding?  Ideas anybody?
> I've heard alot of people have epoxied them in place but I worry about 
> the durability of the epoxy.  How long will it take for gas to break it 
> down is one of my concerns.  I don't know but epoxy just sounds Mickey 
> Mouse.  Am I way out of line here?
> 
> My bosses have an outside diameter of 0.845 inch and I've drilled a 14mm 
> hole through the centre for the O-ringed part of the injector to fit into.
> I have access to a lathe so I can mill them down to 0.75 inch diameter.
> 
> What kind of angle between the boss and the runner are you going to use?  
> The Corkey Bell book claims 20 degrees is maximum.  If you look at what's 
> out there (i.e. Accell for example) they mount bosses straight up.  The 
> intake runner is at about 45 degrees in that case so the angle is between 
> the boss and the runner is also 45 degrees.  So much for the 20 degree rule.
> 
> Perhaps I'm sweating something really trivial and I should just get on 
> with it.
> 
> cheers
> jw
> 


I welded mine.  Lots of heat.  About 250 amperes worth for about 24 
linear inches of weld.  I drilled all the bosses is a chunk of 0.75 by 
1.00 inch aluminum.  That keeps the centers consistent. Welding shouldn't 
be a big deal, if you warp the mounting surface, it should be minimal 
,and a dust off on a belt sander should fix that, of if you want to get 
trick, a flycut on a mill.  The intake gets hot for the use of DGEBA 
(room temp) epoxies with the usual amine curing agent.  A pre-preg epoxy 
for use and cure at elevated temp should be fine.  One I use cures for 1 
hr at 325 F.  We use the stuff on several different intake parts.

Seth Allen