Re: manifold machining

[Peter Gargano <peter@ntserver.techedge.com.au>]

Mr Natch' says "use the right tool for the job"!

Bruce and Mike, thanks for the tips...

nacelp wrote:

[snip]
> > >  1. About 5-6 inches away from inlet valve, using existing (carby) inlet
> > >     manifold. Has a 90 degree turn (injectors vertical, valve stems
> > >     horizontal)
> 
> Sounds like #1 is the easiest.
> That's what I'd do.
> Make it easy, and cheap, it don't work carve a new one.
> what ya gonna do if say heat is a bigger problem, then expected, and you
> have to move them from the head?...

I actually have 8 spare heads (that's from four motors), and only one spare
manifold (but either way, they're easy to obtain!). Most rebuilders go for
the slightly "hotter" twin carby engine, with twin Weber DCOEs. The heads
are very slightly different, and, with the twin carbs, put out 10-20% more
ponies (requires a hotter cam too!). So, there are a lot of "standard" heads 
floating around that no-one wants. For me this is academic as I'm looking to 
add a turbo at some stage. BTW, the rest of the motor is identical!

> I've used literally pounds (OK kilograms, maybe decagrams(?))of epoxy
> filling manifolds I screwed up.

> Grumpy
>   The throw away manifold champian.  Just look at my cross fire collection
> <g>...

mike mager wrote:

[snip]
> (Is the AlfaSud 1500 liquid cooled?)

Yes, water cooled. And the heads are very light - unlike the cast iron block.

> First, _every_ head is machined, iron, aluminum/magnesium, other(?), so it
> can definitely be cut!  You seem confident, and the plan seems reasonable,
> but none of us have seen it.

I drilled a small pilot hole in one of the heads (with a hand held drill!) to 
see if I could get a good line, through the port, to the inlet valve. I got the
angle pretty good (IMHO!).
 
> You've got at least one development/practice head, right?  Spot-face with a
> larger endmill as a first step before the bores;  drillbits are generally
> inferior to endmills for the bores, BTW (use a center drill first, if you do
> drill);  if the bore size is odd, you can get a tool-sharpening shop to
> resize a generic endmill to just the right size  (right, and be sure to
> _know_ just the right size!).
 
I'll talk with a machine shop tomorrow. I'd really like to be able to buy
something for my bench press, and I'd make up a one-off jig to clamp the heads
while I drill them. Possible complication is that injector hole needs to be
angled at about 20 degrees relative to the closest flat face of the head - this
just means making the jig isn't a trivial exercise.

> IMHO, as they say:
> Oh, yeah, don't even think about trying your first one on a drill press -
> save that for later;  no doubt somebody has done it with a hand drill!
> 
> You've heard it before:  (I read a shop book, once)
> "Measure twice, cut once"
> "clamp your workpiece securely"
> "don't force it, let the tool do the work"> 

Thanks for the advice - just need to find out about the correct "tool".

PG.
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