Michael,
If you increase the diameter of the oil gallery, you effectively increase
the volume, not the pressure.
Regards,
Ed Hamilton
----- Original Message -----
From: "Nolan Penney" <npenney@erols.com>
To: "Graziano, Michael" <michael.graziano@csfb.com>
Cc: <spitfires@autox.team.net>
Sent: Monday, February 21, 2000 9:27 AM
Subject: Re: 1500 head modification questions and others (kinda long)
>
>
>
> "Graziano, Michael" wrote:
>
> > 1. From the John Twist article and list member suggestions "draw out
the
> > oil pump shaft housing and increase the diameter of the center oil
gallery
> > from 1/4 inch to 5/16 inch (doubling the cross sectional area, hence
> > doubling the oil available). "
> >
> > Can this be done without having to dismantle the entire engine? I'd
like
> > to do this as the engine oil pressure can get REALLY low in the summer
when
> > it's hot, but I also don't have an endless supply of cash.
>
> Your low oil pressure problem is almost assuredly wear, which this will
not
> address. If you really want to fix the oil pressure problem, tear the
engine
> down, and at least replace the bearings.
>
> > 2. Also, port and shave the head. I've been reading the "Theory and
> > Practice Of Cylinder Head Modification" by Vizard. I'm not very far
yet,
> > but with almost two hours of commuting time a day, I'll have read a lot
> > (maybe the whole thing) within a few weeks. How difficult is this?
Vizard
> > makes it seem that anyone with a brain, and a few tools (like a dremel
w/
> > flex shaft) can port and polish a head. Is this a realistic approach
for me
> > to take? Can it be done by a shade tree mechanic?
>
> It takes no great skill to operate a grinder. Removing metal isn't
difficult.
> Removing metal in a way that doesn't destroy the head and improves air
flow,
> that's a horse of a different color. To do that, you need a flow bench,
and
> several heads to destroy as you learn. You can make a flow bench easily
> enough. And you can destroy heads easily enough experimenting. Will you
have
> learned enough to actually improve the flow and performance of the engine?
> Honestly, doubtfull.
>
> Not only is porting and polishing tuned for specific applications, it's
specific
> to the engine. As in where are the water passages, what are actual
> restrictions, etc. You are best served by having a shop that is
experienced in
> your specific engine do the work. They are the most likely to get you
good
> results, without destroying your head. Off hand, I'd suggest you contact
> Paeco. They are expensive, but they seem to be very good, and quite
experienced
> with Spitfires.
>
>
>
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