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Re: [Spits] Engine rebuild: What to ask and say to the machine

To: "'Nick Moseley'" <nmoseley@dccnet.com>, <nass@yahoogroups.com>,
Subject: Re: [Spits] Engine rebuild: What to ask and say to the machine
From: "Gene Eighmy" <w4eae@netzero.net>
Date: Mon, 9 Jul 2007 14:46:17 -0500
Nick,


> -do machine shops expect the crank removed, or would they prefer it in?
>

Leave the crank in.  It must be reassembled in the exact same order and
orientation.  If I were you, I would mark each bearing clamp with a metal
punch.  Punch the front with one mark, the middle with two and the rear with
three, etc.  Then take a detailed picture so you can verify that they put it
back together properly.


> -what about the camshaft, in or out?
>
I upgraded to a better camshaft and included it so they could check the
float.  I don't remember if they had to do anything but I included it just
in case.


> -do they expect to be told what to grind it to, or will they measure and
> decide?
>

My machinists said they could skim the head for 9.5:1 (premium gas).
Fortunately, I measured everything possible before taking it to the machine
shop.  When I got it back, I measured and verified everything and noticed
that they only took 0.010" off the deck and 0.010" off the head.  When I
called them on it, they said they didn't know how to cc a head and asked how
much I wanted off... I think they know how to do it but it is more of a
liability issue.

For more info check out my woes:

http://webpages.charter.net/eighmy/spitfire/


> -should I be giving them the head as well to install new valve guides and
> skim?
>

Yes.  While you have it apart, you will want to reseat your valves which
will improve your performance.  They will need all of it.


> The machine shop I've chosen comes recommended, has worked on Spits and
> LBCs
> in general, and is located next door to a mechanic that works on LBCs and
> others. I've never used that mechanic, but they also come recommended.
>
> Should I be taking my own measurements and telling them what to grind it
> to,
> or letting them know the over-bore sizes available and let them get to
> it!?
>

Will they supply the pistons and rings?  When I rebuilt mine, I ordered
flat-top pistons to bring it up to UK specs.  At the time, 0.020" and
0.050/60" were still available.

> As you can tell by now I'm sure, the big question is: what do I ask and
> say
> to the machine shop, and what should I do to prepare before-hand?
>

Figure out what you want to accomplish first.  Do you want stock US/Canada
performance?  Or do you want UK performance?  Or a race fuel powered rocket?


It is VERY IMPORTANT that it all goes back together in the same order.  Do
not take a box of parts to the machinist without knowing how it all goes
back together.  Mark parts and take pictures to document.  Trust but verify
your machinist.

Measure twice... you can only cut once...


Gene Eighmy
Birmingham, AL
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