spitfires
[Top] [All Lists]

Re: GT6 crank confusion

To: Sam Gentry <sam@spit6.com>
Subject: Re: GT6 crank confusion
From: Joe Curry <Spitlist@gte.net>
Date: Sat, 23 Nov 2002 11:07:53 -0700
Sam,
Your summary seems to profile the difference in early Spitfire 4
cylinder engines and the later (Large Journal) ones.  I don't know much
about the GT6 engines, but it would appear that the later ones follow
the same sizing as the Spits.  I suspect you have a later GT6 engine,
correct?

Joe

Sam Gentry wrote:
> 
> OK... I am confused... I am checking the crankshaft from my 73 GT6 and the
> dimensions that I get are not even close to the numbers in my Bentley.  The
> rod journals are right on, but the main bearings are way off.  The book
> says 2.001 to 2.0005, but I measure 2.312!!! I have used two micrometers
> and a dial caliper and get the same answer.  I have an old crankshaft that
> measures more or less the same (it is fairly worn).  Does anyone know the
> correct crank main bearing specs?  I don't see how I could be off by 0.311!!
> 
> While I am at it... What is the correct bore diameter?  The book says
> 2.9405 to 2.9416 in three grades, but pistons no longer seem to be
> available in grades.  The book says that the bore can be as much as 0.010
> over, but over what?  What is the nominal dimension?  Of course,
> 2.9405-2.9416 is only 0.0011 so I guess it does not matter much which
> dimension I use.  The middle is 2.941 and that is a number I have seen.  My
> bore is about 2.945-2.947 which is within 0.010 of 2.941.  It is even
> within 0.010 of the smallest diameter specified.
> 
> More while I am at it... If the bore is less than 0.010 oversize does that
> mean that I can use standard rings?
> 
> Thanks, Sam

///  spitfires@autox.team.net mailing list
///  or try  http://www.team.net/cgi-bin/majorcool
///  Archives at http://www.team.net/archive


<Prev in Thread] Current Thread [Next in Thread>