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Re: Flywheel

Subject: Re: Flywheel
From: "Dereck C" <>
Date: Thu, 27 Jul 2000 15:12:52 GMT
Ok, I reread the your message (Lawrie) and I think I got the whole deal.  
1/4 is there for timing the block to TDC if do this by utilizing a hole in 
the bellhousing (which I believe a B doesn't).  If you don't use the mark, 
it doesn't matter which side is up or down.  I think I was trying to 
overanalyze the whole situation.  I was wondering how a machine shop would 
balance a fly wheel (separately) to account for the difference in the weight 
of the crank.  When in fact it is independent of the crank and the mark is 
there for convience of bringing an engine to TDC.  Just like me to over 
complicate things.


1970 MGB

----Original Message Follows----
From: "Lawrie Alexander" <>
To: "Dereck C" <>
CC: <>
Subject: Re: Flywheel
Date: Thu, 27 Jul 2000 07:38:56 -0700

When you realize that the 1/4 mark represents "one slash four", not "one
quarter", that should answer your question, Derek. If number one piston is
at TDC, number four must be also. If the 1/4 mark is at the top at the same
time as the numbers one and four pistons, then that marks presence at the
top of the flywheel indicates that numbers one and four pistons are at TDC.

If you put the flywheel on 180 degrees from that position, then the mark
will not be telling the truth. It will say that one and four are at TDC
when, in fact, two and three are.

This all dates back to the days when some engines had an inspection hole on
the top of the bellhousing, through which the 1/4 mark could be seen when
you were trying to set the engine at TDC. Since the MG bellhousing does not
have such a hole, the 1/4 mark no longer serves any real purpose.

British Sportscar Center

-----Original Message-----
From: Dereck C <>
To: <>
Date: Thursday, July 27, 2000 6:01 AM
Subject: Flywheel

 >It is proceeding at a snails pace but I am progressing.  Yesterday I
 >performed step #2,534b the installation of the flywheel (on a complete
 >engine rebuild).  Checking my many manuals (Haynes, Complete Guide...,
 >Twist's rebuild) they all point out how to align the flywheel to the crank
 >flange.  Align the 1/4 mark on the flywheel with the corresponding mark on
 >the flywheel flange.  I see the 1/4 mark on the flywheel but not on the
 >crank.  In the Haynes manual there is a mention of the mark being up when
 >is TDC (the picture shows the engine upside down, so what is up?).
 >I have my engine with #1 at TDC and I installed the flywheel with 1/4 mark
 >at 12 o'clock (engine standing up right).  Is this correct?  What happens
 >you get it 180 degrees out of alignment (the only other option)?
 >1970 MGB


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