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Re: Piston ring gap

To: <>, <>
Subject: Re: Piston ring gap
From: "Lawrie Alexander" <>
Date: Sun, 9 May 1999 14:07:50 -0700
This just goes to show that Haynes manuals are not always correct!

A ring gap of 22 thousandths in a B motor is not something any competent
engine builder would tolerate. The lower number quoted by Haynes is closer
to correct.

Generally, good mechanics consider that 3 thousandths per inch of cylinder
bore diameter is about right for either compression or cast-iron oil scraper
ring gaps. (Multi-part oil rings don't usually need their gaps measured, due
to their design.)

So, your 9 thou. compression ring gaps are close to perfect, your oil ring
gaps (assuming they are the one-piece cast iron rings) are a bit on the wide
side but they are acceptable in an engine with nice straight bores. If the
bores have any appreciable taper, however, you may find it consumes more oil
than would be considered normal.

British Sportscar Center
-----Original Message-----
From: <>
To: <>
Date: Sunday, May 09, 1999 1:37 PM
Subject: Piston ring gap

>I can't find my exact engine number in my Haynes manual. My question is on
>the proper ring gap. The manual shows the ring gap as .012 to .022
>{compression rings}. My engines #1 cylinder is .009 on all three rings. The
>oil ring is .014.
>My engine is an 18V836V L. Does anyone have a manual that shows my engine?
>would like to know if these readings are correct for my engine.
>R. B. Sexson

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