mgs
[Top] [All Lists]

Re: Running Rough (the saga continues)

To: Charlie & Jennifer Schellinck <jschelli1@shaw.ca>,
Subject: Re: Running Rough (the saga continues)
From: Barney Gaylord <barneymg@ntsource.com>
Date: Fri, 14 Dec 2001 01:13:57 -0600
At 09:48 PM 12/13/01 -0800, Adam Schellinck wrote:
>Fixed the problem for a couple of days then it came back with a vengance. 
>.... plugs no 2&3 are black and fouled, I am thinking that it is a leak in 
>the gasket between these cylenders am I correct in that assumption?? ....

Yup, a pretty good guess.  First thing is to do a compression check on all 
four cylinders.  If they don't match within 10%, or if any of then is less 
than about 110 psi, then you have some internal problems there.  If #2 and 
#3 are both low and nearly the same, then you likely have a blown head 
gasket, or possible burned exhaust valves on those cylinders.  You can also 
squirt a little oil in each cylinder and repeat the compression test.  If 
the pressure reading increases at least 10 psi you probably have bad rings.

For a better diagnostic approach before disassembly you can do a blow down 
test.  For each cylinder in turn, rotate engine to exactly TDC on the 
compression stroke, apply about 20 psi of air pressure to the spark plug 
port, and listen.  Hissing at the carburetor is a leaky intake 
valve.  Hissing at the tail pipe is a leaky exhaust valve.  Hissing at the 
oil filler opening in the valve cover is leaky rings.  If you remove the 
pushrods or move the rocker arms to one side so the valves don't open, then 
you can do the blow down test at BDC and not worry about the engine 
spinning from the applied air pressure.

Once you acquire this information we can all lend you some more informed 
suggestions on what to do, and hopefully you won't be spending sums of 
money on unnecessary repairs while guessing wht might be wrong.

Barney Gaylord
1958 MGA with an attitude (and a compression tester in the traveling tool kit)
     http://www.ntsource.com/~barneymg

///
///  mgs@autox.team.net mailing list
///  or try http://www.team.net/cgi-bin/majorcool
///


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