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Re: Cylinder Head, Compression tests

To: british-cars@autox.team.net
Subject: Re: Cylinder Head, Compression tests
From: sggy@crux2.cit.cornell.edu (Roger Garnett)
Date: Tue, 17 Nov 1992 08:52:41 -0500
kmwheeler@ualr.edu scribed:

>  Right now my street car ('76 MGB) is sitting in the driveway
>  sans cylinder head.  The head gasket had started to leak around
>  bore #3, and was weeping coolant down the starboard side of the
>  block.  #3 was also blowing coolant out around the sparking plug.
>  Looks okay though.  Seems to be just a gasket leak. 

Common enough. You should have the head checked for warpage, no
more than .003 total, or just go and get it lightly surfaced to be sure.
Remove all head studs, and slightly champfer all the stud holes in
the block. The metal that pulls up around the studs can be enough
to keep the head from seating correctly. These 2 simple chores
will ensure that your new gasket lasts longer.

This is also the time to de-coke the combustion chambers, and
check the valves if you can... 

Paul Gilders scribed:
 Subject: New method for one-person compression test
> Well, on Saturday I attempted to conduct my first compression test on
> my MGB. Having asked Scott Paisley about the procedure, I followed his
> advice, took all the plugs out and pushed the compression tester with
> its rubber seal into no.1 plug. I stepped around the car, put the
> gearstick in neutral and started the ignition.

Paul has learned why, for a couple more bucks, they sell compression testers
that screw in. I despize those push & hold jobs. THere's a couple things you
forgot in your test proceedure, so here's the hole thing :-) :
(I know we've done this, but it's not on hoosier, or in my files, and
 the sol wais server isn't responding)

1) Warm up engine to operation tempature
2) Remove all plugs
3) Disable spark (Disconnect distributor primary wire, or you can just
   leave the key off on cars with seperate starter switches)
4) Install compression tester in first plug hole.
5) Open throttle full (Setp on the pedal, eh?)
6) Turn engine over about 3 or 4 cranks with the starter.
7) Read & write down the measurement.
8) Repeat for all cylinders. (This is the "dry" measurement)
9) Repeat agein for all cylinders, first squirting some oil into the
   plug hole (about a teaspoon). This is the "wet" test, the oil will
   seal around rings better.- if compression increases much, worn rings
   are indicated. 

Here's a chart fo fill in, if you don't already have the whole
tech check-list off hoosier:
               Compression Test     1    2    3    4    5    6    7    8
 (Engine warmed up, first
  test dry, then with a      Dry   ____ ____ ____ ____ ____ ____ ____ ____
  couple of squirts of
  engine oil to check rings) Oil   ____ ____ ____ ____ ____ ____ ____ ____
   ________
  /___  _  \        Roger Garnett              (Roger_Garnett@cornell.edu)
 /|   ||  \ \       Agricultural Economics   | "The South Lansing Centre 
| |___||  _  |      3 Warren Hall            |  For Wayward Sports Cars"
| | \  |   | |      Cornell University       | (Lansing, NY)
 \|  \ |__/ /       Ithaca, N.Y. 14853-7801  | (607) 533-7735
  \________/        (607) 255-2522           | Safety Fast!


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