[Healeys] playing detective

Bob Haskell rchaskell at earthlink.net
Fri Sep 28 04:30:59 MDT 2007


My leak down tester only uses 100psi. It can rotate my MGB engine (haven't 
used it on the Healey six), usually happens when the piston is not quite at 
TDC.  I use a wrench on the crankshaft nut to keep the crank from rotating. 
  In gear helps too - with the rear wheels on the ground and/or the parking 
brake on.

Bob

Richard Ewald wrote:
> If you put 150 PSI into a cylinder you will wind up pushing the piston to
> bottom dead center.  Pushing the piston to BTC will open one valve,
> depending on which way the engine rotates.  ask me how I know this.  An
> engine only runs about about 60 PSI at idle, and that is enough to push the
> piston down.  even with a large leak in the cylinder there is an excellent
> change that your compressor can supply the air faster than the problem can
> leak it out.  In this case the engine will still rotate.
> I am going to go with there is a problem with the valve train.  Either a
> rocker is bound up, valves are mis adjusted, a valve is hung up in the head,
> or a pushrod is somehow stuck holding the valve open.
> 
> Rick


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