[Vwdiesel] Piston selection--- (when reboring or re-ringing)

[H . Hagar.]

Checking piston fit with feeler gauge might take a lifetime to learn. Piston & bore are round, while gauge is flat. Also the thicker the gauge, the less it flexes to conform to gap between piston & cylinder wall. Bore gauge is the way to go & large mic for pistone.
Truth be told, pistons in my Jetta are so loose they slap under load & have for the last 50k miles. No oil use though. Never had any problems caused by loose piston fit in any engine. A little noisey maybe is all.
 
Bob 

Bob in Entire State  and ALL  :    Lets take a look at the issue.   Nick has farmed out a reboring job
to a good shop.  After 5000 miles he gets oilusage and lots of blowby . He decides to  pull head.

Pull head ?   I Hagar say a little early  ----but ok   .    So the question is  was job done correctly ?.

Loren say and I agree the pistons wear next to nothing in 5000 miles in a diesel ---so use the
feeler gauge as a fast simple test of boring and piston fit.
The bending of the blade is part of why this test works.   ----  no need to be finniky ----this is a
good test ---kind of like kicking the tires ?  --you can't tell if you have a flat ?.

Use it as a GO   --- NO go test.        ----------   I have all the most up to date mesuring
instruments available  -----and yes to use a micrometer to measure bore ?  and a mike
on pistons ? yeah fine.     ----BUT if piston falls through --- ?  you are wasting your time.

Now Shawns case is different ----- he is honing and re ringing ---and probably think on using
old pistons.   ----           I have heard my share of Piston slap SLAP in gassers ---but not one slap
in a diesel EVER.
I am going to use my Texan  ---bragging skills a bit.    my home town Copenhagen Denmark  
(super place in 1950)     it is the birthplace of Aluminium,BIG diesels and ????? i forget ----
Niels Bohr ?       ----so I was weaned on dieseltalk  -----Worlds Biggest   etc.
Burmeister and Wain  ----diesels.     When you can rollerscate on top of a piston ? ---is that
big enoughf to qualify ?.    -------every time I tell this story ---I see this picture of the kid
on the piston with a broom.   When they turned the engine over.------safety was improved after
that.

In Shawns case it may be time to go to a compression ring  --with extra pressure to expand.
I know they work like stink ---but of course they do not last as long as standard rings.

I know that Roger Brown know the brand name. ---Same principle as a leather in a bicycle
pump or a bottle jack or a coleman lantern for gasoline.

By the way I make DIY  leathers from Moose hide  ---yeah I shot them.  (not proud).

Hagar.

PS : I used to murder Bambies.  ----NEVER no more.