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

slatersfb at aol.com slatersfb at aol.com
Tue Apr 12 16:11:59 EDT 2005

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 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 
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 
(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

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 
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 


PS : I used to murder Bambies.  ----NEVER no more.
Pistons in my jetta had valves crash more than once, complements of PO. 350k miles when I bought her. 
Believe me when I tell you they are LOOSE. I did not measure because it is not necessary. Rings fit tight in grooves.
And grooves are clean. Piston rocks a bit in bore and slaps - worse in winter. One is a bit louder than others, 
but all do it. Uses NO oil. I've built other motors under adverse conditions also & had piston noise, 
but as long as rings are tight in grooves, and broken in correctly, no sweat. I'm driving the proof every day.
As for shooting moose. Be proud. You use the hide for leather, probably eat the meat, also. 
At least you do this honestly. Part of the food chain as all living things are. Is not murder.
Better to let someone else kill the animal & then you buy in store? 
Some people think meat comes from the super market. 
My old man taught me it was OK to kill as long as you ate what you kill.
A good rule to go by, I think.

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