High blow by

Hi sajjan1969


Excessive blow-by is compression leaking through the rings or the piston to cylinder wall gap is passed tolerance. Do a leak down test on all cylinders find out which cylinder is leaking.


Question: Were the cylinders oversized and re-sleeved?


post back your findings.

Do you mean rebuilt instead of designed?

BG

I valve timing is not right, you can get excessive cylinder pressure, which can cause blowby.

If it's a fresh rebuild, you'll often get blowby for the first few hundred miles until the rings seat.

I have had were a new engine gets blow by cause the ring is not seating .... not good cross hatching ... what we use to do was mix up a mixture of water & comet or any other type that is gritty ... with the engine running we would pour it in a little at a time ... makes a hell of a smoke cloud but it help to like sand blast the cyl walls and get rid of any glazing on them, then take it for a ride and wind it up and down for a couple min


do you have the 2 compression rings so the gaps are 180 deg from each other

if you are 100% sure the rings are 100% good . then your exhaust valve has to opening to late ... first thing you need to do is like octaneman said ... DO a leak down test dont say oh the rings are this gap and that gap DO the test ... testing is the only way to discover the prob ... you ask for our help and a damn good tech told you what you needed to do

forgot about one other thing
crank case ventilation
Since diesel work on much higher compression its a lot easier to build up pressure in the engine oil bath system... you need to make sure that engine is breathing good enough to release pressure in it.If you dont have a PCV valve you will need to add one and you might need to add a breather filter to the valve cover