Counter-bore tools and parts...

[Rawze]

(01-16-2017 )ceff_by Wrote:  nice vid. If headgasket blown counterbores MUST be checked -- coolant pressure and blown gasket in 90% is consequence -- reason is bad counterbores (usually exhaust side) and\or head cracks. Wondering that many shops have no idea about liners fretting\moving issue, they just drop new gasket and replace bearings with the hammer.. Wtf. . Here is manual from cummins. Its easy way to see if liners need to be repaired even without actual measurement.

I agree, but not every mechanic is willing to pull pistons and liners out every time a head comes off. - They might as well be doing an inframe at that point. Because of this, many will simply check liner height, and call it good if they are in spec on height alone. They will assume that since the height is good, the liner is not fretted, and there is no problems.

BIG MISTAKE TO ASSUME THIS! -- Yet it seems to be the most common method, and a lot of engines have problems again in only a short while, all that money wasted for the repair.

====

FIRST AND FOREMOST! -- ALWAYS, before the head is going to be removed from an ISX, a coolant pressure test (letting it sit over-night) with 20-PSI should be done with the oil pan off. After it sits, checking for coolant buildup at the bottom of the liners, etc. but even this will not reveal liner issues sometimes, but it should be done regardless. Sometimes, a liner simply will not show leakage unless it is under high compression (engine load) while the engine is running.

A slightly better method for determining liner fretting this is to compress the liner on the passenger side to 100 ft-lbs, and only 10 ft-lbs on the intake side, and check the heights, but even then, it will not always reveal itself.

SO,... This leads to the question of what else can be checked while the head is off, without pulling pistons liners out?

===

Here is one alternative method...

http://rawze.com/forums/showthread.php?t...48#pid7648

That method can reveal a lot sometimes, but the head has to be as old as the engine block for this method to work.

Another method is to measure the thickness of the fire rings in the head gasket and compare the thickness from the drivers side to the passenger side for each cylinder. This will almost always reveal what the differences in height are at the counter-bore before the liner is pulled out. The fire ring gets crushed unevenly when there is liner fretting.

====

There is a truck with a CM2250 engine in Mr. Hags shop right now that had 2 dropped liners in it. It was taken to another shop the first time it started spitting coolant out of the radiator cap, and the first shop told him he had a bad head, and bad head gasket. They checked liner height and said everything else was good. -- a month later, coolant issues again...

when the liners were tested, they were all correct height,.. again, but compressing them on the passenger side only revealed that some were as as low as 0.004" below where they should have been. The bottom of the head showed no signs of the fretting, because it had just been replaced and had not worn from it yet. - I will bet that the old head would have had grooves in it like I mentioned here -- http://rawze.com/forums/showthread.php?t...48#pid7648

Anyhow, the head gasket also revealed the height differences too.

Sad part is that they charged this guy almost $13,000 dollars to replace the head and gasket. NOW he needs ANOTHER NEW HEAD! because they in fact did NOT put a new head on, although they charged him for it. They put a head on that was date stamped 2012, and when they were called out on it, they revealed that they had installed an old used head that had been cleaned up a bit.

Some of the other of what I would consider mistakes they made, included re-using the injector fuel supply tubes that go into the head. This caused massive multiple leaks in the fuel rail. YOU SHOULD NOT RE-USE THOSE TUBES IF YOU REPLACE THE HEAD!. The chances of having a leaky rail after a while becomes very high. - His truck had exactly this problem only a few days after the head was replaced by them.

- I think the guy clearly got taken for all he was worth on that,... I can understand a shop not being great at ISX engines,. ok,.. but to charge so much money and only put a stinking used head on it? -- C'mon -- That is downright dirty if you ask me!. .. It is sad indeed the poor quality of what shops do these days.

It is now at Mr. Hags shop getting done correctly this time. I happened to go over there for other things, and decided to help the guy out a bit, so I used the opportunity to show another forum member how to counter-bore a block that wanted to learn more. We counter-bored his block for him for free and the new liner height is going to be 0.013". Much better than the 0.010" it was from factory. We were shooting for 0.014" but had to cut a bit extra to clean a questionable step out of one of the holes that was there from the factory.