Head Gasket cm2250

[Rawze]

(11-16-2019 )keepitrunning Wrote:  Thanks Rawze, I have been a fan of your for a long time. I have rebuilt a out 50 Cats this is the first Cummins, they are not a forgiving as a Cat

red engines have ZERO forgiveness to them at all. Everything by the book with only the exceptions mentioned. Everything torqued properly, etc.

only exceptions are mostly liner height to minimum of 0.014" ( some info on this: http://rawze.com/forums/showthread.php?t...9#pid28349 )and to torque is the head itself a better way.

Here is what should be done differently on the head bolts ...


The manual says to torque the head bolts in increments 75 ft-lbs, then 150 ft-lbs, then to 300 ft-lbs. Then add an additional 90 degrees on the head bolts as a final setting.

-- Instead of doing what the book says ....

Start out by torquing the head bolts in increments 75 ft-lbs, then 150 ft-lbs, then to 300 ft-lbs, same as book.

-- THEN let the head sit over night so the gasket can crush.

THE NEXT DAY, Re-torque the head AGAIN to the 300 ft-lbs a second time after the gasket has had time to crush. - It is not unusual to get another 1/4 to 1/2 turn or more sometimes out of the bolts in several places to get them back to 300 again the next day.

THEN AFTER THAT SECOND GO AROUND at 300 ft-lbs ... AFTER THAT, Then add the additional 90 degrees on the head bolts for the final setting.

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BTW: just for reference, the final overall tightness after turning them that last 90 degrees will be roughly around 480+ ft-lbs, up to roughly 500 on some of them. i always do this by hand instead of using a impact so that it can be felt to see where they want to actually stop past the 90-deg, but that is just me.

[keepitrunning]

Thanks

[Rawze]

(11-16-2019 )keepitrunning Wrote:  Because they are all even add a shim?

Those mid-stop liners are red engine's biggest weakness!,.. it has to be absolutely right!

ALWAYS counter-bore, I donlt care what the factory height was.. Counter-boring requires shimms to raise liners, and to get it up to 0.014" ... when replacing pistons and liners on old engine, ALWAYS CUT FRESH COUNTER-BORES!!!, DO NOT RELY ON WHAT HAS BEEN THERE FOR HALF A MILLION MILES OR MORE!!! YOU WILL REGRET THE HELL OUT OF IT LATER!!! == You will be doing it again.-- The original factory height is also too low for the compression ratio of the engine!,.. and trying to get an old engine with age on it to re-seal and not fret liners is impossible the second time around without fresh cut counter-boring, raising liners, etc.

here is some related info: http://rawze.com/forums/showthread.php?t...9#pid28349

don't end up like this guys...
http://rawze.com/forums/showthread.php?t...5#pid41315

[keepitrunning]

Thank you that's what is was wondering adout.