Case 5150 head gasket replacement, any tips?

[Frogpit]

1994 Cummins 6T-590/92. Weeping water externally cyl one above water pump area.
Use OEM gasket? Checking for distortion? Always skim head? OR, just re-torque bolts and check?
I need the torque numbers, ideally a manual. Thanks.

 

[Mursal]

Make sure its actually weeping from under the sealing surface of the gasket?
Get it hot (cardboard over the front of the radiator matrix) give the bolts 1/8 to 1/4 turn, depending on what you'll get away with.
Torque settings will be of little use as there already tightened down, it will take more torque to get them moving again, than if they were loose.
Mark the head of the bolt with tipex first so you know exactly what your getting on each one.
Don't go mad with the tightening, you can always give it more, but you cant put the threads back in.

Good luck ...........

 

[Frogpit]

Thankyou, Mursal. I take it you mean to tighten down all the head bolts in the final sequencing right across the head? Is this in the circular pattern starting from the centre, or, linear, working from one side for the final torque up? Like you say, the bolts will be 'set' and the washers/ bolts will not be lubricated after all this time.

 

[Gapples]

Hi
The bolts are angle torqued & extremely tight !
It's recommended that you replace the bolts when you do a head gasket as they are designed to stretch.
I'll see if I can find out the torques & angles

 

[Frogpit]

Hello Gapples, I really appreciate your help in this. Yes, bolt replacement sounds a good practice. I am not familiar with your use of the term 'angle torqued' ?
Thankyou.

 

[Pistonbroke]

Don't laugh but my 5120 was damp there 7000hrs ago and a bottle of k seal stopped it and hasn't needed topping up since

 

[Frogpit]

Thankyou Pistonbroke. I can believe that. I have used about three K-Seal bottles over about 500 hours. It worked to start with, but when everything gets hot under hard going, then the weeping is enough to spatter out to the front mudguard. Engine is only on 7200 hours now. Having to add about 3-4 pints coolant every couple days now.

 

[Timbo]

Thankyou Pistonbroke. I can believe that. I have used about three K-Seal bottles over about 500 hours. It worked to start with, but when everything gets hot under hard going, then the weeping is enough to spatter out to the front mudguard. Engine is only on 7200 hours now. Having to add about 3-4 pints coolant every couple days now.

Head off- skim it new by bolts check valves etc etc do it properly.

 

[Frogpit]

Thanks Timbo. I am inclined to agree. I just hope the engine block top surface is not eroded by the leak stream at that point.

 

[Mursal]

Yes if you're already on the sealer, its time to do things proper ...........

 

[Gapples]

Hello Gapples, I really appreciate your help in this. Yes, bolt replacement sounds a good practice. I am not familiar with your use of the term 'angle torqued' ?
Thankyou.

Hi
Sorry I don't have the correct torques to hand. Angle torque is where you initially torque up a bolt to a lower setting, say 40lbft & then say 120 degrees.

 

[agrimax]

@Gapples ,would the torque settings be the same as a 5140? If so, I think I have them downloaded somewhere.......

 

[Dmc]

@Gapples ,would the torque settings be the same as a 5140? If so, I think I have them downloaded somewhere.......

I'd say they're the same.

 

[Timbo]

Exact same engine, just a slight change in fuelling

 

[agrimax]

Have part of a manual in pdf form,but can't upload it or take a screenshot of the relevent section!
Basically the tightening sequence is to start in the middle and alternate around the bolts in a circle. Hard to describe without a picture but I can't upload one.............
Tighten bolts in 4 steps.
1st to 30 ft/lbs
2nd to 66 ft/lbs
3rd stage is to tighten all to 88ft/lbs, except the outside row on the rhs looking foward towards the fan.
4th stage is tighten all head bolts an additional 90 degrees.
Rocker arm bolts to 18 ft/lbs and valve clearances are 10 thou for inlet and 20 thou for exhaust.......

 

[Gapples]

@Gapples ,would the torque settings be the same as a 5140? If so, I think I have them downloaded somewhere.......

Yes, exactly the same settings

 

[Frogpit]

Thankyou, everybody. I know the gasket compression amount is critical, and the four stages of tightening plus 90 degrees. I shall take your advice, and get the head checked professionally. I don't have a straightedge tool to check the block after cleanup, might be able to hire something.

 

[Mursal]

The back edge of a hacksaw blade will be fine.
Double check it back to back with another one for daylight, if your in doubt ..............

I don't have a straightedge tool to check the block after cleanup, might be able to hire something.

Let us know how you get on ...........

 

[Frogpit]

OK, thanks again. I keep hearing that this Cummins engine is prone to head gasket failures, is this valid?

 

[Gapples]

OK, thanks again. I keep hearing that this Cummins engine is prone to head gasket failures, is this valid?

Yes, they were prone leaking at the front, LHS if I remember correctly
Usually ok once the gasket had been replaced though.
Keep the cooling system well flushed & use good quality antifreeze.