Detroit 60 series 12.7 head gasket

if your leaking from the under head gasket motor more than likely needs rebuilt

 

I am pretty sure in what I am about to say:: you don't necessarily need a thicker head gasket, but installing one so that the cam gear lash is the same as new is helpful. I don't know how easy it is to buy a thicker gasket. I remember that Pittsburgh Power had them specially made. They claimed (some years,ago) that a truck they were working on got extra torque on a before and and after comparison test on their dyno.

 

I personally am unaware of a readily available “thicker”, (and by how much), head gasket for a 60. I know that the difference between the upper and lower limit of the head height is .011”. The front gear train lash is .006” to .009”. I know Detroit Diesel doesn’t recommend third party surfacing of the heads because of the complexity of fixturing, account of the fact that a new or good head isn’t flat per se. They should maintain a .006” “bow” in them when not under tension. (I am also aware that people do resurface them however).
It is my understanding that if a head is to be remaned by OEM shops and it’s determined to be out of limit in straightness or demension, it is spray welded up slightly and resurfaced to original specs. I had never been taught or instructed to use anything other than an OEM part number gasket during overhaul.
As a side note, the thickness of the head gasket on a 60 has no bearing on how high the head sits above the piston at TDC, as the fire deck of the head is sitting on top of the liner circumference. Thickness of the gasket affects the compressibility of the fire ring on top of protrusion flange only, which should only be .001”-.003”.

 

How many miles, and how bad is it leaking?

 

Anytime you replace a head gasket, you need to have the block and head cut. When they cut the head they will check it for cracks.

 

That information is incorrect. Just because you have a head gasket falure, an inframe is not required, which is what will have to happen, as you cant "cut" a block deck surface or counter bores, with the liners in place. If there is a head gasket failure for whatever the reason, the liner protrusuion should always be measured the proper way so as to confirm counterbore specs.

 

I think when they mill a head they install different depth valve seats. I was told Detroit has taken back quite a few bad aftermarket heads that were milled too much. I had a head gasket blow at just over 500k, out of warranty. It blew between the fire ring and coolant jacket. Liner was pitted outside of the fire ring surface. It lasted less than 300k and blew again. This time hydro locking and dropping a cylinder. Protrusion was under spec. Had all 6 cot and rebuilt the engine. Once the heads off, might as well do an inframe. Cost wise, it makes sense, you’re over halfway there.

 

I never mentioned anything about an inframe. What I said is you should ALWAYS have the block cut and the head cut as well when replacing a head gasket. And the machine shop will also check the head for cracks. If the head and block are not cut, it will most likely result in premature head gasket failure. You do realize that liners can be remove and then replaced without doing an inframe? I have had it done in the paat.

 

Where is it leaking? At the left front corner of the head?