I just finished replacing the head gasket on mine after it sprung a leak to the outside passenger side. Had the head shaved .014 and as per Piers recommendations replaced it with 20 over Cummins marine gasket. I used the original head bolts as I saw nothing in the shop manual that said to replace them even though they are torgue to yield. I fiqured they could be reused once. I have just over 200,000 klms on mine and have pulled the TT across Canada and up to the Yukon with my current mods and was supprised the head gasket lasted as long as it did. The engine was in great shape. No wear on valve stems and crosshatching still in cylinders. Just relapped the valves by hand and put it back together and it is running fine. Bought the head gasket and other related gasket sets from Piers. I did it at home in my shop for a total of around $550 Can which included filters and new thermostat and oil.

 

What is the actual difference in the Marine VS the regular HG?

 

Local diesel shop has been through the head gasket & cracked head woes.
Mike sourced after market heads and after viewing the product decided to only recommend porting & o-ringing on a new head. They are cast very well.

On the head bolt question, I say no. Now is a great time to upgrade to studs. Torque to yield bolts require a complete cleaning of the block threads to assure uniform clamping force. They also do not re-torque as easily as studs.

I do not remember the difference between the regular and marine gasket, but was told the marine gasket is what Cummins supplies in all the kits these days.
Can anyone verify or shoot that down?

 

When I talked to Cummins in the Twin Cities when I did my headgasket, they said they never heard anything about using a marine gasket on our engines. I was advised by piers haisley machine to go with a .010 over standard gasket, which I got for about 95 bucks. I'll be honest, I was in a bind when I did my HG and didn't take the head in for resurfacing or magnufluxing. The cleaner at the machine shop was broken so I would have had the truck down for another week so I ran a square all over the block and head and it was still very true to my eye. Cleaned it up and put her back together with studs and haven't had any problems since. A bit of a crap shoot, I know, but so far so good...

 

I believe the marine gasket was designed to hold more horsepower with improved firerings. Also on another note here is a little shop tip that I fiqured out to help keep the crud out of the open cylinders when cleaning off the block. I used the short plastic sour cream tubs and pushed them into the cylinders as they are a nice tapered fit. Then take a box knife and trim them level or just under level with the block. All the crud will be caught in the tub which can then be easily removed when done.

 

Great tip!!

 

My Cummins manual calls for all the head bolts to be torqued to an initial 65ftlbs, then torque "the Long ones" which if I recall were #16,18,21,23 or something like that, the ones on the exhaust side of the head. Torque these to 120ftlbs. Then it says turn ALL the bolts another 90 degrees. To me this would give uneven torqueing of the bolts? Is this what they reccomend? dosent sound right to me.

 

I don't know why the 95 would be different than my 94 manual. Mine says to torgue all the bolts to 66 ft lbs first. And then torque all the long bolts, which are the ones that go through the push rod pedestal to 89 ft lbs(six of them) Then tighten all the bolts an addtional 90 deg. You can follow the torque sequence in your manual or as a general rule you can start from the centre and stagger your way to each end alternating back and forth. When I did the last 90 degree torque I marked each one after I did it so as not to loose track of the ones I did and accidentally try to add another 90 deg to one and possibly break it off.

 

that is strange on the manuals. Mine says it covers up to 94, I didnt see any reason it wouldent cover most of my 95`s so I bought it. Seems we have differing info.

 

Well, My take on the cracks...

if the machine shop says it is cracked, replace it.

Reason being, if they pressure check it and it holds now, how do you know the crack won't 'finish' in the next 10 or 20 thou miles and then you are doing it again ??

It's too much of a hassle for me to not put a new head on.

 

Pretty much my thoughts, specially with my track record with these trucks.
but I`ll have it checked. The Cummins manual have some specific guidelines also. But a crack is a crack ,and they say if its not thru the valve seat its OK to reuse. IMO no way, it make a boat anchor of it and get a new one.

 

mine is cracked between the intake and the exhaust valves on 3 cylinders. many 12vs do this that have been up in hp a while. i am bolting mine back on with a set of studs and a 20 over marine gasket. it was running fine with these untill i put in 50 pounds of boost and stock head bolts. but i guess the 20 degrees of timing didn't help either.