Engine/Transmission (1994 - 1998) 12V headgasket Repair Pics

[JJW_ND]

I added a few pictures to the Photo Gallery under JJW-ND 96 12V https://www.turbodieselregister.com/user_gallery/displayalbum.php?&albumid=476



Finally fixed the extrenal coolant leak I have had for over 100K. Oil analysis every 6K showed nothing getting inside. Leaked about 3 gallons in 100K.



Pictures are from the inside after head removed, under side cover (it leaked badly), and varies pictures of the process.



Took about . 008 off the head to get smooth. UPS never showed up with the . 010 so put a . 020 in. Added a 16CM turbo housing and 60 lb valve springs while everything was off and apart.



Valves look fine, cylinders looked fine, generally everything (shop techs opinion) looked very clean for over 220,000 miles. Engine has had synthetic oil since 50K that is changed every 24K (no bypass).



I would be interested in any comments good or bad, observations from those of you who see the insides of these engines.



Did a dyno before and after (a few mods added after) fyi.



If link does not work, please feel free to add one that works.



JJW

ND

 

[Deezul1]

Thanks for the pics, always nice to see it after hearing about, makes it much easier to understand where everything is

 

[CumminsPower98]

I just did a head gasket on a '97 with 132k on it. It had just started to leak a little externally by the thermostat. It also had an internal leak on the #2 cylinder about 3/4" long. It leaked some compression into the coolant but there was no sign of coolant in the oil.

 

[John_P]

JJW-ND:



I had my head gasket replaced back in January of this

year.



I "blew" mine at the #1 cylinder and after the head was

taken off, we noticed that it was getting ready to "blow"

at the #3 cylinder also. I blew the head gasket while

racing a Ford PSD (he lost ) and was seeing about 52lbs.

of boost from the B-1 turbo at the time it happened.



Like you, the inside of my engine looked good! A couple

of things Scheid Diesel found were; #1) Cylinder #3 had

some very minor "scratches" on the backside which they

said was probably caused from me "getting it too hot"

at one time. They said the scratches had been there

awhile though. #2) Found that Cummins apparently

forgot to put a valve seal on the #3 intake valve! That

valve was O. K. , but it did have some carbon build-up on

the bottom side. They did a valve job anyway while the

engine was apart. I also had them install the 60lb. valve

springs on all of the valves.



That headgasket was done @ approximately 155,000 miles.

I have 178,000 miles on the truck now and have had no more

problems with the head.



Scheid Diesel recommended the "ARP Case Hardened Head

Studs" which I had them install.



Anyway, thanks for your pictures!! Good write-up!!



-----------

John_P

 

[The patriot]

Looks like the return line would be an easy fix right now even though it's been done before.

Eric

 

[HFletcher]

JJW-ND, you said you changed your synthetic oil every 24,000 miles - I assume you did filter changes in between, correct?

 

[JJW_ND]

Synthetic Oil

New filter, quart of oil and oil sample grabbed every 6K.



I was pleased to see the exhaust Manifold and head near the exhaust was in as good a shape (not shrunk to much) no cracks. I have got to 1600 degrees many times. Some hard pulles put the pyro on 1200 for hundereds of miles at a time.



Truck is alittle raspier with the higher timing. But it sure revs crisp and revs real clean past 3K. Before it did not sound as smooth over 2800. Gained 30hp with just the timing increase. Added four degrees onto what it was stock. On the dyno my GSK did not cut back fuel even at 3600. Now with the heavier springs, I don't worry about the higher RPMS.



Any comments on what the extra . 012 headgasket clearance ( . 008 removed - . 020 gasket installed) will do?



jjw

ND

 

[T. Baker]

Why the paint mark across the valves?

 

[Gary - K7GLD]

I'm a bit puzzled by the seemingly SEVERE etching and erosion of the heads surfaces seen here:



[https://www.turbodieselregister.com/user_gallery/sizeimage.php?&photoid=2657&width=2]



Comment?

 

[RHARVEY]

I may be wrong... but is this not water that is applied when the head is being surfaced?????? Actually. . the head surface looks good



Rick

 

[Gary - K7GLD]

AHhh - you must be right - now that I look closely with the "water" bit in mind, that is probably what appears to be erosion...

 

[JJW_ND]

Gary and others the I think I put three pictures of the head as it was being resurfaced. The stone to a 1/2 . 001 or slight more each time. Took . 008 to get it totally smooth. Yes that is water. The surface was very smooth when finished.



The white marks on the valves were done to keep the valves in the same positition. This shop rarely found a need to grind the valves in these motors (unless many many miles or abuse). Mine only had 220K. We marked them and then one by one inspected each one. All were fine and were pushed back in the exact same positition. No carbon or buildup anywhere.



jjw

ND

 

[JGK]

The white marks on the valves were done to keep the valves in the same positition... ... We marked them and then one by one inspected each one. All were fine and were pushed back in the exact same positition.

JJW,



Are you implying by this comment that the valves tend not to rotate in the head? I once had a mechanic (gas engine) say they do indeed rotate. The issue came up regarding losing a timing belt and having a valve hit a piston. He said if one is lucky and experiences a very mild case of valve crash the valve will get ever-so-slightly bent and that over time, due to rotation, it will re-seat itself. I believe that may have happened to me in my Nissan truck BCD ("Before Cummins Diesel"). The belt slipped a few notches. After replacement, it sounded a little odd and didn't run quite as strong (I felt) but after 5K or 6K miles it was fine.



-Jay

 

[T. Baker]

The last two times I had the head off my Nissan diesel I lapped the valves lightly. You could see by the valve stem wear that they were not rotating. I turnded them 180 deg. so they were wearing on a new serface. When I had the head off again and lapped the valves I turned them 90 deg. to wear on another new area of the valve stem. After a light lapping they didn not leak when I tested them.

Heavy duty chevy engines have valve rotators and hydrolic lifters. I'm not sure why Cummins dosen't use them.

 

[Ben Rumson]

Great post and Pics - THANKS

- Ben

 

[JJW_ND]

Valves do not rotate!

Jay!



The shop tech marked the valves prior to removing the springs (I installed 60 pounders). That way the valves would go back in exactly like they came out. He said this can be particularly important if no valve work occurs (mine did not need any). It is highly likely that you will get all valves in the same orinataion when removing springs, pulling valves to inspect and install new seals.



That is whey the white marks.



The only downside too this project (but a very minor one) is the extra white smoke (and very stinky now combined with the higher timing) because of the lower compression. Otherwise truck runs great, revs very crisp and fast even when cold.



jjw

ND

 

[JohnE]

Is the <em>crisp reving</em> frrom the advanced timing or the governor springs? I noticed the governor springs really improved the cold weather driving, too.



I'm enjoying almost no white smoke with my 20&deg; timing in this cool winter. Idling, it sure is stinky.



Speaking of cold, keep it on your side of the valley. Temps dropped 20&deg;F thisafternoon/evening.