: My Photo Essay N* Head Gasket Repair Job



SMS
11-21-07, 02:52 PM
Recently wrapped up the repair with Timeserts on a 99 DeVille. I'm too lazy to type this all over again, so here is a link to my project on our sports car board. Several pictures and some narratives for the non-Caddy guys, but if you are thinking about getting into one of these, this may help to visualize some of the process.

Car was the textbook overheater with no other problematic symptoms.

Thanks,

Bill

Link to Northstar project:
http://www.midwestscc.com/viewtopic.php?t=205&page=1

kdcing
11-21-07, 07:39 PM
Awesome, awesome, awesome. Thanks for taking the time to show
where many of us may need to go some day.

codewize
11-21-07, 10:12 PM
Wow very nice project, very nice documentation.

Thanks for posting.

Ranger
11-21-07, 10:57 PM
"70% will fail"? Where are you getting your figures from? Also, it is my understanding that the Northstar head bolts ARE NOT torque to yield.

BTW, Nicely done. Thanks for posting it.

zonie77
11-22-07, 01:05 AM
Great job SMS!

Cadillacboy
11-22-07, 12:02 PM
That's a scrumptious job !

JN in CA
11-23-07, 10:42 AM
Wow. Excellent photos and commentary. Really awesome. Thanks for taking the time to crosspost it here.


"70% will fail"? Where are you getting your figures from? Also, it is my understanding that the Northstar head bolts ARE NOT torque to yield.

Well, he wrote: "bolts are torqued to a low setting (30 on this one) then twisted 60 degrees of rotation 3 times for final tightening, rather than to a torque setting." So I think he is confirming they are not torque to yield.

As for that 70%, if it was that high I think Cadillac would've been forced to issue a recall. Let's hope he's not getting that number from a dealership. :(

Ranger
11-23-07, 05:54 PM
I agree on both counts.

pjw315
11-23-07, 11:01 PM
Very nice write up.

Playdrv4me
11-24-07, 03:38 AM
70 percent is probably an exaggeration, but for that body style of Deville especially, the rate seems to be pretty high.

97Concours1
11-24-07, 11:03 AM
SMS,

I think when you take on and successfully complete a Northstar head gasket repair, you join the ranks of those who have achieved other great feats like... climbing Mount Everest or winning the New York Marathon. Congratulations on your success!

Ranger
11-24-07, 04:15 PM
Yeah, there should be a hall of fame section for that.

stoveguyy
11-24-07, 11:06 PM
i noticed in some of your pics that it looks like the balancer pulley is pushed in about 1/8" too far so the serp belt is slightly misaligned. i did the same job on my northstar motor and i think my pulley is in too far. maybe its the angle of your pictures. its easy to see if you crawl under the car. of course you have to take off the balancer bolt again and than use your 3 jaw puller to tweak the balancer out slightly.

SMS
11-26-07, 10:35 AM
Thanks guys for the Hall of Fame nomination, I'm flattered!

Ok, the 70 will fail is a bit of an exaggeration, it sure seems like it though because anybody talking about it has had an issue!

The serp belt alignment looks OK and is not showing any signs of wearing, but thank for the heads up, it is always good to triple check everything, like the steering coupling boot that did not seem to snap into place properly.

About 2000 miles racked up already, the car is fun again. :)

AJxtcman
11-26-07, 01:44 PM
Take a close look at the pictures below

http://i121.photobucket.com/albums/o225/SMSC1/cad5.jpg

http://i121.photobucket.com/albums/o225/SMSC1/cad7.jpg

http://i121.photobucket.com/albums/o225/SMSC1/cad13.jpg

AJxtcman
11-26-07, 01:55 PM
Look at the amount of depth from the crush
http://i224.photobucket.com/albums/dd25/AJxtcman/Northstar/222.jpg

Look at the head gasket bunching up from the heat cycles. :hmm: The head moves around quite a bit.:hmm:
http://i224.photobucket.com/albums/dd25/AJxtcman/Northstar/111.jpg

SMS
11-26-07, 02:14 PM
Excellent commentary and notes on the photos. Note that this enging looked great on all 8 holes with a compression test, but a leakdown test revealed that the 4 corners had a higher % of leakage, this one pictured being the greatest.

AJxtcman
11-26-07, 03:15 PM
Excellent commentary and notes on the photos. Note that this enging looked great on all 8 holes with a compression test, but a leakdown test revealed that the 4 corners had a higher % of leakage, this one pictured being the greatest.

It is very normal to have higher compression readings on the bad cylinders:thumbsup:

This may hold true to more than just Northstars, but that is a Northstar test result.:thumbsup:

NAFTA
04-10-08, 01:32 AM
How long did the whole job take you to drop the engine and rethread it and put in new gaskets ?

SMS
04-10-08, 01:42 PM
How long did the whole job take you to drop the engine and rethread it and put in new gaskets ?


I think I had 42 hours in it. The meticulous drilling and tapping for the Timeserts was very long! I also spread it out over some period, but did track the time I spent working on it. That is from pulling it into the garage to driving it out when finished.

zonie77
04-10-08, 06:45 PM
I think I had 42 hours in it. The meticulous drilling and tapping for the Timeserts was very long! I also spread it out over some period, but did track the time I spent working on it. That is from pulling it into the garage to driving it out when finished.


My brother's was the first one. We had 40+ hours in it. The second was much faster, still quite a long procedure.