: 4.6 Northstar



dtino
01-03-10, 02:25 PM
People, I am doing my irst Northstar head gaskets. So far so good, but the Haynes manual was a waste of money of the this issue. I found the tightening specs, but I need to get the tightening sequence. Can someone help here? I have a 94 Seville SLS which I really like and want back on the road asap, any help would be GREATLY appreciated.

Thanks, Dave

Submariner409
01-03-10, 03:03 PM
Chilton's and Haynes are useless - far too generic.

For your needs, right now, subscribe your car to www.alldatadiy.com (http://www.alldatadiy.com) - GM service manual as well as rate, labor, recall, warranty, Technical Service bulletins, more info than you can ever read for your particular car.

Otherwise, the GM manual comes from www.helminc.com (http://www.helminc.com) or eBay.


Here's the torque sequence BUT there's a very specific method of setting starting torque and then three additional passes of a certain number of degrees of bolt rotation - there is not a final torque value.

dtino
01-03-10, 10:10 PM
Thank you, Thank you! Now if I can ask one more question, which service manual do I need to get? I look at your link and they are showing two, Shop\Service Info and one that they are calling a supplement. I will order right away, I need my car back as soon as I get it back together now that my older caddy is acting up.
Thanks, dtino

Submariner409
01-03-10, 10:27 PM
I'm spending your $$$, but if you are looking at Helm, Inc. manuals OR Alldata I would order the manual and supplement - there are always running corrections published.

Krashed989
01-04-10, 01:33 AM
The 94 year has 2 Service manuals. 1 for chassis and drivetrain and the other for electronics. Guess which one is fatter.

dtino
01-04-10, 07:48 PM
First of all, THANK ALL OF YOU!! Everyone has been a lot of help in this new journey. I have one last question before I get deeper into this Northstar, does the intake have also have a sequence as to the tightening? Haynes show the sequence for the service cover, what about the intake itself?
Thanks, dtino

zonie77
01-04-10, 10:22 PM
Are you planning on dropping the engine or are you going to try it in the car?

Here's a thread I did after doing one. There are other good threads that I lost links to so you will have to search (do an advanced search). The one by Tateos has a lot of tips in it.

http://www.cadillacforums.com/forums/northstar-performance-technical-discussion/5052-n-head-gasket-repair-part-i.html

dtino
01-05-10, 07:53 AM
Thanks!, I am doing the head job while the engine is in the car. So far so good and it is coming apart fairly easy. It helps to have small hands. I hope to be done by the end of the month, I have to work and only get to do the car on weekends. I will be nice to be able to drive her again. My 85 Fleetwood has lasted me 25 years without any problems, I was hoping to get the same out of the 94, but things happen. I have to put in a heater core due to the overheating (engine found a weak spot), it looks like that job is going to be harder than the head gaskets! Many thnks to all of you.
dtino

Krashed989
01-05-10, 01:40 PM
On the 94 there are only four 8mm bolts holding the intake manifold down. The tightening sequence is not critical, but I usually go in a criss-cross pattern.

codewize
01-05-10, 02:29 PM
I would not trust AllData for torque specs. They're a great reference resource but I'd go with a FSM for that type of project. I've found AllData to be wrongs about torque specs on a few different occasions.

zonie77
01-07-10, 07:04 PM
Only a few people have sucessfully done it in the car because that is by far the hardest way to do it. Bigtony (not sure if that's correct ID) is the only guy who said it wasn't bad.

Here's Tateos's thread: http://www.cadillacforums.com/forums/northstar-performance-technical-discussion/126253-97-etc-n-head-gasket-project.html

codewize
01-08-10, 10:16 AM
Wait, I'm confused. Does the 94 SLS have a N*? I thought that was 4.9 till 95 or 96.

Well, apparently it does if you're asking so yes, doing that job in the car is a last resort ditch effort from what I understand.

tateos
01-08-10, 01:03 PM
Not positive, but I think in '94: Seville and Eldorado got N* in both trim levels - Deville was the one that had 4.9L in Deville, N* in Concours trim. Fleetwood was 5.7L

dtino
01-09-10, 06:14 AM
I have found that the N* also was in the 93, I have found some used manuals for a 93 and am going to see what the differents is in the 93 and 94. So far doing the HG's in the car isn't hard at all, but of course my hands are thin and small and I am able to get to bolts most people can't. I was surprised at how easy the water pump was. The only hard part is getting the gas lines apart! And what were they thinking with the starter? LOL LOL I enjoy learning about this N*, I am a caddy man all the way and really want this N* to come out right. I have had my Fleetwood for 25 years and it has never failed to start (of course I am the only one that works on it). After the SLS is done I am doing a total restore on the 85 . I will have both car till I am gone.

dtino
01-10-10, 10:41 PM
Well I am updating my travels with my N*. So far I am down to taking the valve covers off, and it has been fairly easy to this point. I am not rushing it, I want this to be a good learning tool too. I have been looking things over as I am working on it, I hope to have her done by the end o this month. I will post more as I go along, again many thanks to everyone that has helped me along the way.

dtino
01-17-10, 09:27 AM
You know guys, I am not even sure if I have a blown HG. The car ran great all weekend then monday night the heater wouldn't come on, I was getting low coolant level, and she was heating up over 230 degrees. I first thought it was a thremostat, so I replaced the thremostat and the water pump. Backed her out of the drive and she built up pressure and blew the heater core out. Of course I know the N* does not mix when the HG blows. I was told that this is how the HG blows so that is why I decided to do the head job on her. Anyone got any thoughts about the above?
Thanks, Dave

tateos
01-18-10, 12:47 PM
Classic blown HG/pulled head bolts symptoms

dtino
01-20-10, 06:40 PM
Thanks, Now I know I am going at it right. I hope to have the heads off this weekend and get them milled and cleaned Monday. I am doing this in the car and it is just as easy as a normal v-8. Many thanks to everyone!!

tateos
01-20-10, 07:23 PM
Whoa!

There's a lot more involved than that - better do a search for "Head Gasket" or "HG"

Here is my thread:

http://www.cadillacforums.com/forums/northstar-performance-technical-discussion/126253-97-etc-n-head-gasket-project.html

A lot of what I needed to know to tackle the job I learned from zonie:

http://www.cadillacforums.com/forums/northstar-performance-technical-discussion/5052-n-head-gasket-repair-part-i.html

http://www.cadillacforums.com/forums/cadillac-tech-tips/31831-n-head-gasket-repair.html

If your heads gaskets are leaking, you need to repair the threads - I used Norm's inserts - Jake's studs are out now, and are considered even better

Submariner409
01-20-10, 11:06 PM
Unless the heads are warped DO NOT MILL THEM !!!!

Like tateos posted, do a LOT of homework before you screw this up, big time.

Insert the block - if you don't, you'll be throwing good money after bad.

Do you have any idea how to lock the timing chains/tensioners and reset timing on this engine ???

All 32 cam followers perfect ?? No dishes ??? Cam lobes square ???

codewize
01-21-10, 12:34 AM
This is probably not necessary and will do more harm than good if it's not.

I hope to have the heads off this weekend and get them milled and cleaned Monday.!!

This is a bad attitude and is very far from true.


I am doing this in the car and it is just as easy as a normal v-8. Many thanks to everyone!!

You're headed down a sure road of disaster, slow down, get educated then rethink doing this yourself.

dtino
01-24-10, 08:10 AM
Appreicate all the feed back, and yes to the timing chains, valves and lobes. Believe me, I am taking my time and going at a very slow pace, the milling was only a "quote". If their not wrapped I only want to clean them. So far it is not a hard job, I just rebuilt a 2.7 dodge which was a pain, not 32 but just 24 valves. I have the right books with the right info and all the tools I need for the job. But I know this is my first N* and I don't plan on having problems (of course there always is) but I do plan on being careful and going slow.
Thanks