Northstar Timing Chain Re-Install & Head Gasket Re-install Feedback........

97BlueDeville · #1 (**permalink**) 04-01-05, 07:53 AM

Hey guys..

I'm almost done with the Timesert / Head Gasket repair on my 97' N-Star.. I did a search, however I only came across a post from Lawrence regarding the timing chain and how to set it up to reinstall.. Anyone have a diagram in detail on how to do this?? I now know to put the Intake and Exhaust dots on the cams straight up, or straight up from the Heads?? Correct?? Since the heads sit at a 45deg angle, I put the Intake and Exhaust cam marks at that same angle correct? The Crank I'm sure needs to be Dot Up correct? Please let me know step by step how to get this bad boy correct..

Also.. The motor has 147k on her, are these timing chains good for 250k miles plus?? Do they break??

The Northstar motor, for the most part I'm very impressed with as far as showing very little wear. Cams look great, springs, heads, timing chains, and the cylinders have the nice cross hash marks still.. While doing the Timesert Job I discovered that aprox 12 of the 20 threads for the head bolts were in bad/poor shape, and would have no way been able to torque down properly with out repairing them. The Timesert job was very much needed here!! Great kit by the way, easy to use, did all 20 bolts and took about 7 to 8 hours to complete the drilling/timesert install.. The Motor saw 260 Deg F 3 times, and did a limp home mode once about 2 miles, so naturally I got the heads milled to see if they were warped. They were only off by 2 to 3/1000ths of an inch. Not bad!! Milled them anyway..

All in All I would say that this is a very extensive job... Never quite did anything like it before. I have re-built LS1 motors and the Northstar motor is much more labor intensive.. Of course the 1st time you do anything, it's harder. I've gotten quite good on my 700RWHP Blown LS1 motor, taking that apart..

1 through 10, 10 being extremely Hard/Time consuming. Working on a motor is not really hard if you have the right tools, just time consuming.

Scaling the Head Gasket Change job I would give it a.

"7" For dropping the Northstar motor and the extensive wiring harness together. F-body motors I give a 3 or 4.

"5" For taking the motor apart to get to the block.

"3" For the Timesert Job Itself. Easy to do, just time consuming.

"3" For putting the heads back on and Re-Torqueing them down.

"7" So far for putting it all back together..

"7" I'm guessing to put everything back into the car, motor, wiring everything..

"8" Time Consuming, checking things over!!

Total Score... About a 6 in degree of difficulty, 8 in the time consuming area....

Do I want to do this again, ummm nope!!.. I would not look forward to it......

Clint

Katshot · #2 (**permalink**) 04-01-05, 08:50 AM

Clint,
I have all the diagrams but no time to scan and email them this morning. If nobody gets to it for you today, I'll try to get them for you by tomorrow morning. Hope that's good enough for you. Sorry, but I was out of the office yesterday and I'm leaving at noon today to go to the NY auto show so my morning is going to be chaotic at best.

97BlueDeville · #3 (**permalink**) 04-01-05, 01:55 PM

Thank you...

Anyone?? I'm leaving my house soon to go up to the Shop and continue working on the car. Need to have her done by this weekend. Anyone have any info available now? BBob.. ??

BeelzeBob · #4 (**permalink**) 04-01-05, 02:54 PM

Put the crank sprocket mark at 12:00 and the mark on the intermediate sprocket at 6:00, install the short chain and slide the sprockets onto the crank/intermediate shaft simultaneously. You will probably need to turn the crank slightly to allow the crank sprocket to slide onto the key. When you have the intermediate sprocket/chain/crank sprocket correctly installed and timed the timing marks should be directly opposite each other for that chain system.

Put the timing pins on the cams at 12:00 RELATIVE TO THE CAM COVER SEALING SURFACE of the heads. Yes, since the cam covers are sitting on a 45 degree angle the timing pins on the cams will be at 45 degrees to the ground...but...just the cam cover sealing surface as a reference and put the pins at 12:00. The sprockets and chains for each side go on next. You'll have to put the chains over the sprockets as you slide them on as there is not much slack. When finished, the chains and sprockets for each side should be on, the tensioners set, slack on the correct, slack side(the side with the movable guide) and all the cam timing marks should be at 12:00 relative to the cam cover surface.

Make sure you retract all the tensioners by working the little link on the tensioner and pressing the plunger in past the mechanical rachet. Stick a golf tee into the hole in the link to keep the tensioner retracted while bolting it in place. When finished, pull the golf tee/grenade pin and the tensioner will pop out and take up the slack.

The chains and sprockets are good for at least 300K so I wouldn't worry about them at all. The guides and tensioner shoes will last likewise. They will "mark" with two grooves from the side plate wear almost immediately and then stay that way forever. Make sure all the tensioner bolts and guide pivot bolts are tight and then move the moveable guides to make sure that they move/pivot freely. If you mix up the bolts and put a non-shoulder bolt in the pivot of the guides they willo freeze and screw up. Make sure that they move freely after everything is tight.

Be VERY carefull if the heads are on and you have to turn the crank and/or be VERY carefull turning a cam if the crank is not turning. It is very easy to bang a valve against a piston if the cam timing chains are not installed and either is turned independently so be very gentle if you have to turn the crank or cams to get them in time. The best thing is to have the crank at #1 TDC and pretime the cams on the heads before you install the heads to prevent bending a valve.

When the timing drive is installed correctly all the marks will line up as described. If you then turn the crank it will take 7 revolutions of the crank before the intermediate shaft sprocket marks line up again. This is as designed and is due to the uneven drive ratio of the system...done to prevent harmonics and noise...that is why the chains run 300K. If you turn the crank 7 times the intermediate sprocket will line up but the cams will be 180 off. Normal. Turn the crank 7 more times and everything will line back up again. It is easy to turn the engine 1 or 2 revolutions and then nothing lines up and think that the timing is off. It isn't. Just keep turning to accumulate 14 revolutions and every thing is back "in time". If you turn it 14 times and it never lines up you have a problem, though....LOL LOL.

Good luck. I agree with your ratings pretty much. The first time thru all of it is a PIA...as are most things. The next time it will go three times as fast.

97BlueDeville · #5 (**permalink**) 04-02-05, 09:24 AM

BBob....

Thank you very much.. Your info was invaluable!! and Thank you for taking your time to type it up... your info worked like a charm!! I would have never figured it out otherwise..

Well the motor is up and in the car. It was task to get her in there, that's for sure. The main problem was the passenger side CV joint popped out of place from the weight of the strut hanging.. Had to take the rubber boot off to push it back in, only to discover that one of the bearings is slightly damaged or dented due to the fact I was trying to push the CV joint back in. The large bearing would not allow the small inner bearings to spin around. While I was fixing the bearing, one of the little needle bearings popped out and I could not find it.. I re-installed it the CV joint without the tiny needle bearing. I'm a little scared by doing this.. I think I will be alright since it only adjusts for when the wheel will travel up and down while driving. Or am I wrong.. I really down want to go buy another CV joint.. Damn front wheel drive cars... Also could not get the metal clamp that goes on the outside of the rubber boot, back on as I don’t have the special tool to re-install it. Guess I need to buy that as well. Hope Napa has one.. Any additional info would be great...

Thank you!!

Clint

CooL · #6 (**permalink**) 04-02-05, 10:08 AM

Hi Clint!

I do the same job with my N* -93. I had low pressure on cylinder 2, losing coolant and the engine run hot, all indicated to a blown headgasket but when I lift the head I could't see any damage on the gasket!!! I also mention that all my 20 threads was in very god shape and the bolts sat very tight. Did you notice any damage on the headgaskets when you where lifting the heads from the block ?

Pjs · #7 (**permalink**) 04-02-05, 10:42 AM

[QUOTE
The main problem was the passenger side CV joint popped out of place from the weight of the strut hanging.. Had to take the rubber boot off to push it back in, only to discover that one of the bearings is slightly damaged or dented due to the fact I was trying to push the CV joint back in. The large bearing would not allow the small inner bearings to spin around. While I was fixing the bearing, one of the little needle bearings popped out and I could not find it..... Also could not get the metal clamp that goes on the outside of the rubber boot, back on as I don’t have the special tool to re-install it. Guess I need to buy that as well. Hope Napa has one.. Any additional info would be great...

Thank you!!

Clint[/quote]

I had the same problem...passenger side liked to pop out. I couldn't get a metal clamp tight enough to stay on so I bought a couple medium sized screw hose clamps and put them together, then cranked it down...it's been a few months and it's still in place

haymaker · #8 (**permalink**) 04-02-05, 12:16 PM

Quote:

Originally Posted by CooL

Hi Clint!

I do the same job with my N* -93. I had low pressure on cylinder 2, losing coolant and the engine run hot, all indicated to a blown headgasket but when I lift the head I could't see any damage on the gasket!!! I also mention that all my 20 threads was in very god shape and the bolts sat very tight. Did you notice any damage on the headgaskets when you where lifting the heads from the block ?

Cool, take a few good close-up pictures of both sides of the head gasket’s fire-ring around the #2 cylinder location and post them. Make sure you have good lighting for the pictures. I would be interested in viewing a picture of the old head gasket(s). You said your block threads were good. Were the head bolt cavities in the block dry (no oil or coolant)?
BTW did you run a compression test or a cylinder leak-down test? You said your N* overheated, did it ever go into limp-home mode?

CooL · #9 (**permalink**) 04-02-05, 01:14 PM

Himarker, I shall post some good picture over the gasket's and I take a picture off the bolts to! I only did a compression test but I will do a complete cylinder leak-down test just to be sure. I shall also do a crack-indicate test on the cylinderheads. The cavities in the block was dry from both oil and coolant! I don't no what state I drove home but computer told me that it shut down the AC and I shall shut down the engine and I did so after 10-20 sec!! I come back with some good picture ASAP!

97BlueDeville · #10 (**permalink**) 04-03-05, 05:59 AM

PJS...

Thank you for the info... I'll put a hose clamp on her, but I'm taking it to a dealer so a proper clamp can be put on.. I hope I dont get any abnormal vibration from the missing small bearing, I don't think I will...

Cool... My head gasket was in poor shape! I could see where the pressure from the cylinder was escaping into the water jacket. Also I see little bits of rust on some of the steel ring on a couple of cylinders, which is a sign that this has been a problem for a while that got worse.. Over the last few months my car did need extra coolant and my low coolant light did come on, a few times before the engine could not hold coolant at all.. Also, my engine would hesatate upon startup then clear itself up after 20 seconds or so, another sign I had coolant in the cylinders. And now come to think of it I sometimes could smell a strange coolant-like smell from my exhaust pipes when I would first fire up the motor..

Clint

CooL · #11 (**permalink**) 04-03-05, 02:42 PM

haymaker, I post some picture of gaskets and all 20 bolts. Hope they tell you something.

clint, I had the same problem with my car exept that I did not smell any strange from my exhaust but sometimes the came out lots of white smoke from the pipes.

haymaker · #12 (**permalink**) 04-03-05, 10:55 PM

Clint, I agree with a lot of your assessment of the N* time-sert and head gasket repair.
To me the worst thing about the job being the near total lack of working room in the engine bay.
After the engine is on the stand it’s not bad to work on and in MHO a nice piece of engineering. I agree that the N* engine’s valve train is more complicated than that of a small block chevy and I have never had a small block chevy that I couldn’t replace the head gaskets while the engine was still in the car or truck much less have any concerns about reinstalling the head bolts. I also thought the time-sert job was strait forward but time consuming. What head bolt torque torque-angle values did you use during reassembly?
BTW which cylinder(s) was (were) leaking on your engine?

haymaker · #13 (**permalink**) 04-04-05, 12:50 AM

Cool, viewing the pictures as presented online it’s difficult to pinpoint the exact area of the gasket that was leaking. Looking at the underside of the gasket in the second picture from the left I see what appears to be the scorching and separating of the soft gasket material from the metal core. The gaskets that came off my ’97 SLS had the same type of gasket scorching and separation around the cylinders that were leaking. It looks as though the hot combustion chamber gases leak past the head gasket into the water jacket around the problem cylinder and cook the head gasket in that area. These hot gases must cool enough as they travel on to the adjacent cylinders as the scorching and separation of the gasket material stops.
So how long had the engine been overheating and had the computer only gone into limp-home mode the one time before you replaced the head gaskets? I am just trying to understand why some N*s blow the head gasket, overheat, cause oil and coolant contamination of the head bolt cavities then the destruction of the female threads in the block during disassembly and some (like yours) don’t? Did you notice any of your head bolts being somewhat looser than the others during their removal? I mean you get a feel for the amount of pressure required on the breaker bar to get that first little bit of rotation and if one of the bolts require much less pressure than the others you notice it right away. I had one loose head bolt per each cylinder head. I don’t see any female threads stuck on your old head bolts.
BTW thanks for posting the pictures.

BeelzeBob · #14 (**permalink**) 04-04-05, 01:38 PM

Knock. Knock.

Who's there...???

Emersome....

Emersome who..???

Emersome used head gaskets alright. Used UP.

CooL · #15 (**permalink**) 04-04-05, 02:07 PM

haymaker, the engine have got hot several times, most time I have stop the car and cool it down, the temp was over 240F sometimes, last time it went hot it was over 250F,maybe for 3 - 5 minutes. The computer told that I should shut off the engine. The engine is still in parts, I'm wating for some gaskets to arrive. I could not notice that any bolts was loose, I have to use the same amount of pressure on every bolt. Do you think I need to do the Time-sert job, even with bolts(I buy new) and threads in condition like mine?