: Northstar 4.6 bottom end



98eldo32v
07-15-11, 07:21 PM
Well,

As the disassembly of the 98 STS continues, I have faced something I really didn't want to do. Unfortunately, the half case seal and the oil pan needs resealing.

The oil pan didn't concern me too much, but the half case seal did.

The motor is on the stand and I can clearly see toward the rear of the motor the half case seal has been "sweating" oil for some time. This motor has 150k on it. I have read the procedure with the new gm sealant, but what I'm a bit concerned with is "disturbing" the lower end.

In order to reseal the bottom correctly the half case has to be disassembled, which means disturbing the crankshaft. If this were a cast iron block, I wouldn't been even concerned about the procedure. Yet, this isn't. Aluminum is a soft and finicky metal. One twist too much, we've got problems.

Another concern is the main and rod bearings. If I disassemble the bottom end the mains will have to be replaced. Do I leave the rod bearings alone and just service the seals and bearings? The crankshaft states it shouldn't be cut. Do I re-use the main bearing bolts or get new ones? I was planning on replacing the oil pump.

I just want to do this one time and for get it. I also believe in if it's not broke, don't fix it. I don't want to disturb anything that I really don't have to, but while I'm in here doing studs and re-sealing I want it all done right.

Any input will be greatly appreciated.

johnny kannapo
07-15-11, 11:34 PM
You have it on the stand ready to go, now you have the do the half case & crank seals or its just plain negligence.

The mains are probably good if you know the the history of maintenance.
You may want to check the upper rod bearing half & see if it has worn through a metal layer or 2.
I would be scraping piston grooves & re-ring if the gaps were big.

If I was there I would leave no stone unturned

97EldoCoupe
07-16-11, 01:10 AM
I've seen a lot of worn rod bearings lately. My 97 ETC was checked yesterday (sort of an on-going, off the side project) and the bearings are worn to the point where I would not re-assemble the engine in this condition for fear of low oil pressure and future rod-knock.

Take care of things ahead of time and you will not be sorry.

Ron, just be careful- when you pry the two halves apart, and when you retorque. Follow the GM procedure to the very last little detail (at least when it comes to torque specs and sequence) and you will be fine.

97EldoCoupe
07-16-11, 01:19 AM
You can re-use the original main bolts but check the threads for aluminum particals, wire brush if need be, check for stretch (VERY IMPORTANT!). If the bolt is stretched (this happens in the M10x1.5 threads) it will snap during the final torque pass and then you're into disassembly again to get the broken portion out. There are 12 main bolts that are VERY sensitive- oil is pressure fed around the shafts of these bolts and comes in the backside of the main bearings to provide lubrication. If one were even just loose, oil pressure will drop to an unacceptable level because it will bypass by the head of the bolt.

You're wise to take care of the bottom end while it's out. The myths of the bottom ends being bulletproof are something I'd already argue with after what I've seen lately. I talked to Scott at GMRP in Roseville and he's said the same thing. Four cars in a row that needed the rod bearings replaced. Main bearings tend not to wear as much. It depends heavily on how the vehciles are maintained.

98eldo32v
07-16-11, 04:26 AM
Thanks for the replies guys.

At this point if the bearings are going to be swapped, are we using standard size bearings? If not, normally one would plastigage the bearings to get the correct size. Yet if the bearings were to go to a different size, normally we'd cut the crank to the size we need, but that's a no-no?! I'm asumming we're going back to stand size if the journals are good.

Jake, now you've got me nervous and on the fence about re-using the main bolts. If one of those bolts snap in that block, I'll probably faint. That's why I have the tendency to get all new bolts. I feel like I'll be playing russian roulette if I don't.

The rod bearings are also eating away at me. I'm accustomed to replacing everything when I have it apart. Yet, if I do the rod bearings also, do I have to get new rod bolts? Why are the main bearings WAY cheaper than the rod bearings? I guess like you said Jake, the problems are with the rod bearings wearing.

Jake which manufacturer are you using for bearings in your rebuilds out of curosity?

If I take out the rod bearings, I might as well put piston rings on.......it never ends.

In late breaking news:

I took off the valve covers, timing cover, right bank chain and tensioners. Left bank chain and tensioners, removed the Vin 9 intake cams. The lifters looked very good on the intake cams, but we had a problem with the rear cylinder head.

The rear cylinder head has a crack in it?! I said to myself what in the world is this? With the valve cover removed, at cylinder number 7, on the exhaust side, in between the intake and exhaust cams you can see a crack. It almost comes from the outer most exhaust seat and spreads towards the intake seat above it. I was shocked. I was told this motor ran without a problem, except that it needed headgaskets of course......

I had wondered if the engine lift bracket bolted to that head caused the problem, but that's impossible for for it to do that. The crack almost looks like something exploded from underneath the head and tried to force it's way outward through the casting.

I guess I'll have to use my eldo heads and throughly inspect them before bolting them on. I'm disappointed because I wanted a spare set of heads to work on.

97EldoCoupe
07-16-11, 09:48 AM
Clevite Perfect Circle, standard size bearings with a mint, polished crank checked for roundness and wear. Cannot have any nicks, marks, gouges, rust, or wear spots.

I will have a stud kit for the bottom end soon. I have the M10, M11, M12 1.5 thread rolls now to make these.

Use new rod bolts.

Cracked heads are a rare occurrance.

98eldo32v
07-16-11, 10:03 AM
Thanks Jake.

I'm just wondering what caused the crack, especially in the location that it's in. I guess i won't know untill I get the heads off, which will be later today.

I guess once I get the heads and the crank out, I'll be reporting my findings.

Thanks again everyone.....

Submariner409
07-16-11, 11:21 AM
The myths of the bottom ends being bulletproof are something I'd already argue with after what I've seen lately.

"Bulletproof" : As in - tough, long-wearing, high rpm potential without failure.

98eldo's engine has 150,000 miles on it. An overhaul without lower end checks, bearings, seals and gaskets would be pointless. Nothing wrong with gauging the crank and dropping in a set of standard main and rod bearings.

I believe you should replace the oil distribution plate. New one........

97EldoCoupe
07-16-11, 11:25 AM
Sorry Jim- I misinterpreted the definition that everyone meant- The good news is the bearings are wearing before the crank journals (usually no damage to crank journals). At 150,000 miles if a set of bearings is required that's not all that bad.

New oil distribution plate for sure.

johnny kannapo
07-16-11, 01:10 PM
Why is the oil plate critical to replace?
Deformation after being torqued down previously?

98eldo32v
07-16-11, 02:52 PM
Thanks guys for all the replies.

I'm definitely getting a new oil distribution plate. Jake stated that the oil pickup tube grommet usually cracks/ tears. Plus it has that sealer on it around the edges, a potential for leaks. With that said, better safe than sorry.

When I get the crank out, I'll post what I find. I was wondering if Sealed Power Main bearing set #7319MA is a good choice as a replacement. Rod bearings are all over the place, Bi-metal, Tri-metal? I'm a bit baffled, but I'll sort it out with some help with you guys.

I need an oil pump too, I believe Melling M188 is the part #.

I'm excited that I'm at this stage, but I want it to go smoothly. I don't want to wonder or doubt.

Like I always stated, "when in doubt, pull it out!"

ternstes
07-16-11, 07:07 PM
Why do you think you need a new oil pump?

I chose clevite main and rod bearings for my 2000 STS rebuild. Rock Auto had the best price I could find. Advance Autoparts has plstigage for checking clearance on the new bearings.

johnny kannapo
07-17-11, 01:00 AM
Nobody is stopping you from replacing the oil pump. You could disassemble & inspect the cover plates surfaces for
irregularities or just run it and save that cost because before you know it you are spending more than planned.

If it was trouble free the oil pump can always be replaced at a future time if it becomes
a problem & since it's external It's not nearly as labor intensive to replace.

98eldo32v
07-17-11, 02:29 AM
Johnny,

I may trust you on the oil pump.

It's just that I have everything apart now and the pump does have 150k on it. If it's the original pump too boot.

I just figured since I'm in here now, just take my time and round it all up.

Yet, like you said I can find myself spending more than I had planned. I guess from all my previous motor builds I've always followed the safe than sorry rule.......

98eldo32v
07-17-11, 02:32 AM
Why is it I can't find a 10mm 1/2" drive hex bit to remove these head bolts?! I had to unfortunately settle for a 3/8" drive after I went all over town looking for a 1/2 drive, do they even exisit?

89falcon
07-17-11, 03:06 AM
Why is it I can find a 10mm 1/2" drive hex bit to remove these head bolts?! I had to unfortunately settle for a 3/8" drive after I went all over town looking for a 1/2 drive, do they even exisit?

Go buy a 10mm 6 side 1/2 inch drive socket.....and go get a 10mm allen key......cut the allen key and make your own......

98eldo32v
07-17-11, 03:19 AM
89falcon,

This may be the route I may have to go....Thanks for the reply.

ternstes
07-17-11, 09:26 AM
I just bought a 3/8 10mm craftsman and used a 1/2 adapter. It is replaced free when it breaks. You don't even need a receipt.

98eldo32v
07-18-11, 02:15 AM
Found my 6 point 1/2" drive 10mm socket. Just have to modify the allen key bit now......

This trick should work nicely......

98eldo32v
07-23-11, 06:47 AM
Well, I utilized the modified allen key trick and it worked like a charm......

I removed the heads. Ironically they came off without too much of a fight. Only one head bolt had some thread on it and it was barely anything.

Some of the heads bolts made a loud snapping sound when being broken loose, while there were a few that didn't. If I didn't know any better I felt this motor had headgaskets done before in it's life. Some of the bolts still had the threadlocker compound on them. I found one bolt that seems to have "indian head shellac" on the threads. (For those of us that are that old enough to remember that stuff), yet it came out clean. I don't know if some of the head bolts intersect with an oil galley, one bolt came out either with oil on it or some type of googey substance.

The headgaskets, looked pretty good by my standards. I've seen some rough headgaskets, but these weren't too bad. Most of the erosion of the headgasket was near the center of each headgasket at the steam holes. Looking at the headgasket facing you with the head off, you couldn't see how bad it was, but when removed from the block and flipped over, it told a different story.

I know a lot of people don't believe the dexcool is a contributing problem to the gasket erosion, but I've worked on too many neglected gm vehicles to see first hand what this antifreeze does to gaskets when it's not changed when it's supposed to. Not to say that it's the antifreezes fault, but more so the lack of maintenance. Yet, I still feel it's super corrosive to gaskets. It's just not something I plan to use in any gm car I have.

The block is now headless. The intake manifold had been off for some time before I had removed the motor, so I have a little corrosion in some of the bores. I sprayed them with PB Blaster and it started to come right off. At this point, I know I have to re-seal the bottom. I have to order main cap bolts/ studs. I may have to order rod bolts too. Bearings, I see in the not so distant future. I might as well say piston rings too in a minute.

This seems like it's turning into a full blown rebuild.......WOW.

Submariner409
07-23-11, 11:08 AM
I found one bolt that seems to have "indian head shellac" on the threads. (For those of us that are that old enough to remember that stuff)

Two bottles on the shelf as I type. Dauber balls and all............good stuff.

98eldo32v
07-23-11, 12:42 PM
Sub, you're not supposed to be TELLING on yourself.....Stop it.....

I agree, excellent stuff when you can find it.

89falcon
07-23-11, 04:17 PM
Well, I utilized the modified allen key trick and it worked like a charm......

I removed the heads. Ironically they came off without too much of a fight. Only one head bolt had some thread on it and it was barely anything.

Some of the heads bolts made a loud snapping sound when being broken loose, while there were a few that didn't. If I didn't know any better I felt this motor had headgaskets done before in it's life. Some of the bolts still had the threadlocker compound on them. I found one bolt that seems to have "indian head shellac" on the threads. (For those of us that are that old enough to remember that stuff), yet it came out clean. I don't know if some of the head bolts intersect with an oil galley, one bolt came out either with oil on it or some type of googey substance.

The headgaskets, looked pretty good by my standards. I've seen some rough headgaskets, but these weren't too bad. Most of the erosion of the headgasket was near the center of each headgasket at the steam holes. Looking at the headgasket facing you with the head off, you couldn't see how bad it was, but when removed from the block and flipped over, it told a different story.

I know a lot of people don't believe the dexcool is a contributing problem to the gasket erosion, but I've worked on too many neglected gm vehicles to see first hand what this antifreeze does to gaskets when it's not changed when it's supposed to. Not to say that it's the antifreezes fault, but more so the lack of maintenance. Yet, I still feel it's super corrosive to gaskets. It's just not something I plan to use in any gm car I have.

The block is now headless. The intake manifold had been off for some time before I had removed the motor, so I have a little corrosion in some of the bores. I sprayed them with PB Blaster and it started to come right off. At this point, I know I have to re-seal the bottom. I have to order main cap bolts/ studs. I may have to order rod bolts too. Bearings, I see in the not so distant future. I might as well say piston rings too in a minute.

This seems like it's turning into a full blown rebuild.......WOW.

The bolts that didn't "snap" were the bad ones......you probably had some anti-freeze leaking on to those threads.......and that "indianhead shalack" stuff was probably the cooling system tabs......

I didn't think the bottom end bolts were TTY......I thought you COULD reuse those.....anyone?

ternstes
07-23-11, 04:30 PM
The main bolts are supposed to be reusable, but I just broke one this afternoon before the bolt was even tightened to 15 ft lbs. A new set from gm parts direct is about 50 dollars with shipping. Part numbers 3542310 and 3542311. The latter is for the single stud which the oil pickup bolts to.

98eldo32v
07-23-11, 05:13 PM
There was an earlier thread stating the same thing, that the bolts were snapping.

THIS is the reason why I didn't want to touch the bottom end. After reading that earlier post I knew I was going to end up buying new bottom end bolts.

They may state that they are reusuable, but with that aluminum block FORGET IT. Either the bolt snaps or your drilling and tapping the block.

If I get them all out without breaking, THEY ARE NOT GOING BACK IN..........

Good Luck......

Now you have to disassemble the bottm end AGAIN, remove the bolt and reassemble? Damn

98eldo32v
07-23-11, 05:15 PM
Thanks for the part numbers Ternstes.

We're nothing but Northstars Jedi's learning the ways of the "FORCE"

98eldo32v
07-23-11, 05:22 PM
89 falcon,

Out of all those head bolts, I think I had top 5/6 that didn't snap. Yet, this all a learning lesson. If you ask me the bottom end bolts, ARE NOT REUSUABLE........

Maybe the oil pan, but anything holding that crankshaft in is getting junked. That's my personal take on it and I'm sticking with it.

I don't have the time to start assemblying one of these things, to get near the finish line and have a bolt snap. Only to come back a do it all over again?!

Better safe than sorry......

98eldo32v
07-23-11, 05:28 PM
Before we go any further, how many bolts/ studs do we need? I just looked on compnine and it stated 10 of each part number?

ternstes
07-23-11, 10:25 PM
There are four bolts per bearing and five bearings so 20 total. One is a special stud hence the other part number.

98eldo32v
07-23-11, 10:35 PM
Compnine states 10 studs needed? item#127

http://www.compnine.com/index.php?u=1&year=1998&artnbr=6M00-037&artsfx=NULL&supplgroup=80&catcode=66O&modelcode=K&makecode=K&modelseries=EA&uid=1&modelid=1147577592&capuid=1&majorgroup=00&grouptype=B

98eldo32v
07-23-11, 11:13 PM
I'll know for sure how many I'll need. Probably latter tonight when I take apart the bottom end.

Submariner409
07-24-11, 10:30 AM
The main caps (halfcase) are 4-bolt mains. 5 main bearings = 20 bolts in all.

Find a better diagram or use the service manual - only one of those bolts has a stud head that is used to secure the brace for the oil pump pickup tube.

Post #29............

98eldo32v
07-24-11, 12:41 PM
Ternstes And Sub,

You are correct. There are 19 bolts and one stud needed for the bottom end.

Well, heres my dilemma.

Now, that I have take the mid case apart that needs to be resealed unfortuantely. I found that my main bearing look all most NEW?!

Most people would be happy at this find while I'm slightly pissed. I have now disturbed something so fragile as this bottom end for a seal leak that could have been sealed probably better from the factory.

I guess I really shouldn't complain because the car does have 150k, the bearings look new and possibly less parts to buy.

Yet, that where the real question comes in. Do I reseal the bottom end with the same bearings in there? Do I get new main bearings and leave the rods alone? Do I get new rod bearings, bolts, and piston rings and do a full blown rebuild?

I really don't like pushing my luck with this aluminum block. I have been pretty fortunate enough thus far without incident.

I thank everyone on this forum for the valuable information in servicing these motors. I hope I have helped a few along the way with the things I have discovered.

I need to get a few opinions on this gents. I know in the end it'll boil down to money and time, but I do believe "if it's not broken, don't fix it". The other side of that "when in doubt, pull it out".

Things are going just too smoothly.....

Submariner409
07-24-11, 01:16 PM
Tough call - in order to get the crank out, and therefore the other bearing halves for the crank, you need to remove the con rod caps.

If the engine was quiet and not burning oil I would be inclined to use an assembly lube on the original mains, do the new GM case seal procedure, and torque it all back together. That entire engine was machined and line-bored as one piece - it's a stand-alone engine. I doubt that you'll throw anything out of alignment, thanks to the 20 bolts and bearing girdle.

(EDIT) The GM manual really wants you to replace the bearings.........(EDIT)

Your oil pump change is a 3-bolt quickie:

98eldo32v
07-24-11, 02:15 PM
Thanks Sub,

This is truly a tough call. The mains looked barely used. I'm pissed that I had to even break those bolts, but since I had the motor on the stand I HAD to fix the leak. I can't stand leaky motors.

At least this new sealant is supposed to stop the leaks. If that sealant had come about, my favorite is Permatex Ultra Black. When applied correctly and allowed to dry, you'll be chiseling apart the to halves you had sealed together.

Well, I have to order the bolts and the stud. The sealant for the mid case seal, a factory rear main seal. I guess I have to ponder over what to do with the mains, the rods and possibly piston rings.

Thanks for the pic of the oil pump Sub.

ternstes
07-24-11, 02:40 PM
If you take apart the rod caps, you will need new rod bolts and rod bearings as well according to the service manual. It gets expensive really quickly once you do that. Trust me, I feel your dilemma. I am under the same problem with my 2000 STS. After my main bearing bolt snap, I agree with you that if you are going to do it, replace everything with the best possible replacements.

Edit: My 2000 manual also calls for main bearing replacement if you separate the case halves.

98eldo32v
07-24-11, 02:58 PM
According to the FSM,

If the crankshaft bearings have been used in a running engine, you must replace them with NEW crankshaft bearings for reassembly. The same applies for the rods.

I can probably replace the main bearings without removing the crankshaft by individually replacing each shell one journal at a time by sliding them out. If I loosen the rod bolts, they're done and have to be replaced along with the bearings. Decisions, decisions, decisions.........

One a side note, diassembly of this motor has gone rather smoothly. Almost too smooth, but I'm not going to complain. Whatever route I take, I hope reassembly goes just as smooth.

98eldo32v
07-24-11, 03:07 PM
Ternstes,

Did you replace the main bearings when you took yours apart. My bearings almost look new.

I have to clean up the mid case, get a new oil distribution plate. Yet, those bolts after taking out the mid case, I doubt if I could ever trust them going back in. When I inspected them, they look so thin/flimsy that if you over torque them I'd expect them to snap.

I want to change the oil pump for piece of mind.

Like you said once you start breaking bolts loose, things add up quickly. Yet, I don't want to overlook something while I'm here.

drewsdeville
07-24-11, 03:09 PM
I can probably replace the main bearings without removing the crankshaft by individually replacing each shell one journal at a time by sliding them out. If I loosen the rod bolts, they're done and have to be replaced along with the bearings. Decisions, decisions, decisions.........


I've successfully done this on other engines for a cheaper job (engine not to be removed from car). Works out just fine as long as you are careful. Rotate the bearing out opposite the tang, and rotate a new one in. Just be careful not to nick the journals while doing so and be very sure the bearing is correctly seated before bolting the caps (or in this case, girdle) back on. The bearings MUST crush correctly when the bolts get torqued...

98eldo32v
07-24-11, 03:31 PM
Thanks Drewsdeville,

I've done it before on other engines also, but this thing is so finicky it's not even funny. We'll see what happens..... Thanks

ternstes
07-25-11, 10:08 AM
Yes, I am replacing my bearings with clevite standard bearings. My original bearings probably look like yours, hardly any wear at all.

98eldo32v
07-25-11, 03:04 PM
Ternstes,

Just out of curosity, how many miles on your motor? It's a shame that bearings can't be reinstalled and used, because they barely look broken in.

What part number Clevite are you using on the mains?

ternstes
07-25-11, 04:53 PM
Just under 90,000. It appears someone poured some kind of stopleak in the coolant. The head gasket passages up to the head were mostly blocked with crud.

Main Bearings are MS2206P (set)
Rod Bearings are CB1648P (8 needed)

98eldo32v
07-26-11, 02:57 AM
Ternstes,

Thanks for the part numbers. Hope your build goes back together smoothly.

98eldo32v
07-26-11, 03:14 AM
Ternstes,

I just came to me while I was thinking about this motor. Since you have your rod bearings out, did they look just as good as the mains or there was more wear on the rod bearings?

johnny kannapo
07-27-11, 04:25 PM
The half case is dowel pinned an will retain its exact positon on reassembly. I did say in post #2 the mains will probably be good.

It's the upper half of the rod insert that wears the most & you are likely to see them worn through a layer or 2 on the thrust halfs.
If any inserts are worn through to the copper that is when crank journal wear escalates.

Unfortunately you have to remove the entire 1/2 case to re-seal. it don't make sense not to re-seal the 1/2 case.

98eldo32v
07-27-11, 06:53 PM
Once the half case seal is broken, It's all over at that point. The half case HAS to be re-sealed.

Yet, the main bearings can probably be serviced without the removal of the crank. Your statement about the locating pins for the lower half case is correct. Yet, once the half case is removed for the resealing, the "crush' you had on the mains isn't the same, which is probaly why the FSM states replacement of the main bearings.

Yet, my question now is, if the mains look like they have minimal wear, what to do rods possibly look like? Once the rod bolts are loosened, it 's like the mains. You have to replace them. The question is, do they need replacement now considering the mains looked new. If they do need replacenment, why are the mains looking new and the rods wearing faster than the mains?

johnny kannapo
07-27-11, 07:11 PM
Even if the bearings are previously crushed in, you torque to spec.

It would only be a relief to know the bearing have been previously crushed correctly.

If using a plasti-gauge you normally crush & re torque. If you are going to uncap the rods as you should, just replace the bearings. with 150,000mi you will probably have some layer wear. You will see it on the thrust half of the insert not the cap insert, more so on rods further away from the pump.

http://i164.photobucket.com/albums/u13/6t9mach1/DSCF3601.jpg

ternstes
07-27-11, 08:59 PM
I would say that my rod bearings showed slightly more wear than the non existent wear on the crank bearings, but the car does nor have that many miles. Pulling the pistons out will give you the opportunity to inspect the rings as well. Do not foret to add the cost of 20 new rod bolts to the rod bearings.

Submariner409
07-27-11, 10:04 PM
FWIW, When I build an Olds 455 marine engine it gets the following NEW bolts or studs: Intake manifold, exhaust manifolds, heads, rocker arm, timing gear, oil pump, flywheel, flexplate, rod, crankshaft and balancer. ...........as a minimum. It costs a LOT more to have to pull it all apart again to fix a halfassed job than to do it right the first time. Considering what those fasteners are asked to do, why take chances ?? It's your money, however.....

The 1970 Olds 461 engine you're looking at currently goes for $6,500. Rebuild your Northstar to new specs for ~1/3 the price.

98eldo32v
07-28-11, 04:48 AM
Well, from what has been stated here it looks like I'm going to do a full blown rebuild at this point.

If the rods are showing more wear than the mains, it's pointless to leave the rod bearings in, when they are the ones taking the most beating.

In essense this was the direction I wanted to go, but I was trying to do so with the least amount of expense.

It's either fix it now, or possibly fix later. Might as well get it all over with now and forget about it.

Thanks gents.......

89falcon
07-28-11, 12:24 PM
Even if the bearings are previously crushed in, you torque to spec.

It would only be a relief to know the bearing have been previously crushed correctly.

If using a plasti-gauge you normally crush & re torque. If you are going to uncap the rods as you should, just replace the bearings. with 150,000mi you will probably have some layer wear. You will see it on the thrust half of the insert not the cap insert, more so on rods further away from the pump.

http://i164.photobucket.com/albums/u13/6t9mach1/DSCF3601.jpg

I wasn't under the impression that Cadillac used the "tri-metal" bearings......so I don't think you'll see copper on worn stock bearings (or 12 point nuts.....)

drewsdeville
07-28-11, 01:06 PM
I thought the same. Personally, what I've seen, GM's been using aluminum bearings in pretty much everything for decades.

tateos
07-28-11, 04:39 PM
Pretty sure the bearings need to be replaced if removed/disturbed. The benefit I see in replacing the rod bearings is that you will be removing the pistons - that gives you the chance to replace the rings and clean out the ring grooves, and THAT (sticking rings and gunked up rig grooves) has been a problem area for some N*s. So, like most of the other have suggested, I say follow your inclination and do it all.

johnny kannapo
07-28-11, 06:12 PM
Pretty sure the bearings need to be replaced if removed/disturbed.sted, That's not true, Inserts can be removed & reused however it's critical they stay in order or the original position.

johnny kannapo
07-28-11, 06:16 PM
I wasn't under the impression that Cadillac used the "tri-metal" bearings......so I don't think you'll see copper on worn stock bearings (or 12 point nuts.....) That is a random worn bearing example, It looks like a Jap rod with a piston squirter, very nice. I wanted to show how the upper half wears while the cap half a has little duty & just looking at the cap half is not show you any true bearing wear.

tateos
07-28-11, 08:30 PM
Look at post 12:

http://www.cadillacforums.com/forums/northstar-performance-technical-discussion/74644-94-97-northstar-interchange-question.html#post698698

johnny kannapo
07-28-11, 11:03 PM
Look at post 12:

http://www.cadillacforums.com/forums/northstar-performance-technical-discussion/74644-94-97-northstar-interchange-question.html#post698698

So there you have it, seated steel based main inserts are re-usable.

98eldo32v
07-28-11, 11:54 PM
So there you have it, seated steel based main inserts are re-usable.

The links to the previous posts are very informative. Thanks

97EldoCoupe
07-29-11, 04:15 PM
That engine is not factory. Those are not GM rod bolts.

johnny kannapo
07-29-11, 06:36 PM
That engine is not factory. Those are not GM rod bolts.I explained in post #56

97EldoCoupe
07-30-11, 09:09 AM
I don't know what I was thinking- that's clearly not even a GM piston/rod combo. Sorry Johnny- I had another dim moment yesterday that made me question the need for a day off this weekend :(

JoeTahoe
07-30-11, 10:09 AM
if you do rering use gm rings I have heard of night mare stories about non gm rings in a Northstar. I have reringed two Northstars with great luck and Jakes input.

johnny kannapo
07-30-11, 03:32 PM
These are 145,000 mile 4.0L Northstar pistons.

Granted they look to have had a rough life.

It just seems to be like sicking your head in the sand not to pull & scrape 'em out
http://i826.photobucket.com/albums/zz183/billytheshoe/northstar%20hijacked%20pics/6_Pistons__Conrods.jpg?t=1312050443
This picture was hijacked from this very impressive link.http://www.fiero.nl/cgi-bin/fiero/showThread.cgi?forum=3&thread=000116&style=printable

98eldo32v
07-31-11, 07:03 AM
Those pistons have oil ROASTED onto them. That engine hardly ever got it's oil changed......

Submariner409
07-31-11, 04:21 PM
Those pistons have oil ROASTED onto them. That engine hardly ever got it's oil changed......

^^^^ Exactly. For anyone who cares, go back through the Northstar Performance AND Cadillac Tech Tips threads and look for Northstar overhaul pictures - there are quite a few examples of pistons that look like they were installed yesterday - after 150,000 miles.

JoeTahoe's series of pics comes to mind................Jake probably has seen everything from squeaky clean to stuff a lot worse than johnny kannapo's picture.

tateos
08-01-11, 09:57 PM
That's right Sub - I didn't disassemble by lower end when I did my HG project - I didn't need to, and I'm glad I didn't mess with it - the car is still running strong. I was just saying that, since there have been reports of sticking rings and high oil consumption, and all the WOT and combustion chamber cleaner fixes, that if someone does remove the pistons, they get the added benefit of being able to inspect and clean the ring lands - that's all. I always used about a quart every 1,500 to 2,000 miles - no more, no less, and I was good with it.