How much fun CAM we have?

[ecombatant]

its bad.  Cracked completely in half the end 1/2 inch.  The pulley puller twisted in the threads and it failed catastrphically.

I need a beer.

And now, parts.  I found a camshaft for $180 online.

What is the breakdown of labor?  The heads don't have to come off, do they?

Crap on a cracker, I love the car, but I hate this amount of work to think about.

Thanks

[Randy T.]

I don't know if you can change the cam with the head off, when you remove the cam stuff happens, may be possible to do it if you had a chain holder tool if there is one for this and I think there may be.

I think you are talking about the water pump pulley on the drivers side giving you problems? What kind of puller are you using? I used to recommend harbor fright ones, but I tear them up quick, they can be rented from local tool stores, takes a certain one.

Don't pay that much for a cam, I have a couple motors in storage that I can take parts of, so if you can't find one and you want one a lot cheaper, send me a pm or email, [e-mail]. 4.6 Cadillac and 4.0 Aurora share the same exhaust cam.

[genedjr]

Another approach to understanding how to get the cam out would be to go to the u-pull-n-pay and figure it out on one of those motors.  If you get it apart with out breaking anything - not only have you figured it out but you have a replacement cam in hand.  And well, if you break it, move to the next motor...
...gene

[XJSman89]

Dec 15, 2014 9:11:39 GMT -6 genedjr said:

Another approach to understanding how to get the cam out would be to go to the u-pull-n-pay and figure it out on one of those motors.  If you get it apart with out breaking anything - not only have you figured it out but you have a replacement cam in hand.  And well, if you break it, move to the next motor...
...gene

My thoughts exactly. I did this with interior parts, when I wanted to take my dash apart I did it on a car at the junkyard first so that I could learn on a car that wasn't the one I wanted to look good when I was done. In the process of getting the cam out you would learn what to do and what not to do. If this is an option available to you, I would take it!

[randnon]

I think their is a special tool to hold the chain tensioniers in place while you pull the camshaft sprocket off. You would need to note the timing locations and of course screw down the cam bearings slowly and evenly till they compressed the valve springs. without that tool it would be dis-assembly. Rich

PS I used some red paint on the chain for a timing mark . You could also use something like a bread tie.

[sall]

According to the manual all you need is zip ties and the gm j-tool.

Set the engine at base timing (top dead center number one piston).
Align the timing marks to the correct position. Refer to Setting Camshaft Timing for the correct timing mark alignment.

Important

The sprocket-to-chain relationship must be maintained throughout this procedure or the camshaft timing will be lost and require further engine disassembly for retiming.

Secure the camshaft sprocket to the secondary timing chain using tie-straps through the camshaft sprocket holes. Use two tie-straps per sprocket.


Working behind the sprockets, install the J 38822 between the chain tensioner and the chain guide. Apply tension by tightening the tool adjusting screw.

www.ebay.com/itm/GM-Northstar-Timing-Chain-Holder-4-0L-4-6L-Same-as-Kent-Moore-J-38822-/390451225920

$72 for the tool.

[ecombatant]

Ok, got the tool (actually the entire kit, with some extras, etc - new, with hard side case, $79 delivered to NC). Cool.

Now questions arise. I have two junker options in the local area. I'll end up choosing one of the two 4.0's that seem the best. Assuming that this is true, and I can get a CAM that is decent:

(1) I didn't see bearings mentioned for the cams. Am I to assume a steel rod (the CAM) is simply removed from a sandwich of two metals (the head housing, itself and the cam lob 'cap') - there are no bearings?

(2) Do I need to worry about wear or can this situation bring me another 25k miles before rebuild (thats my plan anyway)? In other words, if the donor cam is very worn, won't this affect the valves on my 2, 4, 6 and 8 cylinders?

(3) What about lube? I see callout from AllData about a special lube. Necessary with wear?

(4) The donor cam - do I need the special cam chain tensior tool I've just acquired at the junk yard with the donor car? I would think not.

(5) The order of disassembly for my car (generalized, me) seems:

(5a) Remove valve/cam cover
(5b) Insert tool
(5c) Zip-tie cam timing chain links through holes in timing chain directly onto cam sproket where they are seated now to maintain timing
(5d) Remove cam assembly [cam + cam sprocket]) (loosen bolts in the pattern indicated)
(5e) Note alignment of old cam sprocket to old cam by utilizing white out or similar
(5f) Remove cam sprocket from cam itself (this is the bad cam)
(5g) Compare new/donor cam to old/damaged cam, and note lobe positioning, cam sproket pin hole, and align new/donor cam back to existing cam sprocket using observed alignment cues

ASSEMBLY

(5h) Seat the new/donor cam into existing cam sprocket hold using alignment holes, connect pin
(5i) Place cam into position, tightening bolts as indicated in order and to torque specified

Is this roughly the process? I get real nervous about this as it's the difference between a LOT of work and some work right now.

Thanks all for the great help so far.

Love the Aurora!

[ecombatant]

Hate to ask for a bump - but I'm likely doing this today. I'm figuring 2 hours for the tear down of the donor car, and then 3 hours for the re-assembly on my car.

The questions I still have really are: (a) there are no cam lobe bearings/cam bearings to replace in this process? (b) the bolts to loosen the cam are the bolts that attach the cam to the head, and there are 8 (or is it 10) of them. Do we loosen them in specific order - I know there is a specific REASSEMBLY order, but didn't see one for teardown. (c) Do I need 'new cam lube' when it's not a new cam? (d) If I have EVERYTHING aligned through disassembly and re-assembly, is there a reason to hand-turn the engine a few cranks to ensure the cam alignment? I know it's 7/8 turns, or 4 times that - or some combination using math. But what if I'm sure as I've really taken the time to ENSURE an alignment using all the tricks (zip ties, marker paint, photos, etc).

Thanks!

[ecombatant]

Dec 12, 2014 15:29:06 GMT -6 ecombatant said:

its bad.  Cracked completely in half the end 1/2 inch.  The pulley puller twisted in the threads and it failed catastrphically.

I need a beer.

And now, parts.  I found a camshaft for $180 online.

What is the breakdown of labor?  The heads don't have to come off, do they?

Crap on a cracker, I love the car, but I hate this amount of work to think about.

Thanks

bump.

lots of beer later.

questions!

[RCA1186]

Haven't tried it yet? I don't know if anyone here is experienced with removing the cam in car or not unfotunatly.

[ecombatant]

Dec 12, 2014 15:29:06 GMT -6 ecombatant said:

[UPDATED SUN 22-MARCH-2015]

Sigh.  For want of a working engine, I guess I just keep running into things that don't seem to be important - but ARE.


History is this:


(1) Replacing Water Pump - used tool incorrectly and cracked water-pump-pulley side of cam end.  
(2) Found donor cam in junkyard
(3) Without really understanding anything else, I have placed the donor (good, from junkyard) cam into my engine
(4) Used the DONOR bearing caps and DONOR bearing cap bolts
(5) Applied the Specified GM PreLube
(6) Matched the timing, teeth, gears and position on the cam (quadruple checked)
(6a) Matched the bearing caps exactly with their direction, position
(7) Starting bolting the cam in using the start-from-center work outwards like spiral or clock (no docs available on exactly how to do this)
(8) To 106ft-lbs of torque


Two bolts snapped while torquing.  I believe because I used the torque wrench (1/2") with a short extension, this caused more torque to be applied than was really being indicated, and so I believe I've over-torqued (and thus snapped) two of the cam-bearing-cap bolts that hold the bearing cap on top of the cam itself.


Bad?  Bad.  I have no idea on how to proceed.  While I'm scratching my head now, a couple of questions arise:


(1) Are these bolts TORQUE then YIELD?  This is essentially a 1-time-usage bolt, designed to snap off after it''s already received it's initial torquing to prevent (I assume) re-use.  Is this even possible in the northstar design?


(2) What is the ACTUAL TORQUE sequence to use?  God forbid if I have to turn a wrench on this pile of rust again (sorry, Rorah, you know I love you really) I will need to understand specific shop-manual procedure to avoid this happening again.


(3) I've determined that the PHYSICS involved in torque wrenches hurt my brain.  Instead of this future brain hurt again, I've determined that I cannot place an EXTENSION onto a torque-wrench as the torque increases.  This was evident in the SNAPT-SNAPT of the bolt as it cracked.


(4) Is there a usage of torque-then-yield bolts in these engines?


(5) How the hell do I get these bolts out and what is the procedure to do this?



Thanks for following this saga as it develops...









[ORIGINAL POST]
.....its bad.  Cracked completely in half the end 1/2 inch.  The pulley puller twisted in the threads and it failed catastrphically.

I need a beer.

And now, parts.  I found a camshaft for $180 online.

What is the breakdown of labor?  The heads don't have to come off, do they?

Crap on a cracker, I love the car, but I hate this amount of work to think about.

Thanks

[RCA1186]

Mar 22, 2015 9:34:12 GMT -6 ecombatant said:

Sigh.  For want of a working engine, I guess I just keep running into things that don't seem to be important - but ARE.


History is this:


(1) Replacing Water Pump - used tool incorrectly and cracked water-pump-pulley side of cam end.  
(2) Found donor cam in junkyard
(3) Without really understanding anything else, I have placed the donor (good, from junkyard) cam into my engine
(4) Used the DONOR bearing caps and DONOR bearing cap bolts
(5) Applied the Specified GM PreLube
(6) Matched the timing, teeth, gears and position on the cam (quadruple checked)
(6a) Matched the bearing caps exactly with their direction, position
(7) Starting bolting the cam in using the start-from-center work outwards like spiral or clock (no docs available on exactly how to do this)
(8) To 106ft-lbs of torque


Two bolts snapped while torquing.  I believe because I used the torque wrench (1/2") with a short extension, this caused more torque to be applied than was really being indicated, and so I believe I've over-torqued (and thus snapped) two of the cam-bearing-cap bolts that hold the bearing cap on top of the cam itself.


Bad?  Bad.  I have no idea on how to proceed.  While I'm scratching my head now, a couple of questions arise:


(1) Are these bolts TORQUE then YIELD?  This is essentially a 1-time-usage bolt, designed to snap off after it''s already received it's initial torquing to prevent (I assume) re-use.  Is this even possible in the northstar design?


(2) What is the ACTUAL TORQUE sequence to use?  God forbid if I have to turn a wrench on this pile of rust again (sorry, Rorah, you know I love you really) I will need to understand specific shop-manual procedure to avoid this happening again.


(3) I've determined that the PHYSICS involved in torque wrenches hurt my brain.  Instead of this future brain hurt again, I've determined that I cannot place an EXTENSION onto a torque-wrench as the torque increases.  This was evident in the SNAPT-SNAPT of the bolt as it cracked.


(4) Is there a usage of torque-then-yield bolts in these engines?


(5) How the heck do I get these bolts out and what is the procedure to do this?



Thanks for following this saga as it develops...

I believe there are torque to yield bolts used in this engine as a matter of fact, Although I couldn't tell you if the cam bolts are. You're probably looking at drilling them out and re-tapping the holes. Using an extension WILL mess with your torque readings...but 106ft/lbs??? That sounds like an awful lot. You sure it wasn't supposed to be inch pounds?

Give me a second and I'll try to find the procedure in my shop manual.

[RCA1186]

Yep, its inch pound, which would explain your problem. I don't think they're torque to yield, the manual doesn't specify a particular order in which to tighten either, but does explicitly mention that the bearing caps must be installed in their original locations

[ecombatant]

@ rca99Aurora - many thanks for your following with this saga.  Your advice and tech snippets are useful!  I miss Goose Island Hex Nut Ale.

@all - this may be the last few posts for the old girl.  She gave me a few good months.  I just don't know where I'm going if this fails to resolve. 

...

Well, the saga continues. I'm running out of beer varieties which tend to quell the pain in dealing with this 'evolving' situation.

A re-cap (har har):

(1) For want of a working water flow, the water pump was changed (helps to avoid overheating these engines, indeed)
(2) The water pump pulley then develops a failure, belts start shredding (ribs gone - 2 belts in 3 days)
(3) The tensioner goes - this and the pulley are replaced with beautiful new canadian parts (both pulley and tensioner)
(4) Reinstallation of pulley CREATES MASSIVE CRACK at end of cam shaft - toast
(5) Donor cam found in identical aurora in junkyard (I'm thinking I should have driven this one out and parked my other, lol)
(6) Cam placed into engine in the aurora in my driveway
(7) Cam caps replaced
(8) Two bolts in the cam caps (#3, bottom and #5, bottom) SNAP while being torqued - top head with 2/3 of bolt comes out loose, nice!!

Problems So Far:

(1) I don't know if I should have installed the ORIGINAL ENGINES bearing caps or the REPLACEMENT CAMSHAFTS' bearing caps.  I went with the junkyard bearing caps.  Was this bad?  I figured if i would have put a replacement cam I should have at least put in the caps that contained that cam - 66% matching parts, imho.  But somehow, this could have been BAD.

(2) I used an extension (5") on a 5/8" torque wrench.  I had the dial set for 105, but with the extension I'm sure it was probably WAY more.  Weird thing, I put the wrench on the bottom (exhaust) caps and felt their bolt tightness - it was WAY tighter than the bolts on the intake which I was re-tightening.

(3) I didn't EXACTLY follow a specific bolt-directed pattern for the tightening.  Should I have?  I went finger tight, then standard wrench tight (no extension, 1/4" drive), then to the torque wrench.  I did all of this using an INSIDE to OUTSIDE spiraling pattern from the center, reverse clockwise.  The torque wrench was done in increments, and it took me a good 5 minutes to do all of this using the torque, as I was very careful.

Apparently not too careful. 

SNAP!  (I thought it was the torque wrench clicker), then ok, ok, ok, SNAP!

I basically wanted to torch the car at that point.  But it's my fault, so here we are.

And here I am today, with the following in hand:

- 5/64 carbon steel/super strength drillbit (#1 in craftsman parlance)
- #1 left-handed screw/bolt reverser
- an assemblage of supporting tools (drills, flat punches), trinkets and good luck rabbit feet

MY GOAL(s):

- Extract #3 and #5 intake cam bearing cap bolts (both lower bolts - top bolts ok) using tools (drill center, insert left hand extractor tool, extract)
- Reinstall two new bolts (should I buy new?  Should I use the DONOR engine's other cam bearing cap bolts?  Are these torque to yield?)
- Avoid snapping the new bolts (all valid concerns at this point)

My 'researched' repair procedure:

- Remove the bearing cap from #3 (But not #5 yet) by taking out the upper/top bolt
- Identify the bottom/lower bolt situation - how deep is it?
- if it is ABOVE the level of the cam cap, use DREMEL to cut roughage off until it's plane/parallel to the level of the cam cap landing - giving me 2-4mm of above-deck clearance
- score/cross-punch the center of the now-levelel/planed bolt stump
- drill into the bolt until I've achived 5-6mm below cam cap deck surface into the bolt stump
- insert the left-handed extractor bit into the 5/64" hole now drilled into the center
- tap ONCE with some kind of imaginary force so that it seats into the hole
- begin to reverse drill the tool out to the left to grab the steel of the bolt and force it out
- clean, inspect and lubricate hole
- reinstall (using proper torque procedures) this bolt
- move on to #5

This is all very RUDIMENTARY because I've never done this.  Questions just on this:

(1) I'm doubting that I even have a solid procedure here, as there seems to be little guidance on it concerning STEEL SCREWS/BOLTS and ALUMINUM heads.  is this a no-no and should it be like materials only?
(2) Should the materials be cold/hot, heated?
(3) Should I use LUBE, OIL or penetrating lubricant?(
(4) Should I use a HAND TOOL to reverse the bolt out using the left-handed thread-tool or a power drill with adjustable torque/spin?
(5) Should I leave the now-installed CAM in the intake side while I do this?  Or remove everything?
(6) Should I leave the bearing cap on as a hole-guide for my drilling?
(7) Is this insane? Yes, I know I can remove the head (it's the front of car/right side-engine, thankfully) - but the head then introduces more work and the potential that I'm going to need to timesert.
(8) Anyone have experience in this?
(9) Anyone have better ideas?

I mean, I thought about:

- Drilling a new single hole, and tap-threading that small hole to fit a new smaller bolt (??) which I'd minimally torque. I think this is the maximum backyard engineering I could handle before I donate the car to law enforcement for target practice.


Sigh.

Beer ideas at least? I'm Greenville, North Carolina - so I'd like a recommendation for a place I can get a pony keg of some good local ale. I'm going to need it.

-e
The CAMSHAFT BEARING CAP bolt (picture closeup of head of bolt, marking) - torque to yield??

She is looking sad folks. Help save her from the pound!

[RCA1186]

I really don't think they are torque to yield. The service manual usually makes not of it if they are.


That's a good question about which bearing cap to use...I'd probably agree with using the donor cam's ones. The manual is adamant that you install them back in their original positions. I'd think as long as you have them in the correct position on the engine (as in the same spot they were in on the donor engine) the donor cam's ones should be ok.




To go over it once again, you are using INCH pound and not foot pound to torque correct?




Do you have any thread sticking out of the head? or rather...do the bearing cap holes have threads or are they through holes? If you have thread sticking out of the head, I've gotten some REALLY tough bolts out using a good locking pliers. Just a thought.


This link has the full FSM procedure on it. If you dont have it

www.2carpros.com/questions/1998-oldsmobile-aurora-replaced-cam-shaft-on-98-toruqe-sequence-specs-bolts-thats


I could suggest some good beers, but I think they're local unfortunately!

[freebird5049]

I had a mechanic do mine. He snapped my camshaft too while trying to replace pulley. Cost me $289 labor, $180 in parts