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Discussion Starter · #1 ·
I'm in the midst of a cam swap and can't get the hub off to remove the timing cover.

Exactly how difficult is it to remove the crank hub? I have a puller and I've read all the posts (Karl Ellwein's, etc.) about having to have a longer bolt (or something else) to make sure you're pushing against the crank and not the hub.

To be more specific, I've tried just moving it because I wanted to get a feeling for what moving it would feel like.
The method I used was to put the stock hub bolt in about 3/4 of the way in. That way I knew the puller would be pushing against that. I know I can't remove it with that method, but I just wanted to test the waters.

However, with a fair amount of torquing on the puller (keep in mind, I'm a 250 lb guy who lifts weights regularly) it didn't budge (not one bit) and I didn't want to end up breaking something without seeing what other people's experience was.

Is it just stubborn as hell in general requiring a HUGE amount of effort or am I doing something wrong?

Thanks.
-Tim
 
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Discussion Starter · #2 ·
Hi Tim,
hummmm, (rubbing chin). I picture from what you said that you put the stock hub bolt into the hub, and test pulled.
If that is the case, the puller is pulling against that bolt and thus it won't budge.
A skinnier bolt must go into the hub and then bottom out against the crank...and then you can pull against that skinnier bolt, (longer skinnier).

hth
 
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Discussion Starter · #3 ·
Oh, also, you mentioned my advice about a longer hub bolt, but that is not needed for the pulling. A longer hub bolt is for intalling, (if you don't have a better tool).
For removing the hub, you need a longer-thinner bolt and your hub pulling tool center nose will push against that bolt. The hub pullers 3 bolts will screw into the hub bolt holes. the effort will be 20 to 50 ft-lb if that. Medium effort.
Karl
 
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Discussion Starter · #4 ·
Karl

While your on the subject this is boud to come up

How do you set the timing chain on a 96 motor?

Dot on the top cam cog at 6 o-clock and the woodruf key on the crank hub at 12? correct?

TAD
 
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Discussion Starter · #5 ·
<BLOCKQUOTE>quote:</font><HR>Originally posted by Karl Ellwein:
Hi Tim,
hummmm, (rubbing chin). I picture from what you said that you put the stock hub bolt into the hub, and test pulled.
If that is the case, the puller is pulling against that bolt and thus it won't budge.
A skinnier bolt must go into the hub and then bottom out against the crank...and then you can pull against that skinnier bolt, (longer skinnier).

hth
<HR></BLOCKQUOTE>

Okay, now I'm a bit confused, but that's not an unusual thing when it comes to engine work. Are you saying that the hub bolt is threaded into the hub and not the crank? What the heck does it do then? Is it there only for turning over the engine by hand?

That would certainly explain my experience, then. Thanks. So I basically need to get a longer skinnier bolt and make sure it's "bottoming out".
 
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Discussion Starter · #6 ·
OK, here's the deal. Unlike other dampers, the front of the crank isn't exposed when you remove the bolt.

So, what I do is this - remove the bolt completely, and then thread it back in 5-6 turns or so. This way, the puller is pushing against the bolt. If you don't do this, the puller will bottom out against the hub, and you'll spend a long time trying to pull the hub apart with the puller (and the puller will give up first, trust me on this).

Still confused? Let us know. This was the worst part of my first cam change on an LT1.
 
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Discussion Starter · #7 ·
<BLOCKQUOTE>quote:</font><HR> This was the worst part of my first cam change on an LT1. <HR></BLOCKQUOTE>

Agreed. Even with the GM LT-1 hub puller tool it's a stupid / dumb job.

I have done it and still dont understand.

TAD
 
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Discussion Starter · #8 ·
Tim, Exactly like Eric said. He said it most simply.
I got a bit confused about the bolt being put back in. It does screw into the crank, not the hub. You are correct. My bad.

If you do it the way you and Eric were saying, it should also work.

Tad, the question on 96 SS top dead center and putting the timing chain on.
(I just did this a month ago on Brad Rosenbergs car.)

1. Crank chain sprocket on, (only one way due to key).
2. Put #1 piston to top dead center, (just feel for air coming out #1 spark plug hole.
3. Cam sprocket and chain on in such a manner that the 2 sprocket dots line up. Cam dot at 6 oclock, Crank sprocket dot at 12 oclock.

I think the crank key would be at around 1 or 2 oclock at this point.

Of course hub gets the cast arrow at 12 oclock when #1 piston is at top dead center. when it's time to press that thing on. (don't forget your crank poss sensor).

HTH, take your time and tripple check all of this.

Karl
 
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Discussion Starter · #9 ·
Can a cam be changed in our cars without ripping the gasket for the timing chain cover to the oil pan?-the little slot the timing chain cover fits into the gasket. :confused:
 
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Discussion Starter · #10 ·
<BLOCKQUOTE>quote:</font><HR>Originally posted by sslegend:
[QB]Can a cam be changed in our cars without ripping the gasket for the timing chain cover to the oil pan?-the little slot the timing chain cover fits into the gasket.[QB]<HR></BLOCKQUOTE>

Every time I've tried to get away with just the timing cover, the oil pan has torn too. But like most GOOD GM mechanics, I put a dab of RTV where the timing cover, block and oil pan meet to prevent leaks. Never leaks, but if you pull it off it will take the pan gasket too.
 
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Discussion Starter · #11 ·
<BLOCKQUOTE>quote:</font><HR>Originally posted by GhoSSt:
Every time I've tried to get away with just the timing cover, the oil pan has torn too. But like most GOOD GM mechanics, I put a dab of RTV where the timing cover, block and oil pan meet to prevent leaks.<HR></BLOCKQUOTE>

Yep, what Kelly said. GM mechanics know the value of RTV


The keyway on the crank is aligned with the crank journal for #1 & #2, if I recall correctly. When #1 is at TDC, the keyway should be aligned with the left-side cylinder bank, 45 degrees clockwise from the 12 o'clock position.
 
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Discussion Starter · #12 ·
Yes, the crank hub is another one of those beautiful designs from the auto manufacturer that drug tests engineers but doesn't know what a Blue test result means.

Using the puller against the crank bolt is a good start. When you get to the point where you only have a few threads of engagement, remove the bolt and use a 1/4" drive extension. The square end of the extension will pass all the way into the crank end (through the hub) and use your puller against the female end of the extension. This worked for me (until the hub hit the enlarged section of the extension and I had to press it out of the hub).

The crank hub, in essence, has two large holes in it - one for the crank end, and one for the bolt end. There is a fat "bulkhead" in the center of the hub that is drilled out for the crank bolt. So when you think you are pushing on the end of the crank, you are really just pushing on the 'bulkhead' of the hub if you didn't go through the bolt hole. You have to go through the bolt hole to hit the crank.

No hub/crank keyway either. There must have been a deal on Sensimilla in Detroit that month.

Go figure. doug
 
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Discussion Starter · #13 ·
Thanks guys. This forum is awesome!
So it sounds like the way I was doing it was okay (at least to get things moving). So it really does take some monster torque to remove these things. What a PITA!
-Tim
 
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Discussion Starter · #14 ·
Tim I know just what your going threw just installed the hot cam last week. and the designer of that harmonic balancer needs to be Fired. I heat the hub and started to melt my optispark before I stop and looked in the hub with a mirror and saw I was pressing against the balancer, but like everyone else told you I stuck a longer and thinner bolt in (about a 3 1/2 inches long 3/8 bolt)and then it pulled off like butter. After that it is fairly easy if your mechanically incline. the dots go dot to dot on the crank and cam. but just line it up before you remove the chain and don't bump the starter. another hard part was changing the ignition wires if you don't have to change the wires it should only take 1 day. Good Luck!!! P.S I didn't put my converter in yet and the car tries to stall in gear but once the converter is in it will be fine.
 
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Discussion Starter · #15 ·
Thanks ddddub. That's great to hear that eventually it was easy. I went out today and bought the bolts I'll need (both for removing and installing).

I'm putting in the ZZ4 cam and it's quite a bit milder than the HOT cam, so I'm hoping I don't have to go to a higher stall TC.

Have you programmed for the cam yet?
 
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Discussion Starter · #16 ·
Well I went out to the garage to give it a try with the new bolts and just like people have said, the hub comes off "like butter" when it's done right. From start to finish took about 10 minutes and most of that time was in assembling the balancer-puller onto the hub.

In addition to the helpful posts above, one more tip I've found, it's imperative to have the balancer-puller on as straight as possible. I'm using the puller from Autozone, but modified slightly (with a dremel) to accept the bigger bolts needed for the LT1 hub (also need to buy said bigger bolts...7/16 course-thread...4-inches long worked perfectly for me). It never required anywhere near the torque I was giving it yesterday.

For any future readers of this thread, I would venture to say that if it feels like it's taking more wrench-turning force than your comfortable with, STOP...you're doing something wrong. Most likely either the puller isn't on straight or you're pushing against the hub or even both.
-Tim
 
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