I've been reading blueprints for 30 years and your wrong, if the parts were directly against each other, there would be one line with no gap and the cross hatching simply would be orientated in opposite directions to denote the two mating yet different parts.
Don't believe it? Just examine the drawing of the pulley itself in the same view. Notice the pulley is an assembly with three or four different components, the OD where the belts run is one piece, then you have a sandwitch/thin portion, then the center hub itself. Notice how the cross hatching is orientated in opposite directions on the maiting areas so you can see the different pieces. Look at the OD of the pulley, see where the different components mate together? One line is used to denote the mating surface interface -yet there is no gap and only one line between them to show you they are stacked together as an assembly yet are made from different components.

You're the one that needs to study this and stop putting out incorrect information.

 

I went out to the garage and pulled my Helm manual down from the shelf to get a closer look at that illustration. You're right, it does illustrate the sprocket. I didn't notice the small gap between the rear face of the pulley and the front face of the sprocket because gap is miniscule when compared to the snout recess. The illustration doesn't even make mention of this gap. This begs the question what stops the gap from being reduced to zero? As you are pushing the pulley home(by using either a bolt or special tool) how are you to know when you have reached the spec. and haven't reduced this gap you speak of to zero causing the pulley and sprocket to come in contact with each other? Do you have to periodically remove the pusher tool to check the recess and gap? Most importantly what keeps the pulley from bucking up against the sprocket if you push the pulley further back to where the recess is reduced to the minimum value(smaller numerically:0.094 min. recess)? How are you to maintain the spec. between 0.094" and 0.174 if you torque the bolt to 240ft/lb.? Isn't the pulley going to be pushed until it eventually bucks up against the sprocket and can move no further? I believe the pulley continues to travel until the pulley and sprocket come in contact with each other. It's the fact that the sprocket and pulley are bucked up against each other that the additional clamping force needed to keep the pulley from slipping on the crank under the full load of the parasitic devices is provided for. I can buy the recess, but I'm still not sold on the gap.

 

I don't care if you invented blueprints; What is illustrated in the service manual is purely that, an illustration not a blueprint. I find it quite disconcerting that you argue with hard measurements (facts).

Again, why don't you skip yourself out into the garage and measure all the components and then tell us there is a gap in the stack-up height of the components.

This is Internet idiocy at it's best.

 

A stock crankshaft timing gear is a one piece component that includes the oil pump drive. The picture from the service manual illustrates the oil pump drive part of the crankshaft sprocket, but not the rear part of the gear that makes up the sprocket. Since the drive and sprocket make up to entire component, part of the crankshaft gear is illustrated.

 

 

I own an auto repair shop, and the balancer pressed tight against the crank gear. There is a TSB for the LS2's if the balancer has slipped/spun on the crank. On some of the LS2's, the crankshaft was flush with the front of the balancer. There is a shim that is to be installed behind the balancer so the crankshaft will be recessed from the front of the balancer.

Russ Kemp

 

 

Hey guys ineresting thread, but I have a novice question regarding these aftermarket Balancers. Whats the main reasons to change them out from stock and how do they acheive HP gains as stated by the aftermarket suppliers ?

Thanks , Tony

 

Congratulations, you’re staring to really think about it and actually get it.

You ask what stops the gap from becoming zero. If you take it to the low of 0.094” it may indeed touch the timing/oil sprocket. But I think there will still be a small gap between them even at the low side of the tolerance. I know the illustration and the nomenclature doesn’t mention it but as you see the gap is clearly represented in the figure. Its probably not mentioned because its unimportant as far as GM is concerned. You can’t really mic the gap with the timing cover on nor can you see it. OTOH if it was a concern that no gap remain, then there would be some mention of it somewhere. Another question you ask is how you know when you’ve reached the spec- I covered that in an early post. Put the pulley partially on approx. ¾ of the way, take your driver off (be it all thread or the bolt), check the current hub/crank recess, subtract the dimension value you desire and divide the result by 0.080” (one turn of the nut/ bolt results in an approx. 0.08” axial movement as the pitch of the thread is 2 mm between threads). This gives you the number of turns to pull it into position. If you read the task carefully you will come to understand that the 240 ft*lbs was GM’s computation of the force required to position the pulley between the desired specification position of 0.094” to 0.176”. They took into account the max and min pulley bore tolerance, together with the max and min crank tolerance plus factored in the length of engagement of the hub, and more than likey the kenetic friction force due to the head of the bolt turning against the stationary pulley interface to arrive at the exact torque value to overcome the force of the interference fit and place the pulley where it needs to be. Had to be a really good computer geek for that one, its one hell of a finite element analysis problem. I assume GM didn’t think a normal mechanic would be able to correctly use a depth mic and do it the way I’ve described above. But who knows what GM was thinking, that’s another thread all by itself. Also there are other ways to accomplish this same position specification. Its simply the one GM chose to use. The only thing driving the pulley is the friction from the metal to metal contact between the crankshaft and the ID of the hub. The large head of the bolt will provide a slight driving force on the pulley from the static coefficient of friction, but its pretty small when compared to the driving force from the pulley/crank interference interface.

In my estimation the main reason for the crank bolt is to ensure the pulley doesn't come off the hub, that and to hold the pulley into position. This is because the belts are exerting a transverse force on the pulley (perpendicular to the axis of rotation) and since the belt drive portion of the pulley is off-set from the hub/crank support attachment point it creates a force-moment arm about the X-axis (simply stated if you look at the crank shaft axially from the drivers side, the force of the belts make the pulley want to rotate clockwise. This resultant two - vector force wants to pull the pulley toward the front of the car and at the same time wants to bend it off the crank snout (Mechanics of Materials).
One thing I do know is when I disassembled mine the dimension from the pulley hub to the end of the crank snout was approx. 0.155”, my pulley was NOT pressed against the sprocket from the factory. When I reinstalled it, I placed it at approx. 0.139” which was within the 0.094” to 0.176” and it still has room to go before it hits the sprocket.

eallanboggs; This buds for you..

 

You very well may be correct on the LS2, I don't recall the LS2 being specifically mentioned in this thread. All my observations are based on my 2002 LS1 stock set-up and my recent cam change.

 

But you have presented no facts thus far, you only have stated your opinion and conjecture of what you think is going on.

You look yet you do not see.

I've shot down every one of your so called "facts" stated thus far. I find that disconcerting that you can come back with no real argument or evidence to support you view. You even put the Helms drawing up and point to it as evidence that you are correct, yet when I point out your mistaken and that it proves my point you then take the posiiton that its just a drawing representation and infer its not to be trusted. Geesh give me a break... Do you still think the world is flat??

Why don't YOU skip yourself out to the garage and figure out what time it is.
Perhaps you may even learn something but its doubtful as your mind is too closed to even see this picture clearly.

Give me another so called inconsistency, or another "fact"-I'll shoot holes in that one too. On this one your WRONG.

 

If you press it home (against the sprocket) and your out of specification (less than the minimum 0.094") you may run into problems with the oil seal. Seems like I recall ID numbers stamped on the hub portion near where the oil seal does its thing. I seem to recall the ID numbers are located toward the center of the hub, IE - away from the nose/edge. (Perhaps someone with a pulley handy can chime in here about exactly where the ID numbers are located on the pulley boss?) Its possible if you seat it too far the sealing portion of the seal will be positioned over these indented ID numbers and will then allow oil to seep and will more than likely impact on seal life from the discontinuity of the sealing surface..
Just a thought.....

 

First the balancer is pressed on with the GM tool or using a threaded rod with a thrust bearing & nut. Note that it takes way less than 240 ft lbs to turn the nut while installing the balancer. You can easily tell when the balancer is seated against the crank gear as the nut becomes tight.

Then the original bolt is installed & torqued to 240 ft lbs then removed. Then the distance between the front of the balancer & the nose of the crankshaft is checked just to make sure that the balancer is on far enough. Then the new crank bolt is torqued to 37 ft lbs, then 140*. That is way over 240 ft lbs, as it takes two people & a 3' power bar to get the 140*!

There is no way that there will be any clearance between the crank gear and the balancer with that amount of tightening torque.

Russ Kemp

 

Well Ok, if your gonna pull yours out I'll pull mine out too.

I'm the senior on-site Engineering Maintenance/Air Worthyness Authority representing the US Army Aviation and Missile Command (AMCOM) - Aviation Engineering Directorate (AED) with oversight over Ft. Rucker. I'm the final authority for all Depot maintenance and all maintenance above unit and intermediate level repair covering all Army rotary wing aircraft in use at Ft Rucker.

 

I'm not sure what you think you have shot down, but I have not presented any measurement data because I want you to prove yourself wrong. I have the data and know without a shadow of a doubt that you are completely and unequivicly talking .

If you have not measured the stack-up height of the components, how can you even state anything that's remotely close to your consistantly wrong stance that there is a gap. The ONLY reason you won't measure for yourself is because you like to blatently mislead people, mistate the obvious, and be disgustingly disagreeable.

Come on, wake up and get a clue or go back to working on your lawn mower.

Finally, to digress to your level, "My dad can beat up your dad."

 

:YAWN: are we supposed to be impressed? What's your point? Isn't this thread about timing sets?

 

I've seen and heard many idiotic things in my life but this is absolutely, positively THE worst CYA lie I've ever heard. I bet that if you repeated this on camera and submitted it to America's Funniest Videos that you could buy a new ZR1 with the money.

 

What kind of moron are you?
You want me to prove myself wrong?
How lame is that?

You don't have the sense God gave lettuce!

You prove me wrong, thats generally how it works.
Your so lazy you want someone else to do your work for you.
I'm not going to take my engine apart for something I know to be correct.
***** in your court fella, put up or shut up!

 

No need for me to prove anything to you. You have offered no FACTUAL proof supporting your position. I've only read jibberish and conjecture from a person that has no data or common sense.

 

I don't expect you to be impressed, your one brain cell is too taxed as it is.