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By following this procedure you will gain access and be able to change the three front timing cover seals (Water Pump, OptiSpark Drive, Front Crankshaft/Balancer)
Unlike its SBC predecessor, the LT1/LT4 Balancer is a two-piece assembly consisting of an (inner) hub, and (outer) balancer/pulley. Removal of the assembly can be frustrating if approached in the conventional way. By following the procedures below, you can safely and quickly remove the assembly with little or no problem.
You may want to consider using Rhino Ramps or jack stands to gain additional access space and elbow room underneath the front of the engine.
1. Drain the radiator by opening the drain valve on the lower right hand (passenger side)
2. Remove the serpentine belt
3. Remove the upper radiator hose
4. Remove the water pump. When removing the water pump, it is important to remember that the LT1/LT4 water pump is attached to the engine with 3 bolts on each side, vs. its predecessor, which only had 2 bolts on each side. The center bolt on the driver side is a challenge, but can be removed without removal of the power steering pump. When removing the water pump, take care to remove the pump drive coupler along with the pump and place it on the pump drive shaft for use when re-installing the pump.
5. Mark the coil wire and all plug wires at the OptiSpark cap for easy reference when re-installing the OptiSpark unit after balancer seal repairs have been completed.
6. NOTE: There is no need to separate the balancer pulley from the hub if you intend to pull the hub off anyway. The only time you need to separate the pulley from the hub is if you are simply changing the OptiSpark. There is a match mark that is cast into the balancer assembly that allows you to mate the two pieces together in the exact orientation that they come apart. If you intend to separate the balancer pulley from the hub, locate the marks and make note for re-assembly.
7. The balancer pulley is attached to the hub with three bolts. The bolts are 7/16” SAE standard, 14 threads per inch, ¾” length (not metric). Fully remove all three bolts, and if you intend to remove the unit as a complete assembly, jump to steps 9 thru 18. If you intend to separate the assembly, continue by rethreading one bolt by a couple of turns. It is now time to separate the pulley from the hub. Most pulleys have been found to be rusted in place and require considerable effort to separate from the hub. Spraying the inside of the pulley with penetrating oil helps. Do not strike the pulley with a hammer in your frustrated attempts to remove. The best method is to position yourself under the engine with a steel rod (or better yet a brass drift) and one healthy hammer. Position the rod/drift on the inside portion of the balancer when striking it with the hammer. This step requires more than a gentle tap. Try to position yourself so you can give a good solid hit at each rotation. Rotate the crankshaft 120 degrees after every couple of heavy hammer blows. Do not hit on the outer diameter of the pulley as damage can and will occur.
8. After successfully separating the pulley from the hub, it is now time to unbolt and remove the OptiSpark module. As with the water pump, a coupler drives the OptiSpark module and care should be taken to remove the drive shaft and place with the OptiSpark module for use when re-installing the unit. When the time comes to re-install the OptiSpark unit on the engine, you should pay close attention to the Notice below
Notice
Contrary to what all the books say, in some cases, the OptiSpark drive coupler can/will go on in more than one position. When the coupler is correctly installed, the OptiSpark unit will slide in place and rest firmly against the timing cover without forcing it into position. The drive spline in the rear of the OptiSpark is keyed. Pay close attention to the key, and match it up with the corresponding slot on the drive coupler.
9. Finally, it is now time to remove the hub. The center bolt that holds the hub on the crankshaft snout is 7/16” fine thread (not metric). I have found that I can generally break the center bolt loose by placing a 6 sided socket on the bolt, with a ½” breaker bar attached. By striking the breaker bar with that healthy hammer you just used in step #7, you can break the torque on the bolt.
10. Fully remove the bolt, remove the washer from the bolt, then re-install the bolt by 3 full turns.
11. Re-read step #10. If you skip this step, you are a screwed pooch.
12. The “General” was thinking when he installed the power steering rack hydraulic lines as he has installed a loop in the lines that allow the use of a balancer puller without interference of the puller jack screw. Check it out, you will be glad that he did this.
13. Use a standard balancer puller that requires the use of 3 puller bolts that fit into 3 slots on the crab portion. Make sure that you use a tip on the jack screw end that is a flat rotating plate, not a sharp point, because you will eventually place the jack screw end directly on the head of the center bolt of the hub and you don’t want to damage it.
14. Next, select three new (or used) 7/16” bolts that are of sufficient length to slip thru the puller and fully thread into the hub where you previously removed the 3 bolts in step #7. If you do not have 3 – 7/16” bolts that are the proper length, you can use bolts that are slightly smaller than the tapped holes so you can slip them completely thru the hub. Make sure that the bolts are of sufficient length so that you can insert them completely thru the puller assembly and the hub, with a flat washer on each end, and a nut on the backside.
15. Rotate the entire hub assembly until the (^) mark is at the 12:00 position before removing the hub. When re-installing the hub, make sure that you install it back in the same orientation. This is a balance mark, and although it really won’t make too much difference if you fail to do this, it is there for a purpose, so try to do the right thing here.
16. Position the puller onto the front of the hub, with the jack end of the jackscrew slid thru the power steering line loop, and attach as mentioned above.
17. You are now ready to slowly remove the hub from the crankshaft snout. The crank may start to turn as you apply force. Placing a 2x4 against the puller and left wheel "A" frame will stop the rotation. If you have access to a micrometer (click style) torque wrench you will find that it will take about 70 - 85 foot pounds of torque before you will see the hub start to move. As you continue to turn the jackscrew in a clockwise rotation, the hub will slide off the crankshaft. Keep doing this until you feel the hub come loose, or until you back it out against the shoulder of the center bolt. It may be beneficial to purchase a 3" x 7/16 grade 8 fine thread bolt and continued the removal with that. Without the 3" bolt you might not be able to get the hub all the way off.
Plan to use the 3” x 7/16” bolt when re-installing the hub back on the crankshaft after your repairs are complete. Just slide the washer over the bolt, start the bolt in the crankshaft, and mechanically pull the balancer back onto the crankshaft snout.
18. You have successfully removed the balancer hub. Now, time to R&R that front seal assembly.
NOTE: I am looking for feedback from those who use this procedure in improving the steps above, and adding a section for re-installing the balancer hub. Please e-mail me at PurpleC4@qwest.net with your feedback.
:seeya Purp
I just did this Sunday and Monday. I basically did what you described however I removed the radiator to get me some room to work, since my A/C lines were empty anyway.
One thing I noticed, yes the balancer has a mark that lines with the hub, but it doesn't matter. You cannot bolt it up the wrong way. The 3 "fingers" on the hub are not evenly spaced. The only way the bolts will line up is if it is installed correctly. I've also found that it's easier to just go ahead and seperate the hub from the pulley, it makes getting the hub off easier.
Reinstallation is pretty straight forward. Occasionally if your balancer hub is off for a little while it can decide it doesn't want to fit when you put it back. I think it oxidizes somewhat. You can solve this problem by taking a piece of scotch brite around the crank a few times, then for the hub you can use another trick. A brake cylinder hone works wonders. Hone it out just enough to "smooth it up" and remove any contamination. You might also want to lubricate the inside of the hub before you try to re-install it. You should be able to push the hub on by hand far enough for you to start to thread the bolt. Tighten the bolt to pull the hub onto the crank. It should be firm, but not impossible. If you feel it is too tight, remove the hub again and hone it some more. The last thing you want to do is strip the threads out of your crank or break a bolt off in it.
Something else to add is that I didn't take the balancer off all the way when I did mine. It just seemed like something not necessary. I undid/redid the 3 outter bolts by sticking a metal rod (12 " or so) between the block and front cross member. I just losened them and was still able to get my opti on/off.
Thanks again Nathan. This sure beats the shop manual info on procedure. Maybe you should take over writting GMs' "Bible"... sometimes it seems they you for a long walk just to go a very short distance.
Neal,
The LT1/LT4 balancer hub is not a bore through, like earlier balancers. With the old style balancers, you could remove the crank bolt and push directly against the face of the crankshaft snout. With the LT1/4 balancer hub, the balancer is not a complete bore through ~ it is only drilled to accept the crank bolt. If you try to remove it without re-inserting the bolt, you will be pushing against the same piece you are trying to remove (the balancer). I hope this is clear.... If not, please let me know and I will try to explain in another way.
Purp
Neal,
The LT1/LT4 balancer hub is not a bore through, like earlier balancers. With the old style balancers, you could remove the crank bolt and push directly against the face of the crankshaft snout. With the LT1/4 balancer hub, the balancer is not a complete bore through ~ it is only drilled to accept the crank bolt. If you try to remove it without re-inserting the bolt, you will be pushing against the same piece you are trying to remove (the balancer). I hope this is clear.... If not, please let me know and I will try to explain in another way.
Purp
Oh I figured that one out. :crazy: I didn't put the bolt back in at first course I didn't have this write up either. Anyway after a turn or two with my wrench I was thinking something isn't right this is just WAY to hard. I stole a mirror from the wifes makeup drawer (oops) & took a peek in the end of the crank. Well I'll be that's how that works.
Put the bolt in & poof it came right off. I asked about the screwed pooch part because I hope I didnt mess anything up. The hub & the balancer went right back together & look OK but I am now wondering if I need to look at anything closer.
One thing you might want to double check that you got the hub pulled back on completely. The last time I did mine I didn't quite, it didn't leak or anything, but the belt was one rib off on the balancer, which was wearing it out quickly. Not real good on a $40 GM only belt that the 92's are cursed with.
Neal ~
OK, I get it. No, from a Screwed Pooch standpoint, you don't have anything to worry about. You figured out the problem and resolved it. My comment regarding screwed pooch was that:
A. You can't get it off if you continue to try in that way, no matter how hard you try.
B. If you try too hard that way, you will either break your puller, or worse yet break the ears off of your hub.
Thanks for helping clarify this issue. I will make sure I make that fact a little clearer in the procedure.
On another point
Nathan, I agree that it is very necessary to ensure that the hub is fully installed for the reason you have listed. Most guys will pull the old balancer back on to the same depth as when removed ~ however, if a speedy sleeve is installed over the hub to provide a new wear point, or if you buy a new hub, then that reference point is lost. In this case, we need to find a good way of indicating in the procedure to watch for full installation.
Thanks guys. This procedure has been one of my pet projects because almost every week I see someone who asks for information contained in the procedure.
:seeya Purp
As always, insightful and correct. Yeah, SOME of us have a little experience with putting the OPTI in without the key being lined up...... after removal and reinstallation of the OPTI for the second time in one day, you will never do it again.....least I wont.... :bb
Tim,
I have a double :bb :bb story. In case you might have forgotten, I re-installed my water pump without the drive coupling. Trying to be a very organized mechanic, I stuck the drive coupling into my old pump for safe keeping. When I re-installed the new water pump, I failed to include the drive coupling. It didn't take long before the heat was rapidly rising and I was thinking WTF? We all make mistakes...... That's why I try to include a little insightful lines like Screwed Pooch to get the point across.
Purp
By following this procedure you will gain access and be able to change the three front timing cover seals (Water Pump, OptiSpark Drive, Front Crankshaft/Balancer)
Unlike its SBC predecessor, the LT1/LT4 Balancer is a two-piece assembly consisting of an (inner) hub, and (outer) balancer/pulley. Removal of the assembly can be frustrating if approached in the conventional way. By following the procedures below, you can safely and quickly remove the assembly with little or no problem.
You may want to consider using Rhino Ramps or jack stands to gain additional access space and elbow room underneath the front of the engine.
1. Drain the radiator by opening the drain valve on the lower right hand (passenger side)
2. Remove the serpentine belt
3. Remove the upper radiator hose
4. Remove the water pump. When removing the water pump, it is important to remember that the LT1/LT4 water pump is attached to the engine with 3 bolts on each side, vs. its predecessor, which only had 2 bolts on each side. The center bolt on the driver side is a challenge, but can be removed without removal of the power steering pump. When removing the water pump, take care to remove the pump drive coupler along with the pump and place it on the pump drive shaft for use when re-installing the pump.
5. Mark the coil wire and all plug wires at the OptiSpark cap for easy reference when re-installing the OptiSpark unit after balancer seal repairs have been completed.
6. NOTE: There is no need to separate the balancer pulley from the hub if you intend to pull the hub off anyway. The only time you need to separate the pulley from the hub is if you are simply changing the OptiSpark. There is a match mark that is cast into the balancer assembly that allows you to mate the two pieces together in the exact orientation that they come apart. If you intend to separate the balancer pulley from the hub, locate the marks and make note for re-assembly.
7. The balancer pulley is attached to the hub with three bolts. The bolts are 7/16” SAE standard, 14 threads per inch, ¾” length (not metric). Fully remove all three bolts, and if you intend to remove the unit as a complete assembly, jump to steps 9 thru 18. If you intend to separate the assembly, continue by rethreading one bolt by a couple of turns. It is now time to separate the pulley from the hub. Most pulleys have been found to be rusted in place and require considerable effort to separate from the hub. Spraying the inside of the pulley with penetrating oil helps. Do not strike the pulley with a hammer in your frustrated attempts to remove. The best method is to position yourself under the engine with a steel rod (or better yet a brass drift) and one healthy hammer. Position the rod/drift on the inside portion of the balancer when striking it with the hammer. This step requires more than a gentle tap. Try to position yourself so you can give a good solid hit at each rotation. Rotate the crankshaft 120 degrees after every couple of heavy hammer blows. Do not hit on the outer diameter of the pulley as damage can and will occur.
8. After successfully separating the pulley from the hub, it is now time to unbolt and remove the OptiSpark module. As with the water pump, a coupler drives the OptiSpark module and care should be taken to remove the drive shaft and place with the OptiSpark module for use when re-installing the unit. When the time comes to re-install the OptiSpark unit on the engine, you should pay close attention to the Notice below
Notice
Contrary to what all the books say, in some cases, the OptiSpark drive coupler can/will go on in more than one position. When the coupler is correctly installed, the OptiSpark unit will slide in place and rest firmly against the timing cover without forcing it into position. The drive spline in the rear of the OptiSpark is keyed. Pay close attention to the key, and match it up with the corresponding slot on the drive coupler.
9. Finally, it is now time to remove the hub. The center bolt that holds the hub on the crankshaft snout is 7/16” fine thread (not metric). I have found that I can generally break the center bolt loose by placing a 6 sided socket on the bolt, with a ½” breaker bar attached. By striking the breaker bar with that healthy hammer you just used in step #7, you can break the torque on the bolt.
10. Fully remove the bolt, remove the washer from the bolt, then re-install the bolt by 3 full turns.
11. Re-read step #10. If you skip this step, you are a screwed pooch.
12. The “General” was thinking when he installed the power steering rack hydraulic lines as he has installed a loop in the lines that allow the use of a balancer puller without interference of the puller jack screw. Check it out, you will be glad that he did this.
13. Use a standard balancer puller that requires the use of 3 puller bolts that fit into 3 slots on the crab portion. Make sure that you use a tip on the jack screw end that is a flat rotating plate, not a sharp point, because you will eventually place the jack screw end directly on the head of the center bolt of the hub and you don’t want to damage it.
14. Next, select three new (or used) 7/16” bolts that are of sufficient length to slip thru the puller and fully thread into the hub where you previously removed the 3 bolts in step #7. If you do not have 3 – 7/16” bolts that are the proper length, you can use bolts that are slightly smaller than the tapped holes so you can slip them completely thru the hub. Make sure that the bolts are of sufficient length so that you can insert them completely thru the puller assembly and the hub, with a flat washer on each end, and a nut on the backside.
15. Rotate the entire hub assembly until the (^) mark is at the 12:00 position before removing the hub. When re-installing the hub, make sure that you install it back in the same orientation. This is a balance mark, and although it really won’t make too much difference if you fail to do this, it is there for a purpose, so try to do the right thing here.
16. Position the puller onto the front of the hub, with the jack end of the jackscrew slid thru the power steering line loop, and attach as mentioned above.
17. You are now ready to slowly remove the hub from the crankshaft snout. The crank may start to turn as you apply force. Placing a 2x4 against the puller and left wheel "A" frame will stop the rotation. If you have access to a micrometer (click style) torque wrench you will find that it will take about 70 - 85 foot pounds of torque before you will see the hub start to move. As you continue to turn the jackscrew in a clockwise rotation, the hub will slide off the crankshaft. Keep doing this until you feel the hub come loose, or until you back it out against the shoulder of the center bolt. It may be beneficial to purchase a 3" x 7/16 grade 8 fine thread bolt and continued the removal with that. Without the 3" bolt you might not be able to get the hub all the way off.
Plan to use the 3” x 7/16” bolt when re-installing the hub back on the crankshaft after your repairs are complete. Just slide the washer over the bolt, start the bolt in the crankshaft, and mechanically pull the balancer back onto the crankshaft snout.
18. You have successfully removed the balancer hub. Now, time to R&R that front seal assembly.
NOTE: I am looking for feedback from those who use this procedure in improving the steps above, and adding a section for re-installing the balancer hub. Please e-mail me at PurpleC4@qwest.net with your feedback. Purp
94 C4 LT1 50,000 miles all original.
I never touched this car since new because it was running just fine. I started with a puddle of clear fluid on the floor that I assumed was coming from my power steering pump. I removed the pump and replaced it. Puddle re-appeared the next day so I just assume it came from a fine spray from the rack and just hit the front of the block. Now, a few months later, following the "might as well do it when I am looking at it path, I am down to the harmonic balancer and want to do all the seals including the timing case. EVERYTHING NOW COMES TO A GRINDING HALT. I would love to replace the balancer too... but measuring the depth of the balancer, it appears to be greater than the space between the end of the crank and the framework in front of it. There is only 1 7/8" between the balancer and the pulley. QUESTION... can the pulley be removed in 2 parts? Is the belt drive part separate from the dampener part? I can see maybe getting the balancer loose... but it is really possible to remove it without lifting the engine? To replace the crank seal and timing cover gasket requires complete removal of the crank hub. I read about separating the balancer from the pulley... can that be done when it is on the car so that it comes off in two pieces?
Another problem I had was finding a 7/16 puller. There is not a single one in Las Vegas.. all are 3/8.... so I had to buy a smaller one, drill it out and find 7/16x14 bolts. I did get the puller onto the pulley but it has not budged yet. I have to make a tool to keep the pulley from turning. Even if I can get the pulley to start to slide off... once it gets to the frame, I believe there will still be a short bit still on the crank and it will be so tight I will not be able to remove the Y part of the puller. I've been reading all the posts and watching the videos. Am I missing something?
Next, when I went to buy the seal set and TC gasket... they show also that you must replace the oil pan gasket???? YIKES !
Richard - Las Vegas
(From Driver's Side) there is less than 1 inch between the steering rack and the balancer (dampener).
(Passenger's Side) there is 1 7/8" between the harmonic balancer (dampener) and the the horizontal frame. QUESTION ; Can the balancer be removed in 2 pieces? is the pulley separate from the balancer ???
Last edited by icanjuggle@yahoo.com; 02-22-2016 at 11:49 PM.
Reason: adding photos and question
By following this procedure you will gain access and be able to change the three front timing cover seals (Water Pump, OptiSpark Drive, Front Crankshaft/Balancer)
Unlike its SBC predecessor, the LT1/LT4 Balancer is a two-piece assembly consisting of an (inner) hub, and (outer) balancer/pulley. Removal of the assembly can be frustrating if approached in the conventional way. By following the procedures below, you can safely and quickly remove the assembly with little or no problem.
You may want to consider using Rhino Ramps or jack stands to gain additional access space and elbow room underneath the front of the engine.
1. Drain the radiator by opening the drain valve on the lower right hand (passenger side)
2. Remove the serpentine belt
3. Remove the upper radiator hose
4. Remove the water pump. When removing the water pump, it is important to remember that the LT1/LT4 water pump is attached to the engine with 3 bolts on each side, vs. its predecessor, which only had 2 bolts on each side. The center bolt on the driver side is a challenge, but can be removed without removal of the power steering pump. When removing the water pump, take care to remove the pump drive coupler along with the pump and place it on the pump drive shaft for use when re-installing the pump.
5. Mark the coil wire and all plug wires at the OptiSpark cap for easy reference when re-installing the OptiSpark unit after balancer seal repairs have been completed.
6. NOTE: There is no need to separate the balancer pulley from the hub if you intend to pull the hub off anyway. The only time you need to separate the pulley from the hub is if you are simply changing the OptiSpark. There is a match mark that is cast into the balancer assembly that allows you to mate the two pieces together in the exact orientation that they come apart. If you intend to separate the balancer pulley from the hub, locate the marks and make note for re-assembly.
7. The balancer pulley is attached to the hub with three bolts. The bolts are 7/16” SAE standard, 14 threads per inch, ¾” length (not metric). Fully remove all three bolts, and if you intend to remove the unit as a complete assembly, jump to steps 9 thru 18. If you intend to separate the assembly, continue by rethreading one bolt by a couple of turns. It is now time to separate the pulley from the hub. Most pulleys have been found to be rusted in place and require considerable effort to separate from the hub. Spraying the inside of the pulley with penetrating oil helps. Do not strike the pulley with a hammer in your frustrated attempts to remove. The best method is to position yourself under the engine with a steel rod (or better yet a brass drift) and one healthy hammer. Position the rod/drift on the inside portion of the balancer when striking it with the hammer. This step requires more than a gentle tap. Try to position yourself so you can give a good solid hit at each rotation. Rotate the crankshaft 120 degrees after every couple of heavy hammer blows. Do not hit on the outer diameter of the pulley as damage can and will occur.
8. After successfully separating the pulley from the hub, it is now time to unbolt and remove the OptiSpark module. As with the water pump, a coupler drives the OptiSpark module and care should be taken to remove the drive shaft and place with the OptiSpark module for use when re-installing the unit. When the time comes to re-install the OptiSpark unit on the engine, you should pay close attention to the Notice below
Notice
Contrary to what all the books say, in some cases, the OptiSpark drive coupler can/will go on in more than one position. When the coupler is correctly installed, the OptiSpark unit will slide in place and rest firmly against the timing cover without forcing it into position. The drive spline in the rear of the OptiSpark is keyed. Pay close attention to the key, and match it up with the corresponding slot on the drive coupler.
9. Finally, it is now time to remove the hub. The center bolt that holds the hub on the crankshaft snout is 7/16” fine thread (not metric). I have found that I can generally break the center bolt loose by placing a 6 sided socket on the bolt, with a ½” breaker bar attached. By striking the breaker bar with that healthy hammer you just used in step #7, you can break the torque on the bolt.
10. Fully remove the bolt, remove the washer from the bolt, then re-install the bolt by 3 full turns.
11. Re-read step #10. If you skip this step, you are a screwed pooch.
12. The “General” was thinking when he installed the power steering rack hydraulic lines as he has installed a loop in the lines that allow the use of a balancer puller without interference of the puller jack screw. Check it out, you will be glad that he did this.
13. Use a standard balancer puller that requires the use of 3 puller bolts that fit into 3 slots on the crab portion. Make sure that you use a tip on the jack screw end that is a flat rotating plate, not a sharp point, because you will eventually place the jack screw end directly on the head of the center bolt of the hub and you don’t want to damage it.
14. Next, select three new (or used) 7/16” bolts that are of sufficient length to slip thru the puller and fully thread into the hub where you previously removed the 3 bolts in step #7. If you do not have 3 – 7/16” bolts that are the proper length, you can use bolts that are slightly smaller than the tapped holes so you can slip them completely thru the hub. Make sure that the bolts are of sufficient length so that you can insert them completely thru the puller assembly and the hub, with a flat washer on each end, and a nut on the backside.
15. Rotate the entire hub assembly until the (^) mark is at the 12:00 position before removing the hub. When re-installing the hub, make sure that you install it back in the same orientation. This is a balance mark, and although it really won’t make too much difference if you fail to do this, it is there for a purpose, so try to do the right thing here.
16. Position the puller onto the front of the hub, with the jack end of the jackscrew slid thru the power steering line loop, and attach as mentioned above.
17. You are now ready to slowly remove the hub from the crankshaft snout. The crank may start to turn as you apply force. Placing a 2x4 against the puller and left wheel "A" frame will stop the rotation. If you have access to a micrometer (click style) torque wrench you will find that it will take about 70 - 85 foot pounds of torque before you will see the hub start to move. As you continue to turn the jackscrew in a clockwise rotation, the hub will slide off the crankshaft. Keep doing this until you feel the hub come loose, or until you back it out against the shoulder of the center bolt. It may be beneficial to purchase a 3" x 7/16 grade 8 fine thread bolt and continued the removal with that. Without the 3" bolt you might not be able to get the hub all the way off.
Plan to use the 3” x 7/16” bolt when re-installing the hub back on the crankshaft after your repairs are complete. Just slide the washer over the bolt, start the bolt in the crankshaft, and mechanically pull the balancer back onto the crankshaft snout.
18. You have successfully removed the balancer hub. Now, time to R&R that front seal assembly.
NOTE: I am looking for feedback from those who use this procedure in improving the steps above, and adding a section for re-installing the balancer hub. Please e-mail me at PurpleC4@qwest.net with your feedback. Purp
removing the LT hub is an issue that comes up again and again. Add a few photos, especially of the hub so people can visualize why an LT hub is different than every other small block hub / damper/ balancer ever made and therefore requires a different removal technique (but not necessarily a $150 Kent Moore puller) and this should be a sticky.
Last edited by mtwoolford; 02-10-2016 at 01:01 AM.
Additional tips to get the balancer assembly loose
Originally Posted by PurpleC4
LT1_LT4 Balancer/Hub Removal
By following this procedure you will gain access and be able to change the three front timing cover seals (Water Pump, OptiSpark Drive, Front Crankshaft/Balancer)
Unlike its SBC predecessor, the LT1/LT4 Balancer is a two-piece assembly consisting of an (inner) hub, and (outer) balancer/pulley. Removal of the assembly can be frustrating if approached in the conventional way. By following the procedures below, you can safely and quickly remove the assembly with little or no problem.
You may want to consider using Rhino Ramps or jack stands to gain additional access space and elbow room underneath the front of the engine.
1. Drain the radiator by opening the drain valve on the lower right hand (passenger side)
2. Remove the serpentine belt
3. Remove the upper radiator hose
4. Remove the water pump. When removing the water pump, it is important to remember that the LT1/LT4 water pump is attached to the engine with 3 bolts on each side, vs. its predecessor, which only had 2 bolts on each side. The center bolt on the driver side is a challenge, but can be removed without removal of the power steering pump. When removing the water pump, take care to remove the pump drive coupler along with the pump and place it on the pump drive shaft for use when re-installing the pump.
5. Mark the coil wire and all plug wires at the OptiSpark cap for easy reference when re-installing the OptiSpark unit after balancer seal repairs have been completed.
6. NOTE: There is no need to separate the balancer pulley from the hub if you intend to pull the hub off anyway. The only time you need to separate the pulley from the hub is if you are simply changing the OptiSpark. There is a match mark that is cast into the balancer assembly that allows you to mate the two pieces together in the exact orientation that they come apart. If you intend to separate the balancer pulley from the hub, locate the marks and make note for re-assembly.
7. The balancer pulley is attached to the hub with three bolts. The bolts are 7/16” SAE standard, 14 threads per inch, ¾” length (not metric). Fully remove all three bolts, and if you intend to remove the unit as a complete assembly, jump to steps 9 thru 18. If you intend to separate the assembly, continue by rethreading one bolt by a couple of turns. It is now time to separate the pulley from the hub. Most pulleys have been found to be rusted in place and require considerable effort to separate from the hub. Spraying the inside of the pulley with penetrating oil helps. Do not strike the pulley with a hammer in your frustrated attempts to remove. The best method is to position yourself under the engine with a steel rod (or better yet a brass drift) and one healthy hammer. Position the rod/drift on the inside portion of the balancer when striking it with the hammer. This step requires more than a gentle tap. Try to position yourself so you can give a good solid hit at each rotation. Rotate the crankshaft 120 degrees after every couple of heavy hammer blows. Do not hit on the outer diameter of the pulley as damage can and will occur.
8. After successfully separating the pulley from the hub, it is now time to unbolt and remove the OptiSpark module. As with the water pump, a coupler drives the OptiSpark module and care should be taken to remove the drive shaft and place with the OptiSpark module for use when re-installing the unit. When the time comes to re-install the OptiSpark unit on the engine, you should pay close attention to the Notice below
Notice
Contrary to what all the books say, in some cases, the OptiSpark drive coupler can/will go on in more than one position. When the coupler is correctly installed, the OptiSpark unit will slide in place and rest firmly against the timing cover without forcing it into position. The drive spline in the rear of the OptiSpark is keyed. Pay close attention to the key, and match it up with the corresponding slot on the drive coupler.
9. Finally, it is now time to remove the hub. The center bolt that holds the hub on the crankshaft snout is 7/16” fine thread (not metric). I have found that I can generally break the center bolt loose by placing a 6 sided socket on the bolt, with a ½” breaker bar attached. By striking the breaker bar with that healthy hammer you just used in step #7, you can break the torque on the bolt.
10. Fully remove the bolt, remove the washer from the bolt, then re-install the bolt by 3 full turns.
11. Re-read step #10. If you skip this step, you are a screwed pooch.
12. The “General” was thinking when he installed the power steering rack hydraulic lines as he has installed a loop in the lines that allow the use of a balancer puller without interference of the puller jack screw. Check it out, you will be glad that he did this.
13. Use a standard balancer puller that requires the use of 3 puller bolts that fit into 3 slots on the crab portion. Make sure that you use a tip on the jack screw end that is a flat rotating plate, not a sharp point, because you will eventually place the jack screw end directly on the head of the center bolt of the hub and you don’t want to damage it.
14. Next, select three new (or used) 7/16” bolts that are of sufficient length to slip thru the puller and fully thread into the hub where you previously removed the 3 bolts in step #7. If you do not have 3 – 7/16” bolts that are the proper length, you can use bolts that are slightly smaller than the tapped holes so you can slip them completely thru the hub. Make sure that the bolts are of sufficient length so that you can insert them completely thru the puller assembly and the hub, with a flat washer on each end, and a nut on the backside.
15. Rotate the entire hub assembly until the (^) mark is at the 12:00 position before removing the hub. When re-installing the hub, make sure that you install it back in the same orientation. This is a balance mark, and although it really won’t make too much difference if you fail to do this, it is there for a purpose, so try to do the right thing here.
16. Position the puller onto the front of the hub, with the jack end of the jackscrew slid thru the power steering line loop, and attach as mentioned above.
17. You are now ready to slowly remove the hub from the crankshaft snout. The crank may start to turn as you apply force. Placing a 2x4 against the puller and left wheel "A" frame will stop the rotation. If you have access to a micrometer (click style) torque wrench you will find that it will take about 70 - 85 foot pounds of torque before you will see the hub start to move. As you continue to turn the jackscrew in a clockwise rotation, the hub will slide off the crankshaft. Keep doing this until you feel the hub come loose, or until you back it out against the shoulder of the center bolt. It may be beneficial to purchase a 3" x 7/16 grade 8 fine thread bolt and continued the removal with that. Without the 3" bolt you might not be able to get the hub all the way off.
Plan to use the 3” x 7/16” bolt when re-installing the hub back on the crankshaft after your repairs are complete. Just slide the washer over the bolt, start the bolt in the crankshaft, and mechanically pull the balancer back onto the crankshaft snout.
18. You have successfully removed the balancer hub. Now, time to R&R that front seal assembly.
NOTE: I am looking for feedback from those who use this procedure in improving the steps above, and adding a section for re-installing the balancer hub. Please e-mail me at PurpleC4@qwest.net with your feedback. Purp
Here's what I did based on the OP's advice about removing the balancer assembly:
1) I used two 1/2" drive socket extensions (12" and 8") coupled together for the driving rod. They're tough, and this task shouldn't damage them.
2) Find a spot under the car where you have a good view of the back of the balancer and can fit the rod in place to hammer against the inner part of the balancer. Hammer away from that spot only.
3) When rotating the crank 120 degrees after each time hammering, try to position the pulley so you have a good view of one of the three crankshaft hub wings, which are spaced 120 degrees apart.
4) As you start to make progress in budging the balancer off the hub, you will see a space start to open up between the hub wing and the back of the balancer.
5) The hub wing also makes a good buttress to keep your rod from moving around as you make your hammer strokes, but don't hammer on the hub wing itself. Again, as the OP mentioned, you want to hammer against the inside part of the balancer, not the outer part. Right next to the hub wings was a good spot in my opinion.
Eventually somebody will get unlucky and break a thrust surface section off of their thrust bearing with the hammering method. I recommend grinding three slots in the hub and using a traditional puller. Put one of the damper bolts in backwards and use a long wrench for counterforce. If there is clearance issues getting the damper out you can either move the rack forward, the engine/trans back, or a little of both.
^ Looks like your referring to hammering on the crank hub (which is a big NO!). The hammering method is used on the back of the BALANCER. A proper tool needs to be used for the crank hub.
Ah, you are correct. I got confused with all of the different terminology being thrown around. Thank you for clarifying. I was really beginning to wonder why somebody would need to hammer off the hub!
03-19-2002, 06:41 PM
LT1_LT4 Balancer/Hub Removal Procedure ~ Attn: Ittlfly
Purp
