Question for Tom Hendricks on 96 LT-1

[Bill H.]

Re: Question for Tom Hendricks on 96 LT-1

Just the way i do it but, the easy way to do the left side plug wires (and the opti for that matter) is to pull the P/S pulley, takes 2 minutes and gives you good access.
The balancers are always stuck to the crank hub but can be tapped off from underneath the car. If you use a little antisieze on the balancer surfaces (where they contact the hub) the balancer will come off the next time with just a wiggle.

[Bill H.]

Re: Question for Tom Hendricks on 96 LT-1

JR------


I don't think you need to pull the harmonic balancer. However, you do need to unbolt the balancer from the hub.

Yep, the rotate the crank so the opti can clear the hub tabs.

[Joe L.]

Re: Question for Tom Hendricks on 96 LT-1

Yep, the rotate the crank so the opti can clear the hub tabs.

Bill-----


Just make sure that the balancer is re-installed in the same position on the hub as when removed so as to preserve the final engine balance achieved during the hot test at Flint. There is no "designed-in" indexing feature for the balancer-to-hub. This was a DUMB thing for GM engineers to do, but that's what they did.

[Bill H.]

Re: Question for Tom Hendricks on 96 LT-1

Bill-----


Just make sure that the balancer is re-installed in the same position on the hub as when removed so as to preserve the final engine balance achieved during the hot test at Flint. There is no "designed-in" indexing feature for the balancer-to-hub. This was a DUMB thing for GM engineers to do, but that's what they did.

That's a great point, Joe. And it's one of the most hotly debated LT1 questions on the web (seems some folks just won't read the FSM). they keep saying the hub is neutrally balanced, it may be but the balancer has weights installed.
And it's impossible to mark the crank until you pull the hub at least part way (pulling the hub is another story, lotsa broken hubs and pullers trying to do it without the extra bolt in the crank trick for the puller to press against).

What I have seen, though it's only on 2 engines since I've been paying more attention to this, there's an arrow on the hub. On both, that pointed towards the crank keyway though that may have been a coincidence.

As far as the balancer to the hub, isn't one of the bolt holes offset so that the two can only go together one way? I think I played with this the last time I pulled a hub.

And, if the hub to crank isn't marked during dissambly, there's a procedure in the FSM to relocate it though certainly not as good as marking it when you pull it.

[Terry M.]

Re: Question for Tom Hendricks on 96 LT-1

That's a great point, Joe. And it's one of the most hotly debated LT1 questions on the web (seems some folks just won't read the FSM). they keep saying the hub is neutrally balanced, it may be but the balancer has weights installed.
And it's impossible to mark the crank until you pull the hub at least part way (pulling the hub is another story, lotsa broken hubs and pullers trying to do it without the extra bolt in the crank trick for the puller to press against).

What I have seen, though it's only on 2 engines since I've been paying more attention to this, there's an arrow on the hub. On both, that pointed towards the crank keyway though that may have been a coincidence.

As far as the balancer to the hub, isn't one of the bolt holes offset so that the two can only go together one way? I think I played with this the last time I pulled a hub.

And, if the hub to crank isn't marked during dissambly, there's a procedure in the FSM to relocate it though certainly not as good as marking it when you pull it.

I am pretty sure you are right Bill. I have never had to pull the hub, but getting the balancer to slide over the hub has always been an issue that makes me want to move to the dry Southwest. I have always had to use a puller to get the balancer off the hub. It just doesn't go as easy as the FSM would have you believe. Although one car I worked on from North Carolina/New Mexico came apart just like the book says. No puller needed.

Joe makes an excellent point about the balance of the hub. I have given up participating in those on-line debates about internal & external & neutral balance. There is a lot more misunderstanding than fact out there.

[Joe R.]

Re: Question for Tom Hendricks on 96 LT-1

Joe and Bill,

Yes, the harmonic balancer has to be pulled off the hub. After 230,000 miles it is a pulling job! The three bolts holding the balancer are not equal distance from one another. Found this out as I had to keep rotating the balancer until ALL the bolts lined up. It will only go on one way or at least on my engine it would only go on one way. One leg must be longer to key the balancer.

Working on the LT-1 in a C-4 is something that is NOT enjoyable but can be accomplished. After my local Chevy dealer pointed out what the labor cost was involved it made the hours a little more bearable.

I had already replaced the water pump a few thousand ago but I replaced the seals on the cover for the pump and the opti-spark.

Probably pulling the PS pump pulley would have saved a little time but the pulley has holes so you can reach the outer mounting bolt on the driver side.

Now my low RPM miss is gone as a result of changing the spark plug wires. THAT was the most time consumming task! Those spark plug wires were installed by a 2 foot grimlin with 6 inch fingers at the factory. If anybody ever wants to change spark plug wires, I would advise paying the extra money for AC Delco wires. They are cut to length and fit properly with correct boots.

Now if I could just get my hands clean!!!!

JR

[Joe L.]

Re: Question for Tom Hendricks on 96 LT-1

That's a great point, Joe. And it's one of the most hotly debated LT1 questions on the web (seems some folks just won't read the FSM). they keep saying the hub is neutrally balanced, it may be but the balancer has weights installed.
And it's impossible to mark the crank until you pull the hub at least part way (pulling the hub is another story, lotsa broken hubs and pullers trying to do it without the extra bolt in the crank trick for the puller to press against).

What I have seen, though it's only on 2 engines since I've been paying more attention to this, there's an arrow on the hub. On both, that pointed towards the crank keyway though that may have been a coincidence.

As far as the balancer to the hub, isn't one of the bolt holes offset so that the two can only go together one way? I think I played with this the last time I pulled a hub.

And, if the hub to crank isn't marked during dissambly, there's a procedure in the FSM to relocate it though certainly not as good as marking it when you pull it.

Bill-----


I don't recall there being any indexing feature for the balancer-to-hub. I could be wrong, but I just don't recall that there was any. In other words, as I recall, the balancer can be installed on the hub in any of 3 different positions. By the way, the 1992-95 hub is different than the 1996. Also, the LT1 balancer is different than the LT4, the latter having a larger balance ring. Both balancers are GM-discontinued but available in the aftermarket.

As far as the engine final balance is concerned, in 1992 we toured the GM Flint engine plant as part of the NCRS National Convention. I was fortunate enough to be in the first group of folks into the plant and I got to spend a lot of time in there. I watched as the LT1 engines were run at the hot test station. I watched the operator run the engine, look at his CRT display, and then install the pin-like weights in certain holes on the periphery of the balancer. So, I KNOW that final engine balance was done this way.

[Joe L.]

Re: Question for Tom Hendricks on 96 LT-1

I am pretty sure you are right Bill. I have never had to pull the hub, but getting the balancer to slide over the hub has always been an issue that makes me want to move to the dry Southwest. I have always had to use a puller to get the balancer off the hub. It just doesn't go as easy as the FSM would have you believe. Although one car I worked on from North Carolina/New Mexico came apart just like the book says. No puller needed.

Joe makes an excellent point about the balance of the hub. I have given up participating in those on-line debates about internal & external & neutral balance. There is a lot more misunderstanding than fact out there.

Terry-----

1986 and later small blocks are EXTERNALLY balanced----sort of. Why? Well, it's because the rearmost "counterweight" on the crankshaft is ROUND and not "elliptical" like pre-1986 engines. That is because of the change to the one piece rear seal. However, none of this has anything to do with the FINAL BALANCE done at Flint for LT1's. The final balance is essentially unrelated to internal or external balance engine design.

[Bill H.]

Re: Question for Tom Hendricks on 96 LT-1

I am pretty sure you are right Bill. I have never had to pull the hub, but getting the balancer to slide over the hub has always been an issue that makes me want to move to the dry Southwest. .

What I do, if you have the luxury of time, use some PB on the balancer/hub parting line from underneath the car, overnite.

Get under the car with a 1/2 in or so by 3 ft. wood dowel and a 3 lb hammer. Place the end on the dowel on the balancer beside the hub. Don't put the dowel on the outer edge of the balancer because it's assembles with the rubber elastomer, etc. 2 wacks and move to the other side.
I've only had to use about 10 hits to do it this way.

The dry southwest-----the humidity here today is 7%.

[Joe L.]

Re: Question for Tom Hendricks on 96 LT-1

Joe and Bill,

Yes, the harmonic balancer has to be pulled off the hub. After 230,000 miles it is a pulling job! The three bolts holding the balancer are not equal distance from one another. Found this out as I had to keep rotating the balancer until ALL the bolts lined up. It will only go on one way or at least on my engine it would only go on one way. One leg must be longer to key the balancer.

Working on the LT-1 in a C-4 is something that is NOT enjoyable but can be accomplished. After my local Chevy dealer pointed out what the labor cost was involved it made the hours a little more bearable.

I had already replaced the water pump a few thousand ago but I replaced the seals on the cover for the pump and the opti-spark.

Probably pulling the PS pump pulley would have saved a little time but the pulley has holes so you can reach the outer mounting bolt on the driver side.

Now my low RPM miss is gone as a result of changing the spark plug wires. THAT was the most time consumming task! Those spark plug wires were installed by a 2 foot grimlin with 6 inch fingers at the factory. If anybody ever wants to change spark plug wires, I would advise paying the extra money for AC Delco wires. They are cut to length and fit properly with correct boots.

Now if I could just get my hands clean!!!!

JR

JR------


Well, I guess there is an indexing feature for the balancer-to-hub. Somehow, I either missed that or forgot it. I'm glad there is such a feature. There is no indexing feature for hub-to-crankshaft, though, although I suppose it's possible that the embossed arrow represents a "soft" indexing feature. All they needed to do was use a keyway----just like they did for every Gen I small block.

[Joe R.]

Re: Question for Tom Hendricks on 96 LT-1

JR------


Well, I guess there is an indexing feature for the balancer-to-hub. Somehow, I either missed that or forgot it. I'm glad there is such a feature. There is no indexing feature for hub-to-crankshaft, though, although I suppose it's possible that the embossed arrow represents a "soft" indexing feature. All they needed to do was use a keyway----just like they did for every Gen I small block.

Joe,

My Vette is a 96 and I believe you or someone else noted that the 96 changed in the area of the harmonic balancer. After getting this balancer off I cleaned it so it would not be hard to install. Lucky that I could spin it around and finally hit the screw hole for all three. Back in 92 when you toured the Flint facility they probably were using a different method or no method at all.

JR

[Terry M.]

Re: Question for Tom Hendricks on 96 LT-1

Joe,

My Vette is a 96 and I believe you or someone else noted that the 96 changed in the area of the harmonic balancer. After getting this balancer off I cleaned it so it would not be hard to install. Lucky that I could spin it around and finally hit the screw hole for all three. Back in 92 when you toured the Flint facility they probably were using a different method or no method at all.

JR

JR
1996 was the introduction of OBD II, and with that you got a crankshaft sensor in the lower part of the timing cover that sensed a trigger ring attached to the crankshaft inside the timing cover. This resulted in a crankshaft with a longer "snout" (I am sure there is a better word for that part of the crankshaft) and attendant dimensional changes to the harmonic damper hub.

[Joe L.]

Re: Question for Tom Hendricks on 96 LT-1

Joe,

My Vette is a 96 and I believe you or someone else noted that the 96 changed in the area of the harmonic balancer. After getting this balancer off I cleaned it so it would not be hard to install. Lucky that I could spin it around and finally hit the screw hole for all three. Back in 92 when you toured the Flint facility they probably were using a different method or no method at all.

JR

JR------

The harmonic balancer was the same for all 1992-96 LT1. However, it did change for 1996 LT4. The balancer hub was different and unique for all 1996, LT1 or LT4.