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Balancer for gen VI 454

anwat

anwat

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I have a gen VI big block which apparently has the wrong balancer on it. When the timing mark on the balancer is lined up at TDC, my #1 piston is about halfway down, and the #8 and #5 pistons are at the top of their strokes. I'm going to pull the balancer to make sure the key didn't break, but I'm thinking it's the wrong balancer.
IMG_3232.jpeg IMG_3231.jpeg


The issue is going to be figuring out which balancer is right. This is a non-vortec engine. The casting number is from a gen VI, 12550313, I have a six bolt timing cover and a fuel pump boss, making me think it was sold as a block only. The issue is that I do not have a roller cam. I thought all gen VI's had a roller cam. Either way, are there different balancers for this engine, and what do I need to consider to figure out which one is right? I guess there's even a chance that the crank has been replaced, so what would be the right way to figure out which balancer belongs on this engine? Or should I maybe just remark the balancer on there and call it a day? To the best of my knowledge, this engine came from an ambulance built by Workhorse. Don't know if that's true, but that was the story when I bought the truck. And since I'm sure someone will know, based on what I described, do I have a gen VI or a Gen V? On a slightly different note, why can I not find a crank pulley for this engine?
 
I think the Gen V is provisioned for roller lifters, also would have thought they were all roller cams.
The balancers I removed from an 86-7 Mark IV, and a 96 Mark VI look identical. Both lined up tdc correctly.
 
could you see if there's any kind of part number on either of those:/ They look to be bigger in diameter than mine, but it's hard to say without a reference point. What's with the large groove cut on the outside edge of the clean one? If possible, I'll get mine pulled Tuesday and see how it compares to that one...Tomorrow I have to get the heads over to the machine shop so they can start on them ASAP. I just need to decide if I'm going to switch out the vavetrain to a roller cam or leave it alone. I think being able to set the timing accurately will probably make a big difference in my performance., but while it's all taken apart.....
 
shoot I just noticed those numbers aren't that clear, I post them up in a few.
 
The cast number on inside is 10216338,. Out side stamped number L S 6338-1556, this maybe a Mercruiser number
 
Is there an alternate timing tab or mounting location?

If the only issue with a balancer is location of the timing slot, you could make a 2nd one or wrap it with timing tape.
 
If it slipped once it'll move again.
Idk 6 bolt covers well enough to know if multiple timing tabs are common.
 
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The Gen VI balancer is going to be unique because of the tone ring for the crank sensor. The snout is shorter to accommodate the thickness of the tone ring. I went through this when I put the Gen VI in my crew cab. I had a Gen V balancer and didn't realize it until I tried to install it.
 
isn't the tone ring for l29 ? Does the L21 need the ring ? My VI didn't have a tone ring, but you know Mercruiser
 
Yea, the L21 has the much coveted higher tooth count tone ring and came factory with coil near plug. At least the trucks did. Although I used the L29 tone ring to set up coil near plug with the terminator ecu.
 
Now I'm completely confused. My balancer looks just like the bottom one in the above photos. Right down to the same numbers. But I don't have a crank position sensor. nor do I have fuel injection(well, at least I didn't from the factory. My block is cast as a gen VI according to the number, but was only used as a crate motor, it never really went into a vehicle. That all being said, maybe this was orginally in a boat? I was thinking maybe it came from something built by Workhorse, but they would probably buy a chassis with an engine and then modify from there, so it would have a regular production engine rather than a crate motor.
At this point, all I can say for sure is that this balancer isn't marked correctly for this engine. And since it seems to be the correct balancer, I 'm just going to have to mark it correctly and go from there. The new headache now is head gaskets, which is a topic for a different post.
 
My understanding is that true crate motors (bought through a GM parts department, not in a chassis) don’t necessarily have all of the same features that a production vehicle engine has (for example, crate engines can accept a mechanical fuel pump whereas a truck engine has an unfinished boss).

I think I’d study up on crate engine differences before you bought anything else or used those head gaskets.
 
I know this is true for SBC. The crate engines maintained the older 2-piece rear main seal, no roller provisions, etc. for at least a couple of decades after production engines got them. I think the casting can be updated, but some of the features not machined.
 
that one I pictured the numbers on was from a boat and it had/has a cruiser tag pined to the bell housing flange.
carburated with a q jet engine so no efi no reluctor
 
I've got quite the can of worms here. Not only do I have a block that was sold as a crate only, but my heads are "Gen V or VI" . Seems like everything on here is oddball. Trying to find new pushrods and rockers. Any help would be appreciated. The rods I have now are 5/16 in diameter and 8.186 and 9.186 long with balls on both ends. They ride on 7/16 studs. I can't even find anything that size. There's not much wear on my valve stems to see how they are riding, but the rockers seem to be wearing normally. Any idea as to whether these would be 1:7 or 1:5? I've got some pitting on a couple of the rods and the pivot washers, so I thought it might be good to replace them now, but I don't know what to replace them with...there's no markings whatsoever on the rods or rockers. The guides, however, are stamped with "PE IV" if that helps. I've looked for gen V and gen VI pushrods to no avail.

IMG_3330.jpeg IMG_3329.jpeg
 
Back to the balancer, though. When the balancer is reading at TDC, it's the #8 cylinder that's all the way up. It seems the balancer is about 45 degrees off. Any reason this would be? If it wasn't on the power stroke, it would be the #1 piston at the top when the balancer comes around to TDC, right? The pulleys all line up and the engine was running just not so well. There are two timing marks on the cover, but neither of them is close to the TDC line on the balancer when the #1 piston is up and both valves are closed.
 
anwat said:
The casting number is from a gen VI, 12550313, I have a six bolt timing cover and a fuel pump boss, making me think it was sold as a block only.
Click to expand...
From Mortec:
12550313...454.......91-up...4-bolt, Gen.V crate motor, Gen. VI 4.25" bare block, fuel pump boss
Click to expand...
anwat said:
Now I'm completely confused. My balancer looks just like the bottom one in the above photos. Right down to the same numbers. But I don't have a crank position sensor. nor do I have fuel injection(well, at least I didn't from the factory. My block is cast as a gen VI according to the number, but was only used as a crate motor, it never really went into a vehicle. That all being said, maybe this was orginally in a boat? I was thinking maybe it came from something built by Workhorse, but they would probably buy a chassis with an engine and then modify from there, so it would have a regular production engine rather than a crate motor.
At this point, all I can say for sure is that this balancer isn't marked correctly for this engine. And since it seems to be the correct balancer, I 'm just going to have to mark it correctly and go from there. The new headache now is head gaskets, which is a topic for a different post.
Click to expand...
Even if you know what vehicle it came out of, that doesn't mean it was original to that vehicle. Someone may have replaced it. Plus, the heads are freakishly clean...
 
The heads are that clean because they just came back from the machine shop. I gave up a long time ago on the vehicle ID, I'm just trying to get to whether this is a gen V or a gen VI. The head casting says it can be a gen V or VI, so how do I tell? What would GM do with a bare block? Would that be sold as a crate block, would they sell it to someone like an aftermarket engine builder? I think the only way I'm going to get the rockers and pushrods correct is going to be to measure them. Especially since I can't even determine which heads I have. What does the 4.25" refer to in that description?
 
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