When your guys originally balanced the assembly, did they use the flywheel and clutch too? I know it's "neutral" balance and adding the flywheel or clutch should not affect the overall balance. But if the guy has the crank and bobweights all set up and balanced properly, then it's no big deal to add the flywheel, damper, and clutch, just to confirm that everything will work with no vibrations after you install it in car.......

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No, because the clutch wasn't on hand. I'm hoping to find a counterweight on the flywheel by chance this weekend.

 

You are getting some good advice here.
It is always nice to see this kind of help on the forum.

 

It is. Things like this really make this place one of the best.

I called Texas Speed, verified the same crank gets used LS1 or LS2/4 save for the reluctor ring, and the clutch/flywheel for an LS1 being bolted to an LS3 makes no difference in my situation. He's emailing me the balance sheets. I'm going to have my tuner look at it tomorrow on the EXTREME off chance it's just a really lean coniditon, but I'm not holding any hope there just because of how pronounced it feels.

 

Houston we have a problem. I think. I found the following thread interesting in my searching tonight: http://forums.corvetteforum.com/c5-t...s2-gotcha.html

So I hop out to the car, can't see much. Pull the #2 plug wire, and lookie what I find:



I think this DEFINITELY could be the root cause of the issues. A not-completely bolted down motor with the block riding on the mount frame. Going to drain and pull the A/C compressor tomorrow and try to fix it.

Could someone do me a favor though and hop out to the garage and see if your mount is sitting flush or not?? Just for verification?

 

Yes they should be flush.

Hmm, looks like I was closest on my guess. JK JK

Glad you found it. Post up the results

 

Welp......wish me luck. I got my yard work done, line lock brackets cut, have a dinner to go to at 6:30, then it's on the car. Looks like I've got to pull the water pump in order to get the A/C compressor out of the way (unless I want to pull the turbo manifold instead.....gee let me think about that one), and then it's going to come down to how accessable the area that needs clearancing is. In the referenced post TPE mentioned notching the mount bracket which I'm not so sure about, but I'll try to see how things go once I get there. If I get lucky I might be done tonight if all goes smooth.

 

Hey, I hope the mount ends up being the issue and it goes well for you on correcting it. Keep us posted on how you make out.

 

Well, here's the update:

Got everything out. Water pump wasn't bad, Compressor was an absolute PITA. Ended up having to take the first inlet tube from the turbo to the pancake pipe off due to not being able to access lower mounting bolts for the compressor or the retaining bolt for the A/C lines. Then had to take off the mounting bracket for the compressor that has the A/C tensioner and idler pulleys on it.

Then, OF COURSE, I still can't see crap. Break out the handy viewing mirror and sure as sh*t, two of the bolts holding the mount to the block are showing a gap between the flange and block, and then I see it plain as day, the one bolt boss pinned against the mount flange. So tomorrow I get to figure out how to grind that bolt boss away blind. I know I'm going to have to jack the motor up, remove the mount/flange, then go in blind on it. Or, like TPE did/does as per the referenced thread, notch the mount flange (highest probability here at this point).

Oh, and I'm 100% committed to redoing the turbo inlets now. The inlet tube I took off tore as it was coming out. Already have an attack for this in mind, just didn't want to tackle it until this vibration issue was figured out.

And I swear on anything and everything, if this is being done for no reason, I'm going to lose it.

 

The grinding of the boss is necessary to achieve the proper fit for the engine mount bracket to engine block. So, no matter what it really needs to be done. That said, be prepared for this not to fix the vibration issue. I hope I'm wrong, but I really think it will be two separate issues. Along with all the work you are having to do to correct the mount to block issue I would highly suggest checking the flywheel and the harmonic damper for added weights.

 

Mount got fixed, no dice.

So I went out there tonight and I pulled the starter to get the small cover shield, put it back in and had my wife crack the engine over. The only signs of anything on back of the flywheel is a single drill hole for the balancing as done by Textralia. No weights, turned true, looked good.

However.........

I decided to put my eye on the crank pulley from the bottom and had her rotate the engine over for a 4-5 second burst. What I saw there was unsettling. Granted the engine was rocking, but it looked like there was some pretty good runout on the crank pulley, like it was actually moving up/down during it's rotation. So I went top side and put my finger between the water pump pulley and the crank pulley (no belts on car right now). There was enough room for me to plan my finger on the water pump pulley and have the crank pulley grazing my fingernail. Had her crank the engine over again and it was skipping on and off of my finger.

So now I'm wondering if the pulley got warped somehow, or worse if the crank snout is bent or something........is there any way to specifically check this short of popping a new crank pulley on there or starting the motor with the one that's on off of there?

 

So, after fixing the mount issue and putting it back together did you run the engine? I really doubt the crank is bent but I can believe that the crank pulley could be mucked up.

I was hoping you would find a balance weight in the flywheel.

 

Yeah, I ran the engine on Wednesday night. I could only see the outer perimeter of the flywheel but I know (at least I think I know) that the weights wouldn't be on the center section of the flywheel.

My only question if the balancer is mucked up is HOW.

Good news is that if I do indeed need to pull the drivetrain to get the clutch out, I have the tools and access to the backs of the turbo's to get the downpipes off the turbo's, meaning I can leave the turbo's and manifolds in place fortunately.

 

So, you ran the engine. Does it still have the same vibration? Did you actually drive the car?


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Didn't need to drive the car. Same vibration as before with it sitting there revving, engine speed based, increasing intensity linear with RPM increase, clutch in or out.

 

It sound like you need to address the crank pulley issue. If that doesn't improve the vibration issue it might be time to find someone local to do the balance. I think you said someone built the engine for you and they gave you the balance info. Does that info show anything about piston and rod, weights, or the crankshaft balance?

If there are no weights in the harmonic balancer or the flywheel, and if the clutch system if balanced the only thing left is something in the engine. Whatever the cause it is likely it could be corrected in the vehicle using a balance analyzer.

 

Here's the balance specs that came to me:

TSP #3777

Rod Rot. 442g
Rod Rot. 442g
Rod Bearing 45g
Rod Bearing 45g
Oil Allowance 4g
Piston/Pin 581g
Rings 35g
Locks 4g
Rod Recip. 176g

Total: 1774g

Balanced: 2g

I'm no engine builder, so I've got no clue what I'm looking at other than possibly before/after weights.

 

Argh........got the steering rack out and put the socket on the crank bolt and just went to set it up for a sally bar so I could crack it free, and when I did that it rotated down almost on it's own. There was almost no torque on the crank bolt.

I'm going to pull the pulley, run the car, verify if vibration is present or not. If it is, I'm debating on pulling the clutch or not to rule it out. If it's not, I'm going to put the pulley back on, PROPERLY torque the sucker down (to ARP's recommended TQ specs) and run the car again. Vibe present, pulley time. Vibe not present, I gotta have a talk with the installers.

 

Ok, I'm not sure what the numbers mean that they gave you. They confuse me. First the “Balanced: 2g”, is that their balance??? Normally we go for a gram or less, much less. The total number is confusing too. They have con rod end twice? For the bobweights it is normally rotating plus half of the reciprocating.

As long as they matched the piston units and connecting rods weights, balancing the engine in the car should not be to hard. Might be worth having them explain the data they sent you and why they have the rod rotation on the list twice.

 

No luck on the first try. I decided to grab an old crank bolt, TQ the pulley to 240 ft/lbs, remove old crank bolt, reinstall ARP and TQ to 190. Same issue.

Pulled the pulley, battery had given up! DOH! It's on a trickle charger now. The pulley looks ok, no weight added. The rubber rings in it though are a little cracked up that you can see, and there's a crap ton of anti seize on the snout/pulley inside that they used apparently.

Soon as my battery is charged I'm firing it back up.