Sorry to hear the bad news, very frustrating to deal with I'm sure.

Have you considered dropping the drive train, leave the motor in, pull the flywheel and clutch out and just use a stock exhaust and see for sure if it's the motor or some kind of drive train problem ?

 

I have run it with flywheel and pressure plate only (verified zero balance by machine shop), NO exhaust save for the manifolds/turbo's (downpipes w/wastegates were off the turbo's) and no accessory drive belt or crank pulley on the front of the motor. I took everything out of the equation but the motor.

Could it be a turbo possibly? The motor ran fine and was responsive, wasn't sluggish or anything which makes me think it's NOT the motor. No, scratch that. Couldn't be a turbo because the vibration is absolutely linear with the RPM's. If it was a turbo it would ramp up and play catch up with the RPM's.

 

At this point I would not assume you can count that out. Sounds like you are going to have to take your car to a shop that does FI for evaluation. If that does not sound doable, then I would flash the PCM to stock, bolt on the factory exhaust, ,and give yourself a sold baseline from which to work.

 

Have you tried it with the clutch pedal depressed ?

This is the only way to know that it is not drive train related.

I don't think the turbos are your problem, but using a stock exhaust is a lot easier to be sure everything is right before you bolt up the turbos and all of the plumbing that goes with them.

 

It's going to go back together and go to PBJ here in St. Louis for a look at on the tune and to see what he things, hopefully next week. I can't afford to pay a shop to diagnose the issue but he said he wanted to see the car and feel the vibe as well as look at/put a baseline tune (His own) in the car for break-in before he fully tunes it. It's still running on an ever so slightly tweaked version of the tune that the stock LS1/TT kit was on, but I'm getting zero indications of that being the issue given the severity of the vibration and that my WB is not showing anything funky.

 

Clutch pedal in or out, no difference.

Don't have a stock exhaust handy to even thing about trying. I suppose I could completely remove the turbo's and run open manifolds, but that's a lot of a** pain at this point. I may do it though because it's not THAT hard to to drop the manifolds at this point, and it's only four bolts and the turbo's are off the manifolds. I'll save that for after Joe looks at it if he can't figure anything out, and make it a last ditch effort as I'm in process of pulling the motor.

 

If the clutch pedal is in and it's still vibrating then you know it's at the flywheel forward.

Remember when I told you my factory assembly was imbalanced and had a corresponding weighted factory flywheel?.... And when I put a zero balanced fw the whole thing vibrated identical to yours?

I'm betting money, it's your rotating assembly, and no amount of fancy tunes or hoping it's a turbo is going to balance your crank/rods/pistons until it's taken apart and worked on.

 

Since the beginning of this thread I've been thinking the rotating assembly was off too like ~JOSHUA is suggesting. I've never found a bad tune or even a miss to vibrate an engine all the way through the RPM range like you have described. Good luck with this, hope you can get it worked out for min $$$.

 

Well, if it is indeed an internal balance issue, TSP has already said they'd stick behind the motor. I'd have to pull it and send it off to them (they'd pay shipping) and they'd tear down the long block and balance, and if it was their problem, then it's on their dime to reassemble and return to me. But, they won't cover the $2K+ I paid in labor and various parts that aren't reusable.

Downside? If they miraculously (sarcasm hinted) find that it's not in the internal balance, I'm paying for everything (shipping, tear down, reassembly, ect).

I have always had a gut feeling it's the shortblock too, but I positively have to rule out everything short of that before I commit to pulling the motor.

I do have one small victory to announce: With the mods I did to the A/C lines, I have managed to fit both APS Filters directly on the Turbo's. Took some creative maneuvering to get them into place, and they look like they were creatively smooshed, but they're in.

Car will be 100% reassembled and back on all fours by the end of the day. I only hope that Joe has some time tomorrow or Tuesday to look at the car.

 

Did you ever find out if there was a local place that could check and/or rebalance your engine in the car. I think I read somewhere on here where a GM tech could do it on site at the dealer ship after someone had a vibration problem they couldn't solve on a Corvette. Maybe you could just sent the builder that smaller bill if so...just a thought.

 

I haven't called around, but I will be calling GM dealerships in the area to see. Problem is that's going to be a BIG bill because the turbo's/manifolds have to come down to get access to the lower bell housing. There's quite a bit of labor involved with that. I'm willing to go that route though if I can find somewhere reasonably close that can do it.

Car is mechanically back together. I still need to put the center console back together, top off the power steering fluid, and burp the coolant system, but she's on all fours on the ground.

You know it's been a while when you pick up your wheels to put them back on and under EVERY wheel about 4-5 brown recluses are residing. They don't react well to brake fluid sprayed at them though. Especially with a small propane torch between said brake fluid can and them.

 

Ok, I may have just hit on something........

The head/cam setup I bought off of LoBoost was Patriot Stage II 317's and a GT2-3 camshaft. He was running this on a stock LS2 shortblock with 7.4" pushrods he included with the setup.

I however, now have LS7 lifters in my motor which apparently require a shorter pushrod by approx .005 on a stock setup. Add to it that I'm also running marginally thinner .045 cometic head gaskets, and you see where this might be heading.........

Thoughts?

 

Tapping can occur from improper geometry, but not a vibration.

 

What if I was bottoming the lifter out though?? It's something that I need to check at this point anyway.

 

You would be having bent push-rods if they were bottoming out. What is your engine vacuum looking like at idle?? If you are having valve issues, the vacuum will be fluctuating and LOW.

BC

 

Idle vac is 16 in/hg. Valvetrain is nice and quiet too so I doubt that's my issue. Vac does fluctuate when I let it try to idle off of a rev and coughs and sputters, but once it recovers vac goes back to 16.

I need to get it out and drive it. I'm noticing that I'm NOT getting nearly as much vibe through the steering wheel or chassis now. It all seems to be coming via the shifter. I Need to get it out and drive it but of course, first time in 3 weeks, it's wet out. Go figure. Kind of hard to tell if it's genuine or I'm just being paranoid considering I dropped those poly mounts into the car.

 

Man, I've been watching this thread like a hawk, as I've had similar vibration issues. Mine did indeed (as I mentioned earlier) turn out to be internal engine balance problems (TWICE!).

Pushrods that are too long would not cause a vibration IMO. They might wear the valve guides quicker (or VERY quickly, lol).

Do you notice this vibration at all engine speeds, or does it come and go? If it vibrates at all rpm's, then I might suggest looking very carefully at tune items. Make sure compression good in all cyls. Check exhaust temp at each outlet with infrared gun to make sure each cyl is very close. Also look for stupid things, like plug wire arcing, and/or vacuum leak. Or maybe a plugged injector.

This stuff can really wear you down. I know my problems wore me down, to the point that I was ready (on multiple occasions) to park the car (a '68 BB Camaro) in the street and torch it, lol. I had sooooo many problems with that car, I ended up hating it - and then sold it. Funny thing is - I NEVER tried to take any shortcuts. I went to high-end machine shops and I spent the money on the top-quality parts.

Hang in there man. You WILL eventually fix this car. But you may not be in love with it anymore when it's all better, so be prepared for that.

I'll keep lurking.....................

 

That is definitely a great option, however, what assurances do you have to verify TSP's findings? Short of watching over their shoulder?

 

Perhaps you could have someone local tear down the motor and send TSP the bill if it's out of balance? It would take a very customer-service oriented company to do that. I'm not sure those exist anymore though....

 

Hmmm......in the immortal words of Stewie Griffin........

Just took her for a spin and it was NICE and SMOOTH!!!!!! There was a little vibe coming through the shifter which I'm attributing to the Pfadt motor mounts, but there was not of the teeth loosening RPM related vibration I was experiencing before!!!!!!!!!!! Hallelujah I think we got it!!!! Paranoia seemed to be running rampant yesterday when I fired it up which is why I told myself to put it back together and drive it before making a rash decision. I only needed a quick blast up and down the street to about 50 mph to verify and she was nice and smooth again!

Going to get it to PBJ this week for a little better baseline tune, and do some break in on the motor. First.......she's getting a BATH!!!

I want to offer a sincere thank you to every person who had input during my searching of this issue, and a very special thanks goes out to AJG1915 who kindly sent me a couple of tools to help working on the car. Situations like this is why the place is as great as it is, and I'm truly thankful to be a part of it. Thank you all for your help and support. I only hope I can be as helpful in the future.

Updated thread to come once it's tuned and everything is good to go, unless more problems arise.