Every since my cam and tranny swap, my car has been vibrating like hell. I attributed that to the big cam, gm847. The mechanic who was doing my opti and plug wire swap said the harmonic balancer was not lined up right, and this is causing the motor to vibrate. He didnt know the correct way to put it together because he said there was no tooth markings or anything. He suggested I go to a dealer to get it rebalanced.

Searching on this site has left me confused. Threads state that the balancer cannot be put on wrong cuz they only go on one way. The belt itself looks fine when the motor is running, but the engine definitely vibrates, shakes the car at idle and shakes my eyes out of their sockets at wot. I thoguht it could be a flywheel balancing issue, but if its the harmonic balancer that should be very simple.

Anyone know how to put that thing on properly?

 

Did you pull the hub off when you did your cam swap? While the hub is suppose to be zero balanced(hence holes in the hub for balancing) it does need to be put on in a particular order. The GM service manual recommends pressing the hub on with the engine at TDC on the number one cylinder. From there locate the "cast" in arrow (more like a triangle) on the hub and press it on the crank in the 12 o'clock position.
When you did your tranny swap , did you pull the drive shaft out completely?

 

I didnt do any of the work, I live in an apt, have limited tools and experience, and little time with school. I'll find out though.

 

get used to fixing others mistakes, im in the middle of a topend rebuild (fixing another mistake). during this process, ive removed the hub. mine is keyed, so the hub is only going on one way. there is a pointy protrusion on the hub itself, and the balancer has a similar protrusion. you line those up and youre good to go. im pretty sure thats the way it goes...

you can try perusing shoebox's site as well, he has a lot of info, and you may get closer to an answer through there...

gl

jb

 

thanks man, I'll have to have a peek at it myself. the #1cyl at tdc method is extremely helpful.

I just got back from the car and it shakes even in neutral when i rev it, i dont mean a bit of vibration, like it SHAKES. It cant be the driveshaft. Does the flywheel turn when the clutch is engaged? (im dumb when it comes to this stuff).

thanks.

 

Just wondering? Did you check your engine and tranny mounts? A unbalanced engine will shake at IDLE too, not just when you rev it.

Flywheel turns all the time. It's bolted to the end of the crankshaft

Did the vibration start after any clutch or transmission work? If so, you could have a out of spec pressure plate.

 

I didnt notice the vibration after the cam swap, it was definitely there after the tranny swap. It shakes at idle as well, but much worse when you rev it, while driving, or while in neutral.

 

The damper placement is not all that critical, and its only a "damper", not a "balancer". That's why they didn't put a key in the hub. I'd be more inclined to suspect that the "tranny swap" is the source of a vibration that can be felt it idle. You could check the damper and make sure that the rubber ring that hold the inner and outer metal pieces together isn't damaged, but you'd see the accessory belt wobbling if that was the case. You could also look at the holes in the damper ring, and see if any of them has metal inserted into it, which might indicate a final "tweek" was done with the damper.

 

thanks for the tips. i was wondering if the spec stage two clutch comes prebalanced. As far as I can tell, they do. Its definitley something to do with the tranny installtion though as it happened after that. The belt does not wobble at all, but the motor sure does.

I'll let you guys know as soon as i find out whats causing this

 

Before you rev it too high, make sure of the problem.

Quite a few years back, I helped a friend install a new clutch and pressure plate in a Ford.
There was a significant vibration after the install -- and it was installed correctly.

After about 100 miles with the vibration, my friend decided to push the clutch in and rev it to about 3K rpm.
The pressure plate exploded and broke the bell-housing in little pieces - the back of the engine fell down on the steering rods because there was no rear engine support.

Tom Piper

 

Well, at least Ford circled the problem!

 

If it was installed correctly, then what ended up being the problem?

 

Since it came apart violently at only 3K rpm (some small pieces came up through the floor), my guess is it had a crack in the pressure plate assembly. And, since the clutch was pushed in, there was no pressure to hold the assembly together and the centrifugal force caused it to come apart.

All the bolts were in it and it was torqued in the correct pattern with a torque wrench.
It was bought as a complete new assembly.

After it exploded, it was in too many pieces to diagnose anything, and there wasn't one piece of the bell-housing left that was connected to both the engine and the transmission.

I should point out, neither one of us were novices at this at the time.


Tom Piper

 

damper is on right, motor and tranny mounts are tight. Does anyone know if the spec clutch, flywheel, etc. needs to be balanced to the stock flywheel or of it comes prebalanced? From what I could search, it seems they come prebalanced, but then the vibration wouldnt make any sense, its definitely mechanical, extremely reproducible.

 

Med_reject:
this may or may not help, but I have been having problems for a while now with my Z28 too. My problem is that it keeps running on 7 instead of 8; and it makes the car shake like crazy, ESPECIALLY if there is a load on the enging... it effectively makes 6th gear completely useless. When you put it in 6th or ask too much of the engine, it shakes the whole freaking car like crazy. When your car idles, does the exhaust pop, and ignite unburned fuel being dumped into your headders? that would be a telltale sign of your engine running on less than 8.

Since you have a huge GM 847, that may only insinuate more of a load at idle to keep it running than a stock cam.

I got MSD Super Conductor wires, and have had nothing but problems with them. From wires that dont want to stay stuck on the Opti, to the wires too big to fit in my looms, so they fall down on the headders and getting burned.
I think I am going to go back to my Taylor Race Wires... they're not too big for their own good. For that matter, I just wish the LTCC wasnt 600 dollars + coils.

Good Luck, I hope you figure it out, it sounds like you have a badass setup.... I'm really jealous of your cam.