SkinnyG's 1977 Chevy Silverado

Beats me. I do know that sometimes shops aren't always honest and up front with customers.  I fore sure never hit anything with the driveshaft.  Who knows.  I do know that it shook like a bugger when I first rebuilt that axle, and it shook like a bugger when they rebuilt that axle. It all goes back to trusting the driveline shops work when they built the driveshaft.  Perhaps it was junk.

Shops here are not consistent in "truing" vs "balancing" driveshafts.  I brought the V8 Firefly shaft to the shop that built the Silverado shaft to have it balanced, and they merely "trued" it.

Truthfully, I just want a fully equipped shop so I don't have to rely on anyone's questionable level of competence....

Pat's Driveline in Port Kells has always done a good job for us but with Greyhound shut down, I don't know if the shipping costs would kill you.

That said, regarding the previous shop. Everyone has a first day, maybe the apprentice built your driveshaft.

Truck shop called.

They had a dickens of the time trueing the shaft. They cut the driveshaft apart and discovered the yolks were so badly cast, that they had to cut a new surface on the yolk with the lathe to weld the tube to. New tube, trued up perfect. Said they took it up to 110km/h (70mph) and only then was there a light vibration, and the slightest of vibration on decel from 70km/h (44mph; I can probably shim that out).

I'll pick it up tomorrow.

Cost for new R&P & bearings & install, & diagnose & true & fabricate new shaft: $2500 CDN ($1800 US).  Wheeee.

Not sure this was wise. I mean, I could have easily bought another truck for $2500.  On the other hand, I know e-v-e-r-y-t-h-i-n-g about this one; I know what I have.  Hopefully I'm good.

Not going to get the driveline shop to build the shaft for my '61, it'll be these guys.

There's the problem...

You used yolks instead of yokes. 

Someone needs a trip to the libary.

Woof. I paid a local machine shop $325 to shorten, replace the u-joints, and "high speed balance" the shaft in our race car. We run the engine up around 5500 rpm (110 mph) and the driveline felt smooth and perfect. And Maryland, USA isn't exactly the cheapest place to get things done. 

Hope your shaft problems are cured now, at least. 

ShawnG: Bad spelling is defiantly a problem

volvoclearinghouse: Golly I hope so. I'm relieved that it WAS the shaft. I'd be pretty miffed if they found nothing. Even more choked if the shaft, left the way it was, would vibrate the new R&P to death.  I may have already mentioned that.

Did you pick it up yet?  If so does your verdict agree with theres on the 'almost' lack of vibration?

Picking it up this afternoon, after my x-ray to see what debris might be still in my hand after a way-too-close-to-the-grinding-stone incident on a knuckle just before spring break.

Just had another thought after (still slowly) going through the V8 Firefly thread.  I know you've done a lot of work on the pinion angle with this, but you've lowered it dramatically too.  While your pinion angle and out put flange angle may be good, have you checked your UJ angles?  Could the trans and axle be far enough out of plane with each other you're getting high UJ angles?

With no added shims, the Trans pinion operating angle is 5° and the axle operating angle is 1°.  Ideally, you want to be around 1°-4° operating angle, preferably under 3°.

I previously raised the transmission to about 1/2" away from the floor to reduce the angle (it was worse), but that's as high as I can go. The next phase, if there is enough of a problem worth dealing with, would be to try and lower the motor mounts.

But yeah - you're right on the money with that idea.

Having said that, it's not like this is the first squarebody with a flip kit.

Having said that, when I build the '61, I will be FOR SURE locating the motor and trans to get a much better operating angle for the axle at ride height.

And there was much rejoicing.

The truck has never driven so smoothly. Holy carp.  And to think I've been chasing shims, driveline angle, u-joints, tire imbalance, wheel imbalance, brake drum imbalance, etc. etc. etc. All the while the custom-made driveshaft was custom-knackered.

I am very, very, very pleased.

volvoclearinghouse: You win. Driveshaft all the way.

In reply to SkinnyG :

i'm rejoicing in Oak Park MI.  Glad to hear you've got my future truck's driveline vibration sorted.  ;-)

Hahahahahaha!  You bet, man!

Took it back Monday because there were puddles of oil under the diff. Told them "if it's not the diff cover, bill me accordingly."

Apparently the rosette welds were leaking. Anyone know what GM used to rosette weld the axle tubes? Anyway, they gooped it up with some fancy stuff and I have it back again.

No leaks now.

Some fancy "Ford" goop they put over the welds.  Yay.

But the more I drive it, the more I notice some wee vibration. Don't get me wrong, it's awesome compared to before.  But I'm getting used to it, and my Fussy-Butt is sensing a distrurbance.

I machined a pair of 2° shims (out of 2.5"x5.5"x3.16" flat) and installed them today with SkinnyKid1, putting the pinion from 1° UP to 1° DOWN. Should see tomorrow how that changes anything. If anything. Fun getting the '61 Apache out of the shop and parking it on the street while we did this.

This is what a failed HEI ignition module looks like, at 463 paces.  Look for the wee baby blue smudge on the left, near the darker trees.

Luckily, I had another one.

At home.

Grrrrr.

That reminds me I should have a spare ignition module in all my HEI Chevy powered stuff.  I definitely don't right now.

In reply to SkinnyG :

You know...

Points would have still gotten you home 

ShawnG said:

In reply to SkinnyG :

You know...

Points would have still gotten you home 

Sigh.

And if I had a hand-crank, I wouldn't won't be needing a battery this summer, I know.

You're almost as bad as your old student teacher in MX at Steveston, and his love of diesels....

In reply to SkinnyG :

Lol...

I couldn't resist after the other thread letting me know how much better electronic ignition and EFI are than the alternatives.

Funny thing though, with all the GM HEI stuff I've owned, I've only ever had one module fail and it was an aftermarket one. Only one HEI failure and never a Ford TFI failure.

I've had three Pertronix go bad though.

I'm getting my comeuppance for hassling Brad all those years ago, the shop owner LOVES diesels, I still can't stand the stink, noise and filth.

I understand the earth-moving torque of diesel, and the great fuel economy, but it still sounds like the Detonation Death to me; it makes the wrong sounds.

The module was in what I think was a "Mr. Gasket - Blueprinted Distributor" I got for free back when I first built the motor, so China for sure. The springs and weights were definitely NOT blueprinted and had to be re-curved. And I had to take it completely apart after one year to weld the weight pins back onto the plate. And the vacuum advance can broke. The weights are all a sloppy piece of crap inside.

Spare module I had at home is an original GM module.  But I ordered another one tonight to keep in the glovebox.

In reply to SkinnyG :

Fortunately it would seem you a nice walk through the vineyards and orchards.

Leave it there overnight for a time out.  That'll teach it to mess with you.

Old Hoffman tire balancer was donated to the school from our local college.

They were kind enough to load it into my truck.  But I had to unload it myself.  I had a bit of help.....

This is a really great thread to read.  I've always lusted after the thought of a stepside square body with a manual transmission and a lopey 350.  After seeing how much constant maintenance and tinkering your truck requires, I think I would be better off with something more modern.  I still love the way they look though, and one day I do want to build up a carbed 350.