huge vibration issue

[Grumpy]

Hello, I just finished rebuilding a 454 block that has 427 pistons and a 396 crank. Just went for a drive for the first time after breaking in the cam, and it vibrates and shakes insanely at 3000+rpm.

I blew up the 454 that was previously in the car (connecting rod snapped in half) so i reused a couple external parts from it including the flywheel and damper. I noticed the damper had a weight, but i didnt think much of it until now.

It's my first rebuild and I didnt know 454s were externally balanced as opposed to 396 cranks. So essentially im totally broke and I need to know the cheapest way to fix that, can i drop the tranny myself in the parking lot and get the flywheel weights cut off or is there a flywheel from another scrapyard chevy model I should use? Also my crank did have a dowel, the 454 flywheel fit like a glove.

I'm kinda losing it because I have to get back to work and this is my only vehicle, I'd really appreciate any advice to help me pull this off (I've never dropped a tranny from under)

1978 Camaro z-28
super t-10 manual 4 speed

3856223 crankshaft forged 396
l2300f .30 over 427 pistons
3931063 427 heads
2 bolt block 361959 1977
11-601-4 03159 comp cam
crane gold roller rockers 1.7
edel rpm air gap

I really hate to point out the facts here as I'm all to familiar with being broke and needing to do costly automotive repair work, but your lack of careful research before bolting the parts together is going to cost you time, effort and money!
obviously the first thing youll want to do is closely inspect the front crank damper and flywheel and the clutch pressure plate because if any of the three are loose or damaged that will cause a noticable vibration.
(be sure the drive shaft, u-joints and yoke are in good condition, )
If everything looks like its properly installed it seems like, youve very likely committed, an understandable but basically UN-correctable screw-up without total engine disassembly and carefully matching components and reassembly after having the whole rotating assembly re-balanced, using the correct balancer/damper and flexplate/flywheel
even a 396 internally balanced crank , with either a 427 or 396 flexplate/flywheel and damper won,t work correctly with a set of heavier 427 pistons without re-balancing as the cranks counter weights are slightly different.
on the plus side , when your working with the Chevy v8 engines SBC and BBC, if you select the correct two piece or one piece rear seal components, many aftermarket manufacturers of flex plates and flywheels to reduce manufacturing costs , build a neutral balance flywheel or flexplate and simply bolt on or weld on a weight to allow the same basic part to work with both potential combos

Counter Weight Kit General Motors Flywheel (1A/2C/3C/4C)

Fits Externally Balanced Applications

1986-1999 SBC

1970-1990 BBC

1991-1997 BBC

1970-1980 SBC 383/400
be darn sure theres a pilot bearing insert in the rear of the crankshaft for the front transmission input shaft to seat into.
your going to have to pull it apart and start over matching the correct components

this is a PRIME EXAMPLE of where a few days of reading link and sub-links prior to engine assembly could have avoided a great deal of expense and trouble later that would have been easily avoided
reading through the links and sub-links should help

http://garage.grumpysperformance.com/index.php?threads/454-bbc-on-the-cheap-well-to-start.11739/

http://garage.grumpysperformance.com/index.php?threads/extending-a-drive-shaft.3381/#post-8925

http://garage.grumpysperformance.com/index.php?threads/a-brief-look-at-clutches.447/#post-840

http://garage.grumpysperformance.com/index.php?threads/cheap-damper-ballancer-source.279/#post-1673

http://garage.grumpysperformance.com/index.php?threads/engine-balancing.3900/#post-10338

http://garage.grumpysperformance.com/index.php?threads/throwout-bearing-noise.6899/#post-22511

http://garage.grumpysperformance.com/index.php?threads/trans-won-t-fully-seat.8164/#post-28342

http://garage.grumpysperformance.com/index.php?threads/168-or-153-flywheels.3951/

http://garage.grumpysperformance.com/index.php?threads/what-fly-wheel.6124/#post-35034

http://garage.grumpysperformance.com/index.php?threads/pilot-bushing-installation.2596/#post-29548

http://garage.grumpysperformance.com/index.php?threads/ballancing-the-components.141/#post-175

where are you physically located (city/state) perhaps theres an experienced local web-site member willing to help who has some experience, to help you rebuild it correctly, that may lend a hand??
http://garage.grumpysperformance.co...lped-several-members-and-may-help-more.11389/

 

[Grumpy]

To clarify, I didn't choose the parts from the rotating assembly, I didn't build the engine I merely took apart what was there, and did a simple rebuild. I bought the engine as a short block with rotating assembly already installed by an apparently reputable builder a few years ago. It was left bolted on an auto tranny in a mud bogger open under a tarp complete flexplate to balancer, all it needed was an intake manifold but i still took it all apart to make sure everything was okay, regreased the bearings, checked the cam timing changed all gaskets, changed the oil pump and pan. Added rockers, pushrods, accessories, intake and valve covers. Nothing gave the impression that it was originally botched by an amateur, everything was in top notch condition and looked like it was built yesterday even years later thanks to professional assembly. it came with a neutral small balancer which I replaced with the bigger one from my 454, didn't realise the small one didn't have a weight until now. the block also came with a neutral flexplate for an auto tranny. The crank looked freshly balanced to my untrained eye (fresh grind marks).

All due respect, and I do respect your advice I'm not defending the fact that I may have to pull the engine eventually, but since I know I definitely have the wrong flywheel and damper I would rather change these two easier things and see if it works than pull the engine again, since I believe the engine was done right by the short block builder for the reasons mentioned above.

Note I am stranded way far from home, did all of this in a motel parking lot and do not have access to a hoist anymore. I am surviving on my credit card till i get this daily driver fixed, i need it to travel back to work.

Just saw the edit in your post
I am in Quesnel, British Columbia in Canada
I sure do hope the original builder took the 427 pistons in consideration when he installed the parts.. Thats something I didnt see in your post before replying

yes your correct,swapping back to the neutral balance 396/427 damper and flywheel will help get you closer to the correct balanced assembly, its surely closer than the 454 damper will provide

 

[Grumpy]

So, how about an update? Are you back in action yet?

Yes I am! I didn't check the forum the past few days but I worked on the car a lot, went through the hurst shifter, changed the tranny oil and greased the driveshaft. replaced the clutch with another centerforce. Went for a drive today to break in the rings, it ran smoothly all the way to 5500, sunk me in my seat but I had to be careful not to get too excited, cops were on the prowl and had a roadblock :angel:

She runs great, I'm very proud that I did all that and I really feel this car is 100% mine now. I just wish I had the knowledge required to tune my demon carb. it's used and I have no idea what jets it has, it won't idle the car but runs fine above 1500 and firing up was much smoother than with the predator sitting on it currently but I didn't want to risk running her too lean with the demon, so I'll have to keep that for a future project.

Thanks guys for all the advice, I'm really grateful. Here's some pics from this adventure if anyone is interested!

Old 454 with direct port NOS

Camshaft broke in 3 pieces, 4 exploded lifters, bent pushrods, connecting rod broke in half

Parts all over my motel room

cheap BBC that turned out to be a 427

Redneck engineered 2x4 tranny support with a ratchet strap

Finally went in with the help of 3 truck drivers, really great guys and they gave me great advice through this. Wish I had a photo with them
http://i32.photobucket.com/albums/d23/simhdukenope/20160707_214157_zpsfitljobz.jpeg

Forgot this little plug behind the power steering bracket. 7 quarts of expensive break in oil on the pavement, I only ran it 10 seconds before noticing. I was not impressed with myself, but hey I'll never forget to check for that plug in the future haha

Second start up after filling up oil, I was pretty tired
http://vid32.photobucket.com/albums/d23/simhdukenope/20160717_125242_zpszn3ks5fm.mp4

Since I slapped the predator vcc carb back on, replaced the harmonic balancer, flywheel and clutch. I'll post a photo of the finished engine bay when the sun comes up.

Thanks gentlemen, I think most car guys in my situation would have done the same thing. That's why Roadkill is such a great show in my opinion, really captures what a financially challenged but passionate guy can do. I was convinced everyday for an entire month that "only 3 more days and It'll be finished". Nope. Get her done like you said!

Yup I'm still in Quesnel and tonight's my last night here, I no longer have a work opportunity since the contract is done and there's nothing till winter. Need to find work fast don't care where, but now I have a running car that'll take me there! Yes! :biggrin: :toast:

dusty engine bay

:toast:
:biggrin: