_BANDIT_

Some time ago you gave some advice for picking the right components for my engine and I have finally acquired those items and completed the whole thing. It works, but I have some questions regarding strange vibrations caused by the engine. It seems that they are to strong, because the whole chassis is shaking, what I find strange, despite some components that could cause some minor vibrations and unstable run. I have not figured out what is causing these vibrations. You can feel it in free run as well as when accelerating. With accelerating the vibration strength is increasing, especially between 1500 and 2000RPM and then slowly fade out, so that by 2500RPM you can barely feel them. I fear that these vibrations might damage my engine, especially in bearings.

I have tried removing my gearbox and torque converter to eliminate the possibility of torque converter vibrations. I have also removed straps in front and literally eliminate all possibilities of any vibration. The only thing that is left possible in front on main shaft is harmonic balancer, that is new.

I have run out of ideas what could be wrong...

I have checked out at friend of mine, who has a Camaro’71 with 350 SB and his motor runs much smoother than mine.

My configuration consists of:

- 383 Stroker Chevy SB (Assembly custom balanced w/pistons fitted to rods.)
- intake manifold: edelbrock performer RPM AirGap
- Holley 4150 series, Double pumper, Mechanical secondaries
- Comp cams XE 274 cam
- roller rockers
- forged crank
- forged rods
- forged flat tops and Dart Iron Eagle Cylinder Heads 72cc, 2.02 int, 1.60 ehx
- hooker competition headers
- Summit OEM : Harmonic Balancer, OEM, Internal/External Balance, Nodular Iron, Chevy Small Block Gen I
- Energy Suspension Prothane motor mounts
- Energy suspension transmission mounts

Please help....

EludeR

The stiffer mounts can definetely do this ,my stock SR20DET powered nissan does with in the exact same rpm ranges , due to my 6puck clutch and nismo engine mounts , Stiffer engine mounts will always give you more vibration. It sounds more like something attributed to stiffer mounts then anything else to me , although i'am not too knowledgable about domestics , it just seems about right to me.

1986camaroz28

I Had The Same Problem On A 383 That I Recently Built. Had Too Much Vibration.... Ended Up Having The Wrong Balancer And Flywheel On It.
The Rotating Assemble Used To Make A 350 Into A 383 (400 Crank) Is Supposed To Be Externally Balanced. Check It Out, Hopefully It's A Quick Fix For Ya'
Benny Messer
86 Z28
388 Stroker, T5 5sp, 450 Hp

Kwiksilverz28

Another vote for the stiffer mounts. The trans mount comes with a piece that you sandwhich between mount and trans that I understand that you should leave out. I sold the Energy Susp. piece, hated the AutoZone rubber one, and added a poly piece from Summit that did not come with that piece, and it is very acceptable....

_BANDIT_

Hi guys!

Yes! With your help I’ve finally found a solution to my problem. Vibrations were caused by the weight on harmonic balancer, which should be removed at the beginning. Now the engine runs very smoothly.

Thank you for all your help!

_BANDIT_

blakeforslund

bandit how bad was the vibration before?