351c vibration

[71ponymaster]

Ok. Fresh 4v cleveland from top to bottom. Bored but Factory stroke

New balancer. Original flywheel resurfaced New clutch an pressure plate

Engine Builder broke in engine said nothin bout vibration. Timing checked and dead on.

Even sittin still in nuetral. feel fine vibration in steering wheel (kind that will put ur hand to sleep in two min) startin bout 1800 rpm

Took belts off to eliminate accesories issues. So to me has to b balancer (as new parts can b bad) or clutch assmbly. Used clutch alignment tool for clutch install an all torque specs followed

Any suggestions how to tell if balancer or clutch assembly is the root?

 

[mycoses]

I assume the engine was balanced. the best balance is with the flywheel and damper to be used on the engine and every thing is spun together w/ the crank. some shops use a mock up of the damper and flywheel when they are not supplied w/ the rotating assembly then if the actual damper and flywheel are not the same as the mock up you get an off balance situation. make sure the damper is a good quality since they are manufactured to more exacting specs than a $100 repop. I believe clutch plates are balanced at the factory but you could have it checked at a shop. also need to know if it was internally or externally balanced. IF internal balance then you need neutral damper and flywheel. make sure the damper and flywheel have 28 oz weights and not 50 oz.if it was externaly balanced. I had a motor built one time without balancing assuming it would be close enough - shook so bad I couldn't drive it. learned my lesson.

 

[barnett468]

.

99.999% of the time it is the engine even if it has been balanced.

is it constant or does it cycle?

does it get worse with increased rpm?

do you have urethane engine and/or trans mounts?

whose pressure plate is it?

all these pieces are supposed to be balanced with the engine.

old alignment tool has nothing to do with it.

 

[Omie01]

My engine builder "required" me to supply him with the damper and flex plate to be used, he said my motor was externally balanced and that if he didn't use the parts going on the motor he couldn't balance everything. Just my input. I got lucky, the PO just replaced damper and flex plate!!

 

[MotoArts]

Flat tappet cam?

Depending on what you're calling a vibration, don't rule out a "flat lifter" - otherwise known as a trashed cam.

 

[71ponymaster]

It is constant once its up to 1800 an increases as rpms go up

I do have a flat tappet cam. Broke in properly an run zinc additive

Can easily chk cam by pullin valve covers

I do have urethane mounts

Brand of pressure plate ill have to chk


Its not anything like a miss tho. Just a high super fast vibration

 

[TommyK]

I do have urethane mounts


Its not anything like a miss tho. Just a high super fast vibration

If/when you have completed your checks and have eliminated all the obvious culprits, change to rubber mounts.

 

[71ponymaster]

Tryin to eliminate the easy ones first for sure

Even chkn cam is way easier than droppin bell housin.

Rubber mtr mounts is now on the list. Thx

 

[Jeff73Mach1]

I'd start with a vacuum check first to see if it indicates any problems. Then I would recommend that you check your plugs, if everything continues to look good, I'd consider a compression check before I tore into it any further. While you say it doesn't feel like a miss, if one cylinder's compression is off due to a ring or valve issue you will get a rhythmic vibration-cross fire from poorly routed plug wires can cause some issues, but I'm guessing you already knew that.

I'd also be talking to my builder.

(Rubber mounts will often help greatly as many factory engines had vibrations from the outset, but they won't eliminate the vibration, they just mask it.)

 

[71ponymaster]

Ok thx. Yep i did know that an plan on dble chkn wires an plugs tomorrow evenin then onto other things if need b

Thx

 

[4mm]

Did you ever fix the issue?

 

[71ponymaster]

Ya. Unfortunatly i had to put a new cam in it. I dial indicated the rockers after checkin the easy things

 

[MeZapU]

You need to crack a beer and read up on this information. I think it will help you.

https://540ratblog.wordpress.com/2013/06/20/motor-oil-wear-test-ranking/

 

[piper62j]

It could also be a part of the engine or tranny is touching the chassis where you actually feel in in the steering wheel.

 

[InjectedMach]

since you have to open it up drop in a roller cam man..

 

[Dave73]

Is it just when driving or when in neutral sitting still? If only while driving could it be drive shaft needs balanced? My U joint was bad and my steering wheel shook because of it. I replaced all U joints and now have a tiny vibration still. Next I am having drive shaft balanced.

Does the engine builder have a warranty? If so I'd try my best to make it his problem.