engine vibration - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars

-buck- · 11-15-2006, 16:40

i have a 84 ford f150 with a inline 6cyl.

was chewing up starters, changed flywheel, now starter is working great, but now have an engine vibration.

would like to know where to find engine id# and if there is one specific flywheel that should be used

any help would be appreciated...............

notty · 11-15-2006, 22:22

did you have the fly wheel machined and staticly balanced???

madmelon · 11-16-2006, 21:54

Static balancing is useless on a flywheel- it needs to be dynamically balanced, otherwise you may get very severe vibrations

notty · 11-17-2006, 20:57

sorry i wasnt direct!
if you are going to change fly wheels you take the old one off take the old one and the new one to the engine machine shop and get them to ballance the new one to the old one thats what i ment by static!
its still not gonna be perfect but its better than nothing!

madmelon · 12-01-2006, 06:45

yes, but that is still my point- static balancing with all the parts still will cause a vibration. This is because it is balanced to provide no rotation if mouned on an axle and left to sit- the shaft/flywheel will not rotate about its axis. Thats fine in a situation where the setup isn't rotating.

When you start to rotate, vibration may occur if the balance weights are not located to produce a net zero moment about the centre of the shaft. It's like having a shaft with a blob on the top at one end and a blob on the bottom at the other. As soon as the shaft begins to rotate, it will twist the mount in the dirction the blobs point... have a look at the diagram below. The shaft with red arrows is statically balanced but not dynamically. The two other shafts show two ways of dynamically balancing the shaft. Each shaft rotates around its axis (AROT) but the unbalanced one also attempts to rotate about the x (XROT). during AROT, the weights move, so the direction of XROT changes continuously. This causes a vibration.

The vibration will be quite sever at some speeds indicating a resonance. This is why wheel imbalance is often only detected at some speeds, especially high speeds. Flywheel imbalance is particularly destructive as it can create very severe loadings on the crank bearings and possibly a thrust force on the rod big end bearings which is highly undesirable.

madmelon · 12-01-2006, 06:51

it seems fordforums won't let me upload images. Will try again later.

madmelon · 12-01-2006, 06:55

Just follow this link...it's so much easier...

http://i103.photobucket.com/albums/m.../balancing.gif

notty · 12-01-2006, 12:40

seems i have miss led you in my definition of static ballancing!
im sorry for the confusion
wat i should have said is get the fly wheel ballanced on its on a ballancing machine at a engine shop and what i ment by static was a term for not ballancing the fly wheel on the crank shaft as you are supposed to!
im sorry i hope that straightens this out!
if you take your old flywheel and the new one to the engine shop they shoul;d be able to put the old one on the maching and the computer in the machine can record the ballancing of your old fly wheel then transfer the data onto the new fly wheel so that you will have 2 of the same fly wheels and if the old one didnt vibratre then for damn sure the new shouldnt!
i hope thats a bit better
cheers!