How to balance an Engine?

[firefighter3931]

Can you explain to me what is the meaning of "Verifying neutral balance with it"? Are you saying to verify if the converter is indeed balanced without the weights on it?
Farouk

Yes, that is what i'm talking about. Either the converter balance is way off or the engine balance is way off. The harmonic balancer & converter/flexplate should offset each end of the crank if everything is well. That being the case....the internal balance being off could be the only other reason for this vibration you are experiencing. By Internal balance....i'm referring to the individual rod/piston assemblies and their weight relative to each other (static balance).


Ron

[is_it_EVER_done?]

I didn't see this post before, but any engine that is externally balanced is never going to be "great". Why didn't you have it internally balanced when you had it apart? I guarantee that ANY competent machine shop could have balanced it, even in your area, as all engines are the same from that standpoint. You are right back where you started!

Those offset flexplates are junk! they can only approximate what the engine requires. You don't even know if you have the correct harmonic balancer.

Sorry to be critical, but you should have had it neutral balanced. Never have an engine externally balanced for anything other than transportation. In fact, there is NO SUCH THING as a balanced assembly with counterweighted components. In all reality, even a neutral balanced engine is only in balance at specific RPM's, but an external one is guaranteed to be "out" most of the time.

At this stage all you can do is have your mechanic add and subtract weight to see if he can get it close. Or disassemble the engine, and throw the flexplate and damper in the trash, and have the internally assembly balanced with neutral components.

Sorry I didn't see this post sooner.

[firefighter3931]

Those offset flexplates are junk!

More nonsense....i guess the thousands of cars running these flexplates are vibrating all to hell too. 

Fwiw, the dampner is the cioorect unit for his engine.

For a "cruiser" application there is nothing wrong with a cast crank/external balance setup. 



Ron

[Challenger_7]

Ron, I could kick myself in the but, but my legs cant reach that far Only today, upon checking with the last mech that I know, he confirmed that he knows someone who has a balancing machine. If only I knew that earlier
Anyway, I will test out all the possibilities as suggested earlier, and if all fails, I will strip the engine apart and have the crank balanced.
I was told to send the crank, pistons and con rods. Is that correct?
Now two questions I have here, if the balancing is done, do I still use the B&M flex plate or go back to the orig one?
Secondly what about the torque conv, still use a neutral one or otherwise? Thanks
is_it_EVER_done? Hey, you are being a bit harsh here buddy and obviously you did not read the full thread thoroughly
My mistake from day one, I did not know of any one having a balancing machine in our area, so Ron was trying to see me through, and 80% of the problem has been resolved. But then again, by now you know me, I want the best and am getting info from the best on this forum So I do want to go that extra mile although as things are now, the caris perfectly driveable. We did check the damper photos and all - down to the part number and it is correct for my engine.

Cheers

[Challenger_7]

Hi all and Happy Easter (in arears).
Here I am back to report on my saga and my final results.

Between traveling and going back to bug my mechanic, As mentioned in my last report, we had the engine removed again to check on the vibration. I am glad we opened the engine as there was serious and irrecgular wear on the crank shaft bearings, and the last journal's bearing had gone down to the brass metal.
We took the crank, damper, felxplate and converter to the machinist for balancing, and discovered that he had a set of wheels where you center the crank between them and check if it stays put! Obviously the most primitive equipment. (see photo)
The machinist discovered that the one who turned the crank shaft to 20 thou under, had left a gap larger than recommended (4.5 instead of 2, I think) and said that this could also be responsible for vibration. I did not buy that but the gap waranted looking into. He suggested now going to 30 thou under, but we decided to check other makes of bearings. We were lucky to find "Clevite" that covered the difference in the gap.
Anyway, crank and damper showed ok, flexplate went slightly out but the converter, due to its internal parts and oil etc, would not check out.
Cleaned the crank, which was still ok, installed new bearings, and piston rings, and had the engine assembled again. Prayed like mad and started again. Same vibrations!!
I decided to change the converter and got a used one, zero balanced and guaranteed to have been ok. Installed it and my fears all disappeared. All is ok with only a minor vibration at 1200 rpm (I will yet confirm if the rpm reading is correct). So we can say that finally, Hallelua, problem is solved.

One question here, whilst reassembling the engine, the mechanic doubted the cam followers and said they might be wrong and changed them. Here is a photo of the two types. The ones I had are the ones without a hole in the center (on the right). The ones he installed are the ones with a hole (on the left), and are actually lower inside. Which ones are correct, and am I standing any risk in keeping them on if they are the wrong type?

Thanks again for all the help received.

Regards, Farouk