Crankshaft balancing

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Model T Ford Forum: Forum 2005: Crankshaft balancing
Top of pagePrevious messageNext messageBottom of page Link to this message  By Richard Gould on Wednesday, October 03, 2007 - 12:55 pm:

Who can I trust to accurately dynamic balance my model T crankshaft in N. California, Sacramento area. I have had this motor down three times trying to cure a vibration problem. The crank has been reground but is quite a bit out of balance. I have been stung more than a few times by having things done by others and would like to find someone I can trust to do a good job.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ken Kopsky on Wednesday, October 03, 2007 - 01:28 pm:

It's a futile endeavor to try and static balance the crank alone and expect a "smooth" engine. There's too many other factors. What rods and pistons are you using? What about the flywheel and/or transmission?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Michael K Johnson on Wednesday, October 03, 2007 - 04:42 pm:

I know little about crank balancing, but agree with Ken. Maybe if you gave more detail about the "vibration problem" some people here might be able to help you isolate it.

Correct me if I'm wrong but ignition and combustion performance as well as the points Ken mentioned can also cause vibration. Perhaps there are more causes than these.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Joseph Wayne Rudzik on Wednesday, October 03, 2007 - 05:24 pm:

Check the brass bushing in the drive plate on the transmission. Murray Fahnestock even mentions this problem with the hole for the shaft being of center.
I had the same problem and with the help of a member in our local club centered a new bushing.
The engine is still running smooth after many miles.

Joe R.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Richard Gould on Wednesday, October 03, 2007 - 06:12 pm:

I have everything else under control. The rods, pistons, triple gears are already balanced. Once I get the crank dynamically balanced, I can handle balancing the flywheel with the crank and trans shaft attached. I may make mandrels to balance low and reverse drums. Don't know yet. Brake drum with driving plate attached isn't a problem.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Richard Gould on Wednesday, October 03, 2007 - 06:19 pm:

In addition all bushings have been replaced and bored to .003-.004" Less than .002" run out on the tailshaft. Everything is ready to assemble once I complete the balancing. Anyone know any outfit that does reliable work near Sacramento?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bob Frink on Thursday, October 04, 2007 - 01:44 am:

It is doubtful that your vibration comes from the crankshaft. The transmission is where you should concentrate your efforts.
Bob


Top of pagePrevious messageNext messageBottom of page Link to this message  By Richard Gould on Thursday, October 04, 2007 - 10:37 am:

Agreed Bob, but since I have it out, I want to balance the works. After pulling the engine three times, wouldn't you? Oh, I might mention I had to add 2 oz free weights to the crank to get it to spin true on a static balancer. My flywheel is only out .5 oz. I realize the throw of the crank journals is far less than the diameter of the flywheel, so in effect the .5 variation is magnified compared to the crank, but 2 oz an a crank is a whole lot off balance. I have never personally seen connecting rods with that much variation.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Michael K Johnson on Thursday, October 04, 2007 - 01:16 pm:

If you can't find anyone to do the work in the North, why not just ship it to LA or elsewhere to have it professionally done. A lot of people here ship there parts (including engines) to hell and back to get the best work done. I guess there is a proper crateing method and reputable carrier for this kind of thing to consider which might take some digging. Best of luck to you and remember the "third time is the charm".


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dan Haynes on Thursday, October 04, 2007 - 06:23 pm:

Richard-
What about that guy in San Andreas or where ever he is? Van Der something? I have his card at home - I'll try to remember to look for it.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Les Von Nordheim on Thursday, October 04, 2007 - 10:02 pm:

Richard Gould-
I have a sunnen static balancer which looks like the one in your picture. Do not give up on static balancing your crankshaft, flywheel and transmission drums. I have static balanced my engine/trans. and helped others with good results. If your crankshaft has counter balances then that is a different story. Without counter balances, the folks doing dianamic (spin) balancing do not really have much to work with. To correctly balance the crank shaft normally Bob?? weights are attached to simulate a percentage of the rod (Reciprotating) weight. I have two friends that first static balanced their T cranks before taking the crank in for dianamic balancing. When they received the crank back they were told that the crank was not out "Very Much". They still got charged the same...Smile! As others have said, the transmission has as much if not more to do with how smoothly a T engine runs. Look back several issues in the Vintage Ford and you will find an excellent write up on trueing up the T trans. You start at the crankshaft flange and work your way to the rear of the trans. It made a significant differance in how smooth my 13 touring runs. Sorry for any spelling error's and do not give up on static balancing. I live in Fallbrook Calif. and would be happy to show you how easy it is to static balance your crank with the static balancer you have. Take some masking tape and attach washers/nuts to the crank shaft in different locations....you will quickly catch on...It's not Rocket Science....Good luck, Also, by chance did you once live in National City? "Les"


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kenneth H. Todd on Thursday, October 04, 2007 - 10:15 pm:

Richard, have you checked the runout of the rear flange?
If the shaft wasn't indexed properly when it was reground, the flange could be off centre.
Don't ask how I know.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Paul Mikeska on Thursday, October 04, 2007 - 10:35 pm:

Richard,

The Tulsa club has posted some great information on alignment and balancing of the T engine and transmission. Check this site out.

http://clubs.hemmings.com/frameset.cfm?club=mtfctulsa

Paul


Top of pagePrevious messageNext messageBottom of page Link to this message  By Richard Gould on Thursday, October 04, 2007 - 10:39 pm:

Les, thanks for the input and offer. I have balanced flywheels before but never a crank and so am reluctant to learn on a crank that is ready to install. I assume its just a matter of grinding off stock opposite where you have to add weights to get the thing true on the balancer.
I have always lived in the Sacramento area, but I was looking to move to Fallbrook a couple years ago. I decided against it when I saw the freeway traffic.
Kenneth, I hear you loud and clear. One of my pet peeves is getting a crank back that was not ground concentric with the circumference of the flange. This one is pretty good, thank God. I still want to balance the flywheel with the crank attached, but after I separately balance the crank. It makes no sense to me to get the rods balanced if the crank is out.


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