crankshaft end movement

[rogerkb1936]

in the process of trying to find what is causing my clutch chatter, using a dial indicator on flywheel friction surface, i discovered that the crank is moving back and forth, with no external forces on it, about 7-8 thou. it does it in the same area every time. what the hell could be causing that? this is a prof rebuild with about 4000 mi on it.

[Tom Wesenberg]

Just sounds like normal end play to me. When I check the flywheel cover with the engine still in the car, I always press the crank forward during the measurements.

[Ron in Quincy]

If I understand your explanation it sounds like the line bore for your crankshaft was not correct; this condition would, after a period of time, would damage the thrust built into the rear main cap and result with back and forth movement of the crankshaft. If you remove the engine you can check the runout with a dial indicator.

Ron

[Bob C]

Are you talking about crankshaft end play or flywheel runout??

Bob

[JoeWay]

Well...7 to 8 thou end play is certainly within the typical range, as Tom says. But if you are getting the same variation in the same place every time around, I would wonder if the flywheel friction surface is ground parallel to the crank mounting surface, or if there is foreign matter between the crank and the flywheel, or if the end of the crank is out of plane.

When I had a flywheel grinder years ago, I took very special care to stone and wire-brush burrs off mating surfaces and clean them before mounting flywheels on the machine. It's easy to imagine some operators might not take such care.

Might be time to take Ron's advice and pull the engine--or the trans--and remove the flywheel so you can check the crank itself and look for trash at the mounting surfaces.

Joe

[rogerkb1936]

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eng is out. i checked end play with indicator at front end. i put a short 5/8 bolt in crank, positioned plunger on exact center of it, and crank moves by itself in and out as i turn it. i made a device a long time ago using a starter shaft and and end plate so i can turn eng smoothly with a ratchet.

[Brian T]

Is the engine mounted on engine stand? if so it needs to be pointing downward at the front so that the weight of the flywheel will keep the crankshaft from moving back and forth, some engine stands do not have the extra hole to rotate to this position.

[Patrick L.]

Since the engine is out,, then like Brain said, stand it on its nose [but not on the crank/ pulley] and measure the rear crank flange for the end play and run-out.. .008" sounds fine for end play but runout should be far less [.002"]..

[rogerkb1936]

took brian t's advice and tipped eng, but could only tip rear end down. which i suppose does the same thing. matters did improve considerably, and i now have .005 tir on friction face of flywheel. will that work or contribute to chatter?

[James Rogers]

.005 TIR should be OK. You would be better off with .003 but .005 is OK. You might surface the flywheel housing and get better. I find that most housings, even uncracked ones, are warped from improper installation over the years.

[Jerry Parr WI]

Originally Posted by rogerkb1936

eng is out. i checked end play with indicator at front end. i put a short 5/8 bolt in crank, positioned plunger on exact center of it, and crank moves by itself in and out as i turn it. i made a device a long time ago using a starter shaft and and end plate so i can turn eng smoothly with a ratchet.

I had one fresh rebuild that would move forward at the same place each revolution and knock at low RPM idle. Caused by a twisted rod.

[JoeWay]

Originally Posted by James Rogers

.005 TIR should be OK. You would be better off with .003 but .005 is OK. You might surface the flywheel housing and get better. I find that most housings, even uncracked ones, are warped from improper installation over the years.

James, he may also have housing issues but right now I think he's checking only the flywheel.

Roger, you need to take off the flywheel and see what the end of the crankshaft is doing. While you're in there make sure there's no trash between the flywheel and the crank.

If you still get 0.005" runout at the crank flange, I'd be suspecting Jerry's problem or something strange at the rear main/thrust.

Joe

[James Rogers]

Roger, I would also use a couple of screwdrivers and a dial indicator on the front or rear of the crank and pry it forward and backward to see just how much end play you have. Factory is .001-.004 and max amount of end play is .012. Any more than that and the crank will become a pump of sorts and cause a leak at the rear main with a drip at the cotter in the flywheel housing.

[PC/SR]

.012 is also the max side play on the rods, assuming they are correctly done. More movement than that on the crank and you start putting lateral force on the rods, which may be able to handle it if there is proper side clearance on the pin, which is connected to the ....
Like BobC I'm a little confused about whether you are talking about crankshaft end play, or flywheel runout. They are very different.

[1931 flamingo]

Feel the LOve.............
paul

[kenparker]

alright you two. time to be nice. ken

[Cob]

Originally Posted by James Rogers

And this is why you build the best and vibration free motors? I love it when someone who has never built a Model A motor, gives advice in an area where they have no experience.

Originally Posted by bbrocksr

I remember a few years back when a cement finisher was learning to pour bearings and all of the sudden he became an authority on the Model A engine.
Bill

Originally Posted by fordgarage

Laughing my ass off!
You have no idea what I know, or have done, but anyone can certainly assess the many things you have said publicly and continue to say.
Carry on.

Originally Posted by James Rogers

Yep, takes about 15 years and is called EXPERIENCE.

Originally Posted by James Rogers

Tell you what Vince. I'll just shut up and let you and Bill keep on giving your bad advice on topics you don't have a clue and I'll laugh my ass off. I don't need your or anyone else's krap.

And this is exactly why posts get closed. The original poster asked for some help and when one guy doesn't agree with another and starts posting there disagreements which does not help the fella asking for help, My mail box lights up with this stuff and the thread gets closed.

In this case - I've condensed where this took a wrong turn and deleted the original posts out of respect for the original poster, please help him if you can.

My advise to you fella's who don't agree with each other is to do so privately.
(Good advise)

Thank you,

Cob

[Kurt in NJ]

Clutch chatter is caused by both the disc and the pressure plate to flywheel having variations ---when a thick spot on the disc passes by a thin spot between the pressure plate and flywheel it will grab ---if the pressureplate and flywheel surfaces are totally parallel a thick spot on the disc has nothing to grab----the friction is about even, if the disc has the same working thickness around it's entire circumference and there is a thinner spot between the flywheel and pressure plate it will have even drag ----but this is where it starts to heat one spot on the flywheel and pressureplate causing hot spots,warping---then chatter appears

Before you install a clutch disc it is good to install it on the input shaft of the trans and give it a spin---2 good reasons, one is to know how well it fits the splines-(better to find out now than after 2 hours of trying to fit the engine and trans together in the car)--the other is to spin it to see if it is damaged and has a lot of runout (bent)

Flywheel housing runout doesn't matter ----yes it is probably a good baseline, and if it is correct you should be ok, but what really matters is the bellhousing runout, the trans case bearing bore to crankshaft/ flywheel alignment ---it doesn't matter what the flywheel housing runout is if the trans bearing bores are in line with the crankshaft. ---this is one area that Chevy had a better idea, in the Chevy shop manual when align boring the mains they show the bar centered by using bore of the bellhousing that locates the trans--insuring crankshaft/flywheel/trans shaft alignment---the flywheel housing alignment didn't matter.

[JoeWay]

In the interest of helping the original poster--by not running him off on a wild goose chase--and in the interest of possibly learning something, I would still like to know how surfacing or replacing or doing anything else with the flywheel housing will affect runout measured at the friction surface of the flywheel.

I still suspect either the end of the crank is running out, or the flywheel was not surfaced parallel to its mounting surface, or there is trash between the flywheel and the crank. If the runout measured at the end of the crank is significantly less than that measured at the outside of the friction surface, it is one of these things. If the end -of-crank runout is about the same as at the friction surface, then it's likely Jerry Parr's twisted rod or or a problem with the rear crank journal and thrust.

Joe

[Kohnke Rebabbitting]

Flywheel housing runout doesn't matter ----yes it is probably a good baseline, and if it is correct you should be ok, but what really matters is the bellhousing runout, the trans case bearing bore to crankshaft/ flywheel alignment ---it doesn't matter what the flywheel housing runout is if the trans bearing bores are in line with the crankshaft. ---this is one area that Chevy had a better idea, in the Chevy shop manual when align boring the mains they show the bar centered by using bore of the bellhousing that locates the trans--insuring crankshaft/flywheel/trans shaft alignment---the flywheel housing alignment didn't matter. "END QUOTE"

Kev, what you said in your post, I agree, but here is the exceptions.

The flywheel housing is the MOST important thing you can do. On a Model A, if that is wrong, all the other things won't matter.

Most Guys do not know how to adjust a Flywheel housing to the block!

You can not just shove a couple of .010 shims under the two bolt ears, and say, thats done. I don't care how straight your bell housing is, bolted up will put bind on the pilot, bearing, and the worst is bind on the rear main, and then wonder why it leaks!

Kev, Chevy did have a good idea, but it has nothing to do with a Model A, as they are not made the same.

The Chevy, had its Flywheel housing made, as part of the block casting, and had no adjustment, like a Model A, to align the Pilot shaft, other then to use the Bell housing to align with the mains durning align Bore.

On a Model A, you don't have to worry about the bell housing, as the Flywheel housing is adjustable.

If you surface grind the Bell housing, and it could be done, what ever you take off, just say .025 thousandths, would have to be made up in gasket thickness, between the bell housing, and the Tranny.

We have checked many of the old engines that came in for rebuild, and the ones that the Flywheel housings out of alignment the worst, were cracked around the alignment pins, and bolts, we seen, when Media blasted.

A bent rod will have nothing to do with end play of a shaft, that will only effect the Rod, Piston, and cylinder.

1. The crank has to be set up to grind, by centering off the crank gear area, with gear off and, the rear flange, O.D., not the main bearing surface! If the flange is off by .005, the flywhell will be off by .005 thousandths. Also, while set up for grinding mains, the face of the rear flange, on the crank has to be ground! We set end clearance to .003 thousandths, and not over four. The last .003 end play is done by hand scraping, as that is the most accurate. If you have clearances starting at .006, and up, the bigger the clearances, the more oil will be lost out the slinger.

One of the most important things in align boring, is to center the crank dead center between the main bolt holes, there are many builders that don't. If the crank is to far side ways, the slinger will have a bigger gap on one side then the other, the shims will have to have the bolt holes elongated, and there is no way to align, or move the pilot shaft, to compensate!

2. The Flywheel has to be ground with its crankshafts mating surface. We never mess with an old pressure plate. The flywheel, should be balanced with the pressure plate, and mark to be assembled the same way as balanced.

"THE FLYWHEEL HOUSING" This is the biggey. The object is to first, get both sides, at the Motor mounts, to read the same, or as close as you can first!

Next, get top and bottom to read the same, or as close as you can. Then STOP, and leave it 24 hours, as the cast iron will warp to the stress position put upon it. Next day, adjust, or check again, and adjust accordingly. Note, you will not have the same amount of shimes under both bolts. Plus, we finish up with .001 thousandths shims, on either sides.

You have to put the flywheel gasket in, and bolt down to stay.
ALL further adjustment is done with shims behind the two bolt ears.
I have never had one out of Square more then .005., and that would be +, or - from 0.

So, when done, both sides should read with in 001, to .002 thousandths, and top and bottom should read the same, and with all that done, clutch should be smooth, as a Model A.

Thanks Herm.