Crank shaft

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Model T Ford Forum: Forum 2005: Crank shaft
Top of pagePrevious messageNext messageBottom of page Link to this message  By Joe Jeffers on Friday, February 29, 2008 - 08:46 pm:

I was cleaning up the main bearings by stroking them a few times on 320 sandpaper. It was to much so I re-lapped them with time saver. I still have .010 shims.
When I put things back together I have .006 end clearance. The book says 2 to 3.
Is there a way I can close this gap without buying a over size bearing?

The rods have .060 shims. That's 2 shims per side. Is that a lot? They fit good after a few strokes on the 320 sandpaper.

There in no telling how many miles this engine has on it and the only wear to amount to anything was the front cam bearing and the piston rings. One cylinder had .003 oval.
I belive the lack of wear is because of the balanced crank shaft.
Joe

crank


Top of pagePrevious messageNext messageBottom of page Link to this message  By Tim ( www.ModelTengine.com ) on Friday, February 29, 2008 - 11:12 pm:

Timesaver will leave you with 0.0015 clearance for oil. 2,3 or 6 is too much. Zero shims is ok, but it means you can't adjust them in the car later if you need to. They are only in there to give you room to correct wear without pulling the engine.

If you decide that you need professional help putting this engine back together properly, we're only a UPS truck away from you.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Pat Punter on Friday, February 29, 2008 - 11:16 pm:

Joe,
Remove some shims -not all- and repeat the process with timesaver (yellow grade). Screw down main caps a bit, clean off the sludge, put back new timesaver and repeat until all main caps are fully torqued. You should then have .0015 - .002 clearance. If you do rods, leave pistons inside block to keep rods aligned during operation. I used thin scotch tape around piston to make sure pistons were a tight fit.

BUT: when you do your mains with timesaver, crankshaft MUST be straight because you are using it as a line boring tool. I had .007 runout and my local machine shop put it back to a very respectable .001 at the center journal... A cheap $15 job WOW! He did not use a press but lightly hit it with a special rounded cold chisel. I was impressed.

Put your crankshaft between V blocks and use a dial gauge at the center main. You will see if it's bent.

Only my 2 cents ...


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kenneth H. Todd on Friday, February 29, 2008 - 11:24 pm:

The thrust face(s) of the cap can be built up w/babbit and then faced off to give the proper end play.
BUT, it takes some finness to do it, with either a large soldering iron or a small tipped torch.
Extreme care must be taken not to melt or distort the bearing surface, it's not a job for an amateur.
Personally, I wouldn't worry about .006" end play if everything else is good.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Les Schubert on Saturday, March 01, 2008 - 01:30 am:

Joe
320 grit paper is going to leave you with a awfully "scratched" bearing surface finish I think. These bearings should be as smoothly polished as you can reasonably get. The bearings in your picture really look rough to me. I would expect short bearing life in that engine.
I see it looks like someone has welded counter weights onto a stock T crank. Can you tell us anything about the counterweights?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Joe Jeffers on Saturday, March 01, 2008 - 01:31 am:

Tim and Pat, I might not have explained very well.

The mains have been lapped in with time saver. A piece of news paper in the cap will lock it up and turn free with it out.
The rods didn't need to be lapped in because they are good. Persian Blue shows 100% contact.

The .006 is in the thrust face of the main bearing. I was concerned because the book says 2 to .003.

Kenneth, I have had a lot of experience with lead soldering but Babbitt might be different.
The only Babbitt I have is some thrust washers and drive shaft bearings. I have been told that it is not a good idea to reuse Babbitt.
I have an idea but I"ll sleep on it.
Thanks, Joe


Top of pagePrevious messageNext messageBottom of page Link to this message  By Joe Jeffers on Saturday, March 01, 2008 - 02:28 am:

Less, I didn't use the sandpaper on the Babbitt just the face of the cap. I was going to peal off the shim but it would have been to much.
The picture does show the bearings to be rough but they are not.
I have 100% contact on all the main and rod bearings.
This engine was built in 1980 or 1982. The man I got it from drove it all over the western US, Canada and down into Mexico until 2000. We think it has around 20 to 25,000 miles on it.
I took it apart because I thought a wrist pin was loose but found the front cam bearing was bad. Also the # 3 cylinder had a .003 oval.
The rings were very bad so I had it bored and new pistons put in. The new pistons were 15 grams heaver the the old ones. I cut 11 grams out of the new ones and got scared to cut more.

The crank has the name of Eisenberg on it. I understand he was from Denver and liked to experiment with engines. I believe he is not with us any more.
It also has a home made sealed bearing ball cap and a sealed pinion bearing.
As I started getting into this I found that everything in the transmission has been balanced.
It has the Watts clutch and the band linings are brake shoe linings. Looking at the fan blade I think it is balanced also.

The crank shaft is being run on a computer program to see the possibilities of making one for testing. I will let that person report or respond if he wants to.

One last thing.
This T is a 23 roadster/PU
It has Ruckstell with 3-1
New Stipe 280 cam. The old cam has a lot of wear.
RAJO over head valve. New valve job.

I am to chicken to see how fast it will go.
Joe


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kenneth H. Todd on Saturday, March 01, 2008 - 11:28 am:

Les, check out Joe's previous post about the counterweights: http://www.mtfca.com/discus/messages/29/48012.html?1203030044


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