Crank End Play

CDubb · Feb 3, 2012

I've stumbled upon this article,

http://www.oldbritts.com/ob_start.html

Which specifies that there should be between 0.005" and 0.010" in end play on crank when installing super blend bearings. I have since installed those bearings with the OEM spacer on drive side. This spacer stayed in the engine casing as, during the dismantle, was found pretty well seized to the casing (almost moulded into the casing). I have measured he end play to be approx. 0.001" but that could be error as the engine casing may have moved in a "moment-arm" fashion by only having the base clamped in a vice. Either way, you could base this as no end play in the crank. Keep in mind that I had no welseal or yamabond between the casings. Is it possible that the liquid gasket may take up approx 0.004"-0.005"?

In reference to the Mick Hemming Vid, he does not even look or mention the aspect of thermal expansion in this case.

If this is an issue, I may have to get the spacer milled out. I don't want to mangle the bearing housing with a chisel.

pete.v · Feb 3, 2012

Is this the spacer of which you speak? This is actually a machined rise in the casing.
I was also able to straddle a 1" mic in there and measure .159" of wall thinkness.

Not that any of this will be helpful, practically speaking, but I might help access your situation.

Here's the timing side.

Matt Spencer · Feb 3, 2012

If the Ball Race ones spun bearings or shafts it would be indicative of differential expansion , like the P U Triumphs .Thermal Shock with the Butane torch and
a wrung out wet rag , on the SPACER . Wear Gloves.Two or three goes , Stareing at it , with intent . :|(First verifieing there is in fact one in there . :|

Were there shims behind the Bearing , on the shaft .

CanukNortonNut · Feb 3, 2012

Charles
I am not sure what you are on about with the spacer as well???? You had a roller bearing on the timing side. 1970-71 engine cases? Is this what you are refering to?
CNN

79x100 · Feb 3, 2012

I think that you've got to have the cases fully bolted up with dummy spacers to accurately measure end play. No joint sealant worthy of the name should alter clearances when assembled.

I've never come across an engine assembled by factory or an ordinary dealer with any shims in but none had less than 0.025" - 0.030" end-float.

I would suspect inner races not fully home on the crank or more likely an outer with a sliver of aluminium behind it. (Unless you're trying to fit a MkIII crank into earlier cases !)

CDubb · Feb 3, 2012

Yes pv, this is what I am referring to. I guess it is not the spacer I saw in the schematics I was looking at.

But my question really boils down to during a bearing replacement job does one take into account or even verifies end play in the crank as per the article above? In my case I do not have end play and no way of alleviating it unless I machine the bearing housings in the case. If I choose to ignore the end play, having none, will this hurt me in the long run?

79x100 · Feb 3, 2012

CDubb said:
If I choose to ignore the end play, having none, will this hurt me in the long run?

"No" end play is probably not achievable. 'Some" end play is OK but pre-load is definitely a bad thing and will cause expensive noises in short order..

pete.v · Feb 3, 2012

CDubb said:
Yes pv, this is what I am referring to. I guess it is not the spacer I saw in the schematics I was looking at.

But my question really boils down to during a bearing replacement job does one take into account or even verifies end play in the crank as per the article above? In my case I do not have end play and no way of alleviating it unless I machine the bearing housings in the case. If I choose to ignore the end play, having none, will this hurt me in the long run?

Yikes! Something seems amiss. FWIW, if you had any shims, unless previously rebuilt, they would have more than likely been on the crank side. Thank goodness there's planty of winter left.

CDubb · Feb 3, 2012

Well I have clean the bearing housing thoroughly and I have also checked the inner bearing races for clearance between the crank and the race. I was unable for fir a 0.001" shim between both. I would not surprise me that the crank could be a MKIII crank as this was a basket case.... still unlikely. How can I verify this?

Pre-load may be possible but the crank rotates smooth as a whistle so I'm no longer certain what is going on... the outer races should be seated correctly. Should I try to fit a shim between the outer race and the casing? It seems like the most logical #1 step in the troubleshooting realm.

Matt Spencer · Feb 3, 2012

That'd close it . Id aim for 6 thou . The Races are suosed to be pressed in , Case Warmed . To ensure theyre seated firmly .
Got a Drill Press ? warm case in oven ,
A desperado could lap a Iota or two of the Outer Race .
Wet & Dry paper on Glass , or Paste . and a few Burbons , or is it CoaCoa for patiance & a Steady Hand / Foot .

pete.v · Feb 3, 2012

CDubb, I am under the impression that you are .010 to .015 too tight. You need more clearance, not less.

When checking play, pop the crank back and forth a little with hard wood and a mallet to see if this gives a few more thou. If so, call it good and use the best oil money can buy.
If not, you will have to decide if it is worth worring about when you should be thinking about your invisibility in traffic.

CanukNortonNut · Feb 3, 2012

CDubb said:
Well I have clean the bearing housing thoroughly and I have also checked the inner bearing races for clearance between the crank and the race. I was unable for fir a 0.001" shim between both. I would not surprise me that the crank could be a MKIII crank as this was a basket case.... still unlikely. How can I verify this?

Pre-load may be possible but the crank rotates smooth as a whistle so I'm no longer certain what is going on... the outer races should be seated correctly. Should I try to fit a shim between the outer race and the casing? It seems like the most logical #1 step in the troubleshooting realm.

The serial # on drive side should date the case.
CNN

79x100 · Feb 3, 2012

If you've assembled the cases with new bearings and especially if you've used bearing-fit then you might find that the bearings are a little tight and don't allow you to measure the end-float once cool.

I don't believe that you can close the case if a MkIII crank is used. Generally, an original MkIII crank has a machined slot in the timing side cheek but I have seen them without.

Hobot · Feb 3, 2012

Highly recommend heating beyond high boiling point more oil smoke frying pan hot so old bearing just drops out and new frozen one slip right it first plop or can get trapped and need oil flash off above frying pan hot to remove, ugh.
Cranks pretty much self center by rods if room too when its swells.

CDubb · Feb 3, 2012

What do you mean by "Bearing-Fit"?
Don't worry Hobot, I used an oxy-aceteline torch to head that baby up. Oil was coming out of the pours.. She was hot like the saturday night poll dancer after a few whiskey shots and beers

79x100 · Feb 3, 2012

CDubb said:
What do you mean by "Bearing-Fit"?

I think that's what it's called. It can increase the interference on the bearing enough to close up the internal clearances when cold.

http://www.bearingshopuk.co.uk/loctite- ... 3142-p.asp

CDubb · Feb 3, 2012

Thats the green stuff right?

lcrken · Feb 3, 2012

CDubb said:
Thats the green stuff right?

The green stuff I use for relatively permanent fits of things like bearing races is Loctite RC/620 retaining compound for high temperature cylindrical fits. There are other brands with the same application. I've tried it witn loose Commando main bearings in race engines, but it didn't last very long. To be fair to the Loctite, the bearings were pretty loose. I ended up pinning them instead (a la Dunstall), and that worked well.

Ken

Crank End Play

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