Learned a little about crank end play...
#1054704
08/17/11 12:19 PM
08/17/11 12:19 PM
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Joined: Jan 2003
Posts: 3,031
Erda, UT
67Charger
OP
master
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OP
master
Joined: Jan 2003
Posts: 3,031
Erda, UT
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For the first time ever (yeah, I know...) I decided to check the crank end play on my engine as I reassembled it. Zero.
-Apply deadblow hammer judiciously to the snout and flange of the crank to "set the thrust" on #3. Zero.
-Loosen #3 to finger tight on the studs. .005".
-Repeat hammer, tighten studs to 45, repeat hammer, tighten to 100, repeat hammer. Zero.
-Re-loosen studs to finger tight. .005".
-Consult 2 engine builders to confirm my suspicions. One said "Don't worry, if the crank turned by hand before the pistons were on, it's fine... I never bother." The other said use emery and sand the bearing face, but after I informed him of the difficulty removing the bearing shell, he said "Check the cap thickness", confirming my suspicions.
Remove #3 cap and inspect. As I remembered, the bearing shell is VERY difficult to remove. Hypothesis - bearing cap is too thick and flaring the thrust faces. Test - measured the grooved area around the bearing saddle and found that the bottom/center of the groove is .0035" thicker than by the ends. I then measured the overall thickness of the caps and found it to be even within .0005". I used a .015 travel KURT indicator and found that when laying on the mill table, the thickness of the cap was even, and the side of the thrust groove was parallel to the caps outer face, as it should be, but the other side , the grove was off by .003, with the deepest part of the bearing saddle being the thickest point.
Solution: I took a fly-cutter and milled down the groove until the thickness was even. As I progressively cut deeper, the edge of the area that was being cut moved closer to the cap mating face. At .003 there was only about 1/8" that hadn't been touched by the cutter., . I remeasured the cap and the out of parallel was below .0005". I r-einstalled the cap, tapping fore and aft as I tightened it down then re-measured the end play. .004". Notice the clearance increased more than the depth of cut. The overly thick main web of the cap had been flaring the sides of the bearing out.
Lessons learned:
-Always check the end play
-Never assume aftermarket parts fit regardless of the quality and/or brand reputation.
-Don't listen to the one guy who says "No problem, it'll wear in."
-Don't fix the symptom, find the problem and fix that.
-Even though it ran fine before with the same parts doesn't mean it was right then
11.33 @ 118.46 on motor
10.75 @ 125.35 w/ a little spray
Now, high Speed Open Road Racing - Silver State Classic Challenge, Nevada Open Road Challenge, Big Bend Open Road Race
Rocky Mountain Race Week 2020, 2022 2.0, Sick Week 2023
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Re: Learned a little about crank end play...
[Re: 67Charger]
#1054705
08/17/11 12:50 PM
08/17/11 12:50 PM
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Joined: Aug 2003
Posts: 43,215
Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,215
Bend,OR USA
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Quote:
For the first time ever (yeah, I know...) I decided to check the crank end play on my engine as I reassembled it. Zero.
-Apply deadblow hammer judiciously to the snout and flange of the crank to "set the thrust" on #3. Zero.
-Loosen #3 to finger tight on the studs. .005".
-Repeat hammer, tighten studs to 45, repeat hammer, tighten to 100, repeat hammer. Zero.
-Re-loosen studs to finger tight. .005".
-Consult 2 engine builders to confirm my suspicions. One said "Don't worry, if the crank turned by hand before the pistons were on, it's fine... I never bother." The other said use emery and sand the bearing face, but after I informed him of the difficulty removing the bearing shell, he said "Check the cap thickness", confirming my suspicions.
Remove #3 cap and inspect. As I remembered, the bearing shell is VERY difficult to remove. Hypothesis - bearing cap is too thick and flaring the thrust faces. Test - measured the grooved area around the bearing saddle and found that the bottom/center of the groove is .0035" thicker than by the ends. I then measured the overall thickness of the caps and found it to be even within .0005". I used a .015 travel KURT indicator and found that when laying on the mill table, the thickness of the cap was even, and the side of the thrust groove was parallel to the caps outer face, as it should be, but the other side , the grove was off by .003, with the deepest part of the bearing saddle being the thickest point.
Solution: I took a fly-cutter and milled down the groove until the thickness was even. As I progressively cut deeper, the edge of the area that was being cut moved closer to the cap mating face. At .003 there was only about 1/8" that hadn't been touched by the cutter., . I remeasured the cap and the out of parallel was below .0005". I r-einstalled the cap, tapping fore and aft as I tightened it down then re-measured the end play. .004". Notice the clearance increased more than the depth of cut. The overly thick main web of the cap had been flaring the sides of the bearing out.
Lessons learned:
-Always check the end play
-Never assume aftermarket parts fit regardless of the quality and/or brand reputation.
-Don't listen to the one guy who says "No problem, it'll wear in."
-Don't fix the symptom, find the problem and fix that.
-Even though it ran fine before with the same parts doesn't mean it was right then
Good find  Some of the old timers that say let it wear in, it will loosen up don't seem to worry about the metal circulating through the motor after it wears in, and wears out other parts  I think a lot of mechanics and machinest don't realize that the Ford, Mopar oil filters bypass a lot of oil into the motor instead of acting like te GM filters that you can force all the oil thruogh the filter before lubing the motor  Stupid is as stupid does 
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: Learned a little about crank end play...
[Re: go green]
#1054708
08/17/11 01:45 PM
08/17/11 01:45 PM
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Joined: Jan 2003
Posts: 3,031
Erda, UT
67Charger
OP
master
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OP
master
Joined: Jan 2003
Posts: 3,031
Erda, UT
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That was one of my thoughts, but using a surface plate and a height gauge I measured the thickness of the cap in 5 places: 4 corners and center at the deepest part of the saddle, and all were within .0005", so the cap is "flat". I then measured the DEPTH of the thrust face groove in 5 places around the semi-circle relation to the surface plate and the top of the cap, and on one side it was also flat, but the other, the groove was at an angle in relation to the surface plate. The ends of the groove were .003" lower than the center, even though the rest of the side of the cap was nearly perfect. I then used mic's to confirm, and sure enough, the width at the ends of the groove was .003" thinner than the deepest part. The surface plate measurements confirmed it was only on one side.
Granted, the cap may still be cocked, but the fact that the truing cuts yielded more clearance than the depth of the cut means it WAS flaring the bearing shell, and that is now back in spec.
11.33 @ 118.46 on motor
10.75 @ 125.35 w/ a little spray
Now, high Speed Open Road Racing - Silver State Classic Challenge, Nevada Open Road Challenge, Big Bend Open Road Race
Rocky Mountain Race Week 2020, 2022 2.0, Sick Week 2023
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Re: Learned a little about crank end play...
[Re: 67Charger]
#1054709
08/17/11 03:19 PM
08/17/11 03:19 PM
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Joined: Jan 2003
Posts: 16,928
NC
440Jim
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 16,928
NC
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Quote:
he said "Check the cap thickness", confirming my suspicions.
Lessons learned:
-Never assume aftermarket parts fit regardless of the quality and/or brand reputation.
Good find.
Were those the stock caps or aftermarket?
When I had aftermarket caps put on my block, they cut that part to spec (thickness and flat, etc). The machinist made a statement about using a single point cutter, FWIW.
If the crank was thinner, giving some crank end play, you might have gotton away with that cap in a mild build, depends. But with zero, that was asking for trouble, IMO.
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Re: Learned a little about crank end play...
[Re: 440Jim]
#1054710
08/17/11 03:44 PM
08/17/11 03:44 PM
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Joined: Feb 2007
Posts: 5,080
organ
maximum entropy
master
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master
Joined: Feb 2007
Posts: 5,080
organ
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it is amazing how many little problems can affect end play (among other things)! and yes, you should always check it.
for what is the good life if not doing things thoughtfully?
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Re: Learned a little about crank end play...
[Re: 67Charger]
#1054712
08/17/11 04:19 PM
08/17/11 04:19 PM
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Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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Good find... you were running this engine before... did it have 0 end play at that time or is something different now 
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Re: Learned a little about crank end play...
[Re: MR_P_BODY]
#1054713
08/18/11 02:29 AM
08/18/11 02:29 AM
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Joined: Jan 2003
Posts: 3,031
Erda, UT
67Charger
OP
master
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OP
master
Joined: Jan 2003
Posts: 3,031
Erda, UT
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As I stated, I had NEVER checked end play in the past. Call it ignorance. The motor was torn down due to a pinhole in a cylinder and given fresh bearings while apart. This was the 3rd set of bearings since I went stroker and added the steel main caps 3 years ago. Both sets of bearings that came out had large, bright copper areas on the thrust faces, telling me in hindsight it was an issue all along. I have many miles at sustained high speeds on this engine.
For informational purposes only, the stroker kit and caps are 440source. I will not bad mouth them at all. I should have checked them before installation, any manufacturer can have an off-spec part slip though. Like everyone, I do not like the fact the kits are imported, but the quality of the parts on the whole has been excellent.
11.33 @ 118.46 on motor
10.75 @ 125.35 w/ a little spray
Now, high Speed Open Road Racing - Silver State Classic Challenge, Nevada Open Road Challenge, Big Bend Open Road Race
Rocky Mountain Race Week 2020, 2022 2.0, Sick Week 2023
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