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S197 @4o6racing Build Thread Profile - S197 Mustangs

583
749
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SoCal
What I'm seeing in that particular chart is a different procedure, which may be different entirely in what corrections may need to happen. It very clearly puts setting backlash ahead of setting pinion depth.
Pinion depth has to be set first by default of assembly order. Backlash can be adjusted without removing the pinion, but pinion depth can’t be adjusted without removing the diff carrier. Adjusting pinion depth also adjusts backlash without adjusting the diff carrier shims. Not sure if that makes sense.


If you’re going from Ford OE gears to other Ford gears (recommended), I would use the exact same pinion shim thickness that was installed from the factory. I tried measuring mine with a tool, and ultimately ended up very close to the OE thickness.

'm pretty sure that differential shims will fit behind the inner pinion bearing race as an alternate method of setting pinion depth deeper toward the differential carrier, mimicking the use of a thicker pinion bearing shim. Can anybody confirm this? Without a press and if needed this might be an easier alternative.

Personally I have not tried this, but conceptually it should work. One challenge will be accurately measuring the thickness of the OE pinion shim without pressing the original bearing off.
 

Norm Peterson

Corner Barstool Sitter
939
709
Exp. Type
HPDE
Exp. Level
5-10 Years
a few miles east of Philly
Thanks for the prompt response.

Pinion depth has to be set first by default of assembly order. Backlash can be adjusted without removing the pinion, but pinion depth can’t be adjusted without removing the diff carrier. Adjusting pinion depth also adjusts backlash without adjusting the diff carrier shims. Not sure if that makes sense.
Makes perfect sense. What I was seeing (as a now-retired professional nit-picker of technical writings) just jumped out at me as being "different".

If you’re going from Ford OE gears to other Ford gears (recommended), I would use the exact same pinion shim thickness that was installed from the factory. I tried measuring mine with a tool, and ultimately ended up very close to the OE thickness.
Yes, Ford gears (3.73). Wasn't going to gamble with Motives, which I've heard tend to be noisier. And I did install the big bearing with the same shim thicknesses - within a thousandth or so - of what was with the OE 3.55. Without re-measuring or chasing my notes down, I think that was 0.032". Those numbers seem to at least be in the ballpark with your smaller ones and not too far away from blacksheep's numbers.

Personally I have not tried this, but conceptually it should work. One challenge will be accurately measuring the thickness of the OE pinion shim without pressing the original bearing off.
I actually saw this approach on some website dealing with ring & pinion setup. It'd just be on me to ensure there were no burrs and that I got everything fully bottomed. My feeler gauge set goes down to 0.002", but like you I was going by sound when first installing the race. 0.002" didn't even feel close to fitting anywhere.

This would be something I'd only be doing after going through the checking distance thing with the Ratech tool and getting an indication of at least 0.010" more shim thickness required. If that happens, I'll probably be on the hook for getting just a shim kit (shouldn't need bearings) so I won't run out when I set the backlash.


One other item . . . I'm considering the idea of heating the pinion flange up by 50°F or so just to ease installation a bit. Should be enough to take a few ten-thousandths out of what appears to be an interference fit at the splines.


Norm
 
3,803
3,745
find or buy a used set of pinion bearings and go at them with a die grinder and sandpaper roll so you can slide them on and off, set the pinion depth this way, and once it is set, them you can press the "real" bearings on. Guys that are real good at this, and do ti all the time, don't need that kind of crutch, but the rest of us do.
 

Norm Peterson

Corner Barstool Sitter
939
709
Exp. Type
HPDE
Exp. Level
5-10 Years
a few miles east of Philly
find or buy a used set of pinion bearings and go at them with a die grinder and sandpaper roll so you can slide them on and off, set the pinion depth this way, and once it is set, them you can press the "real" bearings on. Guys that are real good at this, and do ti all the time, don't need that kind of crutch, but the rest of us do.
That's what I should have done, and would have done if I'd been looking far enough ahead at the tyme.

But maybe with a little luck this'll turn out to be a non-issue. One can hope.


Norm
 

Norm Peterson

Corner Barstool Sitter
939
709
Exp. Type
HPDE
Exp. Level
5-10 Years
a few miles east of Philly
Sorry for dragging your thread a bit off of its nominal topic.

I'm going to continue my adventures/mis-adventures in my own build thread now that I've been able to at least make some real measurements.



Norm
 
583
749
Exp. Type
Time Attack
Exp. Level
Under 3 Years
SoCal
In need of some help from the TMO pros on a little mystery with my engine. Session 2 at AutoClub Speedway. Had just started my first hot lap when the car went into limp mode exiting T4. Flashing CEL, so I limped the car to track exit and back to the pits. Pulled the codes, which were several misfire; random and cylinders 2 & 7. Cleared the codes, restarted and the misfire code would quickly return. Called it a day and drove the car back home. Could tell by exhaust sound it wasn’t quite right, however no crazy knocking or engine noises and it was actually running OK.

Decided to pull the plugs and take a peek in the cylinders with a bore camera. Started with #7 since that’s where I was getting a consistent misfire:

73FA5B07-2CF0-48BC-A964-CA0DE0B2EAA3.jpeg

This made me nervous to peek in the cylinder, which surprisingly didn’t look too bad:

9CB9F900-9155-403F-B64A-2B4A5A9BB6BF.jpeg

But for the life of me, I can’t figure out what that shiny object is on the piston. I tried hitting the cylinder with compressed air to see if that object would move around in the cylinder, which it didn’t budge. Something obviously caused the electrode strap on the plug to collapse, however there’s no sign of physical damage on the strap like I would expect if something hit it.

I looked at all the remaining cylinders, and no noticeable damage to any of the pistons and the cylinder walls all look good.

-Any thoughts on what caused the electrode strap to collapse?

-Any theories on what that weird looking shiny spot is on the piston?
 
583
749
Exp. Type
Time Attack
Exp. Level
Under 3 Years
SoCal
Broken Piston. The shinny object looks like the piston ring.
I suspected piston ring as well because it’s the exact curve of the cylinder wall. I was thinking it looked like a loose piece sitting on top of the piston, however looking at it closer, perhaps the ring is still in its place, with a small piece of the piston missing - is that how you’re seeing it? Would explain why it didn’t move with compressed air.

Hey @Mad Hatter, I think we need a group buy on short blocks!
 
4,447
4,231
Exp. Type
W2W Racing
Exp. Level
20+ Years
Pleasanton: 1/2 way between Sonoma and Laguna Seca
I suspected piston ring as well because it’s the exact curve of the cylinder wall. I was thinking it looked like a loose piece sitting on top of the piston, however looking at it closer, perhaps the ring is still in its place, with a small piece of the piston missing - is that how you’re seeing it? Would explain why it didn’t move with compressed air.

Hey @Mad Hatter, I think we need a group buy on short blocks!
Yeah, that's part of the piston top missing, showing the ring and the reflection of the ring in the cylinder wall.
 

Mad Hatter

Gotta go Faster
4,018
2,513
Santiago, Chile
I suspected piston ring as well because it’s the exact curve of the cylinder wall. I was thinking it looked like a loose piece sitting on top of the piston, however looking at it closer, perhaps the ring is still in its place, with a small piece of the piston missing - is that how you’re seeing it? Would explain why it didn’t move with compressed air.

Hey @Mad Hatter, I think we need a group buy on short blocks!
Boy, sorry to see that! Probably scored the piston walls running it after the first signs of problems. Hope Ford gets on with supplying parts soon!
 
4,447
4,231
Exp. Type
W2W Racing
Exp. Level
20+ Years
Pleasanton: 1/2 way between Sonoma and Laguna Seca
Ugh what the hell is happening around here. Motors dropping like flies the last month or two. Maybe I’ll just leave my car parked till next year...
Don't say that...I have a 4 day race weekend coming up this Thursday.
 
4,447
4,231
Exp. Type
W2W Racing
Exp. Level
20+ Years
Pleasanton: 1/2 way between Sonoma and Laguna Seca
What would have caused all this? Do the valves for that cylinder look ok?
When I see ring lands taken out I think Detonation.....but I'm no motor expert, although I have exploded more than my share over the years.
 
4,447
4,231
Exp. Type
W2W Racing
Exp. Level
20+ Years
Pleasanton: 1/2 way between Sonoma and Laguna Seca
You got tuna magic in your car. It cant go wrong!
Yup. he's the one that keeps saying go ahead and wind her to the moon....so I do.....and she's lived.
 
4,447
4,231
Exp. Type
W2W Racing
Exp. Level
20+ Years
Pleasanton: 1/2 way between Sonoma and Laguna Seca
Like Shaun said, why do they blow up? Its the oiling.....if you have the right oiling mods its not a problem.
Really good crank scrapers and a custom windage tray are huge....unfortunately the guy that makes them is backlogged for months. At least he was when I did mine but they are worth the wait, and proven to work.
 
583
749
Exp. Type
Time Attack
Exp. Level
Under 3 Years
SoCal
Like Shaun said, why do they blow up? Its the oiling.....if you have the right oiling mods its not a problem.
Really good crank scrapers and a custom windage tray are huge....unfortunately the guy that makes them is backlogged for months. At least he was when I did mine but they are worth the wait, and proven to work.
I need to go back through your build thread and study your oiling mods - definitely going to take the opportunity to upgrade oiling and cooling while it’s apart.
 

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