General Category > General Discussion
V7 II Broke Down, Metal Flakes in Crankcase = Poops.
Frenchfrog:
Defective material for the thrust washers is a possibility.Another is extra wear by holding the clutch in at lights or insufficient lubrication.The latter was what juiced my friends one's.
Kev m:
--- Quote from: Tom H on October 12, 2022, 10:27:07 AM ---Kev,
In the first pic I posted you will see the main bearing area with the worn thrust washer laying across it. If you look to the right you will see a folded over bit of metal sitting on the block sealing lip. That's the mangled one that was fitted to the inside of the block. Oddly enough, it appeared to be the correct thickness. Just the outer was worn away.
--- End quote ---
:thumb:
Copy that, I misunderstood and thought you were commenting on Dirk's pics.... but I'm easily confused. :boozing:
Dirk_S:
Another photo dump. This time I have the crankcase halves side-by-side for comparison. Turns out my crankcase halves have different part numbers to them, and you can see in the casting texture and a couple minor features that there are indeed differences.
Curious about the area near the rear main bearings that look like unopened oil passages.
You can see that the Hamlin engine case is certainly nicked and worn at the thrust locations. Hmm. Might have to go with my crankcase after all??
Dirk_S:
I might have the problem zero’ed in with regards to why the bad batch of V7 II motors failed. I could be wrong, and maybe it’s just on this one I received. I mean, there’s reason I didn’t go on to detective school, and I did occasionally call my hand too early playing Clue and Guess Who.
I did measurements of all 3 cranks that I have in possession—mine, the Bad Batch crank, and this one I purchased off eBay with “20-30,000 miles” (which happens to be made differently from mine and Hamlin’s. Hmm).
No journal diameters. Solely focused on longitudinal lengths.
The pics included have the measurements written on them. I used 2 calipers that measured to 0.0001. Measured a couple times each, Used the average as base number:
I noticed on the Hamlin crankshaft (Bad Batch motor), that there’s a step on the main journal that’s not present on the other 2. This step occurs precisely where the other two flywheel flanges begin. Also notice that the flywheel flange on the Bad Batch crank is skinnier than the one on mine:
I don’t see how the flywheel flange can wear. It’s hardened, and presses against the thrust washers. Maybe the hardening step didn’t get that area? But still, that flange is only seating against the softer thrust bearing. Looks to me like the lathe hit the precise mark at the flange, then jumped up and continued machining for a few more mm.
The end play is measured by checking the gap between thrust washer and crankshaft. Should be 0.05mm-0.233mm.
The thrust washers from my engine are still within thickness tolerance, so I included them onto the Bad Batch crankcase and crankshaft. The gap measured at over 0.5mm. Too much.
I then threw the Bad Batch crank and my thrust washers into my engine case, and the gap… is still 0.5mm+. Too much.
Finally, I tried both my and the eBay crankshaft in my engine case with the thrust washers—both gaps are within spec.
The skinnier flywheel flange adds extra space to the main journal and allows for the extra throw.. At least in my instance.
——————————
So my crankshaft is toast.
The Bad Batch crankshaft is no good.
Hopefully the remaining tolerances work out on the eBay shaft, and I can use that.
I’m also going to stick with my crankcase, as the Bad Batch case has uneven wear, especially at the inside thrust bearing seat area. This means I’ll need to flush my case up real good.
I’m wondering—if I want to strip the paint off my cases, should I do it now before flushing them, or wait until I have it all back together?
From the Bad Batch motor, I can still use the top end, and will also transfer the stator and rotor over to mine (I returned the one I bought new).
P.S.—And gosh-dang, why is that eBay crank a different hue and texture from the other two??[/i]
Frenchfrog:
best to strip the cases when they are empty. Aqua bead blasting after paint stripper would probably be the best way.
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