V7 II Broke Down, Metal Flakes in Crankcase = Poops.

[Dirk_S]

Got the left side cylinder and piston off tonight, and through the magic of television, you can see and hear for yourself. Here’s hoping it’s just the big end bearing, but I guess I’ll find out soon enough…

https://youtu.be/SaPIyQ5BUxY

[buck]

Got the left side cylinder and piston off tonight, and through the magic of television, you can see and hear for yourself. Here’s hoping it’s just the big end bearing, but I guess I’ll find out soon enough…

https://youtu.be/SaPIyQ5BUxY

The crank journal will be damaged as well.

[Stretch]

Man, that's too bad.

Looks like you're in the market for big end bearings, and probably
a crank regrind. (If you're super, super lucky and have been living
a good, clean, life, maybe just a crank polish, but I'd bet heavily on
a regrind.)  Let's fervently hope you don't need a new crank. That's
a lot of play in that starboard side big end.

Hats off to you for diving right in - I hope you get it buttoned back
up before the snow flies.

                                                     -Stretch

[Dirk_S]

Looks like you're in the market for big end bearings, and probably
a crank regrind. (If you're super, super lucky and have been living
a good, clean, life, maybe just a crank polish, but I'd bet heavily on
a regrind.)  Let's fervently hope you don't need a new crank. That's
a lot of play in that starboard side big end.

All new big end bearings, thrust washers, and main bearings were ordered a couple weeks ago. Hopefully on a ship soon crossing the Atlantic!

Not sure that working on the crankshaft is doable— the service manual states:

CAUTION
THE CRANKSHAFT IS NITRIDED AND CANNOT BE GROUND; IF WORN, TAPERED OR DEEPLY SCORED, THE CRANKSHAFT MUST BE REPLACED.

I’m assuming I should take the manual at its word? Fortunately I have 2 other used crankshafts waiting in line to potentially be sub’ed in if needed (provided they’re cleared to go themselves.

Hats off to you for diving right in - I hope you get it buttoned back
up before the snow flies.

Thanks, Stretch. I’m staying positive on this… so long as the crank bearings arrive by mid-November as promised and at least one crank is in good order.

Of course, I’m not too egotistical to recognize that ignorance is bliss.

[Alfetta]

Not sure that working on the crankshaft is doable— the service manual states:

CAUTION
THE CRANKSHAFT IS NITRIDED AND CANNOT BE GROUND; IF WORN, TAPERED OR DEEPLY SCORED, THE CRANKSHAFT MUST BE REPLACED.

Hummm....  I have no idea what the cost of a crank is, but I do know that there are people that do Nitride work, If you replacement cranks don't measure up to spec, I personally, would not hesitate to re-grind and re-treat, if the dollsrs make sense.

[guzzisteve]

I don't think there is undersize bearings available for small blocks, crank would have to be welded up, machined back to spec & re-nitrated.

[Stretch]

So, I think guzzisteve has the correct explanation concerning grinding nitrided cranks. 

It can be done. Grind of the bad stuff and existing nitriding, weld, grind back, nitride, and finish grind to stock size.
Replace rod bearings with the stock size and you're good to go. Cost?
$500-$1,000 depending?

Not cheap, and you're on a budget. One of those used cranks should get ya goin' if the stock one is shot, eh?
(All of this is just discussion for fun, yes?  Not telling ya what to do.....  )

This link explains things pretty well, I think.

https://www.dsmtuners.com/threads/the-crankshaft-co-s-take-on-nitride-treated-cranks.309281/

                                                         -Stretch

[Dirk_S]

Got the crankcase split apart and disassembled the con rods. Drum roll…





As a reminder, the damaged con rod is the right side, and has scored that side of the crank journal enough that it feels somewhat like an emory board.

I think the wear on the left conrod may be OK/normal, but I will probably stick with using one of the other pairs that I have together.

[n3303j]

Guess "they" figure the timing gear would last as long as the crankshaft. I'm used to seeing that sprocket as a removable part.

....nevermind. Timing sprocket did last as long as the crankshaft!

[Dirk_S]

Curious— is this abnormal wear from the thrust washer pressing back on the rear of the lower crankcase?

[n3303j]

Isn't the thrust washer keyed so it can't rotate against the crankcase?

[Dirk_S]

Isn't the thrust washer keyed so it can't rotate against the crankcase?

Thanks for knocking sense back into me. I need that often!

I looked at a couple used crankshafts from previous years, and they all have this area milled / cut down

[n3303j]

I assume they face the case so it's somewhat perpendicular to the crank axis.
Only time there's a real thrust load on the crankshaft is when you disengage the clutch.

[Frenchfrog]

I don't think there is undersize bearings available for small blocks, crank would have to be welded up, machined back to spec & re-nitrated.

You are absolutely on the money...no oversize's available for the smallblock.I'm pretty certain that there must be somewhere some that are adaptable but never found them .Possibly for Fiat's.

[Stretch]

OW OW  :sad:OW!!!

That RH big end and the crank journal are TOAST!!!   

I'm guessing that you'll be replacing things there......

                                                  -Stretch

[Dirk_S]

Just tore apart the cheap, used motor I bought that had previously suffered the infamous V7 II crank issue. I was impressed by the cleanliness of the pistons and valves, and kinda embarrassed by the carbon buildup on mine (although mine had 30,000 more miles more).

…Anyway…

Before tearing the case apart, I checked the endplay. Video link here (heh heh):

https://youtube.com/shorts/u6Tcj5rz1Ik?feature=share

Ahem. Again…Anyway….

Popped the halves apart, and this is what I see:





Crankshaft is in good condition. Case is pretty clean of debris. Con rods feel good radially.

But you might ask yourself Dirk, what about the other thrust bearing?

Funny, because I’d also like to know about that other thrust bearing.

Not. Present.

Just one bearing, sandwiched between the seal and crankcase. No thrust bearing on the inside of the wall, and there is indeed supposed to be another thrust washer on the inside. That would explain the amount of endplay that I noted before pulling the halves apart, and maybe that’s why others in that bothersome batch failed, too?

But back to me: I have a question: The seal and surrounding metal around it got eaten up, as well as the area up by the cam, as shown in the following pics.

Does that mean this engine case is no bueno to use? Or are those war wounds inconsequential?

[Tom H]

The engine you pulled apart. The outer thrust bearing looks like the wafer thin one in the engine that I posted the pics of. But the inner thrust was in the pan all wadded up.

I have not seen a new crank to know exactly what to look for. On the clutch side of the crank. The face that rides up against the outer thrust has a lip on it. It is not flat from the bearing surface to the edge of the flange. Should it be  flat or have that lip????

If the cam end cover is not leaking,you should be OK?????

Tom

[Kev m]

Just tore apart the cheap, used motor I bought that had previously suffered the infamous V7 II crank issue.

<snip>

Crankshaft is in good condition. Case is pretty clean of debris. Con rods feel good radially.

But you might ask yourself Dirk, what about the other thrust bearing?

Funny, because I’d also like to know about that other thrust bearing.

Not. Present.

Just one bearing, sandwiched between the seal and crankcase. No thrust bearing on the inside of the wall, and there is indeed supposed to be another thrust washer on the inside. That would explain the amount of endplay that I noted before pulling the halves apart, and maybe that’s why others in that bothersome batch failed, too?

But back to me: I have a question: The seal and surrounding metal around it got eaten up, as well as the area up by the cam, as shown in the following pics.

Does that mean this engine case is no bueno to use? Or are those war wounds inconsequential?

Is this the motor from Hamlin?

Dude, I'm sorry if I sound like a broken record, but I have no reason not to believe him on the WHY this happens. The crankshaft is NO GOOD because it's undersize. It was MADE too small, which allowed enough movement for the thrust bearings to come out of place (maybe one at a time), and get ground down by the crank.

This is why the one is worn and the other is possibly waded up in the pan (Tom I don't see what you're seeing but it's early and I'm bleary eyed and probably not looking in the right place). But THAT is probably why some people are claiming a thrust washer was "left out". NO, no-one at the factory was actually stupid enough to FORGET a thrust washer. They placed them there with a crank that  was mm out of spec on end length/throw width or the like. It was just enough to eventually, under the load from the clutch, allow that bearing to move, block an oil passage and/or make forced contact with the crank and chugga chugga chugga.


I can't say if the crankcase is ok without seeing if anything is worn/damaged, but I trust Hamlin enough to say the crank is NOT good.

[Frenchfrog]

The cases need checking also. Years ago a friend's v 50 which works exactly like this had a similar problem with the thrust bearings and it was got around by skillfully machining the crank and cases ,then making oversized thrust  bearings.

[Dirk_S]

Is this the motor from Hamlin?

Yes it is.

Dude, I'm sorry if I sound like a broken record, but I have no reason not to believe him on the WHY this happens. The crankshaft is NO GOOD because it's undersize. It was MADE too small, which allowed enough movement for the thrust bearings to come out of place (maybe one at a time), and get ground down by the crank.

Very well may be right, but I never got a definite answer from Jim on the why. “Undersize crank, I think”

Maybe the bearing fell out while I was taking it all apart, but I’ve yet to find it. I’ll clean everything up tonight and do a good search.

It’s not in the sump, and I never heard anything clanging around inside when I was flipping it constantly during tear down.

Or perhaps it was found in the sump and removed prior to my purchase?

(Tom I don't see what you're seeing but it's early and I'm bleary eyed and probably not looking in the right place).

He was referring to the engine that he worked on, not mine.

They placed them there with a crank that  was mm out of spec on end length/throw width or the like. It was just enough to eventually, under the load from the clutch, allow that bearing to move, block an oil passage and/or make forced contact with the crank and chugga chugga chugga.

I suppose there’s no easy way to measure the length of a crank down precisely?

I can't say if the crankcase is ok without seeing if anything is worn/damaged,…

I don’t feel any scoring, but I can begin measuring diameters, etc., with the measuring tools that I got for just the occasion.

I have not seen a new crank to know exactly what to look for. On the clutch side of the crank. The face that rides up against the outer thrust has a lip on it. It is not flat from the bearing surface to the edge of the flange. Should it be  flat or have that lip????

I’ll take a look after work. I have my original crankcase and shaft here as well, and I want to compare the two anyway.

The cases need checking also. Years ago a friend's v 50 which works exactly like this had a similar problem with the thrust bearings and it was got around by skillfully machining the crank and cases ,then making oversized thrust bearings.

…Oh boy.

[Kev m]

I suppose there’s no easy way to measure the length of a crank down precisely?

I don’t feel any scoring, but I can begin measuring diameters, etc., with the measuring tools that I got for just the occasion.
I’ll take a look after work. I have my original crankcase here as well, and I want to compare the two anyway.

…Oh boy.

Well, the good thing is that you have two cranks to compare now right?

Assuming there's no scoring or wear, perhaps measure the width of the crank at the thrust surfaces (between the surfaces that contact the thrust bearings) using a sliding caliper or the like? See how they compare. If the one from Hamlin's motor is smaller you may have your answer.

[huub]

I would just make a thrust washer out of phosphor bronze, so you can set the clearances as needed.
easy for me , but you need access to a lathe
i would not hesitate to reuse the cases.

[Kev m]

I would just make a thrust washer out of phosphor bronze, so you can set the clearances as needed.
easy for me , but you need access to a lathe
i would not hesitate to reuse the cases.

So even IF the crank is undersize, you could in theory make the crank fit the block with different size thrust washers.

Makes sense.

[Frenchfrog]

Of course kev.I've no idea how the V50 fix lasted but it's certainly worth a go.
The other issue is that with the small bloc cranks there are no oversize main or big end bearings available and I have never found anything that could be modified...there must be something out there that would work though.

[Tom H]

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.

I still think that maybe the thrust bearings were made with defective material. The clutch side one I believe is worn from working the clutch AND/OR a clutch adjusted too tight.
When you work the clutch, it pushes the crank forward putting pressure on the outer thrust washer. Once the outer wore enough, then the inner fell out.

JMHO
Tom

[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]

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.

 


Copy that, I misunderstood and thought you were commenting on Dirk's pics.... but I'm easily confused. 

[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.