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YOUR RESEARCHLaying crank on its side, Truth or wives tale?
Leading reported evidence
Use crank at this point
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Performed · outcome unconfirmed
Personally, I wouldn't take a chance with this used crank at this point.
Leading evidence: 'Use crank at this point' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, the most frequently mentioned possible cause is 'somewhere in its journey' (1 discussions; 0 report identifying it and 1 suggest it). The most frequently discussed action is 'Recommend looking up best oil or' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
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Suspected cause
I suspect somewhere in its journey from manufacture to your location, it sat on its side somewhere.
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Suggestion
you want to read a ton of stupid internet drivvle, I recommend looking up best oil or which procedure to use to break in your new engine.
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Suggestion
If I were you, I would purchase a new crate engine from Porsche (be prepared to spend some serious money) and use the crank from that engine.
Use piece of string and a significantly weighted nut
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Suggestion
Easy visual is to use a piece of string and a significantly weighted nut.
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29 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
Rennlist: 1 discussions
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Outcome without a verified action link
Just store the crank inside the crank carrier (with the main bearings of course), problem solved.
I recently purchased a 3.4 crank for my rebuild and some people told me to never lay it on its side. Although Im not the one directly building the engine I sent it to be measured and its straight as an arrow.
Any thoughts on this?
Thanks!
My thoughts incline toward the notion that a crank that can't stand being laid on its side isn't one you want in your engine.
But I'll await better-informed views.
When I rebuilt one of my previous cars engines I'm sure I had the crank on its side plenty with no ill effects. It lays horizontal in its finished installation as well. Maybe people who have said that were confused and thinking of plasma TVs.
Apparently a bit of poking around on other forums reveals that it can be true - a crank can bend over time.
I think a lot depends on how it's stored and what it's actually resting on. If you lay a crank down on its side on a concrete surface, you could easily damage a journal. Apparently folks have reported a bend in a crankshaft after it was sitting for a long time.
After doing a bit of research there is a sound argument for not storing one on its side for any extended period. I think its a stretch to insinuate that it would be ruined by laying it down for a short duration though. This is going in a normal car, not the space shuttle. I don't think the tolerances are critical enough that a few out of place atoms will be detrimental. That being said, no reason to risk it. Just store it on its end or build some wooden stands to support it along the points where it rides on the bearings.
Plastic deformation of steel? Googling suggests that this begins at temperatures around 600C.
If you keep your garage thermostat in a reasonable range, you should be okay.
I'm just saying that there's tons of forum posts on this and everyone is weighing in for or against with no real science. Someone suggested a perfect case for Mythbusters. I also found someone suggesting that this is a"very basic bridge-esge statics problem"
Source here:
https://grassrootsmotorsports.com/fo...s/27724/page1/
"You have force acting on the system, gravity and crankshaft weight, acting in the center of the unsupported span, middle of the crank in this case. Then after a bunch of seemingly trivial math, based from you force diagram, you end up with how the forces are acting on your object. Then after some more math, involving material strength and thickness, you end up with either something broken or holding its own just fine, but bending in the direction of the force applied.
Easy visual is to use a piece of string and a significantly weighted nut. Place the nut in the middle of the string, then attempt to pull the string taunt horizontally. You will see that the nut always droops a bit even though you have the string to the point of breaking. Eventually, your crankshaft will do the same. Reason is the unsupported span doesn't have either enough mass in the vertical direction to avoid the deflection or doesn't have enough mechanical properties, total material strength or already deflected in the opposite direction, to resist the deflection either."
a thread about the block bending if left on an engine stand went on for a few pages......mostly by
our inhouse engineers ........some times the entertainment value here is priceless...........engineers ....ninja pleeezzz
Uh this isn't how the physics works. The crank would have to go through plastic deformation in order to bend and stay bent after it was removed from its horizontal resting position. As stated above, the crank would need to be over 600F for that to happen with gravity as the force.
Entertaining stuff, though.
If you are truly concerned, my recommendation would be that you get a rotisserie motor and build yourself a Crankshaft Storage Device. If you live in an area with an unreliable power grid, you may want to consider UPS or solar backup.
One way to get a handle on this question is to think about the force (tension) in a wheel lug bolt.
I don't know the exact value - it would be a function of bolt diameter, torque, and friction. But it certainly exceeds thousands of pounds. Yet lug bolts routinely last the life of the vehicle without deformation.
Rabbit hole..... you want to read a ton of stupid internet drivvle, I recommend looking up best oil or which procedure to use to break in your new engine.
Then go read a box of piston ring break in instructions and explain the wild difference. Most people posting about the best way to store a crankshaft have probably never taken a set of micrometers to one in their lifetime.
yeah. I laughed at that one also. My engine was on a stand with 3 bolts holding it there for 2 years
and the crank laid on its side in a box
I'm Loco.
Never heard of this before, so had to dig up some old threads from internet.
It seems that the cast iron cranks can creep after machining.
So the deformation is only happening because cast it self had inside tensions and removing material affect on these.
Nothing to do with how its kept on the table.
More BS. It happens when machining because the machinist in question is cutting too deep or too fast generating too much heat. Then the cooling afterwards causes things to be out of spec. I've watched more than one idiot with a lathe or mill f up steel this way. There is a reason CNC machines spray coolant continuously since they are generally cutting at pretty high speeds.
I'm one of those weird engineers that spent all his time growing up and since actually fixing things and "redesigning" things. A degree in engineering is a good thing, but being able to work with your hands is just as, or even more important.
store it on it's side
there is more danger (potential energy) involved in it potentially falling over and dinging a journal than there is in plastic deformation.
Doesn't someone screen these calls?
You are worried about a casting? You do realize there are zero finished castings in any engine assembly, right? Any casting used in any high tolerance application is going to require lots of machine work. It is all about the machinist and their skill or lack thereof. casting is about the least sophisticated process for making parts.
Personally, I wouldn't take a chance with this used crank at this point. Of course that's just me and YMMV. If it wasn't bent already, it was probably bent in the process of being "measured" (or in shipping, sitting since the measurement, etc).
If I were you, I would purchase a new crate engine from Porsche (be prepared to spend some serious money) and use the crank from that engine. When you disassemble the new engine be prepared to immediately transfer the crank to your rebuilt engine. You must have the rebuilt engine ready to immediately accept the new crank. Do not put the crank down when transferring it and do not handle the crank for too long as the heat from your hands could potentially deform the crank. Make the transfer as quickly as possible because every second counts at this point.
You can then sell off the other parts from the new Porsche engine (keeping the IM$B, of course, for a proactive swap into your rebuild several months down the road) to recoup some of the cost of the new engine.
The only thing your old crank is good for at this point is an ornamental mailbox post. Just be aware that it will bend and your mailbox will tilt in short order(make sure the mailbox door has a strong latch so you don't lose your mail).
Granted, I'm not an expert on this subject but that is how I would handle this situation. I'm sure others will chime in any minute now if my info or logic is flawed here.
I wonder how many rebuilt M96s experience CEF due to a bent crank being used for the rebuild??? Oh well, just add it to the mile long mode of failure list...maybe we should start a poll?
Heh, no I'm not worried about castings. Or keeping the crank on it's side.
On my first post I was just saying my opinion, where this whole saying is coming from.
It seems that I haven't just written it clear enough.
This is a source reference. Confirm exact model applicability in the original material.
