Crankshaft included in rebuilt

[28tbsfan]

I know this is on me but if my engine was rebuilt (full rebuild w/ added HP), would I not assume the crankshaft would have been included? After my 3.2 was rebuilt, the mechanic mentioned the crankshaft lost a part because of the increase in power and now had to be replaced.

Would a 25k+ rebuild typically not include a new crankshaft or at least a repolish?

[LT86]

Always depends on what has been agreed upon.

I've seen people call overhauls 'full rebuild' without opening the bottom cases. You mention more hp, what has been done to the engine? 25k is a lot of money but again, depends on what has been done as standard parts + labor costs can become a hefty sum quite fast.

To me, a full overhaul would indeed logically include a detailed check or rework of the crankshaft but if they figured it might have been still 'good enough' it could have been put in again as is to save cost.

Also, what part of the crankshaft has been lost?

[28tbsfan]

Originally Posted by LT86

Always depends on what has been agreed upon.

I've seen people call overhauls 'full rebuild' without opening the bottom cases. You mention more hp, what has been done to the engine? 25k is a lot of money but again, depends on what has been done as standard parts + labor costs can become a hefty sum quite fast.

To me, a full overhaul would indeed logically include a detailed check or rework of the crankshaft but if they figured it might have been still 'good enough' it could have been put in again as is to save cost.

Also, what part of the crankshaft has been lost?

Thank you. They are redoing the pistons and heads to allow for more air flow to drive more HP.

[28tbsfan]

Originally Posted by LT86

Always depends on what has been agreed upon.

I've seen people call overhauls 'full rebuild' without opening the bottom cases. You mention more hp, what has been done to the engine? 25k is a lot of money but again, depends on what has been done as standard parts + labor costs can become a hefty sum quite fast.

To me, a full overhaul would indeed logically include a detailed check or rework of the crankshaft but if they figured it might have been still 'good enough' it could have been put in again as is to save cost.

Also, what part of the crankshaft has been lost?

He mentioned part of the crank shaft failed, so I have to inquire if that means a full replacement is necessary. I’ve received quotes upward of $40,000 for engine rebuilds in the Chicago market. This gentleman is a reputable mechanic of 40+ years, so I trust his guidance. I’m just struggling to see why this wasn’t part of the project.

[stownsen914]

Replacing a crank isn't typical for rebuilds as they are generally durable and have gotten expensive. A typical rebuild might include a thorough cleaning and a polish, which are simple procedures. If yours has failed in some way, then it would need more attention, and of course repairs or replacement would be part of a proper rebuild. Depending on the nature of the failure, it may be repairable. Hard to say without knowing how it failed. A common type of damage is a journal being damaged - a fixable problem in most cases.

[Dpmulvan]

Originally Posted by 28tbsfan

I know this is on me but if my engine was rebuilt (full rebuild w/ added HP), would I not assume the crankshaft would have been included? After my 3.2 was rebuilt, the mechanic mentioned the crankshaft lost a part because of the increase in power and now had to be replaced.

Would a 25k+ rebuild typically not include a new crankshaft or at least a repolish?

Crankshaft lost a part because of increased HP?? Sounds sketchy to me.

[28tbsfan]

Originally Posted by Dpmulvan

Crankshaft lost a part because of increased HP?? Sounds sketchy to me.

He told me it looked like somebody had messed with the crankshaft back in the 90s or something. He mentioned something about the increased power taxing the crankshaft and potentially failing. He is a well-known reputable mechanic of 40 years who is cited several times on this forum so I trust his judgment. The problem has been locating parts and the rebuild taking over a year.

[28tbsfan]

Originally Posted by stownsen914

Replacing a crank isn't typical for rebuilds as they are generally durable and have gotten expensive. A typical rebuild might include a thorough cleaning and a polish, which are simple procedures. If yours has failed in some way, then it would need more attention, and of course repairs or replacement would be part of a proper rebuild. Depending on the nature of the failure, it may be repairable. Hard to say without knowing how it failed. A common type of damage is a journal being damaged - a fixable problem in most cases.

That was my interpretation as well. I just wonder if perhaps he overlooked something before he began to rebuild. I suppose I would rather this happen now then when I get the car back, the car horsepower has increased to around 300 HP. He did mention something about, the car lacking performance prior and that could have something to do with the crankshaft.

[Dpmulvan]

Originally Posted by 28tbsfan

That was my interpretation as well. I just wonder if perhaps he overlooked something before he began to rebuild. I suppose I would rather this happen now then when I get the car back, the car horsepower has increased to around 300 HP. He did mention something about, the car lacking performance prior and that could have something to do with the crankshaft.

So do you need a new camshaft or can yours be fixed?

[mepstein]

A good working crank isn’t usually replaced during a rebuild. It’s not generally a consumable part. Like it was said, clean and polishing is the norm. If something is wrong, that’s a different story. Same can be said of other main parts like heads, case, cam towers, etc. Getting another 20 + hp out of an engine won’t damage a crank.
how was it messed with?

[mikedsilva]

I've never had to replace a crankshaft yet. My machinists actually comment on how durable the Porsche cranks are, compared to the other engines they perform work on.
They always check mine for cracks, straightness etc and always perform a micro polish.

I have seen cranks that have had a rod bearing fail and that can spoil a journal.

[al lkosmal]

I always have the cranks inspected, measured, magnafluxed and micro-polished.....I've only had to replace one, to date.

regards,al

[Dpmulvan]

Originally Posted by al lkosmal

I always have the cranks inspected, measured, magnafluxed and micro-polished.....I've only had to replace one, to date.

regards,al

Al you invented YouTube shorts!! Credit where credits due.

[28tbsfan]

Originally Posted by Dpmulvan

So do you need a new camshaft or can yours be fixed?

I have a call into him later this week. It sounded like he was looking for a part as opposed to a brand new CS.

[28tbsfan]

Originally Posted by mepstein

A good working crank isn’t usually replaced during a rebuild. It’s not generally a consumable part. Like it was said, clean and polishing is the norm. If something is wrong, that’s a different story. Same can be said of other main parts like heads, case, cam towers, etc. Getting another 20 + hp out of an engine won’t damage a crank.
how was it messed with?

Adding 80+ HP. Sounds like it was damaged prior.

[mepstein]

Originally Posted by 28tbsfan

Adding 80+ HP. Sounds like it was damaged prior.

80 still shouldn't be an issue. I've seen quite a few damaged cranks. Usually it's a connecting rod bolt, an oiling issue or some other problem that causes catastrophic damage to the engine and damage to the crank is just a by product.

[Henry Schmidt]

Originally Posted by 28tbsfan

I know this is on me but if my engine was rebuilt (full rebuild w/ added HP), would I not assume the crankshaft would have been included? After my 3.2 was rebuilt, the mechanic mentioned the crankshaft lost a part because of the increase in power and now had to be replaced.

Would a 25k+ rebuild typically not include a new crankshaft or at least a repolish?

I hesitate to get involved in what sounds like a service dispute but increased horse power will not in and of itself cause a crank failure.*
To answer your question, a new crank is not a standard replacement part during a basic overhaul.
The rod and crank configuration is one of the weak links in the 3.2/3.3 engine design.
They wanted to make the rod journal larger but given the oil pump proximity, the big end rod dimension was limited. That limitation forced the designer to use a 9mm rod bolt instead of the much stronger 10mm bolt used in most Porsche flat six engines. Smaller bolt with compromised yield strength. We always use a rod upgrade or at least ARP bolts.
Getting back to the horse concern, the 9mm rods bolt has limitations based on rpm not so much horse power. If the horse power increase was produced by revving the engine above *7400 or so, that may cause a failure.
Without really knowing more than "lost a part" I can't comment on the true cause of the failure but experience tells me you're looking at a connecting rod failure.
Causes: low quality rod bearings, rod journal in spec but out of round, rod out of spec, rod accidentally assembled wrong (number to number mis-match....people are human)
Lastly oil contamination. Oil lines, oil cooler, oil tank all collect junk while cars sit around waiting for the new engine.

[Oregon 911]

Originally Posted by 28tbsfan

I know this is on me but if my engine was rebuilt (full rebuild w/ added HP), would I not assume the crankshaft would have been included? After my 3.2 was rebuilt, the mechanic mentioned the crankshaft lost a part because of the increase in power and now had to be replaced.

Would a 25k+ rebuild typically not include a new crankshaft or at least a repolish?

I have a 1974, 911 had the engine rebuilt in 2023 the machine shop magna fluxed my crankshaft and Miked the bearing surfaces said it was still good and they polished the crank which worked for me,and I checked online and a brand new crankshaft for my engine at the time was $15,000.
Needing a brand new crankshaft or to be replaced with a used crankshaft would significantly make the cost of an engine rebuild much higher, wouldn’t it. Good luck rebuilding your engine and have a good time with your car after the rebuild.