65 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCHBent crank
Reported or suspected cause
running 19" wheels
Reported cause
No successful repair reported for this finding.
1
Identified cause
0
Suspected cause
0
Reported fixes
Read evidence and context
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Discussions that report identifying a cause
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Reported cause
Looks like part of your problem is running 19" wheels.
Leading evidence: 'running 19" wheels' (1 discussions report identifying this cause; no attributable repair resolution). Across 1 matching discussions, the most frequently mentioned possible cause is 'running 19" wheels' (1 discussions; 1 report identifying it and 0 suggest it). The most frequently discussed action is 'Check crank as part of a rebuild project' (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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Performed · outcome unconfirmed
I've only checked a crank as part of a rebuild project.
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Performed · outcome unconfirmed
It's why NHRA IHRA and most sanctioning bodys for drag racing require "scatter shields' to be installed on all race cars other than Pure Stock.
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Performed · outcome unconfirmed · Original poster
I was told by the last owner that when he put the trans back in it ran really rough.
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Discussions that suspect a cause
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Suspected cause
Probably an incorrect downshift, to too low a gear, spun the clutch assembly to incredibly high RPMs and it exploded taking the transmission housing out with it.
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Suggestion
You'll most likely need to find a new crankshaft if it is indeed damaged - if it IS damaged I'd be sending the rest of the parts out to a machinist to check for further collateral damage.
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Suggestion
Luckily the engine withstood the over-rev and all I had to do was replace clutch and transmission, plus repair brake lines and a hole in the floorboard.
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Suggestion
Luckily the engine withstood the over-rev and all I had to do was replace clutch and transmission, plus repair brake lines and a hole in the floorboard.
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Suspected cause
Probably an incorrect downshift, to too low a gear, spun the clutch assembly to incredibly high RPMs and it exploded taking the transmission housing out with it.
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65 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
Rennlist: 1 discussions
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I am looking to purchase a 2001 that i was just told might have a bent crank. The engine was just built to a 3.8L monster . The person who has the car now does not know anything about it. Is there a way to check if it�s bent and the other fun fact is the transmission is not in the car so I can�t start it up. I was told by the last owner that when he put the trans back in it ran really rough. If it�s bent how much of a pain is it to get that fixed?
I'm not aware of any way to measure the crankshaft without having the crank cradle on my workbench and getting measurements with a dial bore gauge and micrometers. I've only checked a crank as part of a rebuild project. I suppose if you've gone that far then to fix the issue you'll need to measure your bearing tolerances within the cradle to ensure that your cradle housing is not also damaged. You'll most likely need to find a new crankshaft if it is indeed damaged - if it IS damaged I'd be sending the rest of the parts out to a machinist to check for further collateral damage. If it got rebuilt to a 3.8 and the crank is presumed to be off then it sounds like someone got the rebuild done without sending their other components to be measured.
How did they diagnose a bent crank? It may be code for "the engine internals are junk". I would assume the engine is scrap with no salvageable parts. If you are lucky, the case may be good for a core. It takes a lot of force to bend a crank. If it is bent, you probably have at least one bad piston, one bad rod, and one bad cylinder, and one bad or damaged head.
Also, if someone says they don't know anything about it, it gives them free reign to lie, under a cover of ignorance.
The guy blew the trans on the track and when he tried putting in the new trans, he said it ran rough. The mechanic was not sure why and thought the crank could be bent but would not know without tearing it down. The owner was tired of throwing money at this point so he dumped the car at car max. I can tell a lot of work has been done and am still trying to contact the past mechanic but he shop Rennology has closed. I would love to see if it was an easy fix and yes I am worried other stuff might be tweaked
I�m hoping to talk to the guy who built it as I was told it is pushing 400hp. It has some GT3 components and a fabspeed exhaust. I have that exhaust on my other 911 and it sounds great but I would love to have a monster motor that worked
You can run the engine without the transmission installed as long as the flywheel is bolted on the crankshaft, and the engine supported...
I would also be wonder WHY they thought the crank was bent, and if I could not confirm, would assume that it WAS, (or maybe worse)
I'm curious about this too. How would you know without disassembly? Wouldn't it wobble in the main bearings and wallow them out? Low oil pressure can be caused by many things, but my first assumption for an engine that failed on the track would be a spun rod bearing. I don't think crank end play would tell you much either.
Maybe put a dial gauge on the outer edges of both ends of the crank at the same time?
All I know is the guy who had this had some other cars and he seems to be well off and did not really care about it as the car was at the shop for close to a year waiting on the mechanics. He claimed they did not install a rev limiter, he missed shifted and the trans broke. After installing another trans he said it sputtered. The mechanic was not sure why and that�s when he said maybe a bent crank. That�s all the story I have so far. I�m hoping to get more info. I�m not sure why the shop closed but I�m thinking it�s trashed. I�m not sure how much I could get a motor and trans for and then slap it in the car. It has some nice goodies on the engine that could be reused
Since there was an issue due to the transmission;
IF you have access to the car, the most you can do is to remove the clutch and flywheel, and put a dial indicator (Harbor Freight- $50-60) on the flywheel flange.
Turn the crank in the engine running direction using a socket and breaker bar on the front of the crankshaft pulley (rear bumper side).
The dial indicator will show if the flange is true, and if it's not, then you have your answer.
I've bought two cars where the seller was selling their car because their mechanic said the engine was blown.
I fixed one for free (had cylinder wash) and the other a $30 pulley with bearing. The bearing melted.
The simple fact they diagnosed the engine with a bent crank leads me to believe they have no idea why it's running rough and are just guessing.
I have never even heard of a situation where an NA engine bent a crank. Maybe a car running over 1000 hp.
Sounds like he "money-shifted" it. Bent some valves or spun a bearing.
I was thinking about getting a used flywheel and mounting it then seeing what happens when I start it up. I have an ODB reader and can see what codes pop up. Anybody know where to pick up a used flywheel for a 2001?
If it�s cheap enough to flip if the engine is bad and recoup your money and taxes, go for it. You essentially should buy it as a roller without drivetrain and pay no more for it. Rebuilding these engines n the cheap should be done by those who have lots of time,experience and lots is good spare parts to pull from. This is a do it right or don�t do it at all engine, simply because of its design and cost of failed parts.
A missed upshift could result in a brief engine over-rev, but I wouldn't think it would typically harm the transmission (or the engine for that matter, unless he just kept the throttle floored after missing the shift).
If the "missed shift" was a downshift, that seems like it could take out both the transmission and the engine. For example, if he accidentally downshifted from 5th to 2nd when he meant to go from 5th to 4th, that seems like it could take out the transmission and cause a huge over-rev condition that would be very likely to damage the engine (a rev limiter would not have helped).
I have no experience with missed shifts, or the results thereof, this is just conjecture base upon the symptoms.
If you can get access to a Durametric you can read the type 2 over revs, which will tell you if it was a money shift issue. That'd be the first place I'd look. Starting it sounds risky to me. Maybe use an inspection camera and go down through the spark plug holes to see if you can see valve/piston contact.
A miss-shift can absolutely lead to breaking a clutch, flywheel, and transmission.
The evidence is definitely pointing towards a "money-shift" as being the culprit.
This is exactly where the term "money-shift" came from. One wrong shift can cause a lot of damage.
Wait a minute! Those pictures show the half the bellhousing still attached to the engine and the other half is broken off. WTF happened to this car for the transmission to break off?
It's just terminology. What pops in my head (correctly or incorrectly) when I hear the term "miss shift" is not making it all the way into the next gear during an upshift. This is the picture the pervious owner seems to trying to paint since he mentions a rev limiter -- but that type of miss shift typically would not damage either the transmission or the engine.
Downshifting into the wrong gear (e.g. 2nd instead of 4th) at speed, however, can easily destroy both the engine and the transmission and clutch the instant the clutch is let out in a gear that is way too low because everything gets immediately spun to RPMs they could never reach on their own.
I think a "money shift" is typically the latter (an inappropriate downshift) and that would explain simultaneous failure of engine and transmission. It seems pretty likely this is what happened (which means there's a very good chance the engine is toast). If this is the case, the previous owner blaming it on the lack of a rev limiter is disingenuous -- a rev limiter is totally irrelevant in an inappropriate downshift.
Probably an incorrect downshift, to too low a gear, spun the clutch assembly to incredibly high RPMs and it exploded taking the transmission housing out with it. If this is the case, the owner is not being forthright in trying to blame it on lack of a rev limiter.
That's not a cut. That's how cast aluminium breaks. Somebody cleaned up the area afterwards to look better. They removed the clutch and the transmission to hide the carnage. Are there any marks on the floor pan from the shrapnel?
I can�t get any other answers as. I have tried reach the past owner and his mechanic. The car is still for sale and while I was hoping it would be an easy fix with adding a trans I can�t believe what I�ve been told. Why would they put on the housing and claim they tried another transmission? The guy who has the car now won�t take less than $8,600 as that�s what he has in it. After putting a motor in you would be upside down in the car. If someone has a motor and trans, this could be a decent buy as the car only had 54000 miles and everything works except the radio and the engi
ne
What I am not getting is: isn't the bell housing (not the transmission side but the engine side) an integral part of the engine casing, therefore this engine is toast because both engine halves would have to be replaced?
$8600 for a roller cab without a transmission except for the sheered bellhousing. Not a chance. Best he could do is drop the engine and disassemble it. Maybe he finds something maybe he doesn't.
I agree with you. This is part of the transmission bell house section and has been cut within a couple of inches from the engine. You can see it's still bolted on the engine. Yikes!
Not worth it. Move on. You have all the signs you need that it's not a good buy. Clearly something major happened. Don't talk yourself into a problem car, you know?
Good luck in your search!
I stand by what I said earlier. Assume the engine is junk. The over-revs can cause significant damage. A "bent crank" is just a vague way of stating that it is not an easy or cheap fix and a complete rebuild is required, assuming there are salvageable parts.
Thanks for all the info. I hate it that the car turned out to be toast as the guy dropped a ton of money in the engine and this would have been a sleeper. Well at least I still have my other 996. Here�s a pic of it. I need to swap out the suspension as it was lowered and it rubs the inner wheel wells. I�ll start looking at coil overs and other possible options. Here�s the new toy and the 944 I just sold.
ions
I have seen transmission housings blown apart like that before. It's why NHRA IHRA and most sanctioning bodys for drag racing require "scatter shields' to be installed on all race cars other than Pure Stock.
The scatter shields are a blow proof bellhousing made from 1/4 inch steel, or a 1/4 steel shield placed above and around the side to keep the explosion of clutch or flywheel from entering the drivers compartment.
Back in the early 80's I had built a 1970 Mercury Capri (the west German model), was a street car with a Turbo 4 cylinder @ 325hp/1900lbs 5.8 lbs per HP. It was crazy fast, would still be fast by todays standards, just look at lbs per horsepower of todays cars !!
Anyways while driving the car I was about a mile from being back to my house and let it rip one more time, and on the shift to 3rd the clutch stuck to the floor ( happens on diaphram clutches if the pressure plate goes over-center at high rpm) the RPM's skyrocket (rev limiters not popular back then), pressure plate explodes, destroyed bell housing like what is pictured here, half pound piece came through the floorboard missimg my right foot my 2 inches. It cut the brake lines, so I had lost brakes in the process, and was a terrible vibration that blurred my vision. Luckily the engine withstood the over-rev and all I had to do was replace clutch and transmission, plus repair brake lines and a hole in the floorboard.
I have no idea if this engine withstood the over-rev or not. but . measuring the runout of the crank flange, and just installing a flywheel, the engine could be cranked to see if any noise or vibration is present. Of course the engine could not be cleared of suspicion until 50 hours run time is accrued..
I have no idea why unless the engine sits in there better when there�s no transmission. The car is on Chicago Craigslist and located in Addison. The last owner said they put in a transmission afterwards but I doubt it since you would have to undo that remaining part of the bellhousing and it does not look like it was removed. Who knows maybe the engine was okay and the mechanic was feeding the owner crap. If anyone has a flywheel, go try to see if it will start. If it�s messed up I guess you can�t screw it up anymore than it is.
I remember the first time my transmission fell out. Weird thing is no one cared to know any details about it because, you know, it happens all the time.
I tracked down the previous owner and he told me what happened and gave me the email of the mechanic. I have tried to reach the mechanic and he has not contacted me back. The current owner has a diesel repair business and bought this at an auction and then decided it would be too much workforce him. I don�t think he knows how bad it is as he did not have the history I gathered on the car from the last owner. Rennolgy was the shop that did the work and they are now closed. He said they used all high end parts and he dropped in a bunch of money as this was a toy for the track. After the trans broke, he was tired of dealing with the car.
There is no way in hell that a professional mechanic, regardless of his/her specialty, doesn't know exactly how bad the car is. They know and that's why they are trying to unload it.
+1. Absolutely. Everyone in the string of individuals associated with this car is being vague, at best. That way, they can claim ignorance and the buyer of this project will have no recourse when they uncover the actual problems.
I've paid for this education in the past. You are getting it for free on this forum. This is personal OE. If the deal seems too good, it is. At $8600, or whatever the current asking price is, they are trying to squeeze every dollar out if it they can. If the 3.8 in this car really was good, they would be asking far more. They probably would have put a gear box in it and either kept it, or sell it at that point. They realize this car is a money pit to rebuild it back to what it was, so they are cutting their losses and moving on.
I personally would not have a problem with buying this car if it is what you are looking for. I would do the math associated with replacing the engine and gearbox. You will find that they will have to give it to you, or pay you to take it, for the numbers to work. Still, it's probably worth something, just not $8600.
Again, very vague with the mechanical description. Let's you think the engine might be good. Judging by the grammar, english is not his first language.
