Is it possible for a crank to be broken and the engine still runs with 60 psi oil pre
02-04-2012, 10:29 AM
#1
Is it possible for a crank to be broken and the engine still runs with 60 psi oil pre Is it possible or have any of you ever heard of a crank being broken in a motor and the motor still runs fine with no misfires or vibrations or anything and it still has 60 psi of oil pressure? Is this possible?
02-04-2012, 12:35 PM
#3
Unlikely. But my Boss dirt car did break a crank and still ran just heard a boom bang and was like wtf was that. They notice when the crank pully was wobbleing like crazy and shut it off. The crank broke in a way where is lock together enough to turn. But when disassembled it came out in two peices. Wouldnt believe it if I didnt see it.
02-04-2012, 02:07 PM
#4
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Who is telling you this and if it had no other symptoms how did they know?
How was it diagnosed?
02-04-2012, 02:25 PM
#5
Yes it is possible for the engine to run but the rest is all BS.
I had a 1985 s-10 blazer with a 2.8l v6 was on my way from Norfolk, VA. to Pensacola, FL. and just got across the state line into GA and the engine sounded like someone had a coffee can 1/4 full of nuts and bolts shaking. The engine would run for around 4-5mins and then seize. Let it cool down for 20mins or so and it would repeat the cycle. I actually drove it to the nearest exit off the interstate and into a hotel parking lot. Called a GM dealership the next monday morning and had them pick it up and diagnose. They pulled the engine and actually were cool enough to install a reman from autozone for me.
The crank was broken in 2 places. Harmonic balancer rubber inertia ring had let go and let the outer metal ring of the balancer spin around it taking the crank out of balance. The oil pressure ran 40psi normally and was running around 10psi when i parked it. The engine ran like it was running on 2 or 3 cylinders and was very rough....but it got me off the interstate and saved me a tow bill. I personally saw the pan off my v6 and it was very easy to see the 2 diaganol breaks in the crank.
I had a 1985 s-10 blazer with a 2.8l v6 was on my way from Norfolk, VA. to Pensacola, FL. and just got across the state line into GA and the engine sounded like someone had a coffee can 1/4 full of nuts and bolts shaking. The engine would run for around 4-5mins and then seize. Let it cool down for 20mins or so and it would repeat the cycle. I actually drove it to the nearest exit off the interstate and into a hotel parking lot. Called a GM dealership the next monday morning and had them pick it up and diagnose. They pulled the engine and actually were cool enough to install a reman from autozone for me.
The crank was broken in 2 places. Harmonic balancer rubber inertia ring had let go and let the outer metal ring of the balancer spin around it taking the crank out of balance. The oil pressure ran 40psi normally and was running around 10psi when i parked it. The engine ran like it was running on 2 or 3 cylinders and was very rough....but it got me off the interstate and saved me a tow bill. I personally saw the pan off my v6 and it was very easy to see the 2 diaganol breaks in the crank.
02-04-2012, 03:08 PM
#6
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Yep, years ago I remember seeing at 76 or 77 Olds Delta 88 that had a crank broken in half and still running. Poorly and noisy with lots of vibration but it ran. It wasn't until the motor was pulled and disassembled that it was found. You would never believe it to be true until you see it.
02-04-2012, 03:17 PM
#7
Well on mine the rear of the crank moves a 1/8th of an inch or so to the right and left. It also moves in and out. When i grab the flywheel and move it like this the balancer does not move at all. There is no indication that there is a problem oher than a metal on metal noise at idle. Once you rev the motor at all the sound goes away. How is it possible for the rear of the crank to move and not the front?
http://www.youtube.com/watch?v=SsuEo0lr-7E&sns=em
http://www.youtube.com/watch?v=SsuEo0lr-7E&sns=em
Last edited by tording99Z28; 02-04-2012 at 03:24 PM.
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02-04-2012, 03:26 PM
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Well on mine the rear of the crank moves a 1/8th of an inch or so to the right and left. It also moves in and out. When i grab the flywheel and move it like this the balancer does not move at all. There is no indication that there is a problem oher than a metal on metal noise at idle. Once you rev the motor at all the sound goes away. How is it possible for the rear of the crank to move and not the front?
DO NOT run that anymore, take it apart before it wipes out the block/pistons...
Post pictures please. I wish I'd taken pics of the Nissan crank.
02-04-2012, 03:34 PM
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After watching your vid I'm going to guess that your crack will be at #4 main bearing. If you're real lucky all you will need right now is a crank and main bearings.
Take it out and apart please.
Take it out and apart please.
02-04-2012, 03:37 PM
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wow...I guess I was wrong lol. I've seen a couple of broken cranks and they were all pretty bad and wouldn't run, but I guess it makes sense if the break isn't clean that it can still stay connected, like a puzzle piece.
I guess you learn something new everyday.
I can't see how the flywheel would move but not the balancer unless the flywheel was loose, but you said it moves in and out also with the crank.
I have an engine on the stand and the crank is solid...lol....I know I'm not wrong about that one.
I guess you learn something new everyday.
I can't see how the flywheel would move but not the balancer unless the flywheel was loose, but you said it moves in and out also with the crank.
I have an engine on the stand and the crank is solid...lol....I know I'm not wrong about that one.
02-04-2012, 03:48 PM
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"14 psi - 10.26 @ 141.42 w/ 1.70 60' @ FMP : 780 rwhp
20 psi - 1005 rwhp 826 rwtq - track times coming soon "
WOW
Just looked at your sig!
I think you broke that with POWER!
What crank is that?
20 psi - 1005 rwhp 826 rwtq - track times coming soon "
WOW
Just looked at your sig!I think you broke that with POWER!
What crank is that?
02-04-2012, 05:06 PM
#12
It's a callies compstar crank. The funny thing is when it broke i was just cruising on the freeway. No WOT or anything. The last time the car saw any track time where it saw WOT was two months ago. Since then I have only cruised in the car.
02-04-2012, 05:29 PM
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One of the "normal" procedures when rebuilding an engine with a forged crank (OEM stuff is what I have experience with) is some form of crack testing. (Magna-flux, zyglo, others)
It is common to find cracks in what appear to be perfectly good cranks.
I can easily imagine a damaged one working fine for a long time.
Thats what I think happened here.
I still think 1000hp killed it.
It just didn't know it was dead for a while...
Was it reworked or mistreated before this?
I'd contact Callies if it was new when it went in. They might be interested.
A mis-installed crank dies in the first hour.... Not an installation problem IMO.
It is common to find cracks in what appear to be perfectly good cranks.
I can easily imagine a damaged one working fine for a long time.
Thats what I think happened here.
I still think 1000hp killed it.
It just didn't know it was dead for a while...
Was it reworked or mistreated before this?
I'd contact Callies if it was new when it went in. They might be interested.
A mis-installed crank dies in the first hour.... Not an installation problem IMO.
02-04-2012, 06:01 PM
#16
It was a brand new crank from Callies as far as I know. AES assembled the shortblock for me. I already talked to Callies and they said to pull the crank and send it to them and they will check it for a bad casting. The gentleman I talked to at Callies said that it should have taken 1000 HP without breaking no problem. I know there are a few guys making serious power on stock cranks without breaking them. They bend sometimes but I have not seen anybody mention breaking the crank.
I am home now and not on my phone so I will give some more details on how this all went down. This past weekend we had Cars and Coffee about 30 miles from where I live so I drove the car there. The last time I raced the car was the first week of December so it has been 2 months since then. I have driven the car just about every weekend for at least a few miles since then but no WOT. There is no reason to go WOT on the street because there is obviously no traction making 700+ HP so I just cruise in the car for fun because I love driving it. I started the car up last weekend for cars and coffee and everything was great. Took off towards Cars and Coffee and just cruised the whole way with no WOT. Got there and everything was great, no noise, car was running good no issues whatsoever. Cars and Coffee was good with some nice cars and I got a lot of compliments on the car. Once it was over I started her back up and took off towards my house. Again just cruised with no WOT. Everything was again going great until I got off the interstate and came to the first light and stopped. When I stopped and the car idled down to 1000 rpm I then heard a metal on metal bearing sounding noise. I revved it up just bit and the noise went away and then came back when it idled back down. When I got home I then got under the car and grabbed the flywheel and torque converter and they moved. I just figured the flywheel bolts were coming loose. I pulled the tranny and that's when I realized it was the whole crank moving and the flywheel bolts were not loose at all. That's the whole back story on how this all went down. During this whole time the oil pressure was rock solid, 60 psi when cold and about 45 psi warm which is where it has been since day 1.
I am home now and not on my phone so I will give some more details on how this all went down. This past weekend we had Cars and Coffee about 30 miles from where I live so I drove the car there. The last time I raced the car was the first week of December so it has been 2 months since then. I have driven the car just about every weekend for at least a few miles since then but no WOT. There is no reason to go WOT on the street because there is obviously no traction making 700+ HP so I just cruise in the car for fun because I love driving it. I started the car up last weekend for cars and coffee and everything was great. Took off towards Cars and Coffee and just cruised the whole way with no WOT. Got there and everything was great, no noise, car was running good no issues whatsoever. Cars and Coffee was good with some nice cars and I got a lot of compliments on the car. Once it was over I started her back up and took off towards my house. Again just cruised with no WOT. Everything was again going great until I got off the interstate and came to the first light and stopped. When I stopped and the car idled down to 1000 rpm I then heard a metal on metal bearing sounding noise. I revved it up just bit and the noise went away and then came back when it idled back down. When I got home I then got under the car and grabbed the flywheel and torque converter and they moved. I just figured the flywheel bolts were coming loose. I pulled the tranny and that's when I realized it was the whole crank moving and the flywheel bolts were not loose at all. That's the whole back story on how this all went down. During this whole time the oil pressure was rock solid, 60 psi when cold and about 45 psi warm which is where it has been since day 1.
Last edited by tording99Z28; 02-04-2012 at 06:14 PM.
02-05-2012, 01:20 AM
#17
few years ago I stopped up at newera to pick some parts up, and told to check this out, just pulled from a car that was driving around and started making noise. This was a new LS6 shortblock only a few months old. Clean break along the inside of the rear counter weight, no other damage, 7/8 rod were still ok! I use the crank still (v6) 
as mockup for valavtrain, and cams with a some other stock rod/piston.
http://youtu.be/alo_s3mtap4
as mockup for valavtrain, and cams with a some other stock rod/piston. http://youtu.be/alo_s3mtap4
Last edited by studderin; 02-05-2012 at 01:26 AM.
You might want to get a Callies Dragonslayer but they're like a $1000 or more. 