Topic: broken crankshaft???

[82 HiLux]

i was wheeling my truck yesterday, hitting some really steep hill climbs and getting on it pretty hard, but not revving really high, and i noticed a weird noise coming from my engine.  it sounded like everything in the bottom end was slapping around.  although, under acceleration the noise would go away and the truck would drive perfectly normal with just as much power as before.  but when i let off the gas and let the truck engine brake, it would make the horrible vibrating clacking noise.  i talked to my friend who has a lot of experience with engines and he says the crankshaft can crack and the engine will still run normally under acceleration.  i looked this up on the internet and some other people mention the same thing.  my friend also told me that the crank can slap the oil really hard when you put the engine at extreme angles (driving up gnarly hills), similar to smacking your hand with your palm open on water.  the engine is only about 600 miles old.  i just built it and finished breaking it in.  i drove it home almost 70 miles after this noise started and it ran fine and had a ton of power on the freeway, except for the noise when i let off the gas or engine braked down a hill.  i looked at the bearings in the bottom end and they are fine, everything is still torqued down. everything in the valve train is still solid and normal.  the crank was brand new when i put it in the engine.  i bought it from engnbldr.com.  the machine shop told me when i gave it to them that it was weaker than my stock one but it should be fine. 

any ideas?  anybody ever had a broken crankshaft before???

[emsvitil]

I would think a broken crankshaft would be catastrophic............

and it would jam up and come to an abrupt stop.

[82 HiLux [OP]]

yeah me too, but i looked it up on the internet and apparantly if its just cracked the engine will still run...

[79coyotefrg]

i dont know what engblder sells  for a crank but the stock toyota cranks are cast steel,  not cast iron like many engines have

pull the pan and see whats going on before you destroy a good motor

[OOPS]

There is a big difference between a broken crank and a cracked one. Back in my drag racing days we broke a lot of cranks in the top fueler and there was no way it would run. I also broke one in my 55 Chevy and it quit on the spot.

[82 HiLux [OP]]

i took it apart today and checked it out.  the crank i bought was cast iron, i remember the machine shop told me that. im going to pull the tranny off the engine soon and check out the flywheel and clutch, because the clunking sounds like its coming from the back of the crankshaft.  i dont really know what to think at this point, everybody is telling me different things. i just need to take it apart further and inspect everything

[82 HiLux [OP]]

the problem is in the tranny.  when i turn the engine over by hand, i can feel something clunking like it has play.  when you push in the clutch and turn the engine over by hand, its totally normal.  but when the engine is connected to the transmission (foot off the clutch) and you turn it over by hand, you can feel somethings all screwed up.  so tomorrow i will pull the tranny to inspect the damages.

im happy its not my new motor! 

[pumkin toy]

i had a problem with the thrust washers in a 22r i had.  i think there is four thrust washers on the crankshaft that ride up against the side of the very middle main bearing cap. (thats the only way i can describe it!)  my engine ran fine but started to make a bunch of noise. i pulled the oil pan off and all four of those thrust washers worked there way out and were laying in the oil pan!!  i could grab ahold of my crank pulley and move the crankshaft back and forth about 3/16 of an inch!  perhaps your thrust washers are loose and causing the crankshaft to move around.  idk  just a thought!

[kneedownnate]

i dont know what engblder sells  for a crank but the stock toyota cranks are cast steel

Forged 

[WHITE_TRASH]

Not that it matters now but an engine can run with a busted crank...  I've seen 2 separate engines with2 piece cranks.. One ran like a bucket of crap, the other actually ran just fine under a moderate load... 

[DAWGTOY]

x2 on checking the thrust washers. pull the pan & check em out.

[79coyotefrg]

Forged 

i was actually thinking they were forged steel  but  wasnt completely sure, i knew they were for sure STEEL though

[Rocksurfer]

I thought they were making them out of carbon fiber these days. 

[LOL @ IFS]

I thought they were making them out of carbon fiber these days. 

You're thinking of power bands.  You can get them in ti or CF. 

[82 HiLux [OP]]

the flywheel bolts had come loose.  everythings back together now, ill be driving it tomorrow

[LOL @ IFS]

 

Good to hear it's something simple!  Be sure to torque them this time!  lol...

[*ROKTOY*]

And don't forget the lock tite.

[82 HiLux [OP]]

i torqued them before with loctite, but this time i torqued them over the rating i did before, and used a lot of loctite instead of a normal ammount