what i thought was crank walk, you wont believe.. pics

[sepulchral]

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i guess this is a result of crank walk, this happened and i didnt drive the car at all, my block appears fine and only a bearing was scuffed up..

do i have to take my block in for machining??

this was a 2.3l 4g64 crank, dang..


so im rebuilding the bottom end, can anyone find me torque specs for all botom end parts and PLEASE CAN SOMONE TELL ME HOW TO TIME THE MOTOR (THE HEAD WITH PISTONS AT BTDC OR W/E)

thanks

 

[sepulchral]

hello?

 

[Doug99RS]

If you don't have a service or chilton manual then you need to go get one. It will cover all the questions you just asked answers for.
Doug

 

[kengsx]

I think you have bigger fish to fry then timing the motor. Crankshaft failures, like yours, are typically due to fatigue crack initiation at the #4 rod or main journal, specifically at the radius between the machined journal transition to the as-forged throw. You'll see a multi-origin fracture which is many points that the cracking starts, until it can't support the load and fails completely. What's the history of this crank? Is this for your '95? So it would be a non-nitrided 7-bolt most likely from a spyder. Did you run a solid, non-damped crank pulley, and what kind of rpms did you pull? Tell us about the setup. Actually, your question about timing the motor (your all caps makes you sound kind of concerned of your own work), this begs the question what did you do the first time around?

 

[sepulchral]

i bought this car a a few weeks ago, and then this happens, its a talon tsi awd bored out with 4g64 crank etc.. rev limit was a normal 7k rpms it broke when i hit rev limiter.

 

[99gst_racer]

I too am curious about the crank. What is it's origin? 6-bolt or 7-bolt?

 

[sepulchral]

6...........................

 

[kengsx]

There's still a lot of questions on the table that need answered. Are the bearings oversized/was the crank cut at all? You say it's a 4g64 6-bolt crank, well those were not as common as the g4cs (mid '90 galants vs early '90 hyundais). Are you saying 4g64 because you know exactly what you have or are you generically calling it that?

What did the previous owner tell you about this? I'd be pretty pissed about this if I bought 2 weeks ago, unless you are willing to share the blame on what happened. Did he build it, some shade tree shop, or a reputable DSM shop? What rods? What kind of boost/compression ratio? Nitrous? I mean, people have broken these cranks before, but typically they are making some real power, or else there is a major defect with yours (that end of the crank is apparently the most susceptible).

OEM crank pulley or un-orthodox undamped pulley?

Your fracture has one major difference than the others I've seen. It has more of a 3 dimensional fracture surface, i.e. torsional bending component versus pure bending. This means it was loaded differently than the common failures. Which bearing has damage, you didn't say? [correction on my last post, I meant to say I've seen the #5 main journal and more commonly the #4 rod journal break]

 

[sepulchral]

the last main bearing was stripped a little, probably from when it broke, it is a 4g64 CRANK. the guy who sold it to me built it himself.. the car has.. had over 400awhp and i smelled the clutch burnign prior to the breaking... the motor lookd completely fine...no scratches, nothing of the sort.. i was really surprised.
\

does anyone have the torque specs for bottom ends on these motors??

 

[Turbocharged]

the last main bearing was stripped a little, probably from when it broke, it is a 4g64 CRANK. the guy who sold it to me built it himself.. the car has.. had over 400awhp and i smelled the clutch burnign prior to the breaking... the motor lookd completely fine...no scratches, nothing of the sort.. i was really surprised.
\

does anyone have the torque specs for bottom ends on these motors??

I wonder if this falls under the lemon law. Probably not but its worth a shot since you only had the car for 2 weeks.

This failure was not a result of crankwalk. Crankwalk is failure of the thrust bearing. Were you seeing a lot of knock when this happened? Are you sure the car was tuned correctly?

Your bottom end torque specs will depend on what hardware and parts were used. We need to know a little more about the motor (ARP main studs and rod bolts?).

 

[Doug99RS]

I wonder if this falls under the lemon law. Probably not but its worth a shot since you only had the car for 2 weeks.

Lemon law only applies to new vehicles and is only an option within a set amount of time from purchase (2 years I beleive).
Doug

 

[mavisky]

I've seen alot of the 4g64 2.4 hyundai cranks fail in this exact manner. They're simply not as tough as the comparable dsm crankshafts. Stick with a true mitsubishi 4g64 crank and you'll have better luck from what I've seen.