Experts - take a look at this bearing
- Thread starter Supraholics
- Start date
The scratches are actually very light. It looks like to me as if the crank journals are resting more on one side than the other. I did figure out where the scratches came from.
If the mains are true to the block and there was no debris under the bearing, then its probably a crank journal with a touch of taper. Thats assuming this is a main bearing. If its a rod bearing, it could also be a bad rod.
Could it have been cause by blocked oiling holes on the crank? I saw this once before on a motor I parted out and am just curious
supraguy@aol;1934167 said:
SupraPieces;1934283 said:
The oil filter proved that the machine shop did NOT clean the crank properly and there was debris (metal shavings) inside the crank. I made the rookie mistake of trusting the shop and installed the crank with minimal cleaning.
Besides microscopic dust, there was absolutely no debris under the bearings. I'm a very thorough individual and I measured everything w/ plastigauges 3 times. Everything was torqued properly and my Snap-On torque wrench cost me $575, so I'm assuming that was good and properly calibrated. I also checked torque specs while removing the bolts and it was consistent throughout. That tells me that it was not an improperly torqued rod or main cap.
I'm leaning towards what Suprapieces has suggested that the metal shavings in the crank clogged the oil hole and once released, it scratched the bearing. Another pointer here is that the rod bearings are completely fine from what I recall. Will have to check again.
I'm now concerned about the right side of the bearing bearing being worn out more than the left. I'm not sure if this is a result of what I described above or that the crank journals were not cut properly or the bore on the block is off.
I'm planning on putting new Clevite 77 (NDC) bearings and ARP main studs. The rods already have ARP rod bolts.
This engine is not being built for high HP or racing and in the short life it had it was never redlined. I just want to make sure that it can be reliable and that it would take some abuse if needed.
If anyone had a similar experience with bearings, please let me know what your findings were. I'll try to post a picture of all bearings this weekend. I didn't get to take them all out yet.
you can see alot of trash in the bearing from the specs of crap embedded in it. Other than that, the wear is a little more on the side, Might check your thrust bearing clearances
Supraholics;1934288 said:
The machine shop doesn't clean anything. I have never heard of one that does. You wash the engine with soap and water when done. And you shouldn't turn Toyota crankshafts. I thought that was already covered here. They put a hard coating on it. Turning it removes it. I don't understand by what you mean inside the crank. Shavings in the oil gallery?
Nick M;1934562 said:
Every crank I had done in the past was delivered to me ready to go as told to me by the shop themselves. This one came from a guy who already had it done. Like I said, it was my rookie mistake to trust the labels on the bag and such.
I wasn't aware of what you stated regarding the toyota cranks. I've heard of this with the Mitsubishi cranks, not with toyota cranks; not saying you're wrong, just that I haven't heard of that. Where did you find that info? So, when one if out of specs, it should be replaced with a new one?
And to your last question, yes, the oil galleries in the crank.
Why did it only run for 200 miles? How could you tell u needed to pull it apart again from just scratches on a main bearing? Just curious of what the symptoms were.
Supraholics;1934563 said:
Well, I am a proffessional automotive technician, and I worked at Toyota after college. And I went to their classes and largely didn't learn anything but we got free coffee and donuts.
The TSRM seems to say that grinding/honing crank journals is okay.
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=EM&P=83
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=EM&P=83
The repair manual also says to put 1.7 qts of trans fluid in an A340F after draining a 4Runner, even though nearly 4 comes out. If you want to grind off the hard shell, go right ahead.
Supraholics;1934563 said:
That's what Toyota intended it to be as far as I know.
For example with the head.. they stated to replace it if out of spec.
Now we're in a year where that isn't an option and parts are almost obsolete now and we're left to find alternatives.... unfortunately.
Induction hardening of the crankshafts started in 1988 for Toyota. A quick google search shows it. Just for refrence....
From my research as long as you don't grind past 10 thou you're ok. If you do need to go further undersized then it would be wise to re harden the journals. With only 10 thou you've still got some hardness left. Obviously ideally you'd want a perfect crank. Mine was ground 10 thou
.02mm is the spec for not being round enough. That is way way smaller than 10 or 20 under. The book also says grind and polish (they assume you won't over do it) or throw it away.
From what ive read from peoples experiences and from the results ive seen in person...taking 10 thousands of a crank and putting in some oversized bearings isn't near as important as the proper clearances and clean assembly of the motor.
I don't doubt it weakens the crank a little but c'mon man milbrum was putting down like 1300 HP on a stock crank so I couldn't see taking a little off it (the right way of course) causing problems with average numbers being thrown at it.
I don't doubt it weakens the crank a little but c'mon man milbrum was putting down like 1300 HP on a stock crank so I couldn't see taking a little off it (the right way of course) causing problems with average numbers being thrown at it.