quick question, possible rodknock issue.

[buldozr]

Hi guys, possible rod knock issue, I havnt been able to fully diagnose the supra and I wanted to see if their was any way to diag without pulling the pan. Unfortunately I live in an apartment now and the management would have a fit if I had the car up on jackstands(they have already threatened to tow it once...). Anyways, I hear a faint metal to metal sound intermittently at idle or off idle RPM, it comes and goes. Oil pressure seems normal but its a stock guage, I guess I need to drain the oil, check for flake first. This sucks, Its my DD! I knew I shouldnt have sold the Rustang. Any suggestions would be great guys.

 

[86_sports_1jz]

check the oil dip stick for shaving, you should see it sparkling in the light.

 

[buldozr]

I bet she is showing copper by now, I should be able to see it, good thinking. I wonder If I could get by with dropping the pan and swapping some bearings... I hate apartments. I will probably have to park it and buy a hooptie to get me by or maybe a wrecked supra with a good motor?

 

[staticpat]

Get an auto stethascope (sp?) or as mentioned drain or look at the oil for shavings. With the stethascope you can hone in on the noise location.

Don't get too hasty on declaring rodknock, both times I've had it I knew the cause (oil starvation from revving or low oil.) Is the sound at engine speed or half speed? Also rodknock seems to be loudest in a certain rpm range under load. I don't remeber the range offhand.

 

[buldozr]

the sound comes in at about 650 to 1200 rpm, I just checked the oil while I was at lunch, looks clean as a whistle, I didnt notice any glitter either. Maybe I am just paranoid. I am going to check the motor mounts before I do anything at this point and cross my fingers. If it is the bottom end, I am for sure going to have to get a puddle jumper.

 

[buldozr]

FOUND IT! The crank pulley bolt was LOOSE! I pulled the fan to get clearance, I found that the bolt has been replaced with a motormite bolt... Someone has been in that motor. I put the car in fourth gear and had someone stand on the brakes while I cranked down, my clutch was slipping before I could get enough torque on it for spec Im sure(used a 1-1/2 foot cheater bar instead of my torque wrench, but it was no where near over 120lb/ft before the clutch slipped) I hope I didnt damage the key way, but I think I cought it in time. I knew things didnt add up due to when I put the engine under a load it quieted down instead of got louder. I hope this helps anyone in the future, Learn from my mistakes!

 

[james_9876]

Never heard of a crank pulley knocking, usually they just fall off.

I just got my motor half-donkey running ( unless spraying starting fluid down it's throat (big fuel leak )) And I have a 'rod knock' at the same RPMs. I keep hearing it from my turbo though... I gotta let it build up some oil pressure after I fix the fuel leak ( pesky cold injector line).

cliff notes:

rod knock- could be the turbo??

Never heard a crank pulley knocking.

 

[7MGTEsup]

Never heard of a crank pulley knocking, usually they just fall off.

A loose crank dampener can sound very much like rod knock. It rattles as it becomes loose and as its attached to the end of the crank sounds like a knocking bearing.

 

[lppro]

how could i tell if mines loose?

 

[staticpat]

My brothers 3000GT (v6) is down right now because the crank pulley is wobbling like crazy. We just assumed he tore up the bottom end and its walking though. Glad to know it was a simple fix.

 

[supraguy@aol]

Funny- I was about to reply about checking the pulley bolt, as this has happened twice to me, but then I read down and saw you already found it. It sounds worst at low rpm, on starting and shutting down as well. If it's a loose pulley, it'll even screw up your acceleration, and cause a heavy vibration around 3500 rpm when accelerating hard.

 

[buldozr]

yeah, looks like it damaged the front crank seal, I will have to tear into it this weekend, I might do the cam seals while Im at it, quick question, does anyone know the proper way to torque the harmonic balancer bolt, even with it in 4th gear and a buddy standing on the brakes, I was still able to move the car before the clutch started slipping... its kinda got me stumped

 

[billwert]

Glad I found this thread. I need to check the one on my parts car. It has a knocking sound around 3000-3500 rpms or when under hard acceleration from those rpms. Maybe this is my problem instead of rod knock.

 

[lppro]

sooo... how do you check it to see if its loose?

 

[supraguy@aol]

You can start by grabbing the crank pulley on both sides, and try rocking it forward and back, however, the best way is to simply put a 1/2 inch drive socket wrench w/ 19mm(I believe) socket on there, and see if it tightens.
If it is loose, the best way to tighten it enough is to remove the inspection cover on the bottom of the tranny, and block the flywheel from rotating, then tighten down on the pulley. It's really a two man job.

 

[buldozr]

sooo... how do you check it to see if its loose?

grab the bolt by hand and turn... if it turns, its loose, if it doesnt, get a socket on it and torque it, if it turns, its loose. I couldnt believe mine was that loose, it was finger tight, the biggest thing is I hope I didnt damage the keyway on the crank or the woodruff key, I will check it out once I get to swap that front crank seal.

 

[supraguy@aol]

If the pulley can be rotated back and forth, the keyway is prolly damaged.
It CAN be fixed, however. I had a guy mig weld some material into the widened key slot, and then I dremeled the wall vertical again. tight as a bangkok midget.

 

[buldozr]

If the pulley can be rotated back and forth, the keyway is prolly damaged.
It CAN be fixed, however. I had a guy mig weld some material into the widened key slot, and then I dremeled the wall vertical again. tight as a bangkok midget.

Welding a crank is an art. Im saying you have to be a badass to weld a crank and have it hold. Some people are gifted I guess.