Inconsistant KNOCK

[hottscennessey]

Hey guys,
I took my car out for the first pull yesterday with my new alcohol injection, it felt pretty nice and smooth. I get back to my house and the car is idling pretty well, and then i hear clank. Clank, and a few seconds later, Clank. within the next couple minutes i hear clank clank clank (repeated). This knock went on for about ten seconds, and is only at idle. I think i can hear a difference in my exhaust, but i cant physically hear it knocking all the time. this is only at idle. This doesnt sound like anything I know about knock, but I'm pretty possitive it is. Its not bad at all yet, i must have just spun a bearing, i dont think i bent a rod? Anyways, this is really werid to me, I had just checked my oil and thrown in a little extra to be safe like 3 hours before. No huge oil leaks or anything... Pretty much I just want to know if this inconsistant knock is normal.

 

[lagged]

throw out bearing?

 

[hottscennessey]

ya know what.. it almost sounded like it could be a tranny problem. Thats true. How do i test it?

 

[estrellainc]

imo-
disconnect the v-belts 1st. see if it goes away.
(mine did it just like that because of the power steering pump)

2, check the oil for shavings-
if not-
your gonna have to get a stethoscope, or a large screwdriver and place it on the oilpan and listen for the knock against ur ear.
move around to various parts too like the valvecovers.
if the supra is cold, you should have plenty of time before it warms up.

and also there is a thread on this cuz theres alot of this goin around.
search for rodknock.
hope it helps!

 

[92SupraMan]

I had a loose cam gear that sounded like rod knock....

 

[92turbo4life]

ive heard of people leaving tools in there too

 

[xarewhyayen]

if you spun a bearing you wouldnt have oil pressure... when you spin a bearing, the holes in the bearings designed to transport oil to the bearing would be moved from their intended location, therefore blocked, killing oil pressure. Hows your pressure?

 

[gixxer750]

spinning a bearing doesn't affect your oil pressure that much. You stick the bearing to the crank usually. The holes are not lined up anymore, therefore that bearing gets no oil, and the wrist pin doesn't get oil from the hole in the rod anymore. BUT, that doesn't affect total overall pressure, just pressure to that bearing.

 

[xarewhyayen]

but doesnt the oil follow a path that starts at the first main and ends at the last? i thought it interweaved through the whole system.. so if one is blocked it compromised the rest.. guess im wrong but i dont know. i thought thats what i learned

 

[92turbo4life]

tru my knock didnt effect mi!ne one bit

 

[shaeff]

to check for rodknock:

pull plug wire #1, start car, still hear the noise? shut off car, plug it back in. do the same for the rest of them, pulling one at a time. if the noise doesn't go away, then it's not rodknock.

if it does when you pull one of the wires, that's the cylander you have knock in.

don't zap yourself, it hurts like a biatch!

-shaeff

 

[92turbo4life]

lmao i learned the hard way.

ok start the zaaaaaaaaaaaaaaaaaaaaaaaaaap owwwwwwwwwwwwww

 

[jetjock]

Again, a note of caution. Any time you open circuit a secondary ignition and allow it to fire the voltage will rise to the highest level possible. (That's why it stings so much Shaeff ). This can arc over the secondary windings or destroy the diodes in the GTE's coil packs. Even if this doesn't happen they'll be weakened. Either ground the plug wire or buy a spark plug simulator. They're very cheap.

For an inexpensive stethoscope that works very well see here:

http://tinyurl.com/zgtcl

Unscrew the probe and you can also use it to spy on your neighbors

 

[hottscennessey]

thanks for all the responses guys... I'm so confused. I started the car up today and was ready to get crackin' pullin the motor. No knock. I listened for 30 minutes. Of course before that i was tinkering with the injector clips and plugs. I've been driving my car all day with no signs of knock. I've been taking precautions, but everything seems perfect. I was so possitive it was knock. I'm going to drain the oil and make sure later, but I have oil pressure, and nothing seems weird? I even went to a machine shop and they said that knock is too much of a mechanical thing for it to come and go like that. They were pretty possitive it wasnt knock. I dont understand what it could be. I'm scared to find out.

 

[supra90turbo]

lmao @ "spy on the neighbors"
that's hilarious..

 

[shaeff]

jetjock, i learned at a young age. (well, i'm only 22 now, but when i was about 10, i thought i'd play games with my dad while he was working on his '70 chevelle, and pull a plug wire to make him think it was running badly.

heh, joke was on me.

-shaeff

 

[92turbo4life]

lmao shaeff!

 

[IJ.]

I prefer to pull injector clips.

 

[shaeff]

i prefer ianburgers for dinner.

-shaeff

 

[IJ.]

One of my Tuners was telling me about the time he got a belt from a CDI on the dyno when the car was revving hard on a power run!

They said it knocked him out cold on the floor and the run had to abort while they made sure he wasn't dead!