So i'm new to the supra community. I just bought an 87 turbo and upon first starting it up there was immediately a knocking sound. I was with my friend's dad at the time and his friend who was convinced it was rod knock. I felt otherwise because the sound was not there when I heard the engine start up a couple weeks ago, which was the last time it had been started. I feel like that's a little quick for a rod knock to suddenly emerge with such ferocity. I pulled the spark wires one at a time to try and determine which cylinder it was coming from if it was indeed rod knock. The sound never stopped. I tried using a stethoscope but I'm not fluent enough in enginese to know where its coming from. I did notice however that the drive belt going to the alternator has about a 3/4 inch piece of the grooved side missing that is actually hanging off a little. Meaning the belt is still in once piece but if you look at the underside of it the grooves are kind of peeled away. The other strange thing is that one of the belts was squeaking VERY loudly when I heard the engine before I bought the car and then once I trailered it home and started it up the squeaking was gone but the knocking was there. I'm not sure if it's possible for a belt to sound like a rod knock. For some information on the sound it doesn't get louder as you increase RPM but the sound gets faster. Anyway i'm looking for any information i can get. I'm at a loss. :aigo: Thanks.
Knock - not rod knock!?
- Thread starter sm00p
- Start date
have you fixed the recall on the 7m yet ? if not you can pull the head off and oil pan take a peek if it is like a rolling or scrapping noise it may be your flex plate bolts at the back of the crank i had my flex plate shoot off on my mkii and the bolts shot throught the bell housing like bullets and when you took turns hard you can hear the pieces rattling in there.
No flex plate in a 5 speed Evil...
Here is another thing you can do, my machinist told me this when my NA threw a rod bearing...
Pull the head off... Put a socket wrench on the crank pully bolt and rotate the motor... As the #1 piston reaches top dead center, slowly rotate the motor a teeny tiny bit till the piston is JUST about to make its downward stroke... Before it moves, take a rubber mallet or the end of a hammer and tap the top of the piston... If the piston drops, then the bearing is gone, and thats the source of your rod knock... Do that with every piston, you should notice it, its quite obvious... When I did it to my NA, the #4 piston dropped 1/4 inch, none of the other ones moved... And sure enough, that was the bad one... Just when you tap your piston, use something soft, like rubber or plastic, dont use metal and pound your piston, lol... We dont wanna damage the surface, just tap it and see if it moves... Wont take alot of force, just a little tap...
Good luck...
Here is another thing you can do, my machinist told me this when my NA threw a rod bearing...
Pull the head off... Put a socket wrench on the crank pully bolt and rotate the motor... As the #1 piston reaches top dead center, slowly rotate the motor a teeny tiny bit till the piston is JUST about to make its downward stroke... Before it moves, take a rubber mallet or the end of a hammer and tap the top of the piston... If the piston drops, then the bearing is gone, and thats the source of your rod knock... Do that with every piston, you should notice it, its quite obvious... When I did it to my NA, the #4 piston dropped 1/4 inch, none of the other ones moved... And sure enough, that was the bad one... Just when you tap your piston, use something soft, like rubber or plastic, dont use metal and pound your piston, lol... We dont wanna damage the surface, just tap it and see if it moves... Wont take alot of force, just a little tap...
Good luck...
My vote is for a bad crank keyway, which would cause the crank pulley to wobble ever so slightly and throw the drive belt off alignment, causing it's slow destruction.
Pull crank pulley and see what's going on down there.
Pull crank pulley and see what's going on down there.
YIKES! Good call Tanya... That just reminded me of something...
When those clowns put my NA back together, they didnt use thread lock on my crank pully bolt, and it slung out when I was on the highway doin 70... I pulled over after hearing that bang, and didnt see anything wrong... Crept the car home, and it was making that little rattle noise... It was louder under deceleration, and would stop when I accellerated... I ended up just parking the car... I would go out once or twice a week to start it up and just let it idle... One day I started it and I hear this LOUD knock knock knock, then clunk, whiz, and the car was purring like a kitten... That freaked me out, so I turned off the car and popped the hood... Laying on the ground was my crank pully... Thats when I realized I slung the crank bolt and it had sheared the key... That knocking was the pully whacking back and forth on the key until it finally sheered it off... You might wanna check that...
Im sorry I jumped to teh worst case scenario, lol... It just seams to be that way with these cars sometimes... I guess you should take some cough syrup before you jump straight into surgery, lol...
When those clowns put my NA back together, they didnt use thread lock on my crank pully bolt, and it slung out when I was on the highway doin 70... I pulled over after hearing that bang, and didnt see anything wrong... Crept the car home, and it was making that little rattle noise... It was louder under deceleration, and would stop when I accellerated... I ended up just parking the car... I would go out once or twice a week to start it up and just let it idle... One day I started it and I hear this LOUD knock knock knock, then clunk, whiz, and the car was purring like a kitten... That freaked me out, so I turned off the car and popped the hood... Laying on the ground was my crank pully... Thats when I realized I slung the crank bolt and it had sheared the key... That knocking was the pully whacking back and forth on the key until it finally sheered it off... You might wanna check that...
Im sorry I jumped to teh worst case scenario, lol... It just seams to be that way with these cars sometimes... I guess you should take some cough syrup before you jump straight into surgery, lol...
heh, I know how it is. I started off 2006 with this same scenario, only car started skipping timing so badly, it stopped running altogther. Crank snout, crank pulley and timing pulley were all ate up from the keyways. Had to buy a remanned crank and install that.
In April, the morning we moved to South Carolina, the engine decided OUT OF THE BLUE to piss some serious oil, but we were all ready to move so we just stopped every 75-100 miles to put 2-3 qts in the bastard. That was a 600+ mile trip, lol
Then after clocking another 900 miles moving to NY and another 2000 miles just putting around up here, we blow the head gasket. Due to not having ANY funds whatsoever, had to drive it like that. Finally got the HG fixed, 2 weeks later #6 con rod snaps in half.
Here's hoping for a new year with non blown up engines :x
In April, the morning we moved to South Carolina, the engine decided OUT OF THE BLUE to piss some serious oil, but we were all ready to move so we just stopped every 75-100 miles to put 2-3 qts in the bastard. That was a 600+ mile trip, lol
Then after clocking another 900 miles moving to NY and another 2000 miles just putting around up here, we blow the head gasket. Due to not having ANY funds whatsoever, had to drive it like that. Finally got the HG fixed, 2 weeks later #6 con rod snaps in half.
Here's hoping for a new year with non blown up engines :x
I'll check the keyway on my next break from school. I would do it now but I have to get a puller and I'm going back to school tomorrow. Is there any chance that you can have rod knock even without combustion in the cylinder that has the knocking rod. And if it's piston slap would i have to get the cylinders bored and then get oversized pistons or am I better off just buying a new block.
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Sure, you can have rod knock on TWO cylinders, in which case pulling the spark for a single cylinder won't stop it.
So knocking noise on idle that goes away with higher rpms, should check crank pulley on an auto?
SOOOOO...I started this post a while ago. Let me update everything. I pulled the motor, which took forever. The worst part was working at night only to find that I need a tool or something that I had to get from a store that was no longer open. Then I would wake up at like noon, non get out of the house until 2ish, get what I needed and work at something for like 5 hours. I'd advance....and would have to go back to the store. Anyway, all complications aside the engine came out. I tore it apart. Got to the oil pan and took that off. Tried nudging all the rods around. The rod in cylinder 6 was having a party banging off of everything. Tried taking the crank off, started by taking the rod caps off. They weren't coming off. I also couldn't turn the crank. I tried doing that by pushing on the pistons. WOAH, rod knock on 2 more cylinders. So i got frustrated and was like screw this the machine shop can dissasemble the damned thing...everything was going there anyway. So they do their thing. The guy calls me back and this is the damage.
The crank is basically screwed. It has to be sent out to be cut. That, with all the bearings runs about 350. Then he tells me he needs to repair all of the rods, cause they too are garbage. He can't repair one of them so he has to buy another. All of that with the new rod is 195. ::breathe:: The pistons were banging around so bad that one of them was actually hitting the head. The damage was minimal though. Head and block are getting machined. Thats about 185 total I think. Cleaning everything is 60. Honing the cylinders is 90. Ummmm...I feel like theres more but I can't really remember. My thoughts are at least all of this stuff is salvageable. Except that one rod ha.
As far as replacing parts, I'm getting a new water pump, thermostat(don't want this piece of a car overheating anytime soon), clutch kit(figured I should since the engine is out anyway), piston rings, and a complete engine gasket kit. For now the engine is going back together like this. Hopefully it will last. With my luck and the way things have gone i'm gonna get this running and everything is gonna be wonderfull....then the turbo will blow in about a month. Moral of the story is...DON'T LET YOUR CAR OVERHEAT. And be wary of buying cars that have overheated(this is what I did). I'm trying to get about 500 dollars out of this guy that sold it to me to pay for the crank stuff. I knew I would be paying to fix a "blown head gasket". Which, by the way, did not look blown at all. My mechanic thinks that the head warped due to overheating which allowed coolant to flow free willingly throughout the gasket, ultimately finding its way into the crank case and screwing everything up from there.
The crank is basically screwed. It has to be sent out to be cut. That, with all the bearings runs about 350. Then he tells me he needs to repair all of the rods, cause they too are garbage. He can't repair one of them so he has to buy another. All of that with the new rod is 195. ::breathe:: The pistons were banging around so bad that one of them was actually hitting the head. The damage was minimal though. Head and block are getting machined. Thats about 185 total I think. Cleaning everything is 60. Honing the cylinders is 90. Ummmm...I feel like theres more but I can't really remember. My thoughts are at least all of this stuff is salvageable. Except that one rod ha.
As far as replacing parts, I'm getting a new water pump, thermostat(don't want this piece of a car overheating anytime soon), clutch kit(figured I should since the engine is out anyway), piston rings, and a complete engine gasket kit. For now the engine is going back together like this. Hopefully it will last. With my luck and the way things have gone i'm gonna get this running and everything is gonna be wonderfull....then the turbo will blow in about a month. Moral of the story is...DON'T LET YOUR CAR OVERHEAT. And be wary of buying cars that have overheated(this is what I did). I'm trying to get about 500 dollars out of this guy that sold it to me to pay for the crank stuff. I knew I would be paying to fix a "blown head gasket". Which, by the way, did not look blown at all. My mechanic thinks that the head warped due to overheating which allowed coolant to flow free willingly throughout the gasket, ultimately finding its way into the crank case and screwing everything up from there.