98 4Runner tick/knock advise needed

Sounds like valvetrain... More like a rattle than anything. Not really a knock.

Any chance a valve isn't closing fully? I know you checked clearance, but maybe a worn valve guide. I guess you would have spotted that though.
 
Having had the valve covers off twice now, it takes me less than an hour to get both them off and a little less to get them back on. A special tool is required to depress the valve to get the shims out.
 
echo4tango said:
If you have a knock at idle and it goes away with more RPM thats exatly what piston slap sounds like
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I think your right. I unbolted the torque converter and removed all the drive belts and I still had the noise. That pretty much eliminates everything except for something deep inside the motor. I'm gonna have to pull the motor and rebuild it or find a good used motor to install. I'm a little bummed, but that's the chance I took when I bought it.:dammit:
 
NTORACN said:
I think your right. I unbolted the torque converter and removed all the drive belts and I still had the noise. That pretty much eliminates everything except for something deep inside the motor. I'm gonna have to pull the motor and rebuild it or find a good used motor to install. I'm a little bummed, but that's the chance I took when I bought it.:dammit:
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I've never torn into a 3.4 before, but can you pull the heads, and then just unbolt the rod caps and push them out the top? Without having to pull the whole engine or unbolt it from the transmission, etc.

I guess you still run the risk of the problem being a cylinder, and not a piston.
 
quicksilvr said:
I've never torn into a 3.4 before, but can you pull the heads, and then just unbolt the rod caps and push them out the top? Without having to pull the whole engine or unbolt it from the transmission, etc.

I guess you still run the risk of the problem being a cylinder, and not a piston.
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Having a 25'X50' shop at my house allows me to take the extra tyime to do it right. I will pull the whole thing and take it apart and send it to the machine shop. If I do it this way and not a used engine, I want to do it once.
 
NTORACN said:
Having a 25'X50' shop at my house allows me to take the extra tyime to do it right. I will pull the whole thing and take it apart and send it to the machine shop. If I do it this way and not a used engine, I want to do it once.
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Good man! Glad to hear it. Hope you have good success, and post up pictures of any interesting finds.
 
NTORACN, Have you tried any B.G. products? It sounds like it could be a lifter noise, after reading all these posts. B.G. has some oil aditives that really do work to unstick the lifters. Also, you might want to remove the valve covers and inspect each cam lobe. You could also have a wiped cam. Good luck!!
 
opie188 said:
NTORACN, Have you tried any B.G. products? It sounds like it could be a lifter noise, after reading all these posts. B.G. has some oil aditives that really do work to unstick the lifters. Also, you might want to remove the valve covers and inspect each cam lobe. You could also have a wiped cam. Good luck!!
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Thanks for the reply. I had the valve covers off twice and I inspected ALL cam lobes both times and took both exhaust cams out to verify that the cam gear clock spring was tensioned properly. I pulled the lifters and adjusting shims out and inspected them and they were fine.

My son and I pulled the motor out today and I'm hoping to blast it apart tomorrow to finally find once and for all what the noise is. I'm thinking its a bad wrist pin. We shall see. I'll let you guys know what I find.
 
If you feel up to it, I'd suggest taking pics during the dis-assembly. The members might like to see the 5VZ-FE as it comes apart.
 
Update

Well its completely apart. Its a complex little motor with alot of nice pieces. This motor rebuild would NOT be for a beginner. The good news is I found someone had installed two new cylinder heads. The bores still had the factory crosshatch patern through all/most of the bores and there is no ridge. The crank and bearings looked good as did the rods. The bad news is, when it overheated, it scuffed two pistons pretty bad. There are also some "hot spots" on the cylinder walls.

I need to get the stuff to a machine shop for cleaning and inspection. I will then have to weigh my options on what I'm gonna do.

I took some pictures during the tear down, mostly for hose and wiring routing. I may try to document the assemble, since most parts will be cleaner than coming apart and I won't foul up my digi camera. More to come.
 
NTORACN said:
Well its completely apart. Its a complex little motor with alot of nice pieces. This motor rebuild would NOT be for a beginner. The good news is I found someone had installed two new cylinder heads. The bores still had the factory crosshatch patern through all/most of the bores and there is no ridge. The crank and bearings looked good as did the rods. The bad news is, when it overheated, it scuffed two pistons pretty bad. There are also some "hot spots" on the cylinder walls.

I need to get the stuff to a machine shop for cleaning and inspection. I will then have to weigh my options on what I'm gonna do.

I took some pictures during the tear down, mostly for hose and wiring routing. I may try to document the assemble, since most parts will be cleaner than coming apart and I won't foul up my digi camera. More to come.
Click to expand...


Glad you found the issue, too bad it ended up requiring a complete tear down. ALthough if you got to do it with your son, that's good time spent.

I hear ya on the dirty hands/digital camera thing! I like take pictures of stuff while I work too, but sometimes it's not worth cleaning the hands up for! lol


I know it's hard to tell without having the bores mic'd yet, but I would hope that you could just replace the bad pistons, and re-hone the bores. After the bores get checked, you'll know for sure I suppose. Good luck with the rebuild!
 
pics

The worst of 3 scuffed pistons.
badpiston-1.jpg~original

The bore
bore.jpg~original


The short block
shortblock.jpg~original


I'll let you know what the machine shop says.
 
the thread of nightmares.......this thread makes me paranoid and uncomfortable,
i hope it all works out for you on the cheap and things go as smoothly as possible, good luck man!
 
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