rod knock / well here goes my story
 

i just bought a 1987 n/a supra with a 7m-ge and when i bought it the car was fine, but as soon as i get it to my house the car has a rod knock. would i be fine if i just replace the bearings, im really short on cash now since i just bought a car... i can go get another engine, but how reliable will it be if i just replace the bearings. is there anyone local to seattle, kent, federal way that can help me out i can do alot but i have never worked on a supra before,please please someone help me!!!

stop driving it if its knocking.. your doing more damage
only thing u can do is replace the bearings and head gasket (if u havent done so)

If you have rod knock, most likely your crank would have had some metal removed from it as well.
If you just slap new bearings in there without knowing what clearance you have or should have, then you'll have it again due to improper clearance and being far out of spec.
It cost more to do the same job twice (and later the right way) than to do it the right way from the start.

Also keep in mind that maybe it is possible that it isn't rod know, but a loose crank pulley, or valves....I'm just wondering if you made an accurate assessment.

Harbor Freight sells mechanical stethoscopes for like $4.
I'd first get one from them, then go from there.

im certain the head gasket has been replaced. whats with this crank pulley idea.. is it common? and also if i did find the right bearings would i be fine cuz all im trying to do is make it last long enough since im ready to do an engine swap if it really is that bad. like i said it wasnt knocking until i drove it home and there definatley was oil and the pressure was fine. i took it to my mechanic and he said yeah that sounds exactly what a spun rod bearing sounds like. im really curious about this whole crank pulley thing now.

I'm saying that there are other things that can make noises other than a spun bearing, so just be sure what it is that is making the noise.

In order to get the right sized bearings, your crank would have to be mic'ed and it would need to be smooth as well. After being beaten with a rod, I doubt it would still be as smooth as it needs to be.

Already told you to get a stethoscope and make certain of what your problem is, before you go ahead and take it all apart.


People that think that you can just swap bearings and you'll be fine don't take in consideration that oil clearances are very precise, that the crank needs to be very smooth, and that the rod may possibly have taken a beaten as well.

Rod knock (if that is your deal) is a big problem in terms of its fix.
Getting another engine is often the best fix.

k so its not the pulley and its definatley something inside, ive talked to a toyota specialist and he says hes heard this sound before and it sounds like a wrist pin problem. then i went on youtube and it sounds just like it, the diagnosis is to take the SP wires out one by one to see if it stops, and if it does than you have dodged the poisonous snake. wish me luck, i have another engine on the way also just in case and if the car is fine then i will build on it. I cant just let this thing go its a top of the line car and im not going back to honda for the life of me!!!!

srzsmack
 

Tony gave you good advice. Regarding the crank pulley. I have an '87 MKIII, n/a. I have replaced the crank pulley three times in less than 150K miles. I bought the Supra with 38K miles. The the first time I bought a new pulley and bolt and had to run a tap into the crank to repair thread damage. Red Loctite was used on the bolt threads and properly torqued. It came lose again and agaim the third time I had to have the front of the crank welded and grounded down..

I wished I had a clue why all the trouble? The sound with a loose pulley is like the sound of a rod knock or even a cracked crank.

If you do not have one you need buy Toyota Supra Repair Manual. I am not sure if the TSRM calls for Loctite or a thread lock on the bolt or not.

Be sure and refer to all torque specs when performing service. If you over tighen you could easily end up with broken bolt. Then you have more truoble.

Good luck .

Dan Swanson

yeah is there a test to determine if it is the pulley or not? cuz ive had cars with rod knock before...

srzsmaack
 

Not a test per se. You need to inspect the pulley and check the bolt to see it is loose.

Due tihe knocking sound you may have damage the pulley and the crank, due a good visual inspection to determine exactly what you need to do to correct the problem. Upon on re-assembly be sure and properly TORQUE the bolt to 195 ft lbs per TRSM manual. Use red Loctie or an equivalent strenth thread locker.

The first time I had a problem the crank pulley ( harmonic balancer) was so loose it through the belts and heated up and I had water spraying on the windshield.

This happend while driving on the interstate at metro speeds. I was able to tighten it back up. And continued my trip at low rpm's and stopped at a dealershio and orded a balancer and bolt. However the old bolt danaaged the threads in the crank. I was able to chase the threads with an 18MM tap.

Good Luck, if I can be more assistance, just ask.

Dan Swanson