Anyone replace either rod bearings or mains in the car successfully?

[Bob Avellar]

Injured my newly restored and painted GN on the dyno last Sun. Developed what I believe to be a rod knock. I haven't dropped the base yet but plan to do it Friday. Sounds like rod knock to me and my oil temp went up for a while on the ride home about 20-25 degrees but gradually came down almost to normal. Oil pressure at cruise was maybe 35 instead of the usual 50 -55psi. When cold the noise is not loud (have to strain to hear it at all) but as the oil warms up it knocks louder on and off the gas. Didn't notice the damage till I was already on the highway home so I just took it easy. Anyway, I'm hoping I pounded a bearing/bearings and didn't spin them. I figure if the Red sox actually won the world series I might get lucky and not find any damage to the crank. You got to believe anything is possible. Just wondering if anyone has done this successfully and had it last? I fully understand that pulling the motor and cleaning, machinining is the proper way but I just spent 2 years and $$$ restoring everything else on the car. Only been driving it for 2 weeks. The motor had 150, 000 on a rebuild. Don't think the crank was turned at that time but I will find out when I check the bearings. I figured if it ain't broke-don't fix it. I think my hot oil pressure was still close to 20 psi (normal for my car) when I arrived home with it so I'm hoping the damage is not critical. Looking for some encouragement here guys. I will probably throw out my oil cooler ( its not in the radiator) but I just put all new braided lines to the cooler. I hope to clean them somehow because they are expensive. Funds are depleted for this project and the wife doesn'r even know about it yet

 

[sumnerw]

Bob -

I've replaced both a coupled of times with mixed success. Replacing the rod bearings is easy. Mains are tougher since rotating out the old tops and rotating in the new tops is pretty challenging (unless you onbolt the flex plate from the converter and you have a loose enough timing chain that allows you to lower the crank a bit). Hope your crank looks good!

Good luck,
Buzz White in Houston, TX

 

[onefastgn]

Ive done it to i replaced them all with the motor in.The only problem is that i really should have pulled the motor because the rods really needed to be turned.But i did get a summer time out of it,but if i had the time like this winter i would just pull the motor.If you have a problem now you will only be prolonging the problem and it might screw your crank up like i did.And that was another $375 for a good one.Just my two cents.Good luckAnd boy do i know about the wife thing!!!They just don't understand

 

[Bob Avellar]

Buzz, You said "a couple of times with mixed success" can you fill me in? Did they not last and that is why you did it a couple of times? I have a new timing chain in there with maybe 100 miles worth of driving on it so I may not have much slack. I do have 2 damaged cranks in my cellar. I have never taken them to a machinist to see how much they'd have to be turned though. I think if the crank looks good I will probably just try it on a lift. I don't feel like scratching the new paint,spending $$$ on more gaskets sets. Cylinder wear is minimul and I don't feel I should even bother with rings or cylinder walls so I would not be benefiting from doing a full rebuild. Heads are rebuilt with new valve springs. Ive never blown a head gasket with either motor-each with 150,000 miles. My first motor threw 2 rods out of the block and 1/3 of the cam out of the back of the motor. Counterweights on the crank got dinged but the journals were perfect and the cylinder walls showed basically NO wear. No ridge at the top of the cylinders or anything.. I realize the rod may be out of round if it pounded the bearing. Does the lower half of the rod or the upper half usually get more distorted-or is there no differenc. I was wondering if I could use a lower half from a spare rod???? Don't know about the fit or the balance if I did that? If I found the lower rod cap to be worse than the top could I even do that? I'm just thinking out loud. $$ really isn't there for a full rebuild now. Ik now there is a right way to do things but sometimes people luck out-not me usually. But... The red sox did win the world series,right? That wasn't just a dream I had was it???

 

[Jeff Rand]

I hate to say this but you are most likely wasting your time just changing bearings if any metal when through the oil passages. I have been there and done what you are attempting to do and it is a crap shoot. Your best bet is to pull the motor and determine what went wrong and get it fixed. You will need to flush out all the oil passages including the external oil lines and oil cooler. Pay close attention to the cam and lifters. Might check for a cracked crank.
Good Luck,
Jeff

 

[klrv6]

I got 1.25 miles out of my bearings

I had the same thing happen to me a month or so ago, now I'm building the replacment engine. I had two weeks on second shift so I thought it would be a great time to fix the problem just like you have. I spent almost five somewhat lazy days replacing the bearings just to have them last 1.25 miles. I now have a rod knock for sure in the original engine replacement is on it way with forged goodies and ported stuff. The funny thing is right before I started hearing that very faint bearing noise, I was given the OK by my wife to upgrade the turbo. I am so glad they went before the new turbo went in, not just because of the junk that would have gone through it but the fact that a day after the turbo would have gone in, I bet the bearings would have been screaming. My wife would have put the thing up in the cars for sale section "Free GN to the first sucker who can get it out of my yard"

 

[ttypewhite]

Pull it and freshen it up properly. Your just rolling the dice on bandaiding the situation. It will end up costing you more time and money in the long run.

 

[Bob Avellar]

So basically even if it has 1 bad rod bearing it is a crap shoot that nobody has ever won? Had rod bearings replaced in a F150 once and never had a problem. I know that wasn't seeing the stress like ours do. If that's the case then I guess the car will just collect dust cause I won't be able to afford a rebuild for a long time. I'm entertaining thoughts of just getting rid of it. I bought it new in 86 and I think I might be reaching the end of our relationship. At least I will save money by not haveing to build the garage that I had planned for springtime. Anything else can just sit outside as far as I'm concerned.Thanks for the advice guys.

 

[Red Regal T]

If you have a rod knock, to me that would indicate a spun bearing. If the bearing is spun, the crank is damaged. If you replace the bearings on a damaged crank, it probably won't last for 50 miles.

 

[klrv6]

Slow down Bob

Bob,

As I posted before I did the same thing you are thinking about doing. My reason for a new motor was I didn't want to highly mod the factory engine (heavy porting, forged pistons, bigger cam and alot of the fun parts that go with it. I am building what should be a very nice 109 block that will run just under $2K to complete. I should have just yanked my original engine and had the crank turned & rods redone, removed the heads and go through everything to remove metal shavings and stick it back in. I might have had $450 in the whole thing. I would hate to think that you are getting rid of your 1 owner 86 because of a few bearings.

 

[clemsgn]

take it slow Bob

Hey Bob, it's Clem from New Bedford. It was nice to see you over in Seekonk on Sunday, even though I had to leave early. Very sorry to hear about your misfortune. I didn't have my car there cause I hurt it up at New England Dragway 3 weeks ago. On my way home, my oil pressure was waay low, but I got her home in one piece. Oil pressure was only 22lbs at 65 MPH and 5lbs at idle. I attempted to replace bearings and crank in the car, but my 2 center steel mains were distorted enough, that the crank was binding. If it wasn't for that, it would have gone OK, but it was tough laying on my back for 3 days, only to find out I have to pull it anyway !
First thing you have to do is verify it's really the bearings. Your oil pressure doesn't sound too bad at idle, but it's a bit too low on the highway. If you have access to a lift and have the time, it wouldn't hurt to open her up to take a peak. Hopefully you caught it in time and don't have a cracked main cap. Do you have steel centers ? I found they will bend B-4 breaking, but will then need to be reworked to fit tight in the block and re-line bored/honed etc.
If you're taking a look at it on friday, let me know cause I'm off and I may have a couple minutes to come by. Whatever you do, don't get rid of the car....you spent too much time on it to just throw it all away now, especially since you've had it since new !!!
If you want, call me, but I sleep till around 10 AM or so
508-998-8852

Take care....How bout them Red Sox !!!

 

[Bob Avellar]

Hi Clem,
It was good to see you also and thanks for your offer. I intend to put it up on the lift at school but I won't be able to until the Thanksgiving vacation. The lifts are all full for the next group of kids coming in. It's not my shop (my buddy is the auto teacher-I'm in carpentry). He told me that would be the best time to have a look. I think I might just drain the oil today and maybe pull the oil filter to see what that looks like cause I need to know something. No one has been able to tell me they had much success changing any bearings without pulling the motor so I don't know. The bottom end is all stock. Was rebuilt 150,000 or so miles ago by Manchester Racing Engines and he must have done a good job. I don't think the crank was turned at that time . I think it was just polished-but I won't know until I check the bearing sizes. Nah, I can't sell it. I'd probably just cover it up and hide it away before I'd bring myself to sell it. It's just frustrating to spend 2-2 1/2 yrs restoring it and just when I think all I want is some new wheels/tires to finish it-it starts knocking... I know that there are tons of people with far more frustrating problems with there cars than what I am having but it's still a PIA. I rebuilt an 85 block for my car to replace the first motor that threw 2 rods and the cam out of the motor. I had never done a rebuild before and I took my time and thought I did everything right . I fired it up and it had good oil pressure and drove just like the original motor. After about 4-5 days I went WOT on the highway and it started knocking and oil pressure went away. Took it out and all the main and rod bearing were toast along with a scored crank. I think I screwed it up because I used the oriiginal oil cooler after the rbuild but I'm not sure if that was really the cause. Now I'm scared to touch anything related to bearings! The car was going to be on display along with a pro street Nova, and Ronnie's race car for the open house next Tues but that won't happen now. I'll let you know what I find.

 

[Red Regal T]

It's easy enough to change bearings in the car. The problem is if you have damaged the crank. Also, someone mentioned a cracked main cap.....that's also a possibility. Just pull down the pan and see what's making all the noise. Inside an hour, you'll know whether you have to pull it or not.

 

[Bob Avellar]

Well, I just drained the oil and took out and cut open the filter. The oil from the pan did not seem to have any flakes of metal but you could still tell there was some bearing material in the oil. Particles were extremely small-just enough to be able to tell that something was being suspended in the oil. Sort of like an oil sheen stting on water. However the filter showed larger flakes (aluminum color and non magnetic). Not very big but I have seen that before when I took out the bearings in the motor I rebuilt myself. Nowhere near the quantity that that motor had-but it's obvious that I have some kind of bearing failure. At this point I don't know if it is even worth the effort to bother pulling the pan to have a look. I would guess that I am looking at having to at least turn the crank and maybe resize the rods.. I couldn't deal with rebuilding another motor and having it go away on me in short order.. I guess I will end up pulling it out and taking it to a machine shop to have all new bearings installed and everything clearanced properly. I may take a ride by Bob Borelli's shop to see if he is around . I'll ask him who he uses for a machine shop-I think its in Brockton, Ma. At least the machinist should be familiar with these motors. I don't know what I should do as far as the cam and lifters if I am changing the cam bearings. I have my stock cam in there now as well as a a cam from an 85 motor. I believe they are the same specs? Wouldn't mind a little more cam but that's extra $$.and alot of people think the stock cam is as good as any. I don't even really want to touch the cylinders if it is not necessary. Maybe by next spring I'll be able to drive it again-if my wife doesn't kill me in the meantime. BTW, I cut the AC filter open with a hand can opener witch did not seem to leave any metal particles. I used a powerful magnet in all the drained oil and did not seem to find any magnetic material in there other than a trace amount of powdery type stuff. The amount was extremely small and probably would not cover the thread end of a 3/8" bolt so I'm hoping that the crank damage is not severe. I can only hope. When I do get it out i will surely check for any damage to the caps, rods, etc. How would I be able to tell if any of the caps "walked"?

 

[clemsgn]

Originally posted by Bob Avellar
Hi Clem,
It was good to see you also and thanks for your offer. I intend to put it up on the lift at school but I won't be able to until the Thanksgiving vacation.

I rebuilt an 85 block for my car to replace the first motor that threw 2 rods and the cam out of the motor......After about 4-5 days I went WOT on the highway and it started knocking and oil pressure went away. Took it out and all the main and rod bearing were toast along with a scored crank. I think I screwed it up because I used the oriiginal oil cooler after the rbuild but I'm not sure if that was really the cause........... I'll let you know what I find.

Bob, I don't know if it was the oil cooler, cause any residual crap in the cooler would have to go through the filter 1st B-4 getting back in the engine. If their were enough to clog it, that may have contributed to it. I would think you would have low oil pressure during the first few days even without going WOT, if that were the case.
I don't like to just fix a problem, I want to know why it occured ! As far as the first motor, were the clearances correct to begin with ? Did detonation occur when you went WOT (how much boost/timing/fuel pressure/octane) ? Was your oil pressure guage truly accurate ?
When I had low oil pressure on my way home from the track recently, I knew it had to be bearings cause I was getting a growl in the bottom end under easy accelleration. At the track, I was running 28 - 30 lbs of boost, but I had nothing but 117 octane in the tank, so I didn't think it was detonation. After pulling the pan and girdle, I found the cause....the oil pickup tube (with extension) was not totally tight !! I hope that it gradually loosened on its own, and not because it was never correctly tightened, but I'll never know ? The bolts didn't have loctite on them, but I still wouldn't think they would loosen ? At least I found the cause....I just wish the repair was as easy
If I were you, I'd cut that oil filter open to see if any bearing material is in there....I had lots in mine
Let us know what you find. By the way, how did it do on the dyno?

Take care

 

[Bob Avellar]

On the motor I rebuilt-not this one- I only used plasigauge to check the clearances and everything looked within specs to me. The bearings in the motor were not really that bad and I know I could have left them alone but I figured i'd go through everything and get it done right but.... I honed the cylinders,put new rings in and all new rod and main bearings. I didn't touch the cam bearings. I did not resize the rods or anything like that.That was years ago and I was never able to determine the cause for sure. At that time I had no knock detector but was running around 16-18 lbs boost on 93. It was only one short WOT blast probably about an 1/8 mile that took them out. They looked like they got contaminated with grit or something. Oil pressure gauge was accurate.
Not that I intend to do it but how the heck would you get out the main bearings-especially the upper thrust bearing while the motor was still in the car? I tried to slide the upper thrust bearing in my old block in the cellar without a crank sitting on it and I couldn't move it. There has to be a trick to doing it???

 

[clemsgn]

Originally posted by Bob Avellar
Not that I intend to do it but how the heck would you get out the main bearings-especially the upper thrust bearing while the motor was still in the car? I tried to slide the upper thrust bearing in my old block in the cellar without a crank sitting on it and I couldn't move it. There has to be a trick to doing it???

The first thing to do is carefully check the pan for any bearing chips or particals. If there's hardly any, then you may not need to pull the front cover off to clean the oil pump cavities. If there's quite a bit, then I would pull it to flush it out and the passage from the pickup in the block. Remove the pickup and clean the screen well.
If you don't find much debris in the pan, and you don't pull the front cover, the best way is to remove the 3 converter to flywheel bolts. Then take all the main caps off except just loosen the rear one so the crank can drop a bit. The upper mains should be able to spin out with a small screwdriver. The thrust bearing will need a cotter pin inserted into an oil hole in the crank. Bend the ends of it so it lays flat on the bearing journal of the crank and carefully spin it to force the upper out. Make sure you spin the correct way so the tang in the bearing is the first to come out and the last to go back in. Going back in can be tough to get started. Need to have crank in position with cotter pin on opposite side of tang in block (I think drivers side?) then put upper bearing in lower main cap loosely. Install main cap, but don't fully tighten it to allow a bit of play (10 thousandths) . Slowly turn crank to force bearing to upper saddle. You may be able to get the upper in by just holding it against the crank while turning, but it usually wants to lift and go crooked. This takes patience, but it can be done. Sometimes you have to file the leading edge of the backside of the bearing just to have a small bevel to help guide it in.
If you had to pull the front cover, you could always remove the timing chain to allow the crank to just hang by the connecting rods. This would give you plenty of clearance to get at all the bearings. Remember, all this is assuming the crank looks ok anyway. If you have any doubt that the crank may be out of spec due to scores etc, I would pull it out and have it checked. Also make sure the main caps (especially the 2 centers) fit tight in the block...if they're loose, you may as well pull the engine at that point
One more thing is, I don't always trust plastigage ! I had some for clearances of .001 - .003 and another for .002 - .006. When I put both on a journal side by side, thay gave totaly different readings. The .001 -.003 showed .0025 and the other showed .0035 !! I would suggest an accurate micrometer every time !!

Good luck and keep us posted

 

[Bob Avellar]

Oh yea, that cotter pin trick sounds familiiar. I would not use plastigauge again either. How should I check the condition of the crank and rod journals with a micrometer if it looks ok? Might they be out of round? I asume I would mic it in different places side to side and at various degrees around the journal? Is there a max variation that is acceptable? Any good way to check the rod ends like with or without bearings in them? I don't know what kind of particles might be left in the bottom of the oil pan but the particles were extremely small when I drained that. The biggest particles (flakes) were in the filter. If I do end up trying it in the car I would pull the front cover, toss the oil cooler and replace it,flush out the braided oil cooler lines, take off the turbo and oil feed line and flush them out. and maybe try to flush out the oil passages in the block somehow but I don't know how. By the time I do all that I probably should just pull the motor If the center caps are loose how can that be fixed?

 

[Pronto]

Bob, I think that popping did you in. It sounded pretty strong. Maybe you might try to find a block and have it rebuilt while this is still somewhat driveable. Then you could do it right. Even if you do the fix with the engine in the car you will always be worrying if something is going to let go. I know you don't want to scratch that paint (it's gorgious) but if you put a bunch of blankets around the fenders you should be ok. That's what I did on my old T/A.

 

[Blown&Injected]

not a bad job at all to change the bearings - I had so much junk that I could not get out that it just took out the new bearings and the crank - maybe just a little bearing material might not be an issue - I also had a cam wiping adding to the metal in the motor.