Got the motor in.

[jory]

Sent the crank out of my good parts engine to the machine shop and had then check it and polish it. Then I pulled the motor out of my car again and took the crank out, and plastigauged every bearing. They are all within spec except for rod #1, the clearance is too tight and when it is torqued the crank doesn't spin. So am I looking at a rod replacement too? I gave up early today after finding that out, and when I was pulling the car back outside a wheel bearing busted.. just my luck! This project didn't turn out as well as I was hoping.

[Ondonti]

Quote:

Originally Posted by Reaper1 Actually I had a rod bearing seize an engine. My 'Baron's origional motor did that. I was on my way to the parts store to get the parts to fix the oil leak...it ran low on oil on the way there on the highway...spun the bearing...kept running 'till I got off the highway and as soon as there was no load on it, the engine seized. It was spun so bad that it wrapped itself around to the other side of the crank journal so the two bearing halves were on top of each other(yeah, they were thin too), and they got so hot they fused together. Later when it cooled down it was able to spin over and run, but OMG did it make a racket!!! LOL

Yeah, your problem was a "no oil" issue which is not the same thing as a clearance problem or something like that which wont seize up no matter how bad the bearing is. The rod cap might let loose but it wont seize if its getting lots of oil.

[Ondonti]

Quote:

Originally Posted by jory Sent the crank out of my good parts engine to the machine shop and had then check it and polish it. Then I pulled the motor out of my car again and took the crank out, and plastigauged every bearing. They are all within spec except for rod #1, the clearance is too tight and when it is torqued the crank doesn't spin. So am I looking at a rod replacement too? I gave up early today after finding that out, and when I was pulling the car back outside a wheel bearing busted.. just my luck! This project didn't turn out as well as I was hoping.

Take your rods (and probably some extras) to the shop and ask if they are serviceable and have them resize the rods.
Honestly its better that this happened then some of the other problems you could have had.


How was your oil supply.....how long did it run before seizing. Did it seize on rod #1 after it had already spun #2 or what do you think?

[phantomrt]

Quote:

Originally Posted by jory Sent the crank out of my good parts engine to the machine shop and had then check it and polish it. Then I pulled the motor out of my car again and took the crank out, and plastigauged every bearing. They are all within spec except for rod #1, the clearance is too tight and when it is torqued the crank doesn't spin. So am I looking at a rod replacement too? I gave up early today after finding that out, and when I was pulling the car back outside a wheel bearing busted.. just my luck! This project didn't turn out as well as I was hoping.

Ah crap. I hate it when a new engine doesn't run more han a minue before crapping out. Definitely no fun!

I disagree about a spinning rod bearing being unable to sieze up an engine. From idle speed, it doesn't take a whole lot to stop the engine, and of course when bearings spin, the parts are welding themselves together at the same time and if the metal is molten, the engine stops, it cools down, it is like welding the connecting rod to the crankshaft.

I may have missed something, but with that bearing failure, that connecting rod has to be replaced also. It may be repairable, but often cheaper just to get a replacement rod because they are so abundant. Of course, that means at least one cylinder head has to come off to remove the piston/rod assembly.

The thing about the engine not spinning after the bearing cap being torqued down tells me right away that there were bearing caps installed backwards and/or interchanged with other connecting rods. I will just about guarantee it. In case you were unaware, no bearing cap can be interchanged with any other connecting rod. Finding new bearings to be incorrect size is very rare.

[Ondonti]

Quote:

Originally Posted by phantomrt Ah crap. I hate it when this happens! I disagree about a spinning rod bearing being unable to sieze up an engine. From idle speed, it doesn't take a whole lot to stop the engine, and of course when bearings spin, the parts are welding themselves together at the same time and if the metal is molten, the engine stops, it cools down, it is like welding the connecting rod to the crankshaft. I may have missed something, but with that bearing failure, that connecting rod has to be replaced also. It may be repairable, but often cheaper just to get a replacement rod because they are so abundant. Of course, that means at least one cylinder head has to come off to remove the piston/rod assembly. The thing about the engine not spinning after the bearing cap being torqued down tells me right away that there were bearing caps installed backwards and/or interchanged with other connecting rods. I will just about guarantee it. In case you were unaware, no bearing cap can be interchanged with any other connecting rod. Finding new bearings to be incorrect size is very rare.

I disagree.

Maybe if the bearing welded itself sealing off the oil feed hole on the crank (very possible)........but this would be an oiling problem not a spun bearing problem.

Ive put the mileage on a spun bearing 3.0 to know. My bearing wrapped around the crank twice and I put 1000+ miles on it. It was loose enough to allow oil to cool off the rod so there was very little burnt oil on the rod..now way it could have seized.

When I pulled it apart...the rod looked 100000x better then a rod from a motor that ran out of oil but the crankshaft was beat to hell and unfixable whereas the bad oiling crank was fixable. The no oil rod was so bad that it bent when it seized.
If I had gone WOT + booost + high rpms when the engine seized up from no oil then the crank would obviously have been toast and the rod completely destroyed.

With lack of clearance..my guess is the moly assembly lube allowed him to get away with metal to metal contact temporarilly but once the motor heated up and the moly pushed out, the motor seized since oil wont protect in that situation.


Would be nice to see if the rod was discolored from heat as that would tell a lot of the story but still wouldnt pin anything down.

[jory]

The spun bearing welded the holes shut and it was spun around 90 degrees when I took the cap off. It was getting zero oil to that bearing, why it spun in the first place I don't know.
#1 didn't spin a bearing and it was fine with the old crankshaft, with the new crank it is too tight. #2 spun a bearing and it has the correct oil clearance and moves freely. The bearing and crank took all the damage and the rod looks good from what I can tell. So if I take off the heads and take the #1 and 2 pistons/rods out can I still use my rings? I'm going to have to bring them to the machine shop with a few rods out of my parts motor now to have them checked and swapped. Probably should get a new set of bearings too.
Oh and I did swap a couple caps around I think. And all the rod caps out of my parts motor are put in a plastic bag from when I took out the crank.

[elemcirca]

hey how hard was it to replace

[jory]

The crank? Easy once you've done it a dozen times.

[Ondonti]

Quote:

Originally Posted by jory The spun bearing welded the holes shut and it was spun around 90 degrees when I took the cap off. It was getting zero oil to that bearing, why it spun in the first place I don't know. #1 didn't spin a bearing and it was fine with the old crankshaft, with the new crank it is too tight. #2 spun a bearing and it has the correct oil clearance and moves freely. The bearing and crank took all the damage and the rod looks good from what I can tell. So if I take off the heads and take the #1 and 2 pistons/rods out can I still use my rings? I'm going to have to bring them to the machine shop with a few rods out of my parts motor now to have them checked and swapped. Probably should get a new set of bearings too. Oh and I did swap a couple caps around I think. And all the rod caps out of my parts motor are put in a plastic bag from when I took out the crank.

Rods are about 15 bucks a piece to resize so its worth the cost.

I guess I am still wondering why the big different in clearance on your new crank.

[phantomrt]

Yep, I've bought many spun bearing engines over the years, and they all still ran and were not locked up by any means. I drove them all home 25+ miles since I live in the middle of nowhere and have no trailer or dolley. I've seen plenty of lawn mowing equipment engines locked up at the crankshaft, but never an automotive engine. Granted, they were all splash lubricated engines. I always figured that a multicylinder engine was just more powerful with its more frequent power strokes and could more effectively tear the bearing apart and not lock up in the process. Improbable, but not impossible to lock up via this method is my opinion. Of course, the lawn mowing equipment often didn't have the same bearings either.

>> #2 spun a bearing and it has the correct oil clearance and
>> moves freely. The bearing and crank took all the damage
>> and the rod looks good from what I can tell.

At the very very least, I would check the roundness of that connecting rod with an inside micrometer. It is too risky to assume it is okay. As for why it wasn't getting oil... that is a mystery we have to find out. Especially if #3 was getting oil, since they're lubricated from the same main oil passage, so as mentioned before, there almost has to be a problem inside the crankshaft's oil galley.

>>So if I take off the heads and take the #1 and 2
>> pistons/rods out can I still use my rings?

I would, even without running a glaze breaker through the cylinder assuming there is no visual damage or heat stress on the parts. Someone may chime in and disagree with me though, so make your own decision on this. Consider that if this connecting rod was not getting any oil, neither was that cylinder wall. So, it wasn't getting lubricated OR cooled. This can cause an engine to lock up and then once cooled down, free itself up again. Without the piston getting cooled, even a cast piston and ring at .0015" clearance can expand enough to jam up in the cylinder, and possibly damage the piston ring lands. It'll all depend on whether or not this thing ran long enough to cause any damage there. Luckily, the engine was idling when it stopped?? The rings and piston ring lands are another area to inspect now. Consider that the piston potentially went up and down in that cylinder 1000 times with no lubrication.

What I do, and it has always worked for me, is very carefully push the piston out of the bore, and with a scribe, mark exactly where the piston ring gaps are on the piston so you can install them the exact same way they came out. When installing, I have successfully compressed the piston rings with my fingers and flat blade screw drivers and pushed the piston into their bores many times--like back before I had a piston ring compressor. VERY dangerous as there is a lot that you can damage if you slip the screw driver into the piston ring land, but I never wrecked anything, YET. Or use the piston ring compressor to just get the oil rings in (the PITA ones) and do the others by hand.

But seeing this thing has so little run time on it and has freshly bored/honed cylinders that should be perfectly round yet, precise piston ring end gap placement shouldn't be much of a concern. Just get them somewhat close, and you'll be fine in that department. But MY decision on what to do would depend mostly on what visual inspection of the parts revealed. Without me actually being there to see it myself, I cannot be the one to make the decision.

>>Oh and I did swap a couple caps around I think. And all the
>> rod caps out of my parts motor are put in a plastic bag
>> from when I took out the crank.

This is a definite problem. It is very very critical to keep the caps and the rods together and not put the caps on backwards either. The next time you do this, label them all in such a way that you cannot get them mix 'N matched before a single rod bolt is loosened. I have a punch sets with ABC's an 123's on them and mark both the rod and rod cap next to the seperation gap for reference.
Now that they're mixed up, I am not sure what to do. The machine shop should be able to give some ideas. I'd get them all re-sized because if they were forced together with a part that wasn't matched up perfectly with it, the roundness could be distorted now. Again, maybe maybe not, but some things I don't like gambling on, and this is one of them.

It is easy to check the crankshaft journal sizes and roundness with an ouside micrometer to make sure that isn't F'ed up. Sometimes machinists unintentionally mess this up. I find that this is the difference between a clean, well orgainized machine shop with non-scruffy looking energetic people working there and a machine shop that is dark, messy, and scruffy people working there who are not energetic. Probably stereotypical, but I see a very distinct pattern in it.

[jory]

The engine was at low idle when it locked up, so it couldn't have done much damage. I want to do just what I have to do to get this engine within tolerances and running. If it doesn't need to be done then I don't want to do it. Only one rod is out of spec so I don't see how replacing the other rods would benefit me.

[jory]

It was #5 that was too tight, not #1. I got the piston/rod out and got a few from my parts engine and it's going to the machine shop tomorrow.

[Ondonti]

Make sure they check your rods for straightness...especially if you try to have them reuse one of the rods that locked up or had no oil. I bent one and in my motor thread I have the pictures of the bearing wearing only on one side because of the bend (i only found out because of another problem which I consider a blessing).

[phantomrt]

How do you know that these clearances measurements are accurate, considering the possibility that the rod caps got mixed up?
Plastiguage works well, but only if everything is a perfect circle and the rods are straight. These parts are potentially not a perfect circle anymore due to the rod caps getting switched around, forced together, and possibly bent out of round. This is the #1 thing that needs to get figured out for SURE before going any farther.

If you *may* have interchanged two rod caps, how do you know you didn't interchange any others? I'm not good at calculating statistics and probability, but the chances of success can't be very good if you don't know for sure.

[mopar3.0]

i really wish i could figure out what happend to my first engine, it ran fine for about 2 weeks, then i was having wirring trouble, it was stumbline off idle and fine at high rpm
took it for a run and was going a run and the car had a hard time getting to 180 kph, used to do it in a flash, anyways, few seconds later it started knocking, pull over,
have full oil pressure, get pissed drive it home. never seized, pull the base pan and its full of shavings ,I mean like a inch deep, and the skirts are borken off few pistons,

So i have a msd timming controller on the car, and i think it may have been set up for a 4 cylinder, last owner said it was set up for a v6. But could timming cause that much damage, i think it was way too retarted