engine failure questions
#61
The plastigage is wrong. period. it's out of the range.
Again, I measured .0266" smaller than the smallest stock size journal limit. They sell undersize bearings at .25mm(.01"), .5mm(.02"), and .75mm(.03"). The .75mm would overlap the journal by .003" so that can't be used. The .5mm US would make it .0069" clearance which is more than 3 times over the largest specified gap (.0022").
Even if a .75mm US bearing would work, I would just replace the crank becuase that means the journal, even though it appears good, had a lot of metal ground off by the spun bearing making it unreliable. I don't have an rA meter and I don't have a micrometer to check for taper and out of round and other critical things as such. So instead of risking another spun bearing, I'm going to just pull the engine and replace the crank and all the bearings.
Again, I measured .0266" smaller than the smallest stock size journal limit. They sell undersize bearings at .25mm(.01"), .5mm(.02"), and .75mm(.03"). The .75mm would overlap the journal by .003" so that can't be used. The .5mm US would make it .0069" clearance which is more than 3 times over the largest specified gap (.0022").
Even if a .75mm US bearing would work, I would just replace the crank becuase that means the journal, even though it appears good, had a lot of metal ground off by the spun bearing making it unreliable. I don't have an rA meter and I don't have a micrometer to check for taper and out of round and other critical things as such. So instead of risking another spun bearing, I'm going to just pull the engine and replace the crank and all the bearings.
#63
Well I finished the engine rebuild a few weeks ago, but the engine was smoking real bad from one of the cylinders (maybe more I don't know) and I was trying to see if I needed to rebuild it again and I was trying to isolate it. Not to mention I bought a 98 Expedition and did a little work on that too along with so many other things. I was so close to calling the rebuild a failure, but I just couldn't give up so quick. I kept starting it and running it to see if I could figure out what cylinder was leaking and why. I even disconnected each cylinders coil to try and find out which one it was. That didn't seem to help. I had added about half a quart of heavy duty oil stabilizer to see if it would help, but it didn't really seem to. This last weekend I decided I would drive it longer because it may just help seal the rings better. There was only about 2 miles on the engine so I had to see if it would get better so I went out and drove it down the road for a few miles. I could see the smoke behind me, but it was a lot less than when I first ran it. Just after about 7 miles, it was hardly leaking!
Now it doesn't smoke at all!!!! It kept getting better and better until it doesn't smoke at all anymore! I'm so grateful it worked. If I would have had to rebuild it again it would have been over $1200 plus a lot of time and time I am in short supply of atm. It also proves it is possible to reuse rings and still have a good seal even after 136k miles. I imagine I'm going to get about 40k-50k miles before I need to rebuild it again, but that's a few years down the road. My timing chain guides are getting close to their wear tolerance, but shouldn't be due for another 35k-40k miles so I'm good for now. The transmission shift quick and very nice too so this one may last quite a while! There are a few other problems with it, but they are minor and will be fixed shortly.
Now it doesn't smoke at all!!!! It kept getting better and better until it doesn't smoke at all anymore! I'm so grateful it worked. If I would have had to rebuild it again it would have been over $1200 plus a lot of time and time I am in short supply of atm. It also proves it is possible to reuse rings and still have a good seal even after 136k miles. I imagine I'm going to get about 40k-50k miles before I need to rebuild it again, but that's a few years down the road. My timing chain guides are getting close to their wear tolerance, but shouldn't be due for another 35k-40k miles so I'm good for now. The transmission shift quick and very nice too so this one may last quite a while! There are a few other problems with it, but they are minor and will be fixed shortly.
Last edited by MetalDrgn; 09-14-2009 at 05:30 AM.