7AFE Rod bearing sizes and replacement

[mjzraz]

I have my 1.8 94 Celica ST engine all apart for repair of head gasket leak. Car was overheated and warped head. I had it milled and pressure checked. I will be replacing valve seals. No valve job needed per vacuum test. I pulled the pistons/rods to change the rings. #4 was the worst and even left a faint line of bearing on the journal. I polished it for like 30 minutes and it looks and feels OK to me. I measured the journal and it appears to be = in both directions and not egged. I will probably polish some more to.

My question is what does the mark 1, mark 2, mark 3 for bearings mean? If I look up at online or local parts places the only size is "STD" If I go to one of the Genuine Toyota parts dealers, I get separate part numbers for mark 1, mark 2, mark 3 bearings. (and they are sold separately - per rod) Are they different sizes? In what way? My rods have three marked "2" and one marked "3" I measured the bearing thickness on a "2" and a "3", but it was the same as far as I can tell.

I plan to use plastigauge, but would like to have some understanding of what these numbers indicate. Also if I could get an opinion on how the bearings and journals look, that would be great. It would be nice to compare my journals with a "bad" one.


Higher res and more images are Here on Flickr
Here is what the rod Bearings looked like:



Here is the Journal after I Polished it with crocus cloth (really hard to get a decent picture):

[mjzraz]

Over in this post, I found the following:

Originally Posted by tashirosgt

The Toyota OEM rod bearings come in various thicknesses that differ by about 2 ten thousandths of an inch. All the aftermarket rod bearings that I measured are slightly thinner than the thinnest of the OEM bearings. So if yo want a tight engine (and can actually use plastigage upside down!) get the OEM bearings.

Wow - 2 TEN Thousandths?? How in the world could I even measure something like that? I have a dial caliper, but even with a digital, the margin of user-error(mine) would probably be greater anyway.

I suppose the best plan would be to order the Gen Toyota bearings based on the numbers on my rods and then use plastigauge to check them. if one journal is off, try the next size up or down. I hope I am on the right track.

I still wonder what caused the bearings to look like this. I know there was some water in the oil from the HG leak and the car doesn't seem that well maintained. I guess I should remove, clean and inspect the oil pump also.

[90gtsindenver]

Contamination in the oil will cause that kind of scoring. Micro particles CAN do that. I've seen it in hydraulic pumps alot. Someone didn't change the oil in it as often as they should have.

While you have it apart, make sure you get it cleaned up really well, since with that kind of scoring there WILL be metal particles in the engine. I agree with your theory though, go with the OEM bearings, in the long run it will pay for itself. (toyota parts aren't cheap, but they're worth it in durability and quality)

Make sure when you clean it, you get it all, all the oil transit lines, and every nook and cranny you can. If you're up to it, utlrasonic cleaning is best, it'll shake loose things that tend to stick in places you can't see. Many machine shops have the ability to clean it out for you. Barring that, just use something safe for the job, and make sure you do it thoroughly. Again, in the long run the ultrasonic cleaning will be your better bet. (I don't know how much you have disassemled, so its hard to say how much you can get to.) IF you just have the bottom end open, and you're already in the reassembly stage, once you get her all buttoned up, FLUSH the engine good. (they make products designed to clean and lubricate) Then change the oil a couple extra times, (at 500 miles, 1500 miles, and again at 3000 to help get any contaminants out.) And by all means, go easy on the new bearings for the first 3k or so, give them time to "wear in" Especially if you removed alot of material on your rods/cams. The bearings were designed to fit a "new" part, so some break in is to be expected.

Good luck, if you do it right, you'll have a car worthy of driving for a few more years! I don't envy you that job though.

[mjzraz]

Thanks for the advice. I ordered the dealer bearings today from 1sttoyotaparts.com. Even with 2nd day shipping they were cheaper than the local dealer.

I did some more work. The problem is, now today I honed 2 Cylinders and pulled a main bearing cap. The honing I did with a flex hone, but there are some pitting and areas where it looked like something corrosive "dripped" down the walls on the front side only. My guess was it came from water leaking from the BHG. Should I keep honing it? I took some pretty decent pictures and on Flickr. You can click on "all sizes" and see the higher res versions. The second problem is the main bearing cap I removed. The wear is not nearly as bad as the rod bearings, but the journal I am worried about. It feels smooth in the rotational direction, but I can catch a fingernail on ever so slight lines going across the journal (right to left)
Here are the pictures: http://www.flickr.com/photos/9237872@N05/tags/7afe/ I can take more if unclear. I did hone some more and they did turn out better.

I am at a crossroads - Do I replace the rod bearings, reassemble the pistons with new rings and and just hope the mains hold out? The plans are to keep the car for a few years for my daughter in college (locally). Or do I bite the bullet and do the only things left, which I think are:
Pull the Block, Remove crank
Regrind Crank, oversize bearings
Bore the Cylinders and get new Pistons/Rings (No idea on new pistons cost)
At that point, New Oil Pump, New Water pump

I just don't have the multiple rebuild experience to know what it should look like. I think I am leaning toward just replacing the rod bearings, rings and putting it back together.

Thanks for any insight to steer me in the right direction.

[Pineapple]

Easier, find another 7A-FE. They're used in 93-98 Corolla. you should be able to pick one up for less then all the bearings you need.