Help! - Engine Bearing Question

[sdoan]

I have a wrecking yard 4ac engine that I will re-ring and re-bearing at standard sizes.

The question is that Toyota claims to have 3 sizes of standard! 1, 2 and 3 . Have any of you replaced standard crank bearings in your 3a or 4a? The Toyota dealer asks me for the sizes (and then lots of $). The bearing supplier through the local parts store doesn't recognize any size differences and this makes me uncomfortable.

What have you done about replacing standard size bearings with aftermarket parts - did you get the correct standard size?

BTW, All the mains are #2 standard, one of the rods is #2 standard and three of the rods are #3 standard.

Thanks for your help.

Shawn

[Mac]

If you go with aftermarket std size bearings, buy some plastigauge to make sure your clearances are A-ok.

when you remove the oil pan, you'll notice numbers stamped on the bottom of the block on the flywheel side of the engine, those are the numbers they were asking for at za dealer.

[takza]

BTW, All the mains are #2 standard, one of the rods is #2 standard and three of the rods are #3 standard.

Thanks for your help.

Shawn

Looks like they more or less custom fit these engines? Which might explain the higher quality.

[sdoan]

Looks like they more or less custom fit these engines? Which might explain the higher quality.

Yes, that appears to be the case. I plastigauged all the bearings and they all came out on the large side of the standard clearance (i.e., closer to 0.002" than 0.001"). I couldn't tell the difference between the #2 standard and the #3 standard on the plastiguage...

Looks like the aftermarket is of the "that's close enough" mindset.

[ARCHINSTL]

This is very interesting (although hopefully I will never have to use the info!).
Please continue with this discourse as you discover more. I had no idea it was this involved.
I would think this is pretty important info for the future - maybe work up something for Repair Guides?

The only engine in which I installed bearings was an ancient BMC "A" over 40 years ago - it wasn't that precise in those times...
Tom M.

[splatterdog]

Standard size Clevites brought my 200k engine from just over .002 to just under .002 on all journals. I was hoping for better, but I wasn't willing to spend the extra time and money for the toyota way and had preordered everything from rockauto. I always hate having to order parts after cracking something open. Especially on a car the dealer considers obsolete and stocks almost nothing for. Some of their youngsters behind the counter haven't even heard of a T4WD!

The biggest difference came from the thrust washers, typical of any engine attached to a manual trans. All the force of your throwout bearing against the pressure plate is felt by the rear thrust washers too.

[Mac]

never thought about the manual transmission thing for the thrust washers. I'm lucky my crank was within spec.

that sucks about having kids behind the counter, at my Toyota dealer Dan has been working there for years, he knows what i drive and always gets the right piece, I guess i've taken it for granted. But that does remind me, one time i went to a honda dealer for some parts for my acura (it was basically a civic) the parts guy was having trouble finding a bolt for the bottom of the shock and the tech that happened to be there so the parts guy asked him if he knew anything about it, so mr.bigshot, says "i've never worked on anything THAT OLD" so I replied "I guess you haven't been a mechanic for very long then!" with a chuckle, shut him up pretty quick

[takza]

The biggest difference came from the thrust washers, typical of any engine attached to a manual trans. All the force of your throwout bearing against the pressure plate is felt by the rear thrust washers too.

Now that we're talking about endplay...what is the story on camshafts. I've seen what looks like a couple of alignment issues where maybe the cam endplay is off, causing extra belt wear from misalignment. Or is this typically more due to a worn crank gear? Or crank endplay?

[sdoan]

This is very interesting (although hopefully I will never have to use the info!).
Please continue with this discourse as you discover more.

The only engine in which I installed bearings was an ancient BMC "A" over 40 years ago - it wasn't that precise in those times...
Tom M.

Hey Tom,

I think the take home message for me was to plastiguage everything. My results were just the same as Splatterdog's - just under .002" clearance using aftermarket bearings. And I couldn't really see a difference between the #2 and #3 standard bearings. Their precision is amazing.

Here's a another thing. There are 2 different rod bearing inserts for the 4A engines. The earlier type (used in 4A engines until 1984 or something) are the same as the 3A and are quickly distinguishable by the smaller 12mm rod nuts. The later 4A engines have 14mm rod nuts. The only difference between the inserts is the width of the locating tang - it is narrower on the later engines to clear the larger rod cap studs.

All the carburetted 4A engines seem to have flywheels with 6 bolts. I found a 1988 Corolla with a DOHC engine with a 6 bolt flywheel. I couldn't use the head but I think the lower end would have fit under the 3A head.

I had a BMC A in an 850 mini. Crude, but fun. I also had a BMC C series engine in a big Healey - Crude and more fun.

Cheers,

Shawn

[golden_glory]

when you remove the oil pan, you'll notice numbers stamped on the bottom of the block on the flywheel side of the engine, those are the numbers they were asking for at za dealer.

yeah, there will be two sets of numbers. One set on each side of the block. Its kinda nice IF you can read both sets (here in the rust bely however...). Toyota basically custom fits bearings for all of its engines. I think you star with the number on the left side (sparkplug side) and subtract the corresponding number on the right side (manifold side). I might be wrong, you might need to add them, I forget which way it works. Aftermarket bearing mfgs will just measure the diameters. If you can read the stampings on the block and have the loot to spend you can get toyota bearings but aftermarket ones will work just fine.

I've got my engine apart right now but the 3rd & 4th digits on the right side were gone due to rust issues so I'm going to have to go with aftermarket. Measured the crank though and its all good, same with my bore diameters so it looks like I won't need to get new pistons or rods and I don't need to get the block machined either. wOOt!! I am going to paint it while its out, gold block w/white heads. Then I want to stencil the old-school Toyoda logo (the Kanji one) on the head in gold with a black outline. Its going to be sweet.