2JZ bearing sizes

[Kristian_Wraae]

I'm doing a 2JZ swap and I'm right now in the process of changing the rod bearings.

What I see from the crankshaft is 1 1 1 1 1 1 (first to 6th cylinder)

The rods say: 2 3 2 2 2 2 (first to 6th cylinder)

So I assume the bearings I should use are: 3 4 3 3 3 3

When I take the rods apart i find no real understandable markings of size on the bearings.

I find this:

1: 3J 23L and 3J 24L
2: 3I 08G and 3J 06G (the first one might be 3J instead of 3I - but it really looks like 3I)
3: 3J 23 L and 3J24L
4: 3J 23K and 3J 24L
5: 3J 23K and 3J 24L
6: 3J 23K and 3J 24L

Does this make sense to anyone? The reason I ask is because I can see that the oil pan has been changed at some point so there is a chance the engine has had some work done and therefore a chance that the markings are no longer valid.

What bothers me is the change of L and K in 1,3,4,5 and 6.

 

[IBoughtASupra]

Look if the bearings say "STD" on them. That means they are the standard size, stock. If it says ".10," that means the crank was cut ten under and you need ten under bearings which you can get from any machine shop.

Take the old one and they can probably look it up. The machine shop around here has a crazy amount of books to look up anything.

 

[Kristian_Wraae]

I just got standard sized bearings according to the markings on the rods and the crank and used some plastigage to check that the clearance was within spec. And they were.

The numbers printet on the bearings have no real meaning as far as I've been told. The size of the individual bearing is marked with a number with ink and it is always gone after some time of use.

So new bearings and plastigage is the way to go.

 

[IBoughtASupra]

I always find "STD," or ".10" on the bearings. They are what is there, Toyota sells bearing in thickness increments of one thou? I doubt that. If the crankshaft has a too big of a clearance, it will need to be cut, not really different size of bearings.

What I have seen is, if it is all "STD," that goes back in as long as the clearance is right. If not, then getting the crank cut and new bearings would Bethesda better option. I hav never heard of different size of bearings on different rods.

 

[IJ.]

I always find "STD," or ".10" on the bearings. They are what is there, Toyota sells bearing in thickness increments of one thou? I doubt that. If the crankshaft has a too big of a clearance, it will need to be cut, not really different size of bearings.

What I have seen is, if it is all "STD," that goes back in as long as the clearance is right. If not, then getting the crank cut and new bearings would Bethesda better option. I hav never heard of different size of bearings on different rods.

"Select fit bearings"

It's a standard Toyota thing, they've been doing it forever to allow for +- tolerences from their machine shop.

There is usually a chart that tells you xx Crankpin size and yy Main tunnel or Rod size will = zz Bearing Shell.

 

[IBoughtASupra]

I didn't know they did that for the bearings. I knew about shim sizes though.

 

[IJ.]

I didn't know they did that for the bearings. I knew about shim sizes though.

So there ya go you've learnt something new
(the day I stop learning is the day I'm slid into the big oven)

 

[CyFi6]

Arent all the manufacturers doing this nowadays too? I found out on my 7m that its best just to measure everything and not use the stamped numbers on the engine when changing the bearings. Measure the rod big end, crank pin size, look it up in the chart and figure out what bearing you need. That way theres no guess work involved and you dont have to worry about stuff being previously messed with. Not to mention if you buy all your bearings at $15 and $20 each, only to plastigauge them and find them out of spec you will be hating your life.

 

[IJ.]

Arent all the manufacturers doing this nowadays too? I found out on my 7m that its best just to measure everything and not use the stamped numbers on the engine when changing the bearings. Measure the rod big end, crank pin size, look it up in the chart and figure out what bearing you need. That way theres no guess work involved and you dont have to worry about stuff being previously messed with. Not to mention if you buy all your bearings at $15 and $20 each, only to plastigauge them and find them out of spec you will be hating your life.

How do you allow for variations in tunnel size of both the rods and block?
(hint: that's what the numbers refer to NOT the journal size)

 

[CyFi6]

What do you mean? Measure journal size, match to chart to get "mark" number, measure rod big end, match to chart, add mark numbers from chart and get bearing mark number. Doing this for each journal separately of course.

 

[IJ.]

The tunnels in the block can have different ID's that's what the stamped numbers denote..

 

[CyFi6]

Thats why i dont get what you are saying, all im saying is he should measure them individually(rods, crank and main bores) and compare to the manual to make sure the numbers stamped still match the actual measurement that number represents

 

[IJ.]

Thats why i dont get what you are saying, all im saying is he should measure them individually(rods, crank and main bores) and compare to the manual to make sure the numbers stamped still match the actual measurement that number represents

Agreed of course you should measure everything to verify the block is a virgin, sorry misunderstood your first post as you didn't mention any of the tunnel ID's.

 

[IBoughtASupra]

You can take a plastic bag, one for each cylinder. Put the bearings for each cylinder in a different plastic bag, zip lock is good here, and go to the Toyota dealer. Measuring the block, head and crank would be a good ideal to make sure it was never touched and the get the same bearings from Toyota. You can even measure the clearances with the old bearings and if they are within spec, the new bearings are highly likely to be in spec as well.