Thread: choosing bearings

So what happens when your ordering something like ACL bearings for a stock crank and aftermarket rods? Those are just one size fits aren't they?

Good info here by the way

Paul

If you are mismatching parts or using aftermarket parts, then you have to measure with plastigauge or bore gauge. It's the only right way to do it. You can't go off of the chart.

I myself have built more than a few motors. The correct way to size connecting rod bearings per the fsm is to add the numbers. For instance...

-Crankshaft reads: 1011
-Rod big side reads: 1110

your rod bearings will then be: 2121.

This is the proper way to size nissan bearings. I have personally even gone as far as measuring the nissan bearings after installed and comparing it to the FSM. The results are within limits of the FSM.


Nissan also does this so the correct bearings can be selected when using rods or a crank from a different engine.

Rods come in 2 diffrent grades.

Grade 0 and Grade 1.

Rods tell you 2 diffrent things.

On one side of the rod and rod cap which is a flat machined surface, you get 2 numbers that match, these numbers are 1, 2, 3 and 4. These numbers tell you what hole the rod came out of, it also tells you the correct way to put the rod cap on the rod and it helps you not to mix up rod caps with other rods. On the other side of the rod machined surface you have another number that is on only the big end of the rod and that tells you the grade of the rod.

Again rods come in 2 diffrent sizes. Grade 0 and grade 1.

If you get get a rod with a 0 and a rod with a 1 you will notice that the bore for the rod is of a diffrent size.

There are 3 diffrent grade bearings for rods from Nissan.

These grades will be 0, 1 and 2.

I can bet 100% that no one has ever seen a crank with a 2 on it for the rods. When you get a crank and you look at the numbers for the rods you will get all 0000, all 1111 or a combination of the these 0s and 1s. Example 0001 or 1001 or 0110.

Now when I build a motor I get my correct rod bearings by adding them up. Then I plastiguage the bearings to the crank and I have never had one not come within specs.

If you get a set of rods that 1111 and a crank that is 1111 you will get 2222 for bearings. This is why the make grade 2 bearings.

The thing is when Nissan puts motors together they match cranks and rods. So you will generally all ways end up with bearings of 0s or 1s.

I will try and get my hands on some rods with 0s and 1s and measure them with a bore guage to prove that rods come in diffrent sizes.

The 300ZX 91-96 runs this same rod grade method also.

I have never had a motor built with stock Nissan bearings have rod knock and I follow this method, LanceSR20 follows this method and has built many a engine for people on the forum and has never had a problem. He goes one step further and uses a bore guage to measure the rods and measuring caliper to measure the crank to make sure his bearing picks are correct.

Well you got me there SWISS, I have never seen a crank with a 2 on it and I have never seen a crank with Roman numeral numbers.

I will keep doing it my way.

To keep things straight with the forum members doit it like the manual says.

You know your sh*t Andreas, nobody can doubt that. Like GregV said we'll agree to disagree on this one.

I have done it the way Andreas and Lance posted. I have put a few SRs together and never had a problem...

Do you guys have the program for the Calum ECU. I am trying to get the best program on my laptop as I am going to start tuning peoples cars with the Calum Realtime.

Also if any of you have any pointers on it let me know. I want to know as much as possible on it before I jump in and mess something up.

I also have to get my 2.3L VE in and tune that so I am getting desperate for the program and some pointers on it.

I always use digital micrometers when doing an engine build, or if I am not worried about mileage, I will just add up bearing sizes and order them up.

.0001" is not going to make a difference imho.