How do I know if these are big rods or not?

[SpoolinGSX]

I am rebuilding what I think is a 90 4G63 NA block. I have the rods/pistons out and I am trying to determine if the rods are Big Rods or not. They have a casting number on them, which I don't have off hand, but does anyone know if the big rods have a specific casting number? Maybe someone knows the dimensions? Any help would be appreciated as I need to make a decision now about what parts to buy.

 

[dsmturboawd]

big rods as in 6 bolts are big and 7's arent?

in that case, you have "big" rods. all 90-early92 4g63 (n/a and t) rods are exact same.

 

[SpoolinGSX]

The car had an engine rebuild at some point before. The block that was put in was an NA block. I'm not positive on the year but I think its a 90. So I have no assurance that these are big rods. That's why I am asking if anyone has any dimension or casting numbers to help me determine what they are.

 

[dsmturboawd]

*flame suit on*

please dont flame for me saying search, but honestly, if you search for pics of 7 bolt and 6 bolt rods, you should be able to figure it out from there.

good luck.

 

[SpoolinGSX]

I have searched around. And I did find a few pictures. Unfortunately in the pictures the casting numbers are not that clear. The difference, visually, between the two rod types is very small. Yes, one is obviously wider than the other, but not to the point where it is completely obvious if you had one sitting in front of you. As well the specs that I have for the main bore journals for the 7 vs 6 bolt are very similar, if not the same. So either rod could fit on the crank, or so my research has led me to believe. So I'm just trying to figure it out, at this point I'm almost ready to say screw it, I can't figure it out, no one has any insight to offer, and just go out and buy some Crower rods or something.

ps Here is a pic I found

 

[dsmturboawd]

looks like 0692 to me. *shrugs*

, dont waste your money on rods. 1g rods are more than good enough for 99% of the people who belong to this forum.

 

[SpoolinGSX]

I can see the number on the bottom, which is the big rod. The rods I have don't have this number. When I looked it up in on the program at my shop it said the casting number for 1g's was G6, and it didn't list one for 2g's. So I don't know if the number is the same or not.

As far as your comment about people not needed more than the 1g rods I'd have to say there is more than strength to consider when looking into rods. I am already going with forged pistons, and in combination with lighter rods removes a good deal of reciprocating weight. The ability to rev and decelerate faster is much more important to me since the car is mostly autocrossed.

 

[kpt4321]

I just measured a 1g 7-bolt small rod, and it's approximately a 17mm x 13mm rectangle measured halfway between the bearing and the wrist pin. Hopefully that will help!

 

[dsmturboawd]

Originally posted by SpoolinGSX
The ability to rev and decelerate faster is much more important to me since the car is mostly autocrossed.

good point. its just gonna be sad for me to see a built motor with a t28 or something like that on it, .

so im assuming youre only wondering what they are for when you sell them? *shrugs*

good luck.