I know the strokes are different, but my question is how would someone identify the GSR crank from the LS one?

is there a number or code somewhere on the crank?

 

Find the specs of the journal and use a digital caliper or mic. to messure.

Im pretty sure there are no codes on the crank from what i have seen (never really payed attention)

 

Search for images between an LS and GSR crank. I did this when buying a GSR crank to make sure I was getting the right one. There were some small differences in markings and how the counter weights look. I forget exactly what they are, but google searching images I was able to compare.

 

There are.

There's a small flat plate surface on the journal closest to where the crank pulley is. That marking helps determine which crank it is without going through all the micrometer headache.

B1-B4 = LS or B20 Crank
R= Type R Crank.
6 = B16
7 = GS-R

I'll edit this as needed, as I remember this through my builder and still have a couple of B20 and Type R cranks still around. I'm going to verify the B16 and GS-R numbers. I went by this plate system and it worked, as I needed to help out Ron and Project "SHE" with a spare B20 Crank I had left

 

Thats sweet^...im saving that.

 

thanks shodan !

 

Shodan beat me too it

 

Was I right on those last two? I'm just trying to make sure I'm not giving inaccurate information.

 

You got it Shodan. ALL of the 87.2mm cranks have a "4" on the center counterweight as well. Here is a Visual for you OP

 

Well I have a crank that I I just picked up with a Gsr block and I didn't really check it out before I left with it and I have a suspicion that it is actually a b16 crank. In the position where the 7 should be on a gsr crank I have a 3 and where the 4 is I have a 2. Any ideas?

 

Post up pics? I'm a visual guy and seeing your crank matched up to these samples above will help tremendously. Sounds like it might be a 89mm crank.

 

I have one other pic if this is no good

 

Anybody ?

 

looks like an 89mm crank to me.

 

Wats a b17a crank

 

B17 cranks are 81.4mm

 

What are the markings on the b17s? Like the b1-b4, 6, and 7.

 

Just came across this thread as I was trying to identify a crank that I have. It proved to be useful. Thought I share my info. This picture is upside down because I took it that way with my phone. You can see the plate that says B2 though. I now know that this is a LS or B20 crank.

 

Look at all the counterweights between 1 & 4, only the outer 2 weights are "full" counterweights. 18a/b have full counterweights on all cylinders. From my experience that would either be a 16a or a 18c. Possibility it is a 17a as well. They look real similar to a 18c. Anyway you can measure the rod journal width?

 

In this import-tooner has a B20/LS. I have the exact same crank sitting in my lab. Even the same markings.

 

^ these two posts alone should qualify this as a sticky.

 

Someone recommended this be added to the FAQ sticky at the top of this section, so it has been added. FYI, that FAQ thread is open to posts, so feel free to post in there if you think something should be added. Both me and Jimmy are subscribed, so we will be able to add it if we agree it belongs there

 

a trained eye can just catch if the journal is wider than it should be or narrower than it should be.

 

your information is incorrect. that small flat plate surface has a letter and a number to allow someone to select the proper bearing size for the #1 main and #1 rod bearings. letters and numbers on the block and rod also determine which bearing to get.

yeah the only way I really know for sure what crank I have is by eyeballing it lol

 

2 GSR cranks


2 more GSR cranks


2 B16A cranks


what I'm pretty sure is an LS crank. Note that a machine shop has done some work to this one