CAT crank for SII?

Squid4life

Well-Known Member
So I have this CAT steel crank, stock stroke, brand new in the box sitting in my closet, was considering selling it with my K1 rods for the 109 I was going to build. I am working on an On-center SII, so know the rods won't work, but what about the crank? Is it a decent choice for a SII? I see a lot of BMS cranks around, usually used. Wondering if the CAT is something to hang onto for the SII build or if I should get rid of it and move up/on to something else. Don't have rods yet, so that should play a factor on whether I get rid of it and spend at least another few hundred on a stroker steel crank, then rods to match, or keep the CAT and pick up non-stroker rods. Opinions? Suggestions? Trades of the K1 rods for SII rods? :biggrin:
 
What length are the K1 rods? I'm in a similar only with the stroker version., I would prefer to put a better crank & rods in the stage2 but if it needs to get built and that's all you have I would use it. Probably better than a BMS crank that's already seen alot of boost.
 
So I have this CAT steel crank, stock stroke, brand new in the box sitting in my closet, was considering selling it with my K1 rods for the 109 I was going to build. I am working on an On-center SII, so know the rods won't work, but what about the crank? Is it a decent choice for a SII? I see a lot of BMS cranks around, usually used. Wondering if the CAT is something to hang onto for the SII build or if I should get rid of it and move up/on to something else. Don't have rods yet, so that should play a factor on whether I get rid of it and spend at least another few hundred on a stroker steel crank, then rods to match, or keep the CAT and pick up non-stroker rods. Opinions? Suggestions? Trades of the K1 rods for SII rods? :biggrin:

I am by no means an expert so take what I say as just a suggestion. If you are gathering parts to build a stage2 then I'd start with a wide journal crank. Since you will need new rods for an on-center block anyway then they really won't be an added expense. Your crank is stout for a 109 build but I couldn't bring myself to put a narrow journal crank in a healthy stage 2 block. That would be like slapping a set of 8 bolt heads on it. IMO.
 
What length are the K1 rods? I'm in a similar only with the stroker version., I would prefer to put a better crank & rods in the stage2 but if it needs to get built and that's all you have I would use it. Probably better than a BMS crank that's already seen alot of boost.
I have the stock length rods, not the strokers. I would prefer better rods and crank as well, but trying not to go for a second mortgage on this build. I know, it is a Stage motor so it will be expensive, but if a piece is way overkill for a price, I would like to find a lesser expensive piece that fits the bill.

I would trade you a complete set of stage2 heads for the cat crank & cash if you want to get rid of it.
I already have a set of SII en route, but thank you for the offer.

I am by no means an expert so take what I say as just a suggestion. If you are gathering parts to build a stage2 then I'd start with a wide journal crank. Since you will need new rods for an on-center block anyway then they really won't be an added expense. Your crank is stout for a 109 build but I couldn't bring myself to put a narrow journal crank in a healthy stage 2 block. That would be like slapping a set of 8 bolt heads on it. IMO.
Definitely considered the wide journal, but trying to find out what is needed, required, and completely optional in this beastly world of SII’s. I guess that is the reason for my post is to ask what is a good solution; sell the crank and get a different one, use it, etc. Very good input, and will have research even more on where to find SII parts. Having a hard time locating rods, but think TA was the last place I saw who carried narrow or wide journal cranks.
Of course, with the purchase of a new crank, it opens the question on stroke. Should I go with a stroker? Again, having a hard time finding availability of rods, which would aide in making decisions. If stroker rods and pistons are readily available and not made out of unobtainium than maybe I would go that route, if I have to buy a new crank anyhow. The good/bad part is… I already have the crank so it sucks to sell it, then turn around and buy another much more expensive one, but I should be used to that by now with these Buicks!

Where does everyone shop for their SII parts? (ie pistons, rods, cranks, gaskets, oiling, etc)
 
I am by no means an expert so take what I say as just a suggestion. If you are gathering parts to build a stage2 then I'd start with a wide journal crank. Since you will need new rods for an on-center block anyway then they really won't be an added expense. Your crank is stout for a 109 build but I couldn't bring myself to put a narrow journal crank in a healthy stage 2 block. That would be like slapping a set of 8 bolt heads on it. IMO.

Great post, I agree 100%
 
James,

The answer is yes and yes. All Eagle cranks were stock stroke / narrow journal.

Neal

Ah, good to know. PM'ed Mike B and will see what we can come up with after he gets back from BG. Speaking of BG, why is everything on the wrong coast? :biggrin:

Thanks for all the inputs guys, truly appreciated!
 
I think Dan Strezo (DLS) keeps wide journal rods in stock, and cranks to go with them. Definitely worth a phone call for advice. A few years ago when the CAT's had been around for a year or so, I think people were estimating that they would be good for 700-800 hp, or maybe a little more. That's stock stroke narrow journal. You can probably find some posts here in the archives with some searching.
 
I think Dan Strezo (DLS) keeps wide journal rods in stock, and cranks to go with them. Definitely worth a phone call for advice. A few years ago when the CAT's had been around for a year or so, I think people were estimating that they would be good for 700-800 hp, or maybe a little more. That's stock stroke narrow journal. You can probably find some posts here in the archives with some searching.

Thanks, I will keep Dan in mind. I talked to him last week about the bore of the block. Better keep him on speed dial!

I would assume wide journal CAT or "CATish" would be a little higher HP, but not much more. Not 100% sure what HP I will be looking at, but want to be safe so will prob upgrade.
 
OK so how much overlap difference is lost when going with a small journal 3.625" stroke vs a large journal 3.625" stroke? What does this translate into difference in strength.

Does anybody have any evidence of a broken small journal crank that was in a motor and then you replaced it with a large journal with out any further problems. or something like that.?

I would like to know, for my application of around 950 ft/lbs, 900HP, will I destruct a small journal crank in a 3400lb GN? I only ask because the only new cranks I can find are small journal. Yes I have already talked with DLS about availability.

Thanks
 
I was going to attempt to answer this but wanted to be clear as to whether we were talking about narrow journal vs wide journal or stroker crankshafts with smaller rod journal diameters?

Neal
 
Well I was doing some run of the mill research and I found no real description of wide vs narrow journal only large and small (diameter). I guess I figured the terms were interchangeable. Now I realize they are not. So does anyone have good information and experience on when a wide journal is a must have or nice to have. Right now I am guessing the 1000HP mark.

Thanks
 
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