A.R. Shale Targa

iTrader: (2)

KCS

iTrader: (20)

The #8 piston just barely hit the reluctor at bottom dead center. That was fixed after about 15 minutes in the end mill as only about .015-.020" was faced off the pin boss. There's still .100" of material in front of the groove for the spirolocks.



The rod bearing clearances are set. With standard bearings, the clearance is .0028"-.0030" which is a little looser than what I was shooting for. However, with half standard and half .001" under, I'm getting .0022"-.0024" which is a little tighter than I wanted, but it will still work just fine.

After setting the bearing clearances, it think it's worth mentioning that the journal diameters on the K1 crank are all on the low side of the tolerances. For example, the rod journals are supposed to be 2.0990"-2.1000", and the K1 journals were all right at 2.0992". This is probably pretty smart, IMO, since you're pretty much forced to run a looser clearance which is usually needed in a performance engine.

speedtigger

iTrader: (16)

My Callies kit came in at .0026" on the rods with the bearings supplied.

KCS

iTrader: (20)

That's where I would have liked to have been, .0024-.0026" but it doesn't always work out that way.

Quick Ranger

iTrader: (2)

The rod bearing clearances are set. With standard bearings, the clearance is .0028"-.0030" which is a little looser than what I was shooting for. However, with half standard and half .001" under, I'm getting .0022"-.0024" which is a little tighter than I wanted, but it will still work just fine.

After setting the bearing clearances, it think it's worth mentioning that the journal diameters on the K1 crank are all on the low side of the tolerances. For example, the rod journals are supposed to be 2.0990"-2.1000", and the K1 journals were all right at 2.0992". This is probably pretty smart, IMO, since you're pretty much forced to run a looser clearance which is usually needed in a performance engine.[/QUOTE]

Looks like the K1 crank is a decent crank for the money.

Couldn't you coat the standard rod bearings like you did the mains to close it up?

KCS

iTrader: (20)

Yeah, that's certainly an option. The coating usually reduces clearance by about .001", so that .0028"-.0030" with the standard bearings would end up .0018"-.0020" or less. I would probably send off a half set of standards and a half set of "X" bearings to get coated, which would put me around .0023"-.0028". I would have to wait a week to get them back from coating, but now as I'm sitting here thinking about it, its probably the smart thing to do. The rod bearings are usually the first to go if there's any oiling issues so having a little extra margin of safety seems like a no brainer.

I could always work on the heads in the meantime.

KCS

iTrader: (20)

I stabbed in a 243/251 cam with a 112+4 LSA. The cam almost hits the rod, maybe .020" clearance.

speedtigger

iTrader: (16)

How much lift?

KCS

iTrader: (20)

It's a .372" lobe. The cam I spec'd for myself is slightly bigger but same lift.

speedtigger

iTrader: (16)

Kip said he could grind you a .020" or so smaller base circle cam no problem. That'll get your clearance up.

KCS

iTrader: (20)

I'll keep that in mind. I'm looking at another option right now which could help without having to do a smaller base circle or lobe offset.

LS6

If possible, to post a picture of the reluctor wheel interface with the piston boss

KCS

iTrader: (20)

I had a picture, but I guess it got deleted or something by accident. The OD of the reluctor went up to the pin bore and the side just barely kissed the piston pin boss. It took about 15 minutes to face off the pin boss to clear the reluctor, which will give you an idea where it hits.

LS6

Impressive detailed work

Did you mill all the pistons boss in the same manner to have equal pistons mass weight to have an equal acting mass forces on the crankshaft?

With this modification, this will require to re-balance the rotating assembly.

KCS

iTrader: (20)

Nah, just #8. It was hardly any difference in weight. Aluminum is about 2.6g per cc, so with so little material removed, the weight is negligible.

KCS

iTrader: (20)

So I ended up swapping out the Compstar rods for K1 rods. The weight was close enough that the crank didn't need to be rebalanced either. Whats interesting about the K1 rods is that they don't give you a torque value for the 7/16" ARP 2000 rod bolts. Instead they give you a stretch value and a torque-to-angle value. These rod bolts go to 30ft-lbs plus 50 degrees, which ended up being about 85ft-lbs. With a set of coated Federal Mogul rod bearings, I ended up with .0026" clearance.

After final cleaning everything, I oiled up the cylinders and finally assembled the shortblock.

Quick Ranger

iTrader: (2)

KCS, was the pin clearance on the K1 rod as good as the Compstars? I know I've seen you say in the past Scat rods needed the pin clearance honed a bit.

KCS

iTrader: (20)

The K1 and Compstar rods were both at about .0009" which will work on most street car builds. The Scat's were closer to what a stock engine has at about .0005", which IMO, is too tight for a performance application. With the long stroke and the potential to see 7500-8000 RPM, I opened them up a little further to .0012".

speedtigger

iTrader: (16)

Nice tidy solution.

Quick Ranger

iTrader: (2)

So, In your opinion, how do the K1 rods compare to the Compstars? I'm looking at rods for my build, 403. I was stuck between the Compstars, and K1.