Nordicflame

OK,
After Assembling a Callies crank and Callies Compstar rods it was found that the rod side clearance ran .031. The rods measure .990 wide and the journal is 2.011 on all 4.
I sent this back as unacceptable and the retailer did not hesitate replacing it stating that they usually run 2.000 wide.

Well we got the second one and you guessed it, 2.011 wide.
Time to call Callies!
I am awaiting a second call back from Callies but thier initial response was that .031 is no big deal and that 2.011 is just a couple thou over their 2.005-2.009 spec. (still not in spec regardless)

He wanted to know where I was getting my .010-.023 range so I told him Mercruiser, Mercury Racing, GM, etc...

We upgraded to Callies rotating assembly for peace of mind

Is .031 an uncomfortable range or am I splitting hairs here?

mrhorsepower1

.031 is on the wide side. I would rather see .020 with a max of .025. I would call them.

DesertRage

Mrhorsepower,

In your experience, is this situation the product of the crank journal width alone or a combination of a wide crank journal and narrower than normal rod? I am wondering what other manufacturers crank and rod widths are.

Thanks,
Jon

BillK

nf,
This seems to mainly be a rod issue. I dont know why, but for some reason most of the aftermarket rods are .990, the factory GM spec is 1.0" Thats a .020" difference when you add the two rods together. The factory GM spec for side clearance is .013-.023. Of course if your rods were 1.0", you would be down to .011 side clearance which os probably a bit tight. I really dont think that .031 will cause any problems in the real world. Does not make it right though. Should be interesting to see what they say. I have two Callies small block cranks at the shop, I will try to remember and measure them Thursday and see how they are.

Bill Koustenis
Advanced Automotive Machine
Waldorf Md

mrhorsepower1

Generally, Aftermarket rods such as crower,Oliver, manley, ect....set the rod width at .990-.991. In this case, the crank width is actually the issue. Most higher end cranks measure 1.998- 2.000. This places you in the range of .018-.020 side clearence. A very good range I like to be at. Wider side clearance will "bleed" off more oil.

Nordicflame

Thanks for the views…
I agree that the crank certainly is not in spec and at first thought I believed it would throw excess oil as well but now I’m rethinking this a bit and would like to get some more specifics and/or views.
This doesn’t seem to be a topic that gets a lot of attention so brainstorming is now in session…

Correct me if I’m wrong but after sitting down and doing the math, rod side clearance should not throw any more oil whether it’s .010 or .030. I’m thinking that the oil flow out of the bearing clearances is what controls oil evacuation in this area. The total oil evacuation area through the bearings on a .0035 clearance motor for one throw is appx .048^2” (4 X .012^2” for each bearing side). The evacuation area for a .015 side clearance is around .104^2”. With this in mind the only time side clearance would influence oil flow would be if it was too tight (around .0070) thus creating a restriction. After this amount why would it matter if it was .010, .030 or even .040 as some of the Mopar and aluminum rod stuff runs at? The same amount of oil will be thrown off regardless of the side clearance due to the closely controlled evacuation of the bearings?
In comparison to other tolerances (i.e. bearings and such) a .013-.023 sounds much more like a comfort zone range than a spec and possibly based on original GM stuff. This can be witnessed in the Mercury Racing specs as well. The motors that use standard GM parts like the HP500, 502s, 454’s etc, all are spec’d at .013-.023 yet when you get into the high end Mercury motors that use Lunati cranks and Carrillo rods they are spec’d at .020-.026. Is this likely based on the fact that the aftermarket rods are narrower and the crank throws wider?
Just a thought…

Side note: Callies measured every crank they had and all were 2.010-2.011 and they just sent $35k worth to Mercury Racing.

Thanks for your input,
Dave

BillK

Dave,
I measured 3 stock GM big block cranks today at the shop and they were all close to 2.010" I did not have any stock rods to measure, but one set of Eagle's measured .990 Like I said in my other reply, I really dont think you will have a problem at .030" Your calculations seem to agree.

Bill Koustenis
Advanced Automotive Machine
Waldorf Md

mrhorsepower1

Stock rods vary from .992-.994 .

Raylar

I don't like to see combined rod side clearance above lets say .022 to .025" in non-racing engines as clearances above this lets say .030" will tend to flip more oil up to the cylinder wall than needed and oil comsumption can suffer and it will also have a slight effect on horsepower.
With larger bearing clearances on bearings the rods or higher oil pressures this will amplify.
I just measured some of our cranks and rods from the 496 engines and crank journal width seems to be around 2.006" and rods all come in at .991 to .990".

Maybe this is that "China Thing" again?

Just my thoughts.

Regards,
Ray @ Raylar

Nordicflame

Thanks for the input again Gents

Ray, it appears you’re in a similar situation with your hardware. If your journals are 2.006 wide and your rods are at .990-.991 your number would be .024 and range to .026 which is well out of the Merc standard specs of .013-.023 and at worst case even at the high end of the Mercury Racing spec of .020-.026 (on the motors that use aftermarket crank and rod combos)
From the data I’m gathering it’s not appearing to be an issue anyway and maybe favorable.

Again, unless I’m missing something, simple physics and math (as shown in my post above) tell me that a motor spinning at a stated rpm with the same bearing clearance and oil pressure would throw the same amount of oil out regardless of whether the side clearance was .010 or .030 as the oil flow out of the throws is controlled completely through the bearing clearance.
The side clearance, by math, seems to have no issue on the oil evacuation of the throw. It seems the only time it would adversely affect the oil throw off of the journals would be if the side clearance was too tight which would restrict the escape route possibly causing other issues

I have spoke in depth with Callies about this and this is their take…
It seems most of their customers are requesting that this clearance be on the high side which is why they are building them at this end of the spec. They have offered up a written guarantee to cover any damage associated to this condition including excess oil consumption and adamantly state that “only” the bearing clearances control oil throw from the journals.
(I think these guys have probably spent plenty of time watching videos of spinning assemblies!)
They also mentioned that the trend is going (as witnessed in NASCAR and many European performance engines) to controlling side clearance thru the piston pin boss and have rod side clearances in the .100+ range.
Just more info to chew on I suppose…
Enough that the short block is going together tomorrow with peace of mind

Thanks All,
Dave