Well today I finally put the small base circle into the motor, got the timing chain on and cranked the motor by hand and checked for clearance. And all the rods cleared the cam!!! But then I ran into a more serious problem. The number 1 and 2 rods that connect to the journal do not have any play (side to side movement). All the other three journals that the rods connect to have play of about .0120” It seems like the length of the journal with the 1 and 2 connecting rods is just a hair too small. Tomorrow I am going to be measuring the lengths of all the journals with a digital gauge that my friend is letting me use (I forgot the name of the tool). I don’t know if this problem is common but if it is too short than Ill just take it to the machine shop and have them fix it. Ill keep my build updated and I hope that I remember to take some pics tomorrow.

 

You might just be able to take some material off the rods yourself.

 

I was thinking about that but I don’t want to run the risk on over doing it and then needing to rebalance the assembly.

 

It's really hard to overdo it. Rod side play isn't all that critical anyway, as long as it's not too small.

 

yeah, you would have to really grind on them to screw them up. Take a flat plate- metal, or glass, and lay a piece of sandpaper on it, like 480 or 600 something like that, and just pass the rod over the paper. the plate underneath will provide a true surface for you, and just go slow. You might want to Mic' the width of the rods and see if they are out of spec. One might be thicker than the others, so concentrate on that one. I know it will be tough with the piston already on it, but just make sure you put even pressure on the big end.

if you're not confident, you should refer to your machine shop however. They'll most likely put it on a belt sander, and pretty much do the same thing, just a bit faster.

one thing to check too, make sure that the rod is not binding on the side of the piston, if they are pressed pin, sometimes, if the pin is not centered correctly, it will kind of jam the rod against one side, and give the illusion that the side clearance is wrong. take one rod/piston off and see that the other rod can move back and forth.

are these parts all new? resized, etc? most rebuilt parts shouldn't have an issue, unless you have a stack-up in tolerance.(like, both rods are on the high side of spec, and the journal width is on the small side). new parts, that have never been assembled, well, sometime youhave to watch for these things.

good luck!

 

I have seen this 2x last year. They were both Eagle cranks.

 

Make sure the rods are on the pistons the right way. That would be, with the tangs that hold the bearing halves in place, facing downward (away fron the cam).

Sounds weird I know, but: typically, aftermarket cranks have a radius fillet where the rod pin meets the throw. Rod bearings are not "symmetrical"; they have a chamfer on the side that's supposed to be the "outside", to avoid riding on the fillet. If the rod is on the piston backwards, then it will force the non-chamfered edge onto the fillet, which will jam the rods together in the center; and may even bind up the crank so bad that it's hard or near impossible to turn when you torque the rod bolts down.

The cure, if the tangs are facing the cam but the pistons are right, is to exchange the 2 R&P assemblies (put #2 in #1 and vice-versa), if they're 4-valve-relief pistons; or, if they're 2-valve-relief pistons, pull them out and turn the pistons around on the rods.

 

My suggestion:
Don't grind a DAMN THING until you measure and pinpoint what is out of spec. If there is that much difference (.012) in one assembled throw and another there is something that is WAY wrong. The tolerances in the bottom end are +(-) .00015 in some places. The reason I'm saying this is a rod that is not straight will have this problem. When the big end is put on the throw it will hug one direction. I have run into this before. Here's what I mean:
(exaggerated)
Piston> [|---,,,__ < big end
Or if it is bent like this: Little end> _____/ < big end

Or if it is bent like this: Little end piston pin> \--------- < big end
(Forgive the crappy art)
A rod that is not straight should be pitched with a clear conscience and champagne promptly bought in celebration that it was discovered during assembly and not when it stuck thru the side of the block.
And yes, new parts can be "not straight". All it takes is for the guy putting them in the box to drop one on the floor or typical shipping.
If the width of the crank throw is .012 not wide enough, put the crank back in the box. If a rod is too wide by .012 put them all back in the box. You get one shot at putting together the bottom end of a hi-performance motor. Everything must be within spec, the first time!
While I'm hanging my hiney out for flames I'd like to respectfully disagree with Ape about excessive side clearance not being a problem. It has everything to do with oil consumption. It puts excessive oil on the cylinder walls and overloads the rings. One of the more frequent causes of a rebuilt engine that uses oil with a new bores, rings, and pistons. Only to find that when the crank was ground the guy couldn't resist "cleaning up" the side faces of the journals.
Exit soapbox.

 

Probabily the rods in backwards like stated above.

 

If that is the case, I give that engine a 25% chance of survival even after the rod is corrected.

 

Side clearance on the rods DOES have a spec, but it's a fairly wide range of acceptable measurements. But first, here's how you actually measure it:

Insert screwdriver between the two rods and pry lightly to separate them. Insert feeler gagues BETWEEN the two rods and find the clearance on a go/no-go basis. Example: .012" fits, .015 does not you then know the clearance is around .013-.014".

Acceptable range: .008" (squeaky tight) to .025" (real loose). Somewhere around .015"-.020" is where you want it ideally.

 

I really love this check. It is in every SB rebuild manual.
But nowhere does it say what to do if the clearance is too big.
Pull the crank and have it "un-ground"?
"Over-wide" rods? -sorry, don't make'em.
Put in a new crank? -just for side clearance!? Not.
BTW, spec is .008 to .014 for early engines and .006 to .014 for late. And remember, over .015 is too worn out.

 

Those specs sound right for factory applications. For performance applications .020 isn't uncommon.