Any small block Chevy engine builders care to help?

[2QWIK4U]

Well I've built alot of engines in the past and the easiest in the world has me stumped??!!I'm putting a 350 together (again) for my dirt track car.(It is a 86 Regal)Every time I start torqing (sp?) rod bolts down the motor LOCKS UP!!!So I think the crank is bad,it was .001 on rods and mains.I get another crank that is .20 rods and .20 mains,new bearings and it still locks down!!!If the rods aren't in, the crank will turn over easily with the main caps torqued.I checked all the rod caps and they are correct on the correct rod,all bearings are Federal Mogul and seem correct.The only thing I can think of is that some of the rods are bent???Any ideas or lessons learned from past experiences will be greatly appreciated!!!!

 

[sixgun86gn]

I would check the rods for being bent or out of round.

 

[chevyII]

start mearsuring sound like wrong bearings/mispackaged?

 

[steve hughes]

Rods aren't in backwards are they? The tang that holds the bearing should face the outside.

 

[REDS HOT AIR]

let me guess 4 vale relief flattop pistons?

sounds like you got some rods backwards

with the bearing in the rod you will notice that the bearing is off set to one side of the rod

that is because there is a radius at the edge of the journals on the crank

long story short the bearings should ride closer to the center of the journal

 

[2QWIK4U]

I appreciate all the replies guys.I thought about the bearings being wrong but 2 diiferent cranks .001 and .020 and same results,had them checked and they are ok.This bottom end was only taken apart so the pistons haven't been off the rods and I've made sure a dozen times that all the "tangs" are turned correctly and the only thing I can think of is that the rods are bad?!Funny thing is that all the bearings looked pretty good when the rods were taken out of the engine to start rebuild,took apart cause of broken ring.

 

[myclone]

Originally posted by 2QWIK4U
I appreciate all the replies guys.I thought about the bearings being wrong but 2 diiferent cranks .001 and .020 and same results,had them checked and they are ok.This bottom end was only taken apart so the pistons haven't been off the rods and I've made sure a dozen times that all the "tangs" are turned correctly and the only thing I can think of is that the rods are bad?!Funny thing is that all the bearings looked pretty good when the rods were taken out of the engine to start rebuild,took apart cause of broken ring.

Were the rod bolts been replaced during the tear down? How bout being over revved and using the stock rods and bolts? Ive seen a couple of engine that were over revved constantly that ran fine but after tear down the big ends "moved" (for lack of a better term). My theory was the rods were stressed from the constant over revving and when the bolts were loosened the big end kinda "sprang". Lousy description I know but its the best I can do.

Ive also seen this happen when rod bolts were replaced by beating them in with a hammer instead of using a press. Same deal here that the big ends of the rods "sprang" and went way out of tolerance.

Anyways, if the crank mics ok then its either the big end of the rods have issues or the bearings are the wrong thickness.

 

[REDS HOT AIR]

are you sure the rod caps are going back on the right rods ?

were they numbered

 

[frankg]

Either the rods big end is the wrong size or you have the wrong size bearings in them. When tightened with zero oil clearance it's like a vise. That or a rod is bent?? Does it stop spinning after just torquing one rod?? Frank

 

[2QWIK4U]

Dropped rods off at machine shop last night and he just called and said they need to be resized.May even have one bent rod he said.I just told him to fix it,especially when he only charges $6 a rod to resize.

 

[chevyII]

I have a set of crower 6" rods new if needed,will make a good deal. send a PM