I just got a phone call from the guy buildin g my engine, that my side clearance ended up being nearly .030.

For street/strip applications, is this way too much?

i understand desirable is 8-12... but... i cant spend $800 on another forged nitrided steel crank to be reground and balanced again. total cost of this crank was nearly $1000.

What can i do?

 

bump...

 

anybody got an idea?

the side clearance i am reffering to is the clearance betwen the two rods on the one journal.

 

you have .030 with all new parts? you're more than double the max tolerance. rod side clearance is about the least thing i'd worry about as far as the specs go but being that far out i'd be looking at something to figure out what the problem was and correcting it.

 

well rods are exactly correct, rods had nothing done to them.

i purchased the crank off ebay, guy had 2 runs on it he went to a 3.75in stroke, and i had the machine shop do whatever needed to be done.

so .030 is double max tolerance?

darn...

 

bump......

 

How did the machine shop do whatever needs to be done, but then they call you and tell you your tolerance is .030" like its going to be okay. Are you sure this engine builder knows what he's doing?

 

machine shop and engine builder are two different people.

I called them today, and they said if the crank was ground that far off, they would replace the crank. So i have to bring it to them and have them replace it, only bad thing is, i gotta pay for it all to be balanced again.

 

update:

turns out, after i got there to the machine shop, they wanted to have me bring everything already assembled. I did this. they cheacked my rod side clearance, and it was indeed, .030, but since other things i have, they said this wouldn't hurt a thing at all.

My 7 quart oil pan, high volume pump, and gm high pressure spring, would subdue just about all that could come bad from this.

There will be more oil leaked and maybe sprayed on the bores, but my rings will rid them of it, and it can also help lubricate the rod sides and have a cooling effect.

thanks for the help guys...

 

Sounds like a bunch of sunshine to me.

 

Rod side clearance should be around .012 - .016". You've got twice that.

Somebody messed up something.

What will happen, is your rods will hammer the Spirolox out the sides of the pistons; and destroy your cyl bores.

The builder can't "build" side clearance away.

Whoever worked your crank, and/or whoever worked your rods, need(s) to fix this.

 

spirolox? these are bushed rods? Either way, the tolerance is there for a reason i'd think...

Then they measured it, and was indeed .030".... Sounds like they are ready to fulfill their end of the bargain, getting you a new crank. If they worked the crank, and are therefore to blame on making it out of whack, then they should be responsible for replacing your crank to get you back to where you should be, ie, a fully balanced setup. They should be eating the cost of the new crank, and balancing, since it's their mistake. If they blame the rods you can easily caliper/micrometer up your rods, .030" off should be easy to tell. (if, 2 rods being collectively .030" skinny...) Then you can blame whoever supplied the rods.

If I was paying a machine shop and engine builder to do this for me, i'd expect nothing less then perfection, that's how they earn $80/hr, if you wanted it half assed you'd do it yourself

 

things are, guy balanced the rotating assembly on the side, not through the machine shop.

Machine shop explained all that this could do, and the possible benifits as well, and after i left did make a good effort to call every machine shop in town(like over 20) and they all pretty much said the same thing. Rod side clearance in performance/race motors is normally higher then a "stock" rebuild anyway, as most said. The exitiing oil makes its way to a lot of things that could use it.

 

tell em you want it replaced and ground correctly!
make sure they give you the same exact crank too,not some stocker or other b.s.!
Eric B