Clearance

[Schiada76]

I went .070 over.
I needed new pistons anyway I had SRP's before and they varied .005 .006 bore clearance on this tear down. I was told the SRP "blower pistons" aren't worth squat so I got the JE's.
Is this just one of those unforseeable occurances or is the crank to skirt clearance always checked?

[Infomaniac]

You always look at that clearance. It is not usually a problem.
I think the combination of big crank counterwieght and short rod is what caused the tight clearance for you. Not a problem now that you caught it before running it.
I hate taking everything back apart also.
Builds character and patience.
[ November 17, 2002, 12:10 PM: Message edited by: Infomaniac ]

[Schiada76]

I'll find out tomorrow where the finger gets pointed, crank or piston.
Info would you recommend I leave it assembled for a profesional looksee? That's what I'm figuring right now but I'm dying to wrench on something. Maybe I'll just go out and polish the blower again.

[Infomaniac]

BradP:
I'll find out tomorrow where the finger gets pointed, crank or piston.
Info would you recommend I leave it assembled for a profesional looksee? That's what I'm figuring right now but I'm dying to wrench on something. Maybe I'll just go out and polish the blower again. You might haul it over to whomever clearances the pistons for you so they can see exactly what is going on. I assume you are going to gain the clearance on the piston because you are already this far along in the project. Taking your chances on the balance.
Fiat 48 had the best advice by having the crank turned down a bit. The crank has the most extra material so to speak and will be the least effected by material removal (strength wise).
Rebalance also. Recheck at least

[Kurtis500]

The crank counter balance is rubbing a piston skirt when the piston is at BDC. The block is fine on clearance for the stroke but the %$&&&skirt is rubbing on the crank. It's a scat crank with JE custom fabbed pistons. Shoudn't this be a fairley "stock" after market setup?
Chevy stuff, I should have known. I run a 7 inch rod in the hemi, probably why counterbalance interference is a non-issue. No wonder I got confused on the skirt clearances sorry

[Kurtis500]

What did you mean by-----I also have 8 buttons in each piston to guide the skirt on the wall.I hope I didnt confuse you too
They are teflon buttons that are inserted into machined holes that are drilled into the skirt of the pistons. 4 Holes on each skirt, with 8 teflon buttons in each piston.

[Schiada76]

Kurtis500:
The crank counter balance is rubbing a piston skirt when the piston is at BDC. The block is fine on clearance for the stroke but the %$&&&skirt is rubbing on the crank. It's a scat crank with JE custom fabbed pistons. Shoudn't this be a fairley "stock" after market setup?
Chevy stuff, I should have known. I run a 7 inch rod in the hemi, probably why counterbalance interference is a non-issue. No wonder I got confused on the skirt clearances sorryHemis are the shit, no doubt. We low buck guys gotta stick with the BBC though.

[Fiat48]

BradP:
Thanks for all the replys. The rods are right (6.135) so maybe I got a crank for a tall deck. The areas I can get to have only about.008 clearance so I'll get everything back to the machinists on Monday.
Fiat I threw you a five to make up for whoever ypu PO'ed. That's probably the deal. Most guys run a .250 long rod or longer when using the aftermarket stuff. Usually the crank info states "minumum 6.375 rod" when you order. Guess yours didn't.

[Schiada76]

The crank box says 4.25 w/6.135 rod on the box (just checked when I put it in the truck). I was thinking though if it was for a tall deck by mistake wouldn't it hit the block?
eek!
[ November 17, 2002, 03:43 PM: Message edited by: BradP ]

[Infomaniac]

Wipe the dirt off the box.
It probably says 4.25 w/6.135 rod except custom J&E piston
LOL J/K