Minimum connecting rod side clearance... It's a factory crank stroker deal...

[bluef100fe]

2.2 Chevy rod journal if that matters. Thanks in advance. Charting new territory for me

[blykins]

The aftermarket crank/rod combos usually come in anywhere from .020-.025".   I personally wouldn't go any lower than .016-.018" on side clearance although you could probably get away with a little less. 

[bluef100fe]

 Brent, is that 0.020-0.025 per rod or per rod journal? (Pair of rods) just to clarify.

Thanks again,

Cody Ladowski

[blykins]

Pair.  Throw both rods on the throw, spread 'em apart and shove a feeler gauge in between.

[bluef100fe]

Thanks for clarifying Brent

[Barry_R]

Brent's measurements are accurate, but I've run them much tighter when I "had to".

Somebody once gave me a minimum value of 4 times bearing clearance.  Don't know if that was "real data" or just a made up number to get me out of his office.  I had an engine with really tight side clearances of just under .010 and a "yesterday" deadline.  Ended up just running it and it performed very well for a long time with no ill effects.

Came away thinking that side clearance was once of those things where you had to have some....

[410ranchero]

Barry, do you happen to know what oil temps that engine had vs one with the more standard .020-.025? I've never ran one tighter than .018, but never done a A-B-A test to see.

A fair bit of oil moves through this area, and the tighter it is, the hotter the bottom end would be(according to Vizard in a  few of his books). In theory it makes sense, but we all know how theories hold up in the real world haha

[blykins]

Seems like every Scat 331/347 combo I do has really tight rod side clearances when I measure during mock-up.  I think a lot of the combinations that utilize a factory FE crank with Scat H-beam rods do as well.  I always have the rods surface ground on one side to open the clearances up. 

As Barry shows, may not be necessary, but we get into the habit of going back to "what works" from past experiences. 

[Ford428CJ]

The old boat runs a side clearance of .015. A little tight I thought for a boat set up but it does work. Doesn't mean it's right LOL

[My427stang]

Late to the game here but I tend to like .020 as a round number.  That being said, there were years as a young guy I didn't even check it...if it had movement, I called it good, so much the same as Barry said

I do check it now though, and I try to pair up rods to make the clearances similar after a quick deburr, then I make a decision whether to cut or not.