side to side rod gap

[Don selleck]

currently putting together a rotating assembly, On the 3-4 rod journal on the crank I'm getting .030 between the rods. rest are within stock spec. Stock dimensions spec between .0060 and .014. Called the balancing/stroker kit guys I purchased it from, they say up to .040 is acceptable for aftermarket assemblies. Sounds like a way to make me go away for now, not sure. Would hate to completely assemble this and have an issue. Any engine builder guys have any thoughts on this, thanks for your time.

 

[440Coronet500]

I had the same issue using SCAT rods on a 340 build. Engine ran well but had low oil pressure. Cold 60 psi, Hot 20 psi at idle. Too low in my opinion. 440

 

[Don selleck]

Imagine that,

 

[pnora]

I had the same issue using SCAT rods on a 340 build. Engine ran well but had low oil pressure. Cold 60 psi, Hot 20 psi at idle. Too low in my opinion. 440

Side clearance will not affect oil pressure.

 

[pnora]

currently putting together a rotating assembly, On the 3-4 rod journal on the crank I'm getting .030 between the rods. rest are within stock spec. Stock dimensions spec between .0060 and .014. Called the balancing/stroker kit guys I purchased it from, they say up to .040 is acceptable for aftermarket assemblies. Sounds like a way to make me go away for now, not sure. Would hate to completely assemble this and have an issue. Any engine builder guys have any thoughts on this, thanks for your time.

We ran into that years ago and was told don't worry about it. I do not remember the numbers but about twice as much as the factory specs.

 

[Don selleck]

I have conflicting answers here talking to some friends also, I was also wondering about the rod bearing clearances effecting the pressure more so than a sloppy cut on the journal, since its basically a thumb over the garden hose thing, if you get my meaning.

 

[DanielSlocum]

Aftermarket rods lack the holes that spray oil up towards the cylinders and cam. Therefore,more side clearance is probably good to sling more oil in that general direction.

 

[RemCharger]

It has to squeeze through. 002 - first. Then just bleeds out the side gap regardless of size.
This topic bubbles to the top again every so often.

 

[Don selleck]

That makes sense.

 

[dvw]

Before all the aftermarket cranks and rods showed up it was common to run BB Chevy width on a Mopar crank turned down to Chevy diameter. The Chevy width .995" vs Mopar 1.007". you can see that added roughly .024" to whatever the clearance was going to be to start with stock rods. Did it bother anything? No. the restriction in oil flow is the rod bearing area which is far smaller than any normal side clearnce figure. Many current high end race engines run piston guided rods with huge side cleaance. There are plenty of items that need scrutiny in a good build. Extra side clearance isn't one of them.
Doug

 

[steve340]

Sounds like the crank grinder caused the problem if you have 3 in spec. That one journal may well be wider. Conrod widths (assuming they are a matched set) usually within a thousands or maybe 2 at most.
You cannot do much about too much side clearance.
The wider rod side clearance will not be a problem. Just check they cannot rub on the piston boss and run in the middle of the wrist pin.

 

[Bird 426]

All of my Molnar rods are loose on my stroker Molnar crankshaft. Have no problems.

 

[Don selleck]

Thanks to all, In the past I have had the rotating assembly done and I finish the rest but, Hard to find someone that's competent, being the older guys retiring etc. The price of parts are nuts and a rebuild, especially a modified one is a major investment. I'll have over alot into this and just freaked out by something being this far off. thanks again for all the info.

 

[dvw]

I've got 3 going right now. 535" street engine. Just recieved the head gaskets today, short block is done. Refresh on my 580" wedge out of my racecar. Every thing except pistons, rods and crank is apart and cleaned up. Need to pull the heads apart as well. Leaked it before disassmbly. Pretty much 10% accross the board cold. Oil filter was spotless when it was cut. So hopefully it won't need to much. And a 588" Hemi coming next week. It's been measured and clearanced but needs to be assembled. Just finished a 727for a 416 stroker The racecar trans got a tune up this week as well. Got to stay busy to stay young.
Doug

 

[Don selleck]

very nice, I got a 86 grand national going back together after a descaling, under body paint and basic going thru after sitting, then an outer body disassembly getting ready for a new paint job. should be finished up by the weekend, and shippping it to a friends paint shop, then back to the cuda engine over the weekend, then off to Ann Arbor to frame some walls early next week and a suspended ceiling in Belleville after that. while coordinating 6 other drywall jobs from Devils lake to Brighton Not feeling so young though, but keeps me busy and out of trouble. Sounds like I need too contact you on the next engine build if your so inclined,