One more time, rod side clearance

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One more time, rod side clearance

Post by Truckedup » Fri Apr 06, 2018 8:50 am

Ok...In general, will excessive connecting rod side clearance increase the amount of oil thrown around and or increase oil consumption? Or does the diametrical bearing clearance have more influence on oil control? Anyone have actual experience on multiple engine builds? Thanks
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Re: One more time, rod side clearance

Post by Walter R. Malik » Fri Apr 06, 2018 9:14 am

Truckedup wrote:
Fri Apr 06, 2018 8:50 am
Ok...In general, will excessive connecting rod side clearance increase the amount of oil thrown around and or increase oil consumption? Thanks
NO ...
unless you don't have enough to start with or more side clearance will uncover the oil supply hole in the crankshaft.
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Re: One more time, rod side clearance

Post by PackardV8 » Fri Apr 06, 2018 11:34 am

will excessive connecting rod side clearance increase the amount of oil thrown around and or increase oil consumption?
Been covered here several times and answer is no to both.

BTW, we might guess several of your bench racing friends warned against increased rod side clearance. "More side space, more oil escapes, just makes sense." This is one of those which fits Mark Twain's, "It ain't what you don't know that gets you into trouble. It's what you know for certain that just ain't so."
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Re: One more time, rod side clearance

Post by Truckedup » Fri Apr 06, 2018 12:04 pm

PackardV8 wrote:
Fri Apr 06, 2018 11:34 am
will excessive connecting rod side clearance increase the amount of oil thrown around and or increase oil consumption?
Been covered here several times and answer is no to both.

BTW, we might guess several of your bench racing friends warned against increased rod side clearance. "More side space, more oil escapes, just makes sense." This is one of those which fits Mark Twain's, "It ain't what you don't know that gets you into trouble. It's what you know for certain that just ain't so."
Yup I have heard that many times,even from some experienced engine builders...In Speed Secrets , Smokey Yunick mentions that excessive rod side clearance will throw too much oil onto the cylinder walls....
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Re: One more time, rod side clearance

Post by SupStk » Fri Apr 06, 2018 2:18 pm

Common sense seems to dictate, diametrical clearances will have more effect on oil flow than side clearance. Unless the side clearance is extremely tight.
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Re: One more time, rod side clearance

Post by maxracesoftware » Fri Apr 06, 2018 2:57 pm

in late 1970's & early 1980's i was doing Machine work + rebuilding + assembling Chevy SBC350 BBC454 and International Harvester 345cid Engines
for 2 Oil Field Companies for their Fleet Hot Shot Trucks these Hot Shot Trucks routinely get 200,000+ miles on their Engines

started using a new Machine Shop to rebuild my Connecting Rods ,
he would grind + open up Rod pair side clearance to +0.025" and Chamfer big end diameters on each side at same time .

Before "open up Rod pair side clearance to +0.025" results ---> no real oil consumption problems :)
After "open up Rod pair side clearance to +0.025" results ---> definetly real oil consumption problems :evil:

now for these "before/after tests" on these various Fleet Engines ...
at that time i was using either [1]= Perfect Circle / Dana Piston Ring sets or [2]= TRW/Ramsco Piston Ring sets

when i saw these results , i quit using that Guy to recondition my Rods !
but it got me to start looking at Oil Ring designs

the TRW/Ramsco and the Perfect Circle/Dana oil ring designs effectively were "BLOCKING" oil flow thru the
oil ring groove back to the crankcase .

those Oil Ring designs would either BLOCK or prevent enough oil flow off the Cylinder walls
at the outside of the oil ring , or inside of the oil ring ( 2 different designs ... but same effects ) :evil:

so i started looking at Hastings and Sealed Power Oil Rings :
the Sealed Power version was mostly exactly like GM was using ... its design was able to effectively move oil off the walls
and funnel it back to crankcase

the Hastings oil ring design was also very effective in moving oil off the walls and funnel it back to crankcase

the Hastings oil ring design is a Vertical type ...its the "forerunner" of the current Total Seal Racing Oil Ring design
... it has the ability to effectively moves oil off the Cylinder Walls ... but at a lower Oil Ring tension , frees a little TQ and HP up 8)

the SpeedPro / Sealed Power Ol Ring design ... effectively move oil off the Cylinder Walls
... but at a little higher Oil Ring tension , so you don't quite free up a little TQ and HP , like the Total Seal / Hastings / Pedwrick Oil Ring design

so here's my Theory ,
if you are comparing whether or not excessive Rod Pair Side-Clearances increase oil consumption or not ??
...you should real-world test various Engines that would have :
TRW/Ramsco and the Perfect Circle/Dana oil ring designs
-VS-
Total Seal / Hastings / Pedwrick Oil Ring design

so that if you have a bad oil ring design with excessive Rod Pair side-clearance
it will then show up oil consumption with TRW/Ramsco and the Perfect Circle/Dana oil ring designs
and NOT so much or no oil consumption if you are testing that with :
Total Seal / Hastings / Pedwrick Oil Ring design or Sealed Power / Speed Pro or GM/Chevy designs 8)

test this out with 200,000 + mile Fleet Hot Shot Trucks :)
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Re: One more time, rod side clearance

Post by Charliesauto » Fri Apr 06, 2018 3:40 pm

Truckedup wrote:
Fri Apr 06, 2018 8:50 am
Ok...In general, will excessive connecting rod side clearance increase the amount of oil thrown around and or increase oil consumption? Or does the diametrical bearing clearance have more influence on oil control? Anyone have actual experience on multiple engine builds? Thanks
Are you familiar with piston guided rod technology? It's utilized by many of the NASCAR shops, has huge side clearance and I assure they are not interested in having any excess oil being thrown around in the crankcase.

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Re: One more time, rod side clearance

Post by maxracesoftware » Fri Apr 06, 2018 3:44 pm

Charliesauto wrote:
Fri Apr 06, 2018 3:40 pm
Truckedup wrote:
Fri Apr 06, 2018 8:50 am
Ok...In general, will excessive connecting rod side clearance increase the amount of oil thrown around and or increase oil consumption? Or does the diametrical bearing clearance have more influence on oil control? Anyone have actual experience on multiple engine builds? Thanks
Are you familiar with piston guided rod technology? It's utilized by many of the NASCAR shops, has huge side clearance and I assure they are not interested in having any excess oil being thrown around in the crankcase.
NASCAR also has the latest very best Hone equipment /profilometers etc + Ring sealing designs
and are definetly not going to go 200,000 + miles on a bad oil ring design with huge side clearances 8)
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Re: One more time, rod side clearance

Post by groberts101 » Fri Apr 06, 2018 3:57 pm

SupStk wrote:
Fri Apr 06, 2018 2:18 pm
Common sense seems to dictate, diametrical clearances will have more effect on oil flow than side clearance. Unless the side clearance is extremely tight.
Right. But nothing is completely set in stone, there aren't many absolutes, and stuff just plain wears out. So the words little or more certainly don't mean nothing. Anything at all no matter how small or seemingly immeasurable is still.. something. Now maybe it doesn't always matter in all applications or parts combos.. but it's still something.

And as Larry already eluded to some applications and combinations of parts might differ from others which were used as the yardstick for which some are basing their desicions and opinions on. Also consider that what was once marginal at controlling oil when new, especially at higher rpms for which it wss never originally designed, can become much less able to effectively do the job when stuff just plain wears out and gets tasked beyond its abilities.

Everyone gets caught up on oil pressure differences but what about oil shedding and cylinder to cylinder distribution of that escaping oil volume? Do the paired rods not gather up on common crank pins to change how much and where that accumulated clearance is aimed at any given time?

If rod side clearances had absolutely no affect whatsoever on oil control then everyone and their cousins would be cutting rods to mimic racers in the quest for reduced friction and it would also be built in from the factories as a win win. Less material, lighter weights, fewer tolerances with less concerns for quality control, no downsides whatsoever. That is not the reality and the first few junk motors that you toss together with less than ideal parts having massive amounts of rod side clearances will usually culminate towards excessive chamber contamination on some cylinders over others. That balancing of various effects is largely the reason we blueprint everything in the first place for improved consistency.

So yes.. imo, rod side clearances change the oil shedding distribution characteristics in a less than desirable fashion for some cylinders compared to others. So I'll continue to worry about it and blueprint accordingly with less regard towards frictional losses in trade for tighter combustion consistency with regard to cylinder to cylinder oil control.

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Re: One more time, rod side clearance

Post by maxracesoftware » Fri Apr 06, 2018 4:20 pm

Thanks ... groberts101 :)

i will add this :
i was using mostly Badger Open-Slot Oil Ring Groove design cast Pistons in these rebuilds at that time
and these Hot Shot Trucks depending upon if they were loaded up with gear to deliver or had nothing,
they either had light plenum vacuum or relatively high plenum vacuum
which compounds or brings to light => excessive Rod Pair side-clearance problems coupled together with a bad oil ring design
at relatively high plenum vacuum , stock oil pan designs , oil levels relatively close to spinning crank assembly , ETC

-VS-

NASCAR turning 9000 RPMs and such that there's hardly anytime left to even feed the Engine from killer Heads/Induction, much less time to burn oil,
relatively low plenum vacuum situations,and high-crankcase vacuum killer oil pan designs, best Hones, Piston Skirt Cam design , ETC.
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Re: One more time, rod side clearance

Post by Charliesauto » Fri Apr 06, 2018 5:57 pm

maxracesoftware wrote:
Fri Apr 06, 2018 4:20 pm
Thanks ... groberts101 :)

i will add this :
i was using mostly Badger Open-Slot Oil Ring Groove design cast Pistons in these rebuilds at that time
and these Hot Shot Trucks depending upon if they were loaded up with gear to deliver or had nothing,
they either had light plenum vacuum or relatively high plenum vacuum
which compounds or brings to light => excessive Rod Pair side-clearance problems coupled together with a bad oil ring design
at relatively high plenum vacuum , stock oil pan designs , oil levels relatively close to spinning crank assembly , ETC

-VS-

NASCAR turning 9000 RPMs and such that there's hardly anytime left to even feed the Engine from killer Heads/Induction, much less time to burn oil,
relatively low plenum vacuum situations,and high-crankcase vacuum killer oil pan designs, best Hones, Piston Skirt Cam design , ETC.

My contention is "excess" side clearance has little to no effect on the volume of oil flowing out of the rod bearing/crank area. NASCAR and other high level engine shops are hyper conscious of parasitic windage losses and go to great extremes(cam tunnels etc.) to limit the amount of oil the crank assembly is exposed to.

I think there is a guy on here who works for one of the more successful NASCAR teams, maybe he has some oil flow data with both scenarios?

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Re: One more time, rod side clearance

Post by maxracesoftware » Fri Apr 06, 2018 6:49 pm

a little more info : :D

early Pedrick forerunner similar oil ring design ( Vertical Type )
Image
https://www.picclickimg.com/d/l400/pict ... ing-MF.jpg

Total Seal and/or Hastings design ( Vertical Type )
Image
http://st.hotrod.com/uploads/sites/21/2 ... C596%3A373
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Re: One more time, rod side clearance

Post by Newold1 » Fri Apr 06, 2018 7:33 pm

Your contention that "excess" side clearance has no affect on oil consumption in an engine based on the single point that some Nascar engines in the past had very large rod side clearance and it was not an issue or reality ! Wow, this tells me you have almost no real experience building performance engines in my opinion!

I have seen the affects of excessive rod clearances in some fleet engines that I was asked to determine why the engines were consuming way to much oil and the excessive oil contamination in the combustion chambers was leading to detonation, carbon scoring of the cylinder walls and coking and sticking of the rings in piston grooves! After we discovered the excess rod side clearances we installed new properly clearanced rods, cleaned up the pistons and chambers, installed new rings and broke the glaze on the cylinder faces and reassembled the engines with all original bearing sets and seals and the oil consumption and oil contamination problems stopped immediately with no changes in ring types or tensions, no reduction in oil pressures and just eliminating the rod side clearance issue.

You cannot and should not make comparisons here for performance enthusiasts, hobby type engine builders and users that you can use Nascar engine building experimentation and exotic parts and build techniques and use those on most all the engine users that draw from and use a lot of information disseminated here on Speedtalk. I am sure that all the very knowledge professional engine builders here on Speedtalk know that excessive rod side clearance is a problem and that is why I am pretty sure that few of them set their builds up that way.

Please remember that all Nascar engine builders are building and prepping very specialized V-8's that have almost nothing in common with any other racing family of engines and they do not share direct information of how they design, build and equip their team engines! Almost all heir employees know that if their special information and data is leaked, their jobs are at serious risk! Comparing today's Nascar Cup engines to all the other engines that contributors here on Speedtalk are asking about or discussing is like comparing a brain surgeon to a chiropractor!

This is some of the internet fed and spread misinformation and comments that make the internet forums dangerous places to get good build information.

Sorry to be so blunt, but let's be careful and correct when we share information.

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Re: One more time, rod side clearance

Post by maxracesoftware » Fri Apr 06, 2018 7:40 pm

Newold1 wrote:
Fri Apr 06, 2018 7:33 pm
Your contention that "excess" side clearance has no affect on oil consumption in an engine based on the single point that some Nascar engines in the past had very large rod side clearance and it was not an issue or reality ! Wow, this tells me you have almost no real experience building performance engines in my opinion!

I have seen the affects of excessive rod clearances in some fleet engines that I was asked to determine why the engines were consuming way to much oil and the excessive oil contamination in the combustion chambers was leading to detonation, carbon scoring of the cylinder walls and coking and sticking of the rings in piston grooves! After we discovered the excess rod side clearances we installed new properly clearanced rods, cleaned up the pistons and chambers, installed new rings and broke the glaze on the cylinder faces and reassembled the engines with all original bearing sets and seals and the oil consumption and oil contamination problems stopped immediately with no changes in ring types or tensions, no reduction in oil pressures and just eliminating the rod side clearance issue.

You cannot and should not make comparisons here for performance enthusiasts, hobby type engine builders and users that you can use Nascar engine building experimentation and exotic parts and build techniques and use those on most all the engine users that draw from and use a lot of information disseminated here on Speedtalk. I am sure that all the very knowledge professional engine builders here on Speedtalk know that excessive rod side clearance is a problem and that is why I am pretty sure that few of them set their builds up that way.

Please remember that all Nascar engine builders are building and prepping very specialized V-8's that have almost nothing in common with any other racing family of engines and they do not share direct information of how they design, build and equip their team engines! Almost all heir employees know that if their special information and data is leaked, their jobs are at serious risk! Comparing today's Nascar Cup engines to all the other engines that contributors here on Speedtalk are asking about or discussing is like comparing a brain surgeon to a chiropractor!

This is some of the internet fed and spread misinformation and comments that make the internet forums dangerous places to get good build information.

Sorry to be so blunt, but let's be careful and correct when we share information.
finally ... someone else who also has witnessed the effects of excessive Rod side-clearances

like you , i also miked each Rod width ,,, paired up Rods so that i was 0.003 to 0.004 total pair side-clearance
after i saw the effects of too great of Rod-Side clearances on these Fleet Hot Shot Trucks

Newold1 ... thanks for this Post !!!
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Re: One more time, rod side clearance

Post by LSP » Fri Apr 06, 2018 8:27 pm

My case might be considered a "tweener".

LS1
OE wet oil pump
OE wet oil pan with accel baffle
Manley H-Lite rods, narrowed to .710" at big end, .680" wide rod bearings, guided at small end
K1 LS1 crankshaft
3mm - 7 lb. Hastings oil ring
5800-8300 rpm

Charcoal gray piston tops and chambers upon teardown.

Everyone can believe what they want, just giving another example to think about.
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