Bearing Clearance
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Bearing Clearance
Ok guys a 12cyl. diesel engine with a 10.236in main journal turning 950rpm max 18-1 compression making 4500hp.
What would you run for clearance & what kind of oil pressure?
Thanks
What would you run for clearance & what kind of oil pressure?
Thanks
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Re: Bearing Clearance
Last edited by Kevin Johnson on Sat Jan 11, 2020 4:49 pm, edited 1 time in total.
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Re: Bearing Clearance
Best to consult the engine manufacturer for their recommendations on bearing clearance and oil pressure specs. I don't think any of us on a high performance site will have the background and experience to offer you any viable recommendations concerning this issue . . . . . . . . . .
Bill
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Re: Bearing Clearance
Ship engine?
Maybe stationary powerplant?
Sorry, very little knowledge to share.
Maybe stationary powerplant?
Sorry, very little knowledge to share.
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Re: Bearing Clearance
Exactly which engine is it ? Make and model ?
Bill Koustenis
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Re: Bearing Clearance
Ok, I am not allowed to say what it is. They are running .003 clearance and 90psi. I really feel that is to little clearance and not enough pressure. Engineers say that is enough but we keep having failures.
Was just looking for other opinions.
Thanks
Was just looking for other opinions.
Thanks
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Re: Bearing Clearance
Check it against the Tribology handbook.
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Re: Bearing Clearance
Why are you not allowed to share the make of engine with us? Secret Service project or FBI? Maybe powerplant for Bill & Hillary's yacht?? I smell BS.
Maybe a Cooper-Bessemer pump station type powerplant?? You are not going to get viable answers to your quiry on a high performance engine site, just too many variables. Contact the engine manufacturer or a factory authorized remanufacturer for accurate answers to your questions.
For instance, my recommendation for natural gas fueled pump station 12 cylinder engine with 38.25" bore, 44.50" stroke and 54.125" center to center connecting rods would be .0065" crankshaft oil clearance and 185# of oil pressure. Considering the use of 22.50 gallons of 70# oil in the crankcase.
Bill
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Perfect Circle Doctor of Motors certification
SAE Member (30 years)
ASE Master Certified Engine Machinist (+ two otherASE Master Certifications)
AERA Certified Professional Engine Machinist
Re: Bearing Clearance
No less than .0005 per 1 IMO
so, .0055" minimum
.003", no,
.03"mm maybe?! double check your units
so, .0055" minimum
.003", no,
.03"mm maybe?! double check your units
Re: Bearing Clearance
So 0.05-0.1% of the journal diameter?
For the pressure, one would want to know what the rpm is and how the oil passages run.
For the pressure, one would want to know what the rpm is and how the oil passages run.
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Re: Bearing Clearance
guy, the oil pressure has been stated.
apologies....misread above post. rainy dreary monday.
GUY, the RPM has been stated!
apologies....misread above post. rainy dreary monday.
GUY, the RPM has been stated!
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Re: Bearing Clearance
This to me? For oil pressure, very little should oil the mains. However the big question is how do the rod journals get oiled, given the large main journal diameter. At 950 rpm it shouldn’t require a lot of oil pressure even with that big main, compared to say (2.75”*7000rpm)^2.bentvalves wrote: ↑Mon Jan 13, 2020 5:27 pm guy, the oil pressure has been stated.
apologies....misread above post. rainy dreary monday.
GUY, the RPM has been stated!
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Re: Bearing Clearance
If the engineers are saying the clearance and pressure are correct (presumably these are the OEM recommendations ) and engine failures are occurring regularly then it is logical to examine other possibilities.
If the engine uses a fluid damper then it could be the case that despite appearing okay visually it needs rebuilding or replacement. The article below points out that this is a common cause of heavy duty diesel engine failure.
Good luck.
http://www.engineprofessional.com/artic ... _64-72.pdf
If the engine uses a fluid damper then it could be the case that despite appearing okay visually it needs rebuilding or replacement. The article below points out that this is a common cause of heavy duty diesel engine failure.
Good luck.
http://www.engineprofessional.com/artic ... _64-72.pdf
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