Sulzer RTA 58T-B main bearing failures and excessive vibrations
Sulzer RTA 58T-B main bearing failures and excessive vibrations
(OP)
For the past three years we have been experiencing repeated failures of the main bearings on our two 5 RTA 58T-B engines, particularly in way of Main Brg #5(the middle bearing).
Does anyone else have such experiences and if so what have they found to be the problem/solution.
On our vessels we have carried out checks of shafting alignment, including laser checks, bearing jack up loadings, fitting of offset bearings to more evenly spread the static loads and still the problem continues, particularly on one vessel.
We have had consultants do metallurgical analysis of the failed bearings and tribology specialists calculate the oil film thicknesses and loadings.
Does anyone else have such experiences and if so what have they found to be the problem/solution.
On our vessels we have carried out checks of shafting alignment, including laser checks, bearing jack up loadings, fitting of offset bearings to more evenly spread the static loads and still the problem continues, particularly on one vessel.
We have had consultants do metallurgical analysis of the failed bearings and tribology specialists calculate the oil film thicknesses and loadings.





RE: Sulzer RTA 58T-B main bearing failures and excessive vibrations
RE: Sulzer RTA 58T-B main bearing failures and excessive vibrations
What does Sulzer have to say? I know there a a few parts of their engines they are still trying to iron out. I'm not sure if the stuffing box blow by issues have been resolved. I'd like to know what you find , if you don't mind, from your other sources, on both your topics.
Thanks,
Matt
There are very few automotive engineers that can fathom crawling aound inside an engine I think this is posted in the right forum.
RE: Sulzer RTA 58T-B main bearing failures and excessive vibrations
RE: Sulzer RTA 58T-B main bearing failures and excessive vibrations
RE: Sulzer RTA 58T-B main bearing failures and excessive vibrations
RE: Sulzer RTA 58T-B main bearing failures and excessive vibrations
RE: Sulzer RTA 58T-B main bearing failures and excessive vibrations
(a) some engine specs / where i can get them
(b) the detail of the rest of your shafting including couplings
(c) oil flow to middle bearing / type of oil
(d) material of the bearing
right
raj
RE: Sulzer RTA 58T-B main bearing failures and excessive vibrations
Have you checked the main bearing bolts themselves, they may be stretched. On one engine we fitted strain gauges and found that the main bearing bolts of one main bearing lost their tension over a relatively short period of time.
RE: Sulzer RTA 58T-B main bearing failures and excessive vibrations
If you don't have or OEM won't give you the spec, you can reference a good brg cap/saddle. Most OEM bore spec's are in the + or -: 0.0005 to 0.001 range depending on the bore dia.
When brgs fail the heat generated pulls the sides of the cap/saddle in. When you replace the failed brgs, the new brgs sit higher than the rest of the chrank line. This condition places a higher load on the subj brg and also reduces its ability to transfer heat. This does not present a problem on every brg failure as the distortion varies with the amount of heat that is developed. However I have found this to be true in most unexplained, repetitive failure's I been involved with. GOOD LUCK!
RE: Sulzer RTA 58T-B main bearing failures and excessive vibrations
The problem projected seems to be of a peculiar nature. Is it like, only the #5 (middle main bearing) which is getting damaged or other main bearings also-may be to a comparitively lesser extent. What is the duration after renewal when the damage is being noticed & the nature of damage(whether damage is at the edges)? What do the alignment checks indicate? Was hardness of the #5 journal checked? How was its surface condition/how are the remaining journals? How about the L.O. analysis reports? Was the entire crank case oil renewed, after thoroughly cleaning the sump, before the last bearing renewal? How is the engine power balance? Atleast the above information are required to assesss the cause of the main bearing failure.
One cause, which I could suspect with the information available, is that the crank shaft is flexing more than the permissible limits, during operation.
Thanks
Guru
RE: Sulzer RTA 58T-B main bearing failures and excessive vibrations
You mentioned that consultants and tribology specialists undertook some analysis - what were their findings? Did they not pinpoint the cause?
I take it you had to grind out the main bearing housings and fit oversize shells after the first failures?
RE: Sulzer RTA 58T-B main bearing failures and excessive vibrations
RE: Sulzer RTA 58T-B main bearing failures and excessive vibrations
Did anyone ever find out what was causing this persistent problem?
Cheers
Nodnerb
RE: Sulzer RTA 58T-B main bearing failures and excessive vibrations
The eventual conclusion and solution was external to the engine. Check the stiffeners in the Double bottoms below your engine, ensure the base is sufficiently rigid to prevent flexing of the crankshaft when the engine is running.
Obviously this may not be the problem, but it does need to be eliminated.
Regards
Diesel DAN
RE: Sulzer RTA 58T-B main bearing failures and excessive vibrations
The engine vibration damper is another suspect in these cases. Check for broken springs.
DIESEL DAN
RE: Sulzer RTA 58T-B main bearing failures and excessive vibrations
RE: Sulzer RTA 58T-B main bearing failures and excessive vibrations
RE: Sulzer RTA 58T-B main bearing failures and excessive vibrations
Good luck
Richie
RE: Sulzer RTA 58T-B main bearing failures and excessive vibrations
I think sadly that XLTSPORT is like too many users of online BBS. Post away for a few days get some answers then vanish till ya need help next time.
Nodnerb2