mobil /exxon oil
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Most of the product line seems OK but there are persistant rumours that the Elite mulitgrade in a bit of a problem.
I can't say tha I have seen anything to back this up but a number of operators (mostly helicopter) won't use the Elite. The usual reason quoted is top end problems.
Of all the multi-grade products on the market Shell has been around the longest and seems to be trouble free.
I can't say tha I have seen anything to back this up but a number of operators (mostly helicopter) won't use the Elite. The usual reason quoted is top end problems.
Of all the multi-grade products on the market Shell has been around the longest and seems to be trouble free.
Join Date: May 2001
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Wasnt there a rumour that it is excellent in a new engine not so good in an old engine. Was the theory it is far more effective at preventing deposits but also removes these in an older engine so all of a sudden what had beded in well no long fits so good.
I have no idea whether these rumours are accurate.
I do know in my race engine when I rebuilt the engine before using sysnthetic it was pretty dirty after a few thousand miles, but next time I opened it up after running on synthetic with a change every 1,000 miles it looked new.
I have no idea whether these rumours are accurate.
I do know in my race engine when I rebuilt the engine before using sysnthetic it was pretty dirty after a few thousand miles, but next time I opened it up after running on synthetic with a change every 1,000 miles it looked new.
Join Date: Jun 2003
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Same Q was posted on flyer.
Some people like Shell some like Exxon (multigrades in both cases).
A&C - what exactly was the top end problem reported? Was it wear, sticking valves, or was it corrosion?
Some people like Shell some like Exxon (multigrades in both cases).
A&C - what exactly was the top end problem reported? Was it wear, sticking valves, or was it corrosion?
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Surely the concern over damage to old engines is more to do with the oil's dispersant properties rather than it being a multigrade? That said, multigrade oils (relating to viscosity and temperature range) do tend to contain dispersant additives; sometimes called detergents. That is the danger for old engines as it will remove the accumulated carbon and oil "varnish" from the crank case and rocker box and hold it in suspension in the oil. The result being a choked oil filter (no or low oil pressure, or the relief valve opening to retain pressure but allowing abrasive "paste" through to bugger the engine). An engine with only a gauze oil filter would happily let the abrasives straight to the precious moving bits.
Arguably if an engine previously run on a "straight" oil (low/nil dispersant) and has a full flow filter, flushing it through with flushing oil should prepare it for multigrade oil. Multigrades usually contain corrosion preventatives and acidity suppressant additives.
Arguably if an engine previously run on a "straight" oil (low/nil dispersant) and has a full flow filter, flushing it through with flushing oil should prepare it for multigrade oil. Multigrades usually contain corrosion preventatives and acidity suppressant additives.
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IO540
Valve sticking seems to be the problem but only for the helicopters, I have no hard evidence to support any problems with this oil however I know helicopter people who would not touch the stuff!
And before anyone asks I know about the Lycoming SB and EASA AD on the subject.
And before anyone asks I know about the Lycoming SB and EASA AD on the subject.
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IO540
Thats the one!..............I have yet to do one of these checks as the all the equipment that I work on has the late cylinders fitted and I dont work helicopters.
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I am not sure that valve guide issue has anything to do with the oil type. It appears to be more of a general wear issue which 'everybody' had been getting, and a helluva lot of planes run on straight oil all the time, not multigrade (the latter costs a lot more).
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IO540
I run all my aircraft on the Shell multi grade for a number of reasons, the cost of changing from W100 to W80 in the winter (labour & oil) almost outweighs the oil cost difference, the lycoming addative will help all in all engines to prevent cam wear and cold starting is much better.
Also the the high temp performance is better with the multigrade mainaning it's viscosity long after W100 has the oil px dropping, this is most imortant when trying to get aboe the high ground on a hot summers day in southern europe.
In terms of cost good quality oil will save a lot of maintenance and so in the long run is the most economic option.
The Shell multigrade has been on the market for a long time and has a good track record but it must be changed at 50 hour intervals (some high utlisation operators do 100 hour checks) as the mineral oil content won't be able to hold the "blow by" lead from the fuel for much more than 50 hours and having the lead staying in the engine oilways would not be a good idea!!
Also the the high temp performance is better with the multigrade mainaning it's viscosity long after W100 has the oil px dropping, this is most imortant when trying to get aboe the high ground on a hot summers day in southern europe.
In terms of cost good quality oil will save a lot of maintenance and so in the long run is the most economic option.
The Shell multigrade has been on the market for a long time and has a good track record but it must be changed at 50 hour intervals (some high utlisation operators do 100 hour checks) as the mineral oil content won't be able to hold the "blow by" lead from the fuel for much more than 50 hours and having the lead staying in the engine oilways would not be a good idea!!
