has Castrol changed?

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Sep 28, 2005
I've always used Castrol GTX 20/50. I just came back from the store with some and noticed that the new ones say "anti-sludge formula". Is this something new? The old stuff was rated SL and the new stuff is rated SM. Busting sludge loose doesn't sound like such a good idea. I hate to ask, but what are you guys using if the new Castrol is a problem?
I have used straight 40 or 50 weight(depending on the season) Valvoline oil in all of my Brit. bikes with no adverse effects,Hughie Hancox -- Triumph guru -- recommended straight oil in place of GTX, Mick Hemming -- Norton specialist -- recommends straight oil also.Ride safely. James.
Hate to ask...but unless the inside of a motor looks like the inside of a kitchen oven, after ten years of use......the anti sludge oil shouldn't be a problem.
I remember, when the stuff started to be made, 60's I think, the advise was to not use it in an old motor, because the thick crap you see inside the valve cover of a car that hasn't had an oil change, just been topped up, for ten years; will wash off the walls and end up in bearings, etc. But if you have been doing oil changes, and the inside of the motor isn't filled with dead goldfish, the anti-sludge oil will just keep it cleaner and certainly not do any damage to a clean engine. If you don't know what is in the engine and you think some PO hadn't given it an oil change in 50,000 miles...then be a bit cautious. I have always done the changes before thousand miles or so, and mine is clean...and has 120,000 on it. But even mine had a lot of goldfish in the oil tank. I was amazed...leaves, screws.....a baracuda.
Would at least, remove the oil tank, and flush it out good. I didn't even know there was such a thing today, as non-detergent oil...I use Castrol too, but this won't make me change my oil brand...will check the old bottles, bet it's detergent oil too...and has been for years.
As to straight oil.....not all of us live in a climate that has a constant temperature......might be fine to run 50 in Queensland, but in the rest of our areas....the "norton leg" is unwelcome. I'd rather run multigrade.

Main point, after all is said and done, might be not the type of oil, but the frequency of the oil changes and maintainance.... :wink:
The anti sludge is required for newer engines, SAAB in the UK have had to give an 8 year warranty on the 95 model turbo engines because of sludge buildup in the sump leading to the oil pickup being completely blocked. This castrol is designed to stop the build-up, but I would only put it in a SAAB after dropping the sump and cleaning the sludge. Its a consequence of longer oil change intervals and hotter running engines. My preference is for a fully synthetic.

Speaking of full synthetic.....I did the Mobil one thing for a couple of years, till I figured out that it was thin as heck and caused much faster and drastic wet sumping and then did the nice thing of pushing past the seal and into the primary case upon startup, because, I'm one of those who has never drained a sump before start up and the sump is always full. Made for a clutch that was a real beast to use, as deep as it was in oil, too. That's how I found the problem and reason for it.

All these points, turned me off to Mobil one and I changed back to Castrol GTX, changed the seal out and just keep the revs low till the sump is empty. Seems there was a long thread about this synthetic stuff, I'd be happy to use it, if it wasn't so darmed thin. Lubes so well. What brand do you use, and have you got some kind of anti wet sump valve installed? I don't, and the oil tank was emptied in a week, into the sump.. :lol:
I use fully sythentic which is 20/60 , so its thicker that Mobil 1 and stays that way on hot days.
My mechanic buys the Castrol 20/50 v-twin oil in a 50gal drum, so I bring a 1 gal container and buy from him. I use it in both my twins. Even though as hewho pointed out, most of the current info points to synthetic, especially if you live somewhere where it gets warm out.

(say Kommando, do you have one of those s---s? I have a '85 900 with 415,000miles on the original engine)
Bruce I have a 94 9000 2.0 LPT, only 125,000 miles so its just run in :D . Its a commando on 4 wheels, mid range gives it really good over taking but gasps a bit at the top end.

I have added an Intercooler off a full turbo but have yet to increase the base boost pressure which the intercooler allows, next stage is a pressure bleed to fool the ECU the boost is lower than it really is, should be good for 200 HP instead of 150 HP. Not bad for £100 worth of mods. When I retire the 9000 a classic soft top 900 will replace it.
I run straight oils 40 or 50 wt. I don't live in Qeensland,I live in Ohio where the temps. are anything but constant, 90 in Summer -20 in Winter,I have NO problems with my motors,in the final analysis, "you pays your money and takes your choice",regular oil and filter changes are the most prudent way to protect your machine.Ride safely.James.
I get my Miller oil from a local Classic Car Rally place, they had a lot of drivers complain of high oil temps coupled with oil burning at extended high revs using Mobil 1. They tried Miller CFS 15/60 on one car and all the symptoms dissappeared so every once else has followed suit with similar results. I bought some to try as my engine is close to needing a full rebuild going by the mileage but I want to get the combat on the road first so trying to make it last as long as possible.
The Word Handed Down From Castrol

For those of you who are interested in this thread, I contacted Castrol and they said they do not recommend GTX for air cooled engines anymore. They said to use one of their motordcycle specific oils in either natural or synthetic. Of course those oils cost 2.5 times what GTX cost. I'm guessing that with 1000miles oil changes the older GTX is fine, but I'm still wary of the new and improved version with the "anti-sludge formula".
Oil / Scotch what is best

This topic is a favourite, it is like asking people which car or bike is best, so many answers. Anyway for my two bob, I have yet to run my Norton, but based on Triumph Trident experience in NSW Australia, I first ran what I call supermarket oil, this was Shell Helix @ $15 per 5 litres. Using the therory that 1000km change at $15 were better than 2000km changes at $30 worth of oil. However a run out to Bathuurst in 35C ambient temps had the oil pressure stating at 80 then after a reasonable period dropping off to near 50 psi. With Idle pressure south of 10 psi. The science experiment then progressed to trying Penrite HPR40 this is a 25/60 oil at $25. Now on the same runs same type of ambients 70 psi is as low as the normal rpm run pressure drops and remains stable.
So I then went to HPR30 which is a 20/50 rating and I am still getting oil pressure that makes me happy. So all I can deduce is for our old clunkers a decent base oil is beneficial and the slightly dearer oil is not the same as the cheap stuff.

Cheers Richard
The great oil debate goes on. I have taken the advice of 3 firms in the UK, 2 of which will nullify the guarantee on rebuilt engines if multigrade oil isused. The third advised that following research into wear on individual parts of engines, multigrade oils produced more wear than monogrades. I n respect of sludge, if using an oil filter a high detergent oil should be in order, so I have been using a straight 40 high detergent Shell Rotella oil. This is obtainable only in 25 litres size but works out at a sensible price ie half that of "classic" oils which are a rip off pandering to a certain market

Thats my 5 penny worth!
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