Would long synthetic oil OCIs guided by oil analysis result in an engine getting any more deposits or varnish in it than more conventional OCIs of around 6,000 miles on a good synthetic?
Long OCI vs engine cleanliness
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It shouldnt, as long as you let the uoa rule and not your emotions.
I am running delvac 1 in my slant six after an arx cleaning and will be trying 7500 mile oci. Will test at 5k just to make sure nothing is wrong. Will also pull sample at drain to check if the oci can be extended.
But hope to eventually take oci out to 10k with bypass filter.
Dan
BTW, I did have a plymouth reliant I did 10k ocis on before I knew about oil analysis. Changed the filter at every 5k, changed oil and filter at 10k using mobil 1 when it first came out. It burned a valve at 80k or so. Engine on the inside was so clean that it looked like someone had worked it over with a polishing wheel. Blew me away. at 80, i had only done 8 oil changes.
[ November 12, 2004, 01:17 AM: Message edited by: Dan4510 ]
I am running delvac 1 in my slant six after an arx cleaning and will be trying 7500 mile oci. Will test at 5k just to make sure nothing is wrong. Will also pull sample at drain to check if the oci can be extended.
But hope to eventually take oci out to 10k with bypass filter.
Dan
BTW, I did have a plymouth reliant I did 10k ocis on before I knew about oil analysis. Changed the filter at every 5k, changed oil and filter at 10k using mobil 1 when it first came out. It burned a valve at 80k or so. Engine on the inside was so clean that it looked like someone had worked it over with a polishing wheel. Blew me away. at 80, i had only done 8 oil changes.
[ November 12, 2004, 01:17 AM: Message edited by: Dan4510 ]
I have been running the amsoil asl on my 91 pathfinder for the last 37K miles (total miles on the truck is 137K) with the longest OCI of 9K miles, and looking inside the oil filler hole its completely black compared to before I did the long oil change interval. But this was before I found this site now I know better than to get a UOA before doing any long change interval.
IF we seperate out any variation on the oil then yes a shorter OCI will produce a cleaner engine all theings being equal! THe problem is how much cleaner? If the additional cleanliness going to offeset increased cost of fluids and time? At some point you will reach a marginal equilibreim(sp)were cost and benifit cross.
Varnish is not consider by most to be a real hazard to long engine life. I consider it to a hazard though.
Some place between 3000 miles and 15,000 miles lies the perfect OCI for your application. Personely I prefer to stay under 10,000 miles or 6 months with an oil. I do not like to let the TBN drop below 3, thin or thicken out of grade, insolubles get above .06 or wear metals to get into high double digits.
I think that the combination of light weight oil recomendations, poor ring design for fuel economy and extended OEM OCI's have made a large market for products like AUto-Rx!
Varnish is not consider by most to be a real hazard to long engine life. I consider it to a hazard though.
Some place between 3000 miles and 15,000 miles lies the perfect OCI for your application. Personely I prefer to stay under 10,000 miles or 6 months with an oil. I do not like to let the TBN drop below 3, thin or thicken out of grade, insolubles get above .06 or wear metals to get into high double digits.
I think that the combination of light weight oil recomendations, poor ring design for fuel economy and extended OEM OCI's have made a large market for products like AUto-Rx!
Probably depends on the engine.Some don't beat
up the oil as much as others.
I yanked the valve cover off my 99 Corolla berfore I traded it in.It was really spotless,no varnish at all.Never used a drop.M1 for 95% of the time I owned it.
The OCI's with M1 were between 3K to 10K miles.
I yanked the valve cover off my 99 Corolla berfore I traded it in.It was really spotless,no varnish at all.Never used a drop.M1 for 95% of the time I owned it.
The OCI's with M1 were between 3K to 10K miles.
Depends on the engine, driving conditions, climate.My Camry has had 7500 OCI with Amsoil 10W30 and clean, 4 cyl Zetec with 10-12,000 annual miles OCI also clean. I doubt the Camry could go much more though due to how it seems to abuse the oil. Buick GM 3.8L SC on 12,000 mile OCI also clean. Camry city driving, others much more highway. Camry has 169,000 miles, Zetec 97,000.
I would respectfully adjust this proposition just a bit. As long as you are within an oil's ability to dissolve and/or suspend potentially damaging contaminants, then the curve is flat. So let's assume that Oil X is good for 10k miles in Car A. Changing at less than 10k in this car won't offer any added cleanliness, because the oil is still holding all the bad stuff in the oil. Once you get past the 10k and the oil gradually starts to fail, then the engine is going to get dirtier and dirtier as the miles go by.quote:
Originally posted by Ugly3:
The shorter the OCI with the same oil the cleaner the engine.
Yep and some engines that are summertime dino killers can do quite well on them in sub 75F ambient .quote:
Originally posted by Alan:
Probably depends on the engine.Some don't beatup the oil as much as others.
Me , I like true synlubes around my ring pack rear round . Especially hot summer and coldest of winter .
T, I disagree. You said;
Controlling/limiting the source of contamination and then filtering or solublizing the remainder is an art.
Different engines seal better than others.
That certainly is a critical measurement of the oil analysis reports we see posted here and the product we use. Rate of contamination is the key point. Knowing what to look for in analysis is another.
Controlling/limiting the source of contamination and then filtering or solublizing the remainder is an art.
Different engines seal better than others.
I'm not all that knowleadgeable, but I try to use an oil that keeps consumption minimal and I do look to keep fuel dilution minimal and flash point up.
If I can also keep insolubles in check, then I think the uoa is telling me I have a reasonably clean engine and my procedure is good. I'm not going to push the TBN limits myself either.
I think a uoa with proper interpretation would almost have to show you sludge precursors. Remember you also have to tell the lab about how much makeup was added.
Maybe Brand X will be consumed much cleaner than Brand Y and the experts know this kind of data that we don't.
Perhaps a lot of problems are caused by internal coolant leaks and emission control system problems. Uoa will show this.
I can imagine some varnish, but not sludging going undetected. Straight dino user have to expect some minimal varnish anyway.
If I can also keep insolubles in check, then I think the uoa is telling me I have a reasonably clean engine and my procedure is good. I'm not going to push the TBN limits myself either.
I think a uoa with proper interpretation would almost have to show you sludge precursors. Remember you also have to tell the lab about how much makeup was added.
Maybe Brand X will be consumed much cleaner than Brand Y and the experts know this kind of data that we don't.
Perhaps a lot of problems are caused by internal coolant leaks and emission control system problems. Uoa will show this.
I can imagine some varnish, but not sludging going undetected. Straight dino user have to expect some minimal varnish anyway.
This makes a whole lot of sense to me:
I am working on consumption reduction in two vehicles in my care. One was recently switched to a higher flash point/lower NOACK oil for this purpose.
I have had two cars over 200K miles with Dino changed every 3K miles or so. Both showed plenty of varnish, never bothered me, and evidently didn't bother them. I have never been a synthetic user, but would some say with syns I wouldn't see as much varnish. Has anyone really correlated varnish deposits to anything that is very negative to engine life and performance? I am not sure if varnish deposits are anything to worry about. Am I wrong?
Good approach. I have actually reduced consumption going to thinner oils based on this. Sometimes the bump up in viscosity is the answer, but more often than not a better quality oil is the answer. It just depends. Some oils just get a better ring seal, I think, but I'm not sure why.
What I did was move from Valvoline Maxlife 10w30 (IIRC, flash =232C, NOACK of less than 15) to Valvoline Synpower 10w30 (flash = 250C, NOACK = 8). On the Maxlife it consumed around a quart in 1500 miles. Only have 300 miles on the Synpower (since Sept 26
) so it's too early to tell. But when the oil is consumed, it sure seems something undesireable must be left behind.
Of course, with the Synpower I am also definitely shooting for a long OCI, maybe a year or so.
Of course, with the Synpower I am also definitely shooting for a long OCI, maybe a year or so.
That was one of, if not the first oil I used in my '92 4.3L Chevy. Did absolutely nothing to reduce consumption.
After that, I ran Pennzoil LL 15w-40 in it for quite awhile which greatly reduced consumption and have since switched to Pennzoil HM 10w-40 which has reduced consumption even more in addition to highly reducing blue smoke on startup...
I wonder how Maxlife 10w40 would have served you. It has a good flash point (at least pre SM) and presumably a decent NOACK. A 40 will definitely be less prone to consumption though. Anyway, if what you are doing is working, that is the important thing.
I guess my "thing" is that I was turned on to Pennzoil LL by the BiTOG message board many moons ago (would have never used it if I had not have came here!) and it has treated me very well.
Since then, I've continued on using Pennzoil engine oils, this time it being HM 10w-40. It has as well impressed me with its performance and although I was been bitten by the BiTOG bug, I've become hesitant to change to another brand (which is very weird for me!)...
[ November 12, 2004, 03:51 PM: Message edited by: Jelly ]
I think you've already found it. Try both or flip a coin if Castrol or Pennzoil HM works best for you.quote:
Originally posted by Jelly:
I was bitten by the BiTOG bug a long time ago, so I'm always willing to experiment...
Off topic here, but who do you think makes the best HM 10w-40?
IMHO, if you are trying to extract the maximum amount of mileage from an engine with minimal problems/issues, internal engine cleanliness is very important...
[ November 12, 2004, 04:11 PM: Message edited by: Jelly ]
[ November 12, 2004, 04:11 PM: Message edited by: Jelly ]
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