oils and oil's

[iancoombe]

Hi all we have just rebuilt our perkins 4 108, so now what oil. We've looked at the mineral and synthetic options but I haven't heard of any problems with synthetic in older type engines, plenty of folks say its a no no and others say its fine.so has anyone actually switched to synthetic in an older engine and what was the result good or bad. We would like to hear from people with real world experience because if we can use synthetic we would as there is little daubt that its superior all round.
Cheers

[UNCIVILIZED]

One thing I've been told by engine guys, is that once an engine hits mid-aged, & older, some of them don't take kindly to having the type of oil being run in them changed. Meaning switching to a synthetic from a non, or vice versa. As some gaskets, as well as parts with close tolerances, like say, valve seats, occasionally have issues with this.

Can't say that I've owned a diesel long enough to say this with any authority myself, but perhaps some other folks can. As if you're out cruising, you may not always be able to pick & choose your preferred brand (or type). Even if it's just to find 2qts to top things up. Since mixing types in an engine isn't always the healthiest practice.

[poiu]

Originally Posted by iancoombe

Hi all we have just rebuilt our perkins 4 108, so now what oil. We've looked at the mineral and synthetic options but I haven't heard of any problems with synthetic in older type engines, plenty of folks say its a no no and others say its fine.so has anyone actually switched to synthetic in an older engine and what was the result good or bad. We would like to hear from people with real world experience because if we can use synthetic we would as there is little daubt that its superior all round.
Cheers

It's a bad idea. In cool running engines designed for mineral oil use like yours you will get better lubrication and cleaning from a non synthetic. Make sure it complies with the manufacturer's recommendations.

[svHyLyte]

Originally Posted by iancoombe

Hi all we have just rebuilt our perkins 4 108, so now what oil. We've looked at the mineral and synthetic options but I haven't heard of any problems with synthetic in older type engines, plenty of folks say its a no no and others say its fine.so has anyone actually switched to synthetic in an older engine and what was the result good or bad. We would like to hear from people with real world experience because if we can use synthetic we would as there is little daubt that its superior all round.
Cheers

The 4-108 will most assuredly not like synthetic and particularly so its real seal. If you are in the US stick with Shell Rotella 15-40 or the equivalent. To minimize real seal seepage--which is all but unavoidable--settle for the oil level being at the mid-point between max and min. Change the oil at 100 hour intervals.

BTDT...

[sailah]

I love oil threads. My other hobbies include motorcycles and an oil thread on AdvRider.com can go 50 pages and ends with harakiri.

I personally use Rotella 15W-40 on my diesel and almost everything else. I probably go thru 30 gal a year between 7 motorcycles, Jeep CJ7, tractor, boat, diesel truck, lawn mower, outboard, snowblower. I use it in my machine shop for lubricating things and keep a few oil squirt cans around for lubing chains.

I had a real princess Austrian motorcycle. It loved this uber expensive Swiss Motorex which is about $25/L and I dutifully complied every year. There were rumors that the factory racing team was using Rotella for better clutch feel after a 1 gal jug was photoed in the race pits. And the regular stuff not the synthetic either.

So I switched. I had always used Rotella in diesels but it was a first. Oil change after oil change, everything stayed in spec, valves were clean, topend was spotless. Over the years I've torn down a few engines I've had running Rotella they always look good. I've sent samples to Blackstone and they come back fine.

I'm not saying there aren't better oils, or ones more highly engineered from unicorn tear base stocks. But when you can standardize on a single oil brand and viscosity that performs so well under such varying circumstances and available cheap from any auto store even Home Depot and Walmart, it's hard to go switching it up. I've been using it consistently in every combustion motor I have (except my Tundra) for a decade and I'm personally convinced and won't use another.

In my Tundra I use full synthetic and my rationale is that I do 10k mile oil changes and feel the synthetic doesn't break down as quickly. Plus it's engineered for 5W-20 and I feel that's too much of a spread to use 15W-40. My sailboat sees about 100 hours/season so far below change interval.

In my previous Duramax diesel I ran Rotella though.

I had the synthetic vs conventional Rotella conversation with a marine diesel tech at Lyman Morse when I worked there. His comments were essentially if Caterpillar recommends it in engines that cost more than your house why would you argue with them.

I think the argument in my mind that would tip me to using synthetic is simply to stretch the change intervals. But in a marine diesel, I'm looking to change more frequently and get the carbon out of the oil suspension as often as reasonable.

Just my thoughts on the subject. I think marketing of synthetic and convincing the public that because it's "synthetic" and costs more, that it must be better. And in some highly refined engines designed for it, I would agree. But a Perkins ain't highly refined and the idea that synthetic would provide better protection is a specious argument in MY mind

[a64pilot]

It won't hurt it a lick to run synthetic, however it likely won't do a lick of good either, it's just not required in vast majority of our engines.

Just me, but I would not run a multi viscosity oil either like anyone's 15W-40 in an old engine design. Again reason is it just doesn't need a multi vis oil, unless you cruise in Arctic waters, that of course is different.
I'd use a good, high quality single grade oil that is widely available, Rotella maybe as it's everywhere and run it, either 30 or 40 weight.
I'd start with 30 then as she gets a few thousand hours on her and maybe when it begins to burn a little, go up to 40

[a64pilot]

There are or were several different oil chemistries if I'm using that word correctly, many are asphalt based, and some paraffin based and others.
Years ago penzoil and Quaker State were paraffin based, that was that layer of black wax on any cooler surfaces like valve covers you used to see, the paraffin would condensate on a cooler surface.
Changing to a different based oil would sometimes break up that paraffin layer and clog oil passages etc.
Most synthetic oils will break this stuff up and when you clean it off, often gaskets and some seals will leak, cause the waxy coating was stopping leaks, so syn oil doesn't cause leaks, but it may clean out your engine enough so that it will leak.

Many years ago people ran non detergent oil in motors, and identical problem, if you changed to detergent oil, it could clean things out, block passages and even increase oil consumption on an old motor, so a motor that had run non detergent oil for a long time, you never changed to detergent oil.

So long story short, most modern oils are easily compatible with other oils, however if you pick a good brand and weight and stick with it, you can't go wrong

[JstaRebel]

Originally Posted by a64pilot

It won't hurt it a lick to run synthetic, however it likely won't do a lick of good either, it's just not required in vast majority of our engines.

Just me, but I would not run a multi viscosity oil either like anyone's 15W-40 in an old engine design. Again reason is it just doesn't need a multi vis oil, unless you cruise in Arctic waters, that of course is different.
I'd use a good, high quality single grade oil that is widely available, Rotella maybe as it's everywhere and run it, either 30 or 40 weight.
I'd start with 30 then as she gets a few thousand hours on her and maybe when it begins to burn a little, go up to 40

I second this post. Straight ol 40 weight oil in an older diesel engine. No Multi grade and definitely no synthetic oil. Your engine will thank you for it..

[iancoombe]

Thanks for the replies, so I take it that no one has made that switch for the reason that its a mistake.we currently use a 40 weight mineral so I guess we'll stick to that . Cheers

[Wotname]

Originally Posted by iancoombe

Thanks for the replies, so I take it that no one has made that switch for the reason that its a mistake.we currently use a 40 weight mineral so I guess we'll stick to that . Cheers

I note you have "rebuilt" the engine and that you currently (i.e. before the rebuild) use 40 weight.

If the rebuild took the engine right back to original specs / tolerances, I would be tempted to use the weight of oil Mr Perkins recommends for a new engine but if the rebuild was less "tight", then use the 40 weight (just my opinion).

[iancoombe]

It is a full rebuild and as new, we will run 30 wgt for the first 20 hours then switch to 40, perkins recommend 30 wgt for the 4 108 but hear in Malaysia its very warm and 40 wgt is the go.when we head south we will changes back to 30 wgt. Incidentally we have never needed to glow pre start yet even before the rebuild.
Cheers

[a64pilot]

OK on an aircraft engine I overhaul I fill it with oil and run it for 10 or 15 min and then drain the oil and cut open the filter to inspect for metal.
Reason is vast majority of break in, wear in or whatever you call it occurs very fast and 99% of the metal particles come off really, really quick, and I want that stuff out of the motor, and just in case there may be any glass from bead blasting or dirt from assembly etc., I want it out, and oil is cheap.
Then say 10 hours on the next change, next one on schedule, again oil is cheap and I don't want that metal circulating around my engine, yes the filter catches a lot, but some fine stuff gets through.

Now here is the hard part, run it easy for the first hour say, but after that you want to run it hard, maybe start out by hard for a few minutes then back off a while then hard again etc.
Reason for that is to seat the rings, run it easy and they may never seat and you will have an engine that is forever a little down on compression and always burns some oil.

Opinions on engine break in will vary as much as which anchor to use.

Forget the stuff about which oil and additives etc, but read this, an engine is an engine to a great extent
https://www.lycoming.com/content/har...t-engine-break

[model 10]

Originally Posted by iancoombe

It is a full rebuild and as new,

I wish people would stop saying that, it ain't "as new". If you actually did the "ovhl" per the manual, most parts would be just within limits, not "as new". The decent ovhl of a Perkins for example is new liners, new pistons, rings, new exh valves, rod and main bearings. The oil pump is probably fine. There are dozens of other things you could inspect but people don't. Not to mention rebuilt fuel pumps, injectors, starters, coolers, waterpumps etc.

[dkenny64]

well..
I agree with the using a straight weight oil..check the temp ratings...
for changing from mineral to synthetic and back..well..yes done that.
why? cost.. first you need to know this is not in my boat diesel. its in my cummins 5.9
truck..same engine used in many diesel boats..
my truck leaks oil...if I can make to 5k miles before the next change without adding oil..great..
most times I need to add oil first...sure with synthetic I could run 10k miles. but it costs about 2x as much..changing the oil and filter is cheap and easy..so switched back..about 100k miles ago..the truck has about 310k miles at the moment and runs great. using delco 15w-40
I agree with the other poster..change the soon and often after a rebuilt..2-3 times then go to a regular schedule. I should add my wife diesel jeep using Shell T6..for the last 130k miles and doing fine
-dkenny

[a64pilot]

I ran T6 in my Duramax the whole time I had it, but it ran much hotter, and if I was pulling heavy, much harder than most little boat Diesels.
I had another computer in line with the factory computer that allowed me to adjust fuel flow, and I turned the boost up to 32 PSI. I had as much pressure in my intake manifold as most people do in their car tires.
Different animal entirely than my little Yanmar. Truck motor was I think making at least 1 HP pre cu in. My Yanmar? Maybe half that.