Can oil save your butt if you mess up?

[booster]

I think I can now say it might be able to.

With all the hype and opinions about oil types, additives, etc it is basically impossible to determine what is necessary vs overkill, vs underkill in oils IMO. Just because an engine makes 250K miles on Amsoil doesn't mean the Amsoil was responsible, or that dino oil would have been worse. If it made 250K on dino oil, it doesn't mean it wouldn't have gone more, or less on Amsoil. Testing accurately is essentially impossible. Used oil analysis is iffy, at best, I think, but some would disagree. Again to test to see if good used oil analysis tests corresponds to long engine life would a many year, many vehicle, impossible to control test.

That said, like most folks, I have had opinions on what I think is necessary in oils, filters, changes etc. Most folks stress that the newer oils are much better than the older ones, and that is why the oil change intervals getting longer is happening. I agree to a point. Most of the properties of the newer oils is better, but not the anti-scuff properties. IMO, the longer change intervals are working fairly well because the engines are built better as much or more than the oil improvements. Better alloys, better quality control, better designs like all rollerized.

That said, again, not all applications are the same, so is the same oil appropriate for them all? Could you get by on low end oil on your commuter gas powered car? What if it has a turbo? How about a van that is hauling its max weight all the time and up mountains (had to get B related here)? Are you better off using lower price oil, like dino, and changing more often, or use high buck synthetics and change less often?

This all kind of came together for me last weekend. We have a section of our land that borders a wetland, maybe 1/3-1/2 acre. I mow it once a year in the fall to keep the aspen and brush down, and have for 8 years without issue. This year we had a very wet spring so the water was closer to the yard and cattails grew where they hadn't before, and stayed after the water receded, so they needed to be mowed. I was also later this year because it has been raining for 3 weeks. It is always a messy job as the weeds and brush approaches 5 feet tall sometimes, and the catttail cut hard, but that wasn't the issue. I cut 1/2+ of it on Saturday in about 2.5 hours without issue. Blew off the tractor on Sunday and went to cut the rest. In about 20 minutes the John Deere lawn tractor (17hp air cooled Kawasaki engine) faltered and puffed some smoke. I slowed it down, and it sounded OK so I sped it back up, and got another puff of smoke. Shut off the blades and headed for the garage. Stopped outside and lifted the hood, and it was hot, hot, hot, but still idled OK. No oil pressure light on. Shut it off. The air intake on the top of the engine was totally plugged with cattail fuzz. The wind had changed from the previous day and apparently had blown it directly into the air intake to plug it so quickly, when the day before it didn't.

I pulled the yellow plastic dipstick out, and it was now dark brown, even after wiping off the oil, which was very brown and smelled horribly burnt and foul. It was similar to the smell you get from a waste oil heater, which is gross. At this point I figured I had just learned an expensive lesson about cattails, as a new Kawasaki engine is over $1500. I let it cool for 1/2 hour and then started it at just above idle speed. It started right up but did a fairly high rpm surge before slowing down. Boiled fuel in the intake, or oil blowby burning? Tiny puff of smoke. Took it in and drained the oil and it was horribly burnt smelling and dark brown, not blackish like used oil. What was odd is that it had not thickened noticeably at all.

Went to my old friend, the internet, and searched for discolored JD dipstick and got quite a few hits. Most said the same thing-light discoloration at 300+ degrees, black by over 400 degrees. I was much closer to the black then light. If the oil at the dipstick was that hot, I wonder what the head temp was? Most also said if it was very dark there almost certainly was damage, probably fatal if it was very dark. Called the JD dealer and they said the same. Pulled the engine and took it apart to see if it was repairable or needed to be replaced. I have found NO bad parts or coked oil on anything. The heads had a tiny bit of slightly thickened oil in the low spots of the drains and that was the worst seen. Piston bottoms spotless, valve guide seals not melted, no burnt oil around exhaust valve guides. Cam, tappets, rockers all fine. Piston skirts with no scuffs, bores clean and round. Heads flat within tolerance even. The only question is the oil rings which look to have very little tension on them, but I won't know if that is normal until the new ones get here. It looks like I will put in rings (std size) just in case, new seals and gaskets, lap the valves and put it back together.

This is where the oil thing comes in. Since this is a flat tappet engine, and air cooled, I have never run car oil in it because of the changes to the anti-scuff additives to save the catalytic converters. For a long time I used Mobile one 15-40 crotch rocket bike oil as it had the full additive package, but then they started going to the same as the auto oils, so I switched to Brad Penn high performance oil in the 15-40. It is called a semi-synthetic and has a "street" additive package so it can be used like normal oils, but is based on their racing oils. It is very high in anti-scuff and anti-wear additives. Nearly all the local roundy round racers use it, and claim much better engine life with lower wear rates (opinions to be sure). I did a sort of viscosity test on the stinky oil with a viscosity cup from my painting stuff, and it was nearly identical to new oil. I took a piston and rod assembly and the dipstick to the JD dealer when I went to order parts, and the were amazed they came out of the same engine.

So the question is, did the oil save the engine from carnage? Would it have looked a lot worse with generic SN rated car oil in it? Would synthetic oil have done even better at the high heat? If the oil did save it, which part was responsible the oil itself, or the high performance additive package?

I find this very interesting, and if I had known what I was going to find, I just would have flushed it out and run it to see if used oil. I was certain I was going to find galled up piston skirts and bores, bad cam lobes, or something that would disintegrate quickly, even if it came back running OK initially. Very wrong on that one!

[booster]

Here as some pics of the results of the overheating

Dipstick



Cylinder head



Piston and rod



What I was mowing-the cattails are about 6' high



I mow into the cattails until I get all the little trees, and brush, like you see on the left. Didn't get to that before it croaked.

[markopolo]

That is interesting and it looks like the high quality oil continued to do it's job at the extremely high temperature.
Looks like you can't use the Brad Penn - Penn Grade 1 High Performance 15W-40 oil in a street vehicle with a catalytic converter.
Does your tractor manual call for 10W-30?

I change the oil in my ride-on, push mower and snow blower once per year. The oil always looks good in the two mowers but looks dark in the snow blower. I hadn't thought of using a high grade oil.

[booster]

Originally Posted by markopolo

That is interesting and it looks like the high quality oil continued to do it's job at the extremely high temperature.
Looks like you can't use the Brad Penn - Penn Grade 1 High Performance 15W-40 oil in a street vehicle with a catalytic converter.
Does your tractor manual call for 10W-30?

I change the oil in my ride-on, push mower and snow blower once per year. The oil always looks good in the two mowers but looks dark in the snow blower. I hadn't thought of using a high grade oil.

The reduced zinc oils showed up on SL in about 1996. It was a partial reduction of zinc and didn't seem to cause major problems. SM showed up in 2004 and was more severely reduced in an effort to preserve the higher tech catalytic converters that were coming out from zinc fouling. If your catalyst if older than 1996 there is no issue with Penn. 1996-2004 some might say there would be. After 2004 the manufacturers don't want you to use high zinc oil. I have never been able to get a straight answer from the oil makers or catalyst makers as to how they determined how much zinc is OK for the catalyst and how much is too much. If you have an engine that is on SM oil at 800ppm zinc, and it used twice as much oil as another engine, why couldn't the second engine use oil at 1600ppm as the catalyst would see the same amount? My opinion is that the zinc amount is based on what the automakers consider maximum oil consumption before a warranty claim, which is often under a 1000 miles on a quart. Our 07 van goes 3000 miles between changes and it doesn't even move on the stick, so we put much less zinc into the catalyst, even if we used the Brad Penn. Let's say I am skeptical

Our tractor manual calls out 5-30, 10-30, 10-40, and straight 30 based on temp. These are often used with snowblowers on them (not us though), so we can stay on the high end which is always good with an air cooled engine. Harley air cooled run 20-50. Snowblowers are famous for dirtying the oil, for the most part. Lots of the engines are aluminum cylinders which wear faster and make the oil black. They also run without air cleaners and are often pretty rich in mixture as they have to cover a big temp range. Good lawn mowers and tractors will have cast iron sleeved cylinders, better carbs, etc so they are much more car like in oil color.

IMO, it is a good idea to run an oil high in zinc on any small engine, or any other engine that has flat tappets. The zinc and associated other stuff are what allow metal to metal contact without galling. Those elements are also sacrificial, so they deplete with time. How fast depends on the amount of metal to metal surfaces there are. Newer cars are rollerized in the valvetrain, which is where the most metal to metal would be, so the thought is that they can get by with less zinc in the oil. You still have oil pumps, rings, etc, but they are lower force than cams and such. I still am leary of an 800ppm oil going 10K (or 20K if you believe Amsoil) miles in a van. It does worry me, and it is impossible to prove anything because it won't cause an immediate failure like the old camshafts would. It would probably show up as worn rings (oil consumption) or low oil pressure (worn pump) earlier than it would with more zinc. How would anyone ever know that their engine that needed rebuild at 150K would have gone 200K on different oil. Pretty safe way for the manufactures to save their catalysts, with the consumer taking the downside risk.

[mlts22]

There is a good reason why anti-seize compounds have zinc and other particles in them, and preventing galling is exactly it.

With what oil goes through, and being used to changing oil at 3 months/30k miles, I don't get how oil magically can run three times as long in new cars. Metal is still metal, and even though engines are better made than in the past, things still wear and metal shards end up in the crankcase regardless.

[booster]

Finally got the tractor running and tested. Only new hard parts were rings and two tappets (I replaced them because the fell out of their holes when I pulled the cam, so I didn't know which lobe they were on). Everything else was seals and gaskets except for the dipstick. I found no real damage at all, even the ring tensions looked pretty good. Go figure.

While we had it all apart, I went through the rest of the tractor also. Hydro trans oil and filter (have to open the case), some new bushings and an idller for the deck, fix a loose deck baffle, new front wheel bearings, still need to add a ball bearing to the rear steering to fix a worn metal on metal bushing as the bearing just showed up today.

Finished mowing the wetland, as the snow had melted, and all was good. Did it with the hood off so I could watch for the cooling plugging. Lesson learned.

[markopolo]

That's quite an overhaul. Sounds like a lot of work but you probably won't need to do anything to it other than maintenance for a long time.

[g1g]

I had a car that wore out a thrust bearing on the crankshaft once. After changing the crank, a couple oil changes later I did an oil analysis and it appeared the same thing was happening. I did one of those PTFE treatments (oil with Teflon) other analysis after that showed that the same wear virtually came to an end. I ended up selling the car after another 100,000 miles and it had no signs of wear.