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This winter I will change my engine.

Took apart an engine.
ALL the crankshaft journals are brown.
Along the sides of the pistons and on the piston bottoms it is brown.
Looks like a stain.

Is this the result of some oil additive like Z-Max?

I just want to put rings, bearings and gaskets in this engine, but was expecting everything to look shinny silver and this brown stain is a surprise.

Everything on the crank and rods measures correct.

What made this happen?
Should I be concerned?

Thank you,
 

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Probably varnish from not having the oil changed often enough.
 

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I have a 305 that was was brown as brown can be, and no wear at all. Also had the blackest hardest crap you could describe packed in the hydrollers. I attributed it to heat. Engine was given to me so oil type and maintenance habits are an unknown but the eng had 69K miles when they stuck a new GM engine in the truck due to lack of lifters. I worked on the lifters for a month of Sundays and cheapo overhauled that little POS for $250 counting a new vortec intake.

I see the brown on crank journals to a minor extent at work on large natural gas compressor crankcases that do not require oil changes(work is separated from the crankcase). I attribute it to heat because the machines it happens on run higher oil temps than any other make and the brown areas of the journals coincide with max load on the stroke.

Cat Natural Gas Engines turn their stuff brown, again in my opinion due to oil temp which in the case of a Cat is around 195° up to 210°. This is for the smaller engines(under about 3 or 4000 cubic inch). The bigger Cat engines do not brown their guts, and run 160° oil and that bastard had better be down before 200 or it will rip itself to pieces. Large pieces. The big Waukesha engines(7000") do not turn their stuff brown, they run 160 oil temps. Same additive package, just slightly higher ash content in the Waukesha engine. These engines make massive torque and it all gets applied to a bigass compressor with 2 to 8 conn rods.

Most gas compressors have the oil temp shutdown set below 180°. The ones that brown their journals run 180° and are supposed to kill by 200(very narrow op range).

In an auto engine sans oil cooler, your hot water temp is very close to your cold oil temp because almost all the cooling occurs as the oil contacts the head surface. A well balanced system will put 10° of work into the oil and take the same 10 back out. In a car engine there is no way to measure the hot vs cold oil temp. On big systems with oil coolers I will usually see about 3 to 5° work put into the water for an 8 to 10° drop in oil temp. After balance has been attained. It can take close to a day for balance to occur and in fact a water medium oil cooler acts like an oil heater for awhile after loading. On a car, balance would occur fast due to the small system but load changes so frequently it is a fleeting thing. But you weren't asking about that crap so I'll stop. I love the crap.
 

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Glad you got something out of it Paul. I love the junk. How junk works.

You will please note I did not attribute the brown to OVERtemp, just high temp. I am like the OP, it may be an additive precipitating and embedding in the metal. OVERtemp oil is a whole nuther subject, and not one that automotive engines experience a high enough load for long enough prolonged exposure for my industries standards to matter. They(automotive) get away with murder in other words. 190 will leech the copper right through a trimetal bearing that is extremely loaded. 200 and the oil film can be measured down in the tenthou range and a screech is imminent(by our standards of 24/7/365 duty). One of our main compressor companies has a newfangled way to measure film thickness in duty. I know one of their head dudes and have been intending to call and ask him how they do it. These boys are smart. They've had bluetooth bearing temp sensors on rod bearings for almost 10 years now in test machines. No wires at all. I can remember going to Cat's R&D facility almost 20 years ago and being amazed at the way they had wires on rod bearings for test engines. Thing of the past now. But jeez measuring an oil film under full load. Man you'd have to have something funky as hell embedded somewhere to do that.

I'll try to get a pic on my photobucket of the monster I'm involved in at the moment. I can't post a pic of the wreck it had due to proprietary stuff but I can post a pic of the machine. Engine weighs 70K lbs. 3750Hp at 1000 rpm, which would be 3.75 times 5252#' torque or about 20K#', continuous. Continuous. That means overload it could do 150% of that for a 5 second 1/4 mile. And live.
 

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Oldtimr that aint nothin :boring:, I built a 350 awhile back pushing........ WAIT, what did you say? 3750 hp and up to 20k torque.

Well never mind.:sad:
 

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2x poor oil change manit ,low quality oil or maybe not correct oil viscosity and or type oil for application,possibly motor running hotter then it should too .

Scott
 

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might have had some coolant in the oil. I've seen some nasty colored stuff due to that.
 

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Someone probably treated the Oil with Snake Oil, like a can of RED STP.

I had to use it once on an Oil Burner to get me through the summer before I tore it down in the fall. It did it's job but believe me the Rings where fused to the Pistons with Hard Shellac and the Main Bearings were Brown as you describe - LOL
 

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well, if you mix pretty pink (MMO) and Brown don't you get taint?

lmao

taint, tainted harharhar

pic in my sig now Paul. btw 3750hp felt wrong as I was typing it but groceries were arriving. It is 4735hp at 1000rpm.
 

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Tim that looks like a plumbers nightmare:D
 

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You wouldn't want to be around one under load for long Paul. It's godawful. Earplugs and muffs.

But it is a blast standing up on the catwalk with one of the behemoths while they are gettin it.
 
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Tim,

The closest that I can relate to was when my now ex-B-i-L took me through the Macon, MO power plant when they had onna their peaking engines down. He showed me where they stitch pinned the crank main journal areas b/c of fatigue cracks!

He said this was SOP for engines like this.

I figure it was a lot smaller than the engine you posted the pic of.

I want to say that it was more like an over the road locomotive engine used for electrical power generation, but I may be way off here??

pdq67

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I used to sell and use a product called Z Bond in the early 90's. It coated the parts of an engine with a brown film that was very slippery and extremely tough to remove. The anti wear and friction reducing properties were fantastic. I saw the inside of 350 engine a customer had treated every 50,000 miles for over 200k and everywhere oil touched was brown with no wear on the metal parts. I treated a BB with it per instructions and after the recomended dosage and miles ran it with out water for 20 minutes after breaking a lower hose on my way home from the lake. I figured the additive claimed to protect from this type of damage so it was tested rather then me pay for a tow. Refilled it with coolant and drove the truck 15 years without any engine problems.
Great product, terrible company to be a part of. I still have some of the differential additive I plan on using in the new rear end under the Nova. I supect the new Z Max may be from the same company, but a different formula. The old formula I was told was made in part from hydrogen and very dangerous to produce.
 
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