2 stroke longevity?

[JimS123]

As a teenager with Grandpa's old 1955 10HP Mercury I used to rent an old tinny up the creek and terrorize the ducks on the Erie Canal with my buddies.

But I DID religiously use "good" oil and kept to the 24:1 ratio. I bought Quaker State 2-stroke OB OIL because that 's what they sold at KMart.

One year I having smoking and running problems, so I took the motor to my local Mercury dealer. Rather than going to the retail store first I simply went to the back door at the shop.

The manager there said it would be a diagnostic fee and it would take weeks. But he offered to let me dunk it in his test tank and listen for free. I started it up and he immediately said shut it down. "You have been using Quake State OB motor oil". I said, OMG that's true. He gave me a bottle of Mercury oil and said good luck.

All these years I still have an old empty plastic bottle of QS, just for nostalgia.

That's my oil thread for the day......LOL.

 

[cyclops222]

A closing unbelievable remark about gas to oil ratios.
Way back a test group decided to see how little oil could run a 2 stroke O B. They settled on 300 something to 1. Even I would not go near that on a dare. Anybody know for sure. What ETEC ran on in California to get EPA and California approval ?

 

[racerone]

But E-tec is a different concept.---Oil is NOT mixed with the gas.----Gas is not in the crankcase to wash oil off the bearings.----An E-tec operates like a 4 stroke for part of a revolution of the crankshaft.

 

[cyclops222]

Thank you racerone.

 

[jimmbo]

The Crankshaft and Connecting Rod Bearings, actually all of the Rotating Assembly, in an E-Tec/FICHT, experiences Higher Temperatures than regular 2 Stroke because there is no Fuel passing through it to Cool the Internals, just Air.
Those DI Engines really Stressed the TCW-3 Oils well beyond the TCW-3 Specs

 

[Mc Tool]

The Crankshaft and Connecting Rod Bearings, actually all of the Rotating Assembly, in an E-Tec/FICHT, experiences Higher Temperatures than regular 2 Stroke because there is no Fuel passing through it to Cool the Internals, just Air.
Those DI Engines really Stressed the TCW-3 Oils well beyond the TCW-3 Specs

Was it the higher temps that stressed the oil or was it that they were trying to get away with using a lot less of it ?
How does the oil get to the mains and big ends ?
The Old Suzuki 2 stroke motorbikes used to have their CCI crank case injection where most of the oil was delivered direct to the mains , a bit went in thru the intake manifold and the big ends got it as it spewed out of the mains and got flicked around in the crank case .....and a bit of good luck . These were piston ported engines

 

[jimmbo]

The FITCHS used Orifices in the Crankcase that would shoot Oil at the Connecting Rod Bearing and Hoses/Tubes going to the Crank Bearings. They also added a very small amount of Oil(300:1) to the Fuel System, to lube the Fuel Injectors.
The DI engines because of the Difference in how the Combustion Process occurred at certain Rpm and Loading, created a very hard Carbon from the Fuel and Oil. This Carbon would collect on the Head, but more Importantly get behind the Rings, and wasn't being softened and washed away by the Air-Fuel mix that was no longer going through the Transfer Passages. In time the Rings would be unable to contract in the Piston Grooves and Scoring would happen.
This is one of the original Cylinder Heads from my 1998 150hp. The Heads were being replaced with ones that had a Deflector placed in the Path of the injected Fuel. These had about 60hrs on them

 

[Mc Tool]

I recall going out on a boat ( friend of a workmate sorta thing ) and he had a ( I think 175hp) Fitch motor , Guy turned out to be a dickhead but any how couple of months later on the motor chundered big time , something to do with a rod , not sure what but it damn near cut the block in half . I dunno how long he ran it for but there must have been a rod or two flapping about in there, last I heard they were fitching ( ) over the warranty.
I did have a wee read about the stratified combustion thing , but interesting that carbon build up behind the rings due to the lack of fuel as you say . Makes me think of and old customer with a Villiers engine on a bore pump that he ran on "1/2 a pint to the gallon" of 30w oil , I cleaned/ decoked that engine out every year inc ring grooves . Things have changed.
Thanks for the info

 

[cyclops222]

I would like a $ 100 bill for every 4 stroke engine screwed up by a DIY mechanic.
Adjusting the valve lash ? HA HA HA
" Engine was always a loser !! "