What kind of bearings on e-TEC and 4 cycle outboards?

[Chris1956]

Conventional 2 cycle outboards have needle bearings for internal main bearings, crankpin bearing and wristpin bearings. 4 cycle auto engines have solid bearing surfaces. What do the HPDI outboards and 4 cycle outboards use for bearings?

 

[steelespike]

Re: What kind of bearings on e-TEC and 4 cycle outboards?

My guess is 4 stroke typical insert bearing,etec needle bearings.

 

[Paul Moir]

Re: What kind of bearings on e-TEC and 4 cycle outboards?

A quick look at the BRP website confirms steelspike's suspicions. Johnson/Suzuki 4-stroke has plain bearings while the E-TEC uses needle. Not surprising since the 4-stroke uses a pressurized oil system and the E-TEC does not. Well, technically I suppose it does, but it's more akin to a traditional 2-stroke recirculation system.

 

[DJ]

Re: What kind of bearings on e-TEC and 4 cycle outboards?

Typically, 2-strokes hardly EVER have bearing failure. The pistons melt first.

4-strokes-opposite.

Most 2-stokes died of neglect. As it turns out, many 4-strokes are suffering the same fate.

 

[Chris1956]

Re: What kind of bearings on e-TEC and 4 cycle outboards?

Thanks for the info. On a related subject. The E-TEC infomercial has a sequence where the motor is able to run for hours at slow speed, after the oil line is cut, w/o damage. I guess I am skeptical about this claim. Anyone have any better knowledge?

Paul, Doesn't the E-TEC have a pressurized oil system, whereby oil is pumped through passages in the crank to lubricate the mains, rod bearings and wrist pins? I had thought that this was the way used to keep oil consuption down, versus, atomizing the oil in the air intake stream.

 

[rodbolt]

Re: What kind of bearings on e-TEC and 4 cycle outboards?

at a dead idle with no load you would be amazed how far any motor will go with no oil. tell the infomercial guys to plane it at 4800 and lets see how long it lives.
pure marketing hype. the reciprocating set up in the etec is basically the same as two strokes have used for more than 30 years, same with the four strokes.

 

[Paul Moir]

Re: What kind of bearings on e-TEC and 4 cycle outboards?

Yes that's true, there is an electrical oil pump. It provides the pressure needed for the oil injectors to function. But inside the crankcase it's still an oil starved environment compared to a traditional 4-stroke. For plain bearings to function properly without wear, they need an ample supply of preferably pressurized oil. Otherwise the oil film between say the crank throw and the rod bearing gets squeezed out and you get metal on metal contact with the associated wear.
Like rodbolt said, the actual reciprocating assembly of the E-TEC is very much like a traditional 2-stroke. Just rather than mixing the oil with fuel before it's pumped through the crankcase, the raw oil is injected just ahead of the reeds.

I don't know much about the ETEC engines, I just try to read what technical articles I can find. Which isn't easy to do given the loads of marketing hype that are out there. If you're interested, you can find a few links to some supposedly technical articles here:
http://www.e-tecinfonet.org/id1.html
Look down and find the IAME articles. They've got lots of hype in them, but you can glean some useful information from them.
The ETECs really do have some technical advances in them, but unfortunately they seem intent on burying those details with that foolish "running without oil", etc nonsense. It's too bad because I think they could really sell it on those technical nuances. How often do you hear them advertise about the computer controlled water injection for exhaust tuning?

 

[Chris1956]

Re: What kind of bearings on e-TEC and 4 cycle outboards?

Guys, Thanks for the info. I am disappointed to hear that the oil is injected into the air stream. I had hoped that the oil was forced through the crank and rods. Heck, my dad's old 4 cycle lawnmower (early 60's Larson/Tecumpseh motor) has a primitive crank-driven oil pump, which did this. One would think that a pressurized oil system of this type for a 2-cycle motor would really cut down on oil consumption. You would want to keep the roller/needle bearings, of course.