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Oil change interval


hpfmnst

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Had my Rotary on E85, rich idle and overlapping ports = Oil would be toast in a couple thousand kms. Thinned out and stunk of corn juice

 

I also crew on a Pro Rotary drag car, running methanol, part of turning the car around between runs is dumping the puke tank.

The puke contains oil, methanol and water, the latter wouldn't be there if it was on petrol.

We drop all the oil and start fresh every meet.

 

If I had a Barra on E85, Id be running a thicker oil than normal and changing it every 3000 or so.

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  • Puff
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1 hour ago, samhouston said:

A fair bit of E85 ends up in the oil, just means oil changes a lot more regularly, which I don't mind :) 

 

Vacuuming my matchbox cars aside,  here is some relevant information.

 

In response to the quote I'd like to point out that this is largely dependant upon ring gap and cylinder pressure. As a general statement, I agree entirely. 

 

In a street car that spends a long time at normal operating temp and stoich mixtures, we will see that raw fuel and water has a chance to evaporate from the oil. 

 

12 hours ago, Ale said:

Had my Rotary on E85, rich idle and overlapping ports = Oil would be toast in a couple thousand kms. Thinned out and stunk of corn juice

 

I also crew on a Pro Rotary drag car, running methanol, part of turning the car around between runs is dumping the puke tank.

The puke contains oil, methanol and water, the latter wouldn't be there if it was on petrol.

We drop all the oil and start fresh every meet.

 

If I had a Barra on E85, Id be running a thicker oil than normal and changing it every 3000 or so.

 

Conversely when we have larger ring gaps (in a piston engine), an afr that is nearly a quarter fuel and is only run for a couple of minutes at a time, there is no possibility that fuel or water can disappate sufficiently to allow the oil to provide sufficient protection in long term use cases. 

 

When we start to veer away from oem design, the need for oem servicing changes.

Edited by Puffwagon
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Comparing Wankels with Pistons is fraught with Danger, won’t even bother trying to draw parallels.

The fact is that the block in this car is built to swallow 4 bar of boost at 10,000 rpm and do it with no “run in time”.

Merely pointing out that Ethanol/Methanol is Hydroscopic and takes on water, so any fuel that is diluted into the oiling system by any means, will not only make the oil thinner, it will add moisture to it.

Yes, to many its stating the obvious.

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