TR-1 Proper Oil Level to avoid RPM loss

[FSH 210 Sport]

I’ve seen a lot of posts about the TR-1 oil level, and been part of a few of them. I’ve seen the claims that high oil levels reduce peak rpm’s in this engine. I’ve also seen at least one video that gave bad information about how to check the oil level which led me to believe that this could be the cause for rpm losses, but I never could figure out the mechanism for the rpm loss until yesterday when I was replying to a thread for @CarolinaJet and excessively high oil levels while out on the water. Then things became clear to me as I remembered another post where a guy had pulled almost two quarts, probably more out of his TR-1 engines. So the following is what I think is happening with the TR-1 engine and its oil levels.

The TR-1 is a dry sump engine, this type of design removes any windage or drag from the counter balancers passing through the oil and also reduces the height of the engine at the same time increasing the power of the engine by removing the parasitic losses. In the picture below you can see the catch / oil pan and the oil pump. You’ll notice that the oil pump has two pick up screens and two outlets. The front screen / pickup #6 is the scavenging side of the oil pump, this side picks up all the oil that falls to the pan and pumps it to the oil tank on the back of the engine, and possibly through the oil cooler, I’m not sure of the exact flow of oil through the cooler. The other pick up, #9 is at the bottom of the oil tank and provides the source of oil for the pump to provide pressure lubrication the the engine.








This the proper oil checking procedure which is straight out of my owners manual.


The engine is run for at least 6 minutes to warm the oil, and additional 5 minutes if the ambient temperature was 68* or lower. Oil expands when it gets hot, so the oil needs to be warmed before checking it, otherwise this will also produce a high oil level at normal operating temperatures. Notice that it states to screw the oil dipstick in all the way when checking the oil level. The other reason the engine needs to be run for a while is allow the scavenging oil pump to pick up any oil that may have drained into the pan and put it into the tank. This is how the engine is when it is running.

The problems begin with the oil level not being checked properly, if the oil level is checked when the engine has been sitting for a period of time, oil can migrate into the oil pan and give a false low reading on the oil level. Adding oil to correct the oil level begins a downward spiral if the same incorrect oil level check is repeated. This results in a higher and higher oil level in the oil pan and at some point the oil level gets high enough that the counter weights on the crank shaft begin to hit this pool of oil which causes drag and slows the engine down. This gets worse even faster if the dipstick is not screwed in all the way when checking the oil level further raising the amount of oil that is in the engine. There was one instance last year where the poster had removed almost two quarts from the engines and the oil level was still high.

In a wet sump engine, like the one in your car or truck, it is best to let the oil drain down for 15 minutes after the engine has been running to check the oil to allow all of the oil to drain back down into the oil pan.

The excessively high oil level causes yet another problem, as the crank shaft counter weights are passing through the oil at high rpm, this causes the oil to vaporize where it is carried into the intake tract via the PCV system. In some cases this causes the air filter to become fouled with oil so air flow is restricted at the same time there is a lot of oil vapor entering the engine and disrupting the burn in the cylinder reducing power, which can result in blackened spark plugs.

I’ve seen posts where the oil level is decreased on the dipstick down to 1/4 full to get back in some cases 500 rpm. I’m very sure that this was done to correct for excessively high oil levels in the engine due primarily to incorrect oil level checking procedures. I have personally verified that lowering the oil level after it was properly set results in no rpm gain, on the day I made back to back runs and reduced the oil level down from full to 1/4 full with zero change in the rpm’s. Atmospheric changes from day to day will in fact change the density altitude and affect the performance of the engine.

These engines hold 3.91 quarts of oil, of which a total of 3.59 can be extracted along with the oil filter. But, it takes persistence to extract all 3.59 quarts, so the engine retains basically .3 quarts of oil that cannot be extracted. When doing an oil change and refilling with oil, it is crucially important to not add in what was taken out or especially the 3.59 quarts as there may still be more than the .3 quarts of oil in the engine, well you can but don’t be surprised if some oil needs to be extracted to set the oil level to the correct level after the engine oil checking procedure in the owners manual. I have gotten to the point now that I keep trying to extract oil from the oil extraction tube and the oil fill tube repeatedly and making sure to get the extraction hose all the way to the bottom of the oil fill tube as there is a shelf in there that gets in the way. When I fill the engine with oil, I do so incrementally I end up putting in 3.6 quarts and the oil level is mid way between the L and F on the dipstick.

So always run your engine for at least the amount of time specified in the manual and check the oil when it is warm and right after the engine is turned off. This will ensure the proper oil level and the best performance out of your TR-1 engine.

 

[drewkaree]

To track and somewhat follow the path of the oil, this makes sense.

Most everyone (myself included) will apply their experiences with cars, to these motors, unwittingly and/or unknowingly causing problems that don't seem to track with "typical" oil change procedure.

This also seems to explain the "why" of just how overfilling cuts speed. I never understood why this would be the case, when it didn't happen to cars with the same drastic effects, I just knew I couldn't argue with the noticeable loss of speed if the oil was high for me.

 

[FSH 210 Sport]

To track and somewhat follow the path of the oil, this makes sense.

Most everyone (myself included) will apply their experiences with cars, to these motors, unwittingly and/or unknowingly causing problems that don't seem to track with "typical" oil change procedure.

This also seems to explain the "why" of just how overfilling cuts speed. I never understood why this would be the case, when it didn't happen to cars with the same drastic effects, I just knew I couldn't argue with the noticeable loss of speed if the oil was high for me.

Right? It certainly wouldn’t be the oil pump and the small gear holding the engine back, it would get destroyed in no time. Once the scavenging pump has no place to put the oil I’m sure it has a relief valve that allows the pumped oil to flow back to the pan.

In our cars we have a drain plug so gravity does the work for us, and our cars don’t have a two chambered oil pan. I see that there is a drain plug on the oil pan on our engines but the area under the crankshaft Is dammed off by the grommet on the intake of the pressure pump so pulling the drain bolt won’t remove the oil in that part of the pan under the crankshaft.

I can’t believe it took me this long to figure it out. On my older dirt bike engines they have a form of dry sump engine, that uses a reed valve at the bottom of the crankcase and when the piston comes down the pressure forces the oil out of the bottom of the crankcase. When I change the oil I make sure to kick the engine through a few times to get the last of any oil out.

So, that’s why it’s so important to run the engines for a bit after an oil change and then check the oil level, any oil that was still in the pan in the forward section will get pulled out and put into the oil tank.

 

[TeenGee]

There is another affect of the counterweights whipping through in the oil causing it to froth. The oil froth is difficult to pump and in the worst case can cause oil starvation to the bearings with permanent and drastically reduced RPM possibly accompanied by some very expensive sounds. This is not limited to dry sump engines. Wet sump engines are susceptible to this phenomena also.

 

[anmut]

So this brings up a parallel question:

On BRP Sea-doo "jetskis", the oil change procedure includes a process of turning over the engine 2-5x AFTER the oil is siphoned from the engine. There's a specific procedure where you depress the throttle and hold it while pressing the start button to crank the engine. Only after that cycle of cranking, siphoning, and cranking is complete, THEN you change the oil filter. If you watch a video of this, there's significant oil coming out after the cranking procedure.

Did BRP figure out a way to extract all remaining oil from the pan? Even if you could hold the throttles open and crank the motor on our boats, cranking without any oil makes me pucker up...

 

[TeenGee]

I suspect the oil was in the filter and the oil pump displaced it by sucking and pumping air. The oil would lubricate the bearings and other components as usual. Just need to pull the MOB lanyard to make sure the engine doesn't start. If you are concerned, remove the spark plugs.
Sounds like a great way to get the oil out of the filter. I think I will try it next time I change the oil.