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Really high oil temps
chrisf - 3/10/06 at 12:34 PM

Hi:

As a follow up to this thread, I have some BEC questions.

Right, before I took a 300 mile round trip a few weeks ago, a friend an I changed the oil in the car. It was rather late in the evening and we had...umm..a few beers when we did this. We drained the oil out of the sump and it was nice, pale black. When we pulled the filter, though, it seems a lot more golden than the rest of the oil. Or so it was remembered.

So, fast forward a month or so and 400 miles later, I saw some 230F oil temps while driving in 95F weather. What's odd is that when I came to a stop light, the oil pressure gauge dropped to 0 very quickly--almost like I was low on oil. It usually stays around 10PSI or so IIRC. Also, on full boil, the pressure jumps to around 60PSI. Yesterday, it went up to 40 PSI at around 6k RPMs.

So what do you think? Is it possible that my oil is not being filtered, and thus cooled? I'm going to check the oil level tonight (to the top of the sight glass on the blade, right?). I'm also shopping for some quality gauges because mine are currently some cheap eBay items. Anyway, it seems that if my oild temps went way up, my water temps would go up as well, no?

--I look forward to your response, Chris

[Edited on 3/10/06 by chrisf]


RazMan - 3/10/06 at 12:57 PM

Surely the oil must go through the filter - the pump is in-line with it. Have you modified the oil system in any way?


chrisf - 3/10/06 at 01:33 PM

Hi:

Everything is stock. TBH, it may have been the way the light hit the oil out of the filter, but it did seem really light.

I still have the issue of the extreme oil temps--or sh_tty gauges. Both of whick raise my blood pressure...

--Thanks, Chris

[Edited on 3/10/06 by chrisf]


RazMan - 3/10/06 at 02:01 PM

It might be a good idea to check that you are using the correct grade of oil but otherwise I am out of ideas.


stevec - 3/10/06 at 03:56 PM

If you have overfilled accidently that could cause high oil temp.
Steve.


chrisj - 3/10/06 at 04:41 PM

Some oil filters have a non return valve which can stick. The other things you should look for is what the operating temps of oil you are using goes to. If it gets to hot it will lose its viscosity and be ineffective in lubricating the engine.

The bigger the oil filter the better the oil pressure. You can usually get any filter to fit its a matter of how much clearance you have. Mine's a giant filter off of a vw van I think.

Have you thought of an oil cooler, very simple and reasonably cheap to fit.

10 psi is thin. I would be looking for a steady 45 psi at regular speed peeking out at 4 bar or 60 psi. 10 psi and I would reach for the kill switch and a layby.

Check out using some racing oils such as Miller fully synthetic 5w 50. It will improve the pressure and has higher operating temperatures.

Their are some threads on this somewhere.

Water temperature can be a bit misleading depending on where the temps being taken from in the system.


DIY Si - 3/10/06 at 04:45 PM

Some bike engines do tend to have near 0 psi at tickover when hot due to having to rev so high. I'd get some better gauges and see what really happening. 60 psi under reasonable load sounds fine, with 40 being low.


ChrisGamlin - 3/10/06 at 05:58 PM

Yep, blades will generally idle at about 10-12psi when hot so nothing to worry about there. As others have said, you couldnt really not filter the oil, if the inlet to the filter gets blocked, you wouldn't get any oil flow around the engine and it would have gone bang long before now, so I wouldnt spend too much time on that one.


As for pressures, I used to get around 5-5.5 bar (~75psi) hot when the engine was under load with all three of my blade engines using a digital SPA gauge and Castrol R4 oil (5w 40?), this maybe dropped a bit when the weather was 30+, but not by very much, so I'd suspect maybe your gauge is reading slightly under, which then makes things look worse than it really is at idle.

To be honest though, your temperatures aren't that extreme, especially the water temp, Ive certainly seen higher oil and water temps albeit on track (but in lower ambient temps). Also some engines do just seem to run hotter than others, two of my engines used to run about 80c water and 90-95c oil on most trackdays, yet the other ran about 10-15c hotter on the oil in the same car with exactly the same cooling setup.

I'd maybe look at fitting a sandwich plate to it and fitting a proper oil/air cooler in front of the radiator and see how it is after that.

Chris


tks - 4/10/06 at 06:56 AM

wil vary allot when fueling and timing is different..

Sow new plugs or old ones...

and fueling setup to the lean side and fueling setup to the rich side...

one thing wich is important is that you measure on the exact moment to be able to compare...and in theory you need to do the exact lap...

etc. etc..

TKs


bike_power - 4/10/06 at 08:27 AM

In my busa I found that the synthetic 10-40 oil was breaking down after just 1700-2000 miles which made the gearchange very clunky, the top end sounded tappety and overall the engine didn't dound very happy and hot oil pressure even under load dipped to 60 psi.

Switched to 15-50 Mobil 4T race or high performance, whatever they call it and the engine is a lot happier. Have no idea if it will start as well on those cold winter mornings but I'll not be finding out either !


tks - 4/10/06 at 08:52 AM

because you upper the thickness aswell as the max temp grade...

10 ==> 15 Thickness at 20degrees

40 ==> 50 Temp grade

Tks


mad-butcher - 4/10/06 at 07:48 PM

Mine gets the living daylights thrashed out of it at trackdays, no fancy gauges (I find they distract me.) Just a nice big red light as fitted by honda to tell me if theres a problem.
Tony


ChrisGamlin - 5/10/06 at 09:01 PM

There's a minor problem with that though Tony, as I found out when the sump plug escaped on my first engine.

The standard fit warning lamp is set at such a low pressure (ie less than idle pressure, so maybe 7-8psi), that if you lose pressure whilst the engine is under load, by the time the light comes on, the engine is very likely to already be damaged.

The ideal solution is an intelligent gauge that you can set to come on if the pressure is below X, but only when the revs are below Y. This way, you can set the warning level nice and high (say 30-40psi), but the lamp doesnt come on when the engine drops back to idle because its below the rpm threshold you've set. Failing that, just fit a higher pressure warning lamp and accept that it will come on at idle.