oil pressure drop @ hard throttle

[paco13]

Before I started this thread I was thinking the oil moving rearward and increased volume being pulled/pushed up top could be my issue. But thought "maybe I'm crazy 'cause"I haven't seen it mentioned before."
I figured I would see if anyone brought it up.
Thank you very much for confirming my suspiscions.

Now how do you go about changing pickup? If I remember the bolt pattern only will fit one way.

 

[trippivot]

I want to address a couple things.

WHO uses 3AN hose to the top end?? I and all my racer friends use #4AN( bigger for more flow and less restriction) 3 is for braking systems

there is no way you are losing pressure when you rev up your bike.

if the o ring was dislodged you would have no pressure at idle. and very little at 3K rpm. you would have ruined the cams and rockers by now.

the idiot light is lying to you. Check the weak spring that controls the contact for the dash light.

the pick up modification is trickier than you might think. just turning it backwards will have you starving for oil when slowing down. (same logic as what has been offered)

more oil in the crank case making the sensor work properly is wrong too.

I run less than 3 QT in my 1428 monster. I run the 1100 oil pump gears. #4 AN in a vortex top end oiler. when I am worried about oil; pressure I check the pressure at the rear main galley and take the cam cover off and visibly inspect how wet it is. never had a oiling problem . I do not worry about flickering lights either. let it flicker.

also remember this is a hi flow - low pressure system. Pressure is not as important as a plain bearing engine. totally opposite here you want high oil flow and not much pressure.

 

[ArttuH]

Did you ever confirm a drop in oil pressure?

Not with a gauge but I was using 0.3 bar (4.5 psi) pressure switch instead of original oil light switch. So I'm sure that there was real pressure drop.

On the other hand I think that short pressure drops aren't that dangerous for the engine, like trippivot said. But I was using a plain bearing turbo which isn't that forgiving.

 

[paco13]

Hmmm. Good info, the only part that doesn't figure is the light doesn't flicker if I overfill the oil. How could the oil level affect the spring or contact?
I do agree that you can't always believe idiot lights.
As said I will add a pressure gauge. I had thought if the o-ring in sump was dislpaced pressure would be bad down low. Maybe I should just double check everything and leave it alone. Whats odd is one thing is telling me I'm losing pressure @ high rpm, yet thats when the oil is pushing out of the oiler fittings.
Thanks

 

[posplayr]

Hmmm. Good info, the only part that doesn't figure is the light doesn't flicker if I overfill the oil. How could the oil level affect the spring or contact?
I do agree that you can't always believe idiot lights.
As said I will add a pressure gauge. I had thought if the o-ring in sump was dislpaced pressure would be bad down low. Maybe I should just double check everything and leave it alone. Whats odd is one thing is telling me I'm losing pressure @ high rpm, yet thats when the oil is pushing out of the oiler fittings.
Thanks

sounds like with more oil the sump pickup (the straw if you will) stays wet and you never run dry. The theory is that too much flow gets at acceleration bets to much oil out of the sump and the straw goes dry and the light goes off. Given your observations that sounds like what is occurring.

 

[posplayr]

I want to address a couple things.

WHO uses 3AN hose to the top end?? I and all my racer friends use #4AN( bigger for more flow and less restriction) 3 is for braking systems

If you are referring to my pic, that is for a guage only. The prefabbed lines for my oiler are -4AN as well.

there is no way you are losing pressure when you rev up your bike.

the idiot light is lying to you. Check the weak spring that controls the contact for the dash light.

more oil in the crank case making the sensor work properly is wrong too.

.

Well I think that is in dispute to be confirmed with a pressure guage. Checking the oil pressure switch would not hurt. The fact that he can correlate the light coming on with 1 qt less oil suggests he starts to run dry at some point.

if the o ring was dislodged you would have no pressure at idle. and very little at 3K rpm. you would have ruined the cams and rockers by now.

.

Agree

the pick up modification is trickier than you might think. just turning it backwards will have you starving for oil when slowing down. (same logic as what has been offered)

I run less than 3 QT in my 1428 monster. I run the 1100 oil pump gears. #4 AN in a vortex top end oiler. when I am worried about oil; pressure I check the pressure at the rear main galley and take the cam cover off and visibly inspect how wet it is. never had a oiling problem . I do not worry about flickering lights either. let it flicker.

also remember this is a hi flow - low pressure system. Pressure is not as important as a plain bearing engine. totally opposite here you want high oil flow and not much pressure.

Makes me think for my street motor to remove my 750 gears and put 1100 gears back in. I will decide after getting my pressure guage working and riding with it. I dont mind 6 PSI, but if I'm hitting 9-12 psi often then that is probably too much (as measured at the right port near oil filler cap)

 

[paco13]

Does anyone know why they have the oil pickup drawing from the front?
Why couldn't it just be picked up from the center, omit the tubes and draw from the recess in the pan?
Seems that you would have a good chance of not sucking air on accel or decel that way.

 

[posplayr]

Does anyone know why they have the oil pickup drawing from the front?
Why couldn't it just be picked up from the center, omit the tubes and draw from the recess in the pan?
Seems that you would have a good chance of not sucking air on accel or decel that way.

I would get a 1.5" gauge with the cheap plastic sensor line first to see what your pressure is. I have your same configuration and from having observed my working gauge (before it died) find it hard to believe I would get a pressure drop. But you never know unless you measure it.

It would cost closer to $100 for a 2 1/8" lite guage with SS line unless you want it permanent.

 

[paco13]

I have a VDO micro and a SunPro automotive in the garage, the sunpro doesn't read below 10psi though.
My issue is I can't test ride this thing till spring unless we get a good thaw. I can and will hook the little one up to the port behind cyl. some time this week and see what it gets at idle and revving stationary in the shop.
Do you know of any accurate electric setups availible? I wouldn't mind a permanent one up by the bars.

 

[posplayr]

I have a VDO micro and a SunPro automotive in the garage, the sunpro doesn't read below 10psi though.
My issue is I can't test ride this thing till spring unless we get a good thaw. I can and will hook the little one up to the port behind cyl. some time this week and see what it gets at idle and revving stationary in the shop.
Do you know of any accurate electric setups availible? I wouldn't mind a permanent one up by the bars.

I'm planning on a permanent handlebar mount with these. For oil pressure I definetly like mechanical and would not go electrical.

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=110364392827&viewitem=&sspagename=STRK%3AMEWNX%3AIT

Details later.

http://www.jegs.com/i/VDO/918/150101/10002/-1?CT=999

The best thing for accuacy is to get as much defelection as you can; that means using a 15 psi scale. Engine vibration and oil pressure pulsation will be big factors to accuracy so that is the reason to mount off engine and get a small diameter hole at the port to push oil to the gauge.

 

[paco13]

OK,
I have the braided stainless line kit in my shopping cart, Now 0-15psi is enough range, correct?

 

[posplayr]

OK,
I have the braided stainless line kit in my shopping cart, Now 0-15psi is enough range, correct?

I would not order the stainless steel line from Jegs or Summit. They are not plastic coated and when you run that under your tank the SS will eat up your wires, paint and anything else it rubs against.

I just ordered a custom line from Paragon Performance. About the same price but it has a clear coating. Call them and tell them what you want ; use the parts in the JEGS/Summit kit and he wil lgive about the same price. The port on the side of the engine is a 10mm

0-15 is the lowest pressure range i have found and is the same as Bruce's 1.5" guage. It would be hard to peg it, unless reved to redline with cold 20-50W oil

P.S. Crap I forgot you were in NY and Paragon is in LA..... he is very helpful anyway.

http://www.paragonperformance.com/

 

[madjack57754]

Bob Bertaut website photo

 

[paco13]

Thanks for the pic.
Looks like he cut the tubes off front and brazed on the rear.
What do you think of omitting the tubes all together and having pick up centrally?

 

[posplayr]

Thanks for the pic.
Looks like he cut the tubes off front and brazed on the rear.
What do you think of omitting the tubes all together and having pick up centrally?

If I was going to do anything I would try to figure out how to always keep the entire tube opening wet.

Since worst case is acceleration (when the motor is being taxed), you want to get as close to the bottom of the pan (without restricting flow), assuming the oil is at about a 45 degree angle to the vertical. (1 G down and 1 G acceleration) Add additional angle if you don't have a wheelie bar. .

That would tend to suggest that rear ward tubes with 45 degree bends down would be best.

At a 45 degree OIL angle the vertical tubes would not be as deep at the rearward facing down curved. At level oil they are the same.


But make sure you are really starving for oil first

 

[Guest]

If I was going to do anything I would try to figure out how to always keep the entire tube opening wet.

At a 45 degree OIL angle the vertical tubes would not be as deep at the rearward facing down curved. At level oil they are the same.

But make sure you are really starving for oil first

This oil light flicker sound familiar. It happened also for me when I installed the 750 pump gears along the turbo. The light started to flicker at top end rpm after hard acceleration. Especially if the oil wasn't completely warm. I think it's combination of two things: 1) increased oil flow keeps more oil in the top end so the oil level in the sump gets lower 2) under acceleration oil goes to rear of the sump and the pick-up is in the front. Together these two mean that there is very little oil in front side of the sump at high rpm and under hard acceleration. So the pick-up can easily suck air.

I solved this by making a deepened oil pan and moving the oil pick-up to the deepest part of the pan.

I t would be interesting to see a pic/drawing of Artuu's fix too.:-k

 

[ArttuH]

I t would be interesting to see a pic/drawing of Artuu's fix too.:-k

All right, here are few pictures:
http://www.iki.fi/arttuh/mopo/project/pohja1.jpg
http://www.iki.fi/arttuh/mopo/project/pohja2.jpg
http://www.iki.fi/arttuh/mopo/project/pickup.jpg

And yes, I know, that square pick-up pipe doesn't look very professional But it works and I hadn't suitable round tube available when I did that.

Oil return from the turbo is connected to front side of the deepened part so that additional wall is there to prevent returning oil getting sucked in the pump right away.

This pick-up works perfectly under acceleration but apparently sometimes sucks air after hard braking. So probably I will add some baffling on the pan.

 

[Guest]

Cool, thanks! Turbo exhaust routing would allow that solution I guess.....with our conventional bikes, the header & collector run pretty close to the pan.You have easy access to that lowered drain bolt too!

 

[paco13]

Nice! Now we're getting somewhere.

Absolutely posplayr, I will verify starvation as soon as Parts,Time, and Weather align. Don't fix what ain't broke, right?

As mentioned, with a street pipe the deep pan isn't an option really, but relocating p/u is. I was asking about centering p/u figuring maybe it might avoid the problem of starvation on braking/decel, but still be rear and low enough to be submerged on accel. If you look at posplayr's drawing the bottem center is always submerged. Any Thoughts?

 

[posplayr]

Nice! Now we're getting somewhere.

Absolutely posplayr, I will verify starvation as soon as Parts,Time, and Weather align. Don't fix what ain't broke, right?

As mentioned, with a street pipe the deep pan isn't an option really, but relocating p/u is. I was asking about centering p/u figuring maybe it might avoid the problem of starvation on braking/decel, but still be rear and low enough to be submerged on accel. If you look at posplayr's drawing the bottem center is always submerged. Any Thoughts?

Reread my post again. You do just what aurthur did just not with a sump extension. Running dry under acceleration is much worse than running dry under braking or normal aspiration at least.
Make an angled sump pickup as close to the bottom rear of the pan as you can without restricting flow. A nice clean slash cut of round tubing at 45 degree down would be about as good as you can get.

See the depth measurement for 45 degree oil level under 1 g acceleration.

When oil level is flat, then there is no difference in being fore v.s. aft(i.e. the center is just as good). However, when under acceelration the rear is deeper as shown in the drawing.