HarleyTechTalk

Technical Forums => EVO 1340 => Topic started by: FTBY55 on October 11, 2019, 03:41:56 PM

Title: Oil Pressure
Post by: FTBY55 on October 11, 2019, 03:41:56 PM
 Have a '96 FLSTF that I think needs a new oil pump. Factory manual says 15 to 35 PSI @ 2000 rpm. Running 20W50 Amsoil Synthetic and I don't see over 22 even up to 4000 RPM.
Cruising at 3500 and I'm lucky to see 22psi. If I stop at light and idle it goes down to 10-12 cold after heated up to 100 deg. it will drop to Zero at idle.
Looking for suggestions/ recommendations. Considering an S&S High Pressure High Volume replacement.
When I tried 20w60 I did see 60 psi cold, could I have overpressurized something and now be bypassing oil somewhere.
Title: Re: Oil Pressure
Post by: Deye76 on October 11, 2019, 04:00:57 PM
The oil light on my old Panhead would flicker at traffic lights, ran it like that for 11 years, then sold the bike still going strong. 
Title: Re: Oil Pressure
Post by: thumper 823 on October 11, 2019, 04:06:41 PM
Some people install a stronger Pressure relief spring.
Some say it is bad.
Some say it is good...I have not ever checked the oil schematic .
I did it about 5 years ago and 20K miles back.
The results have been spectacular.
Title: Re: Oil Pressure
Post by: FTBY55 on October 11, 2019, 04:23:48 PM
thumper 823,

It seems when the oil gets hotter pressure drops. 20W50 thinning out, just changed and less than 200 miles on it. Oil oil pump springs, ball check and screen recently changed.
Title: Re: Oil Pressure
Post by: thumper 823 on October 11, 2019, 04:42:58 PM
Most oils (if not all) have the same pour points after heated up..
Title: Re: Oil Pressure
Post by: Ohio HD on October 11, 2019, 04:55:42 PM
I'd ride it.

Unless things change, or you have noise, ride it.
Title: Re: Oil Pressure
Post by: Thermodyne on October 11, 2019, 06:00:11 PM
What /\ he said.  Just ride it, anything over 7 is fine for an Evo.

Title: Re: Oil Pressure
Post by: Hossamania on October 11, 2019, 07:56:26 PM
How old is your gauge? What did it run in the past, when did it change, did you notice a difference in running or sound when it did?
Title: Re: Oil Pressure
Post by: FTBY55 on October 12, 2019, 01:28:00 AM
Gauge is new, changed out twice as the first leaked. second was supposedly reading incorrectly. shop confirmed this one with their gauges. Bike used to run twenty PSI higher and had hit sixty on startup. Now 22 to 25. The drop to 0 on warm idle worries me. Been doing some research and realized I can't do a full change out without removing engine. Will have to use existing drive shaft. Oil returning to tank is well aerated, Many little bubbles. Wondering if I am somehow getting crossover, internal leaks..
Title: Re: Oil Pressure
Post by: thumper 823 on October 12, 2019, 03:40:03 AM
Try a new Oil Pressure relief valve spring.
As i said, a new slightly stronger one fixed all my low P problems.
Title: Re: Oil Pressure
Post by: hbkeith on October 12, 2019, 05:47:26 AM
Quote from: Ohio HD on October 11, 2019, 04:55:42 PM
I'd ride it. :up:

Unless things change, or you have noise, ride it.
:up: Hell , my last EVO bagger with a gauge ran at barley over 5psi at idle when hot , was like that for 50000 miles , its a Harley
Title: Re: Oil Pressure
Post by: Dan89flstc on October 12, 2019, 05:52:52 AM
Throw the oil pressure gauge into the scrap bin, or keep it as a tool, but take it off the bike.

If the pressure is too low the lifters will tell you right away.

Don`t wast your money on the S&S high volume pump, it is unnecessary.
Title: Re: Oil Pressure
Post by: FTBY55 on October 12, 2019, 08:02:06 AM
Quote from: thumper 823 on October 12, 2019, 03:40:03 AM
Try a new Oil Pressure relief valve spring.
As i said, a new slightly stronger one fixed all my low P problems.

I replaced the spring and check this spring with no change. Does somebody make a higher pressure replacement?
Title: Re: Oil Pressure
Post by: thumper 823 on October 12, 2019, 01:05:07 PM
Ebay.
Title: Re: Oil Pressure
Post by: screem on October 12, 2019, 03:40:06 PM
Quote from: Dan89flstc on October 12, 2019, 05:52:52 AM
Throw the oil pressure gauge into the scrap bin, or keep it as a tool, but take it off the bike.

If the pressure is too low the lifters will tell you right away.

Don`t wast your money on the S&S high volume pump, it is unnecessary.

I made the switch to Synthetic Oil on my evo some years back .. same issues as the OP a guage that would read zero at hot idle, changed the spring, to a little higher pressure spring with little to no change... the red idiot never ever came on and the lifters never got loud. I changed the guage out with same result of zero/hot.
   Just to make sure there was no other oiling issue, i dropped the synthetic oil and filter and put 20-50 dino oil back in it and the oil pressure went to 8lbs at hot idle, and 28 or so running on the highway.
   I have never put Synthetic back in it... over 150,00 miles, took top end off 110,000, everthing looked great, cleaned up the jugs, re-ringed, new studs and slapped it back together.
   
Title: Re: Oil Pressure
Post by: thumper 823 on October 12, 2019, 04:14:59 PM
I use amsoil and have zero problems
Title: Re: Oil Pressure
Post by: Burnout on October 12, 2019, 04:21:41 PM
Often incorrect application oil light switches are substituted for the Low Pressure Switch used on a HD.
The switch has to tolerate the high pressures found at start up yet only turn on the light at very low (3psi?) pressures.
I won't trust offshore light senders unless they specifically state the pressure.
There are many senders that look identical to a HD sender but have a different pressure rating.

Oil pressure gauges are useless. A 60 or 80 psi gauge will show zero at the low hot idle pressures seen on a HD.
A low pressure gauge will be damaged by the cold oil pressures at startup.
Title: Re: Oil Pressure
Post by: FTBY55 on October 12, 2019, 07:35:20 PM
Replaced the pressure switch with new HD unit. Light would come on and not go off with rpm rise. 0 psi at traffic light. Took to shop and they replaced both new switch and new oil gauge that I had installed. Will see 25-30 on cold start, 28 mile run and gauge is staying about 22 at 3500-4000 rpm. When I stop at destination 0 on gauge , no indicator light lit. Start bike back up after a coffee and bagel and oil pressure is about 10 and takes a while to come up at 3-4K rpm. I see that they suggest a 0.40" shim for T/C plungers. Someone posted to add 0.20' shim to evo spring. Another suggested a #10 washer. Bought a few but they don't fit in plunger or cap. Put 2 #6 washers in and didn't see any real change so I sat down and decided to modify a 1/4-20 SS allen head bolt. I used a drill and file and took the diameter down until it fit smoothly inside the plunger. Next I took the head height down to 0.185" and filed the threads smooth o as not to bind on the spring. Inserted into plunger and placed spring over it. Hoping this will bring my hot idle oil pressure up to around 10 psi at idle.
Title: Re: Oil Pressure
Post by: thumper 823 on October 12, 2019, 08:27:28 PM
https://www.ebay.com/itm/Harley-Evo-Shovel-Oil-Pump-Harley-Oil-Pressure-Relief-Spring-Kit-73-99-SP-1/323872178070?hash=item4b68493f96:g:NUcAAOSwbjNcMiSH

stronger spring
Title: Re: Oil Pressure
Post by: FTBY55 on October 12, 2019, 09:02:32 PM
 Thanks thumper, saw that earlier while searching.
Does raising the spring pressure starve the lower end and cam?  Any thoughts on ERT's adjustable spring pressure unit? 
Title: Re: Oil Pressure
Post by: Burnout on October 12, 2019, 10:35:24 PM
Replacing the pressure relief spring will not raise idle oil pressure.
It relieves high pressure it won't make up a lack of pressure.
Title: Re: Oil Pressure
Post by: FTBY55 on October 12, 2019, 10:51:57 PM
Quote from: Burnout on October 12, 2019, 10:35:24 PM
Replacing the pressure relief spring will not raise idle oil pressure.
It relieves high pressure it won't make up a lack of pressure.


The mod I did just raised my start up oil pressure 10 PSI. Will try again tomorrow when cold.
Title: Re: Oil Pressure
Post by: Benjie40 on October 13, 2019, 01:30:20 AM
If the light ain't coming on at idle, your good to go... It's not a typical SBC with clevite 77 bearings on the journals. So it ain't gonna build pressure at idle.. 5-6 psi at idle is normal..
Title: Re: Oil Pressure
Post by: thumper 823 on October 13, 2019, 02:57:06 AM
Here is some things to think about in all of this -
With the Evo, HD said "dont idle it to tooo SLOW as it will be damaged because of LOw OIL P.
So by obvious deduction, assimilation, and a contraction or too,,we can deduce that no oil P for any reason at an idle is prolly a bad thing.
Being there are no flat bearings in an HD engine to actually create a hydraulic separation of parts using Oil P,  we can arrive that it is not engine tolerances issue causing the low readings once we have verified  no oil P..
If you have checked relief valves , springs ETC  and all is well, i would have to suspect a pump.
DONT buy a CHINESE one!
Title: Re: Oil Pressure
Post by: MikeL on October 13, 2019, 04:30:23 AM
Them old Detroit Diesel 2 strokes would run 5psi at idle hot and they had babbit bearings. Might try 60sae oil. I put Amsoil 60 sae in all 3 of my Twin Cams and Shovel.
Like what has been said if the valves aren't clacking Run it!!   


                                                                                                       MIKE
Title: Re: Oil Pressure
Post by: capn on October 13, 2019, 05:21:51 AM
Get a regular billet S&S pump.Not the high pressure one.Also those Ultima pumps work well if you are short on cash.I have one of each no problem with either one.
Title: Re: Oil Pressure
Post by: thumper 823 on October 13, 2019, 06:47:52 AM
After studying life in bars, then oils, I have not ever found one that had much of a different pour point once hot.
The oil enginemeers use 212 deg for the control point
The Viscosity label    "W" is the information for cold starts.
The "W" stands for Winter, and a higher number will stand for better shear when hot.
Pour points are measured with cold oil and hot.
The hot number means little after 212 deg*
It is a very common mistake to think 60 weight is *way thicker at 200 deg the 30 weight. 

https://www.motorstate.com/oilviscosity.htm

https://www.yourmechanic.com/article/why-does-motor-oil-viscosity-matter

https://autosneed.com/oil-viscosity-and-weight/
Title: Re: Oil Pressure
Post by: JW113 on October 13, 2019, 03:25:00 PM
As Dan said, if tappets are not clacking, there is nothing wrong with the oil supply. HD does not operate on oil pressure, but rather just pushes oil around to keep things wet. At hot idle, if the light is not on solid, you're good to. I kind of recall that in the owner's manual, it even says if the bike is hot the light might flicker, but is considered normal.

-JW
Title: Re: Oil Pressure
Post by: FTBY55 on October 13, 2019, 06:41:22 PM
So after reviewing the oiling system diagram I am concerned about increasing the spring pressure as that would leave my lower end and cam chest unoiled longer. As plunger rises the top end is oiled first plunger raises and opens passage to lower end and cam chest.
Increasing pressure is only masking the problem. I believe the pump is worn.
when I take the plunger out oil flows out fairly quick. Working with positive displacement gear pumps for forty years we would only see that when housing. wear plates or gears were worn.
Looking at the S&S Billet information and it says that the OEM drive shaft can not be used. Will the camchest have to be opened and will the motor need to be removed?
Title: Re: Oil Pressure
Post by: FTBY55 on October 13, 2019, 10:08:00 PM
FROM S&S Instructions:


With engine hot, typical oil pressure reading is 3-4 PSI at 1000 RPM idle, 12-15 PSI at approximately 2500 RPM. If oil pressure reading is low, confirm with accurate mechanic's gauge . Oil pressure warning light comes on at approximately 3 PSI. Light may flicker at low RPM, but should quickly go out with slight increase in engine speed.
Title: Re: Oil Pressure
Post by: hbkeith on October 14, 2019, 12:37:39 AM
majority has said , nothing wrong , but yes pull engine do complete rebuild
Title: Re: Oil Pressure
Post by: rigidthumper on October 14, 2019, 05:06:16 AM
The pressure gauge actually only indicates resistance to flow, that's why increasing spring pressure makes the gauge go higher- you have effectively increased the resistance to flow. HD uses roller bearings, so the oil has to be able to flow through the passageways, across the rollers to lube & cool, keep the lifters full, and travel back to the bag & dissipate some of the captured heat. As has been said, the HD system relies on volume, not pressure. If the lifters are not clacking, and the light is out, you're OK. If you are hearing sounds that concern you, have an experienced rider/mechanic listen to it.


BTW, oil pressure gauges have sold more oil pumps & fancy springs than any accessory catalog :)
Title: Re: Oil Pressure
Post by: FSG on October 14, 2019, 09:31:25 AM
I put a pressure gauge on my Fatty years ago, I took it off not long after, best thing I ever did

OK an Evo Oil Pump has a Non Return Valve in it, the Ball that notoriously gets a bit of crud under it and leaks when the engine is not running, a small spring keeps the ball in the closed position

It takes 3 PSI to over come that spring and have oil flow

The OEM Oil Pressure Switch operates at 5 PSI so if the oil light is off then you have at least 5 PSI, if the light flickers at idle then ......  so what

NOTE: I said OEM Oil Pressure Switch,  anything else ....... Taiwan Ted, Corner Store Switch ......  I've no idea

The lower/upper oil passage plunger spring operates at 15 PSI

if no oil light and no tappet noise I'd leave things be, now I do like Synthetic Oil BUT could easily just run Dino in an Evo

Title: Re: Oil Pressure
Post by: Burnout on October 14, 2019, 10:36:13 AM
OK I'll re word my previous post.

Replacing the pressure relief spring will not raise HOT IDLE oil pressure. This is where guys are having trouble.
It relieves high pressure it won't make up for a lack of pressure.
A high idle has never damaged a Harley motor.


At a hot idle the light is coming on because

A) The oil is too thin (20-50 with no cooler is too thin)
B) The pump output is weak due to wear
C) The IDLE SPEED is too low (this is a biggie)
D) An incorrect oil light switch has been installed

I won't discuss actual pressures because that is a cesspool of argument and conjecture.

Can we agree that you can have oil FLOW at very low pressures? Pressures lower than a gauge will indicate?

Now for the part that guys cant wrap their heads around.
Any oil pressure measured on a non-twincam Harley is entirely coincidental.
A Harley oiling system is not pressure based, only FLOW.
A Harley oil pump is a feed pump not a pressure pump, it merely "lifts" the oil up to the lifters and rockers.
The pressure that turns off the oil light is created by the check valve spring and the flow resistance of that passage.
DO NOT INCREASE THE CHECK VALVE SPRING pressure as that may/will restrict oil delivery (especially if the pump is worn)

Most of a Harley's oiling is done by splash.
A Harley's crank bearings are not "pressure" lubricated. The only things that need "pressure" are the lifters and the rockers.
The big end of a Harley's rods get fed 10 times the amount of oil they need, that oil is thrown up to the pistons to lube and cool them.
A very small portion of that oil lubes the outer crank bearings as it drips down from above.
Another point is a blown up Harley will still show oil pressure until it is run far enough to damage the oil pump.

FIRST is oil
Very near the front of the manual in the maintenance section a chart is provided showing that 60w oil should be used at ambient temps over 80°F (this even applies to twincams).
So if you're going to run 20-50w You should have an oil cooler installed. If you can keep the oil temps down you can run lower weight oil.

SECOND is Idle speed
Forget the "potato potato potato" idle as cool as it sounds it is the worst thing you can do to a Harley motor.
Many leave their bike out in the driveway chugging away at less than the recommended idle speed to "warm it up" they think they are being nice to their motor.
This starves the pistons for oil and cooling.
A cold motor actually needs a higher idle speed to throw the thick cold oil up to lube and cool the pistons. 1200-1500 rpm cold.
It is much better to ride the bike away as soon as the spark plugs are warm enough that the bike won't stall.
Wait til the oil tank is hot before you "ride it like you stole it".

I have a very high mileage 87 FXR in my garage that has been ridden very hard (extremely hard).
The distance the front wheel has been in the air can be measured in miles, more than some ride on two in a year!
It does not smoke or use oil and will keep up with the fastest 80"ers and beat most stock'ers.
It has been across the central valley of California many times in temps 80-100°F over 100mph for entire tanks of gas (mileage is crap at that speed) loaded down with gear and even a passenger.
There was a time that if my rear tire lasted 2 oil changes I was happy, many tires did not last that long.
Most of my friends had smiley faces burned into the pavement in front of their houses, by me.
It has near 100k miles on it, and still has the ORIGINAL PISTONS, RINGS and VALVE JOB!
I attribute this to not ever allowing it to idle at less than 950 and it has never idled for an extended period (more than a couple of minutes)
I use 20-50 Harley Dinosaur oil because my motor runs quieter with it than with other oils and it has ALWAYS HAD AN OIL COOLER on it.
MY OIL LIGHT HAS NEVER COME ON ANY TIME IT IS RUNNING with this setup.
Harley Synth oil is not as thick (not in my bike) Harley's marketing dept says to use it in everything. (Do Not believe the marketing speak)

So check your A B C D's
And as long as your lifters are not clattering you have enough oil "pressure"
Title: Re: Oil Pressure
Post by: Dan89flstc on October 14, 2019, 10:54:08 AM
Quote from: Burnout on October 14, 2019, 10:36:13 AM



FIRST is oil
Very near the front of the manual in the maintenance section a chart is provided showing that 60w oil should be used at ambient temps over 80°F (this even applies to twincams).

Actually, the manual says you can use SAE 60 if ambient temperature will never drop below 80 degrees Farenheight.

Nowhere does it say you should use SAE 60.

Title: Re: Oil Pressure
Post by: Burnout on October 14, 2019, 10:55:17 AM
Word games. The only reason NOT to use 60w is if you cant start it because the oil is too heavy.

It's your bike run it however you like.
Title: Re: Oil Pressure
Post by: JW113 on October 14, 2019, 06:39:20 PM
Actually, even the tappets do not operate on pressure from the oil pump. That's why at even seemingly zero PSI, you don't hear the tappets clattering as long as you have oil flow. Take a dry tappet, dip it into a cup of oil and push the plunger down. Bet you can't do it more than three or four times. Tappets suck their oil in, and the check valve holds it in. They just need to be sitting in a cavity full of oil to function, which the oil pump provides.

-JW
Title: Re: Oil Pressure
Post by: thumper 823 on October 14, 2019, 07:05:48 PM
Not too be rude But I post oil stuff once in awhile, -None of you guys seem to understand an oil index OR the pour and V1 correlation
if I can I will post a very simple index.
LOOK at the dam thing.
The viscosity is all about the same hot
The pour point very a lot within breeds for cold weather start. Not hot!  (The engineers use 212 deg.)

To make this short - once oil is HOT the viscosities are all bout the same with the shear and pressure factors (not oil P,) protection change.
This is very important to understand.
Don't shoot me.
I just bring you the message, try to benefit yourselves.
It has taken me a long time to study all this and most people just repeat BS found on the net.

Read slow, read again.
Carry on.

https://www.micapeak.com/info/oiled.html
Title: Re: Oil Pressure
Post by: FTBY55 on October 14, 2019, 09:07:20 PM
Thanks All,

Bike has been a Mobil1 20W50 user since 500 miles. Tried LiguiMoly 20w60 once last year and then went to AMSOIL 20W50.  Idle has always been set at~1050 with choke running about1500 to 1800 ride about a mile and it's off. Seldom see temps over 215 at oil tank even here in AZ. Running slightly rich.
Appreciate all the responses. Came home today, parked my other bike and pulled the shim out of the plunger. Gonna ride it like it is and not worry about those old higher pressure readings.
Will spend the money on upgrading the camchest of the '02 Ultra.

Thanks again... You guys are a wealth of information and greatly appreciated.
Title: Re: Oil Pressure
Post by: michael133 on October 21, 2019, 09:04:56 AM
it aint the presure,,its the flow on ol evo..only time i see 30 lb. oil presure is in cold weather at start up...flow.....
Title: Re: Oil Pressure
Post by: david lee on October 23, 2019, 02:08:58 PM
Quote from: JW113 on October 14, 2019, 06:39:20 PM
Actually, even the tappets do not operate on pressure from the oil pump. That's why at even seemingly zero PSI, you don't hear the tappets clattering as long as you have oil flow. Take a dry tappet, dip it into a cup of oil and push the plunger down. Bet you can't do it more than three or four times. Tappets suck their oil in, and the check valve holds it in. They just need to be sitting in a cavity full of oil to function, which the oil pump provides.

-JW
another good summary
Title: Re: Oil Pressure
Post by: thumper 823 on October 23, 2019, 02:14:54 PM
I have always had 10 at idle  even in Sturgis, super Hot out, flat footin through twn.
I replaced the gauge last year cause it got cloudy-the new one reads the same.