V-Twin Forum banner

oil pump shims for added psi?

10K views 22 replies 14 participants last post by  Flashkev 
#1 ·
I'm still shopping for who's to wrench my build... The last indy said he would add shims under the oil pump spring to lower overall engine temps, and to keep the oil pressure up at a constant 40 - 60 psi. He admitted this could rob 1-2 HP by keeping the pump running non-stop but he would compensate for the loss by adding a crank case breather valve to gain about 3 HP.

PROs and CONs with adding the oil pump shim?
PROs and CONs with adding the crank case breather valve?

This easter egg hunt is becoming an obsession. It's a good thing I'm enjoying the ride...
:brows:
 
#2 ·
Oil pressure shimming

We were using small washers when the T/C's first cam out, as per a conversation we had with Ron Dickey, (Owner, Axtell Sales) in regards to the oiling of these. We then decided to manufacture a spring shim. That is what we use. If we run out of those, and are too busy to make more at the time, we buy 'em from Zippers. Same part, does the same job. Works well.
Scott
 
#4 ·
An old main jet from a CV works, freebee
The stock spring is all over the map as far as height, I would spring for a baisley spring and call it good. Very consistent QC and a new beter relief curve only blowing off at peak rather than partial amounts right off idle to max like the stock spring does. I know this because I test them. The Baisley tests at 52psi all day long on the bench. With hot oil in the motor a little different story. The stocker begins to bleed at 15psi sometimes less, no consistency.
 
#5 ·
nw_guy4_fun said:
The stock spring is all over the map as far as height, I would spring for a baisley spring and call it good.
I echo what nw guy says. If you put the Baisley spring beside the stock one, it makes Harleys look like a cheap part out of a toy.

Chris
 
#6 ·
Thanks

All, thanks for the replies. I now understand adding a shim/washer to the OEM oil spring is better than not doing so, and swapping out the OEM spring for a Baisley is better yet. Good to go.

Crank case breather valve a big deal? PRO/CON
 
#7 ·
Flashkev said:
All, thanks for the replies. I now understand adding a shim/washer to the OEM oil spring is better than not doing so, and swapping out the OEM spring for a Baisley is better yet. Good to go.

Crank case breather valve a big deal? PRO/CON
DO NOT USE THE S&S BREATHER VALVE. It is not a help. Concentrate on the problem at hand, good ring seal and head breathing and forget the valve.
 
#8 ·
I feel the spring is the best way to go,.. cost is only 13.50 for it and it is a true fix. I have used the shim in the past but have had the oil pressure go back to near stock as the spring ended up collapsing some . Same deal if you stretch it, they have a memory. If you are removing it anyway why not just replace it with a better quality spring. -2$en#e-
 
#10 ·
HDWRENCH said:
I feel the spring is the best way to go,.. cost is only 13.50 for it and it is a true fix. I have used the shim in the past but have had the oil pressure go back to near stock as the spring ended up collapsing some . Same deal if you stretch it, they have a memory. If you are removing it anyway why not just replace it with a better quality spring. -2$en#e-

Could you please explain what year TC's need the new spring? My 05 RK with the HD accessory manual oil pressure guage shows 45 to 50 pounds of oil pressure going 70 MPH. My 07 Street Glide shows 32 pounds of oil pressure on the stock gauge at 70 MPH.

I know the HD accessory gauge should show a more accurate reading than the electric gauge on the 07 SG, as it is a manual direct pressure gauge VS an electric gauge that can be off a few pounds.
 
#11 ·
I had a Baisley and took it out in less than 1000 mi.and gave it away.I replaced it with a stock spring that was on the long side(compared a few).I then shimmed it with a brass washer.The pressure runs between 32-38psi.cruising with hot oil.
I'm happy.
 
#12 ·
hdforme62 said:
I had a Baisley and took it out in less than 1000 mi.and gave it away.
Maybe you could elaborate on the reason you took it out.

Chris
 
#15 ·
If the bike is making 30 psi running down the road great but what is it at once hot and you stop to le the bike idle?? I have seen planty that you cannot even tell if the needle has moved at a hot idle. I feel that if you running that low of oil psi at idle that you can starve the engine for oil. The spring can be used in any year t/c. I would not swap a spring if you have 12 psi hot idle and good spi when running .

I checked a 07 here that had 220 oil temps and with a true gauge( auto meter tapped in) it had 3 psi at 1040 rpms. It was a rather loud engine as far as t/c's go. We swapped out the spring and it has 11 psi hot idle and will hold 30-32 at crusing rpm
 
#19 ·
HDWRENCH said:
I feel the spring is the best way to go,.. cost is only 13.50 for it and it is a true fix. I have used the shim in the past but have had the oil pressure go back to near stock as the spring ended up collapsing some . Same deal if you stretch it, they have a memory. If you are removing it anyway why not just replace it with a better quality spring. -2$en#e-
The beauty of syn oil is that it flows well when cold AND hot.

Running DINO 20-50 in I think the guy is from Montana may have some challenges on cold days. Now in Arizona and S Florida where it's hot all the time thicker is better. A cold night here is 60F.
 
#20 ·
Flashkev said:
Is there a valid concern of having too much oil pressure?
How much is too much?

... Assume correct level of oil (as reflected on dipstick).

The rule of thumb , not set in concrete, for an automotive engine was ten pounds per 1000 RPM as being acceptable. So at 4,000 RPM you should have around 40 pounds of oil pressure. At least that's what we looked for in a car engine.

Pressure and volume are two different things. A lot of engine builders in the old days always put high volume pumps in high performance car engines. We since learned that the stock oil pump usually put out more than enough oil pressure and volume if the crank and rod clearences were set correctly.

I have hand primed many an oil pump on a new engine using a 1/4" drive drill motor. When the pump primes up the drill motor would almost come to a stop there was so much torque needed to turn the oil pump. Lessoned learned was that high volume and pressure oil pumps take more HP to turn them.
 
#21 ·
"Lessoned learned was that high volume and pressure oil pumps take more HP to turn them."

Yep, that's the main reason I left mine alone. Worked fine for 13,500 miles like HD built it so I'll take my chances that it'll keep on working like that. If it ain't broke...
 
#22 ·
How Much Is Enough

I’m curious, about the oil pressure issue. How much pressure is actually necessary?

As I understand it an engine oil pump is a positive displacement gear type.

Positive displacement pumps move oil at all speeds and volume increases as speed increases.
Increasing engine speed causes restriction to that flow. The restriction is what causes the pressure to increase up to the pump relief valve setting. This valve is necessary so you don’t break the pump.

So a Harley engine needs pressure to keep the hydraulic lifters pumped up.
It does not need pressure to support rod and crank bearings like an auto engine.
It just needs to have a continuos flow of oil to lubricate and help cooling.
Piston cooling jets need some pressurized oil and rocker arms only need enough volume to keep the bushings lubed and valve springs cool. Everything else gets oil by splash and mist within the engine.

In fact centrifugal force pushes oil out of the crank pin and at idle there should be more than enough oil for necessary lubrication.

All this said, I think the amount of pressure necessary is to keep the lifters happy.
Anything else is wasting power and excessive oil volume in the flywheel area can actually be detrimental.

It seems to me what is most important is scavenging the circulated oil out of the engine to minimize drag on rotating components.

A factor the lifters have to deal with is valve spring pressure when the valve is moving.
Is there a formula to determine the amount of oil pressure necessary for the hydraulic lifters?
 
#23 ·
NCC1 said:
I’m curious, about the oil pressure issue. How much pressure is actually necessary?

As I understand it an engine oil pump is a positive displacement gear type.

Positive displacement pumps move oil at all speeds and volume increases as speed increases.
Increasing engine speed causes restriction to that flow. The restriction is what causes the pressure to increase up to the pump relief valve setting. This valve is necessary so you don’t break the pump.

So a Harley engine needs pressure to keep the hydraulic lifters pumped up.
It does not need pressure to support rod and crank bearings like an auto engine.
It just needs to have a continuos flow of oil to lubricate and help cooling.
Piston cooling jets need some pressurized oil and rocker arms only need enough volume to keep the bushings lubed and valve springs cool. Everything else gets oil by splash and mist within the engine.

In fact centrifugal force pushes oil out of the crank pin and at idle there should be more than enough oil for necessary lubrication.

All this said, I think the amount of pressure necessary is to keep the lifters happy.
Anything else is wasting power and excessive oil volume in the flywheel area can actually be detrimental.

It seems to me what is most important is scavenging the circulated oil out of the engine to minimize drag on rotating components.

A factor the lifters have to deal with is valve spring pressure when the valve is moving.
Is there a formula to determine the amount of oil pressure necessary for the hydraulic lifters?
Excellent question. I'm guessing any answer will vary based on RPM
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top