[a_cmc_2b]

What High Volume Oil Pump would you suggest for a 2002 Twin Cam Engine in a Road King. The engine will not have any Horsepower related modifications, just going in for some preventive maintenance and while there wanting to replace the OEM oil pump... Will also be doing the same thing to a 2003 Heritage in the not so far off future...

If there are previous threads covering this, then by all means please post links to them... I did run a search, and it came back with 471 threads, so I thought asking y'all would be faster than reading all 471 Threads...

Thanks Y'all!

 

[Greg_E]

Drag Specialties has a high performance pump, but a stock flow would probably be fine. I put a high performance in my 05, but kind of thinking that might have been a mistake. With life being what is has been, haven't gotten enough miles to really know.

 

[Uncle Salty]

There are a lot of smart folks around that have their favorites and I'm not one to knock them. I just have my personal experience to share. I did a 95" topend on my 2004 Road King at somewhere around 25,000 miles. Went with ported heads, Wood TW6G cam, etc. It's making somewhere around 100 HP. I've toured on it, ran it hard at times with the limiter set at 6,200 RPM. It's in semi-retirement now with over 60,000 miles. It still has the stock oil pump that it came with from the factory with a shim in the bypass. Still runs fine with no issues.

 

[tall terry]

harley enginengineenginengines do not need a greater volume of oil,,,, i have seen high volume pumps drain the pan/tank, before the return can replentish the tank/pan... leading to sumping and oil starvation.... sounds like an oxymoron doesnt it...
if you choose to go this direction, choose wisely.. not all components manufactured for an engine are improvements...
its not always the case but does occur.

 

[Sturge]

I can't remember exact part numbers but I put the SE hydraulic tensioner upgrade in my '02FXSTi years back and this included a high flow oil pump and improved camplate. I put it in myself and immediately noticed higher oil pressure at idle. Prior to that on hot days there were times when I couldn't see the oil pressure needle move off zero at idle. Bike had previously been bored to 95 with cam and head porting and had about 55K miles when I added this. I felt much better about things after that mod because I ditched the old tensioner setup and improved oil pressure in one swoop. It's at over 80K now but don't run it much seeing I picked up a '19 RG Special with the M8 114ci.

EDIT...found this. Pretty sure this is what I put in

Screamin' Eagle Hydraulic Cam Chain Tensioner Plate Upgrade Kit - 25284-11 | Harley-Davidson USA

This kit updates the cam chain tensioner of your Twin Cam 88® engine to the latest design, as featured on the Twin Cam 96™ engine. The billet cam support plate has been designed to allow the installation of the Twin Cam 96™ hydraulic cam chain tensioner to Twin Cam 88®-equipped models.

www.harley-davidson.com

 

[tall terry]

high volume has nothing to do with pressure,,,, the reason for there being a jigh volume pump,, a high pressure oil pump and lastly the high volume high pressure pump.. however if there were any obstruction to higher flow,,, not meaning anyrhing was wrong,,, just after all the passages were flooded with the extra oil the high volume pump provides the pressure could rise...

 

[Don Dorfman]

Listen up, Terry nailed this. Dan Thayer is the subject matter expert. His three stage pump and plate scavenges both the cam and sump side and has an adjustable pressure relief. When I asked him many years ago what to set it at he said "stock pressure" which is 42lbs. He also said his bonneville racers run at 35lbs flat out. The Drag pump for the early motor is 0932-0087. Higher pressure and volume than stock. My recommendation inspect the parts and replace as needed with stock parts. Use Baisley oil pump relief spool. Use the stock spring.

 

[Thermodyne]

For a stock motor, just go with the replacement pump from Drag Specialties. 0932‑0087 IIRC. It's a step up from the oem pump, little more pressure, little more volume and a lot more scavenge. So it reduces oil carry over out of the breathers. And it costs about the same as the oem part cost before it was discontinued.

 

[Don Dorfman]

Drag specialties lists their pump as "high volume".
Literature says the following:
"Gain of 20% oil pressure, 125% pressure volume and 135% scavenge volume over OEM stock TC88 oil pumps"
The twin cam oiling system leaks and circulates oil in many spots by design. Some include bearings, shafts and bushings, and lifters to name a few. If you take a stock motor and pump higher volume you create a higher volume of sump oil. The higher scavenge volume takes care of that. The higher volume does increase oil to the top end of the engine where it is not needed and takes a separation system that works marginally at best and pushes it over the edge. As far as added oil pressure this is not possible in a stock cam plate because all of the added pressure potential goes right over relief right above idle. Added oil going over relief just loops and is sent back to the supply side generating more heat. The larger gears also take more power to run but that is a minor side effect. The pump is made overseas.
All that said It is not the worst or a terrible choice just not the best. Fueling makes an "OE +" oil pump which, if forced to buy new parts after inspection, would be a better choice in my opinion. Made in the USA, drag number is 0932-0089. It costs $239 list, dealers do discount these online.

 

[Thermodyne]

Drag specialties lists their pump as "high volume".
Literature says the following:
"Gain of 20% oil pressure, 125% pressure volume and 135% scavenge volume over OEM stock TC88 oil pumps"
The twin cam oiling system leaks and circulates oil in many spots by design. Some include bearings, shafts and bushings, and lifters to name a few. If you take a stock motor and pump higher volume you create a higher volume of sump oil. The higher scavenge volume takes care of that. The higher volume does increase oil to the top end of the engine where it is not needed and takes a separation system that works marginally at best and pushes it over the edge. As far as added oil pressure this is not possible in a stock cam plate because all of the added pressure potential goes right over relief right above idle. Added oil going over relief just loops and is sent back to the supply side generating more heat. The larger gears also take more power to run but that is a minor side effect. The pump is made overseas.
All that said It is not the worst or a terrible choice just not the best. Fueling makes an "OE +" oil pump which, if forced to buy new parts after inspection, would be a better choice in my opinion. Made in the USA, drag number is 0932-0089. It costs $239 list, dealers do discount these online.

You read the numbers, the increase on the scavenge side is greater than the increase on the pressure side. I've put a few of these pumps in motors that had low oil pressure do to high mileage. and never saw more than a 10 lb increase from the oem spec.

The rotors are basically the same as the later style pumps that came with the upgraded cam-plates from Harley.

 

[Don Dorfman]

You read the numbers, the increase on the scavenge side is greater than the increase on the pressure side. I've put a few of these pumps in motors that had low oil pressure do to high mileage. and never saw more than a 10 lb increase from the oem spec.

The rotors are basically the same as the later style pumps that came with the upgraded cam-plates from Harley.

This is what Drag says about this pump compared to the stock 96" pump:
"Gain of 16% oil pressure, 66% pressure volume and 100% scavenge volume over OEM stock TC96 oil pumps "
Not trying to make war man just state the facts.
Like I said, and just my opinion, it is neither the worst or the best choice. It works.

 

[Greg_E]

The Drag pump is what I installed, but for the 88. Pressure is definitely up, especially at idle where I now have pressure when hot which is different from the stock pump which would read nearly zero and sometimes light flickering. But again, not enough seat time to know if it was a good choice.