Oil Pumps for Bevel Engines

Complete Oil Pump Guide

Oil Pumps

If the oil is the lifeblood of your engine, then the oil pump is the heart.

It’s a part often overlooked by Ducati bevel owners, but its role is very important and contributes greatly to the longevity of your engine. If you have a poorly performing oil pump then your engine will simply not last as long as it would if your oil pump was at peak performance.

The good oil

The bevel drive Ducati engine is air-cooled so the oil does more than simply lubricate the parts inside it. The oil’s other job is to cool the engine. As your oil gets more and more contaminated, its ability to lubricate and cool gets reduced. And that contamination in the oil gets pumped through the oil pump, causing damage over time. Contaminated oil and poor filtration is a killer of oil pumps and therefore, engines.

Under pressure

Most Ducati bevel drive engines have roller bearing big ends and require oil pumps with low pressure compared to the 1000cc Mille engine found in some late Mike Hailwood Replica and S2 models which have plain bearing big ends that require high pressure oil pumps.

The needle roller bearings in the big end are very small in diameter and as you might expect, are designed to ‘roll’ around the crank pin. The factory oil pumps are designed specifically with the right pressure to ensure the rollers ‘roll’ and don’t ‘skid’. Too much pressure from your aftermarket oil pump and ‘skidding’ of the rollers can occur, which causes abnormal and accelerated wear.

Check your pump

How can you tell if the oil pump in your engine is ok? One way is to rig up an external oil pressure gauge but this isn’t so easy for the home enthusiast. The best way is to pull the oil pump out of your engine for an actual physical check which isn’t as difficult as you’d think and well within the scope of someone with reasonable mechanical skills.

We have produced a video which you can watch, click on the image below: 

This is for the round case Ducati bevel drive twin cylinder engine. There are some differences between the round case and square case engine when it comes to oil pump removal and fitting. They do look a little different from the outside but work essentially the same way. The main difference is the lower bevel gear arrangement between the two engines which requires a slightly different approach for removal to gain access to the oil pumps.

Once you’ve removed your oil pump and disassembled it, you are looking for wear or damage to both the pump gears and the pump body. Any broken parts from inside your engine, whether it be tiny bits of gears that have broken off or even carbon inside your oil will eventually find its way into your oil pump. Over time this causes damage to the body and gears, which increases the gap or ‘tolerance’ between the gears and body. This in turn reduces the pressure the pump can produce. (See Gallery for examples)

You can replace the pump gears if they are worn or damaged but you can’t repair the pump body. If there is scoring or even minor ‘chunks’ taken out of the pump body then it really does need replacing.

Filtration

Ducati’s attempt at filtration for the big bevel drive engine might have looked good on paper but time takes its toll on the filtration system. The sump plug for the bevel drive engines is attached to a plastic oil strainer which then slots into a rubber seal. Heat eventually shrinks and warps the plastic strainer and expands the rubber seal it slots in to. It’s then essentially unserviceable and straining almost none of the oil that enters the oil pump.

An oil pump will suck the oil from the sump via the path of least resistance. If there is a gap between the strainer and the seal then that’s where the vast majority of the oil will flow, around the strainer instead of through it.

Vee Two manufactures a billet alloy oil strainer with a removal and cleanable mesh filter inside it. We also manufacture an alloy/o’ring end seal that sits inside the crankcases. The oil strainer’s end slots inside this end seal, eliminating any chance of unfiltered oil finding its way through the oil pump and your engine.

Click on the image below for the Vee Two video - Learn about the Filtration and fittament:

Difference in technology

How do you compare a new Vee Two oil pump to an original? Well an original cast alloy pump has most likely been worn out after decades of abuse, and there’s also the fact Ducati stopped making them a generation or so ago. You might find an NOS (new old stock) pump sitting on a shelf somewhere and you could run that.

There’s nothing wrong with the design of the original Ducati oil pump. It works fine but like any moving part inside an engine, it will eventually wear out.

Brook Henry from Vee Two Australia has worked with these engines for nearly 50 years and found original Ducati oil pumps harder and harder to get for engine rebuilds. He thought he might as well make his own and make it better as well.

How much better? We have already spoken about having too much pressure from a pump in an engine with a roller bearing big end so he knew more flow and pressure was not the answer. But less clearance between the pump gears and the body was. As stated, there were no issues with Ducati’s original design but mass production and worn machinery can tend to ‘dilute’ the design somewhat over time.

Vee Two’s billet alloy construction has a more dense and stable material and the body and gears are manufactured with tighter tolerances.

And thankfully you can buy new Vee Two oil pumps for your round or square case bevel drive engine.

You won’t have to hunt around to hopefully find a NOS one sitting on a shelf covered in dust.