Trying to fix a serious engine oil consumption issue on my Alfa Romeo

At long last, Marc opened up my Spider engine! Just to recap. Earlier this year Marc did a complete overhaul of the Spider Engine. Ever since it has been suffering from serious oil consumption. During our trip to Scotland about 1l per 350 kilometre! So that is even more than before the overhaul. I noticed the oil consumption within a few weeks of the overhaul. We investigated and concluded that the engine was running way too rich. We replaced the fuel pressure regulator, the airflow meter and the O2 sensor.

But it only got worse. Marc suggested that keep driving it during the season and start investigating during the winter as I don't use the Spider during the winter. (I can't drive it during the winter months due to some silly classic car rule).

Although you always hope for something obvious and simple which can be fixed easily, I knew this was going to be a complex problem.

Marc had taken the engine head off again. Everything checks out fine. The valves are looking great. Valve stem glands and seals are as new (which they are).

Here is the problem, or rather the symptoms. All four brand-new liners look polished on the inside. The normal "honing" marks you would expect to see are virtually gone. On all four, in an identical way. Piston rings, compression and scrape rings were fitted correctly, oil disperse holes in all pistons are open.

This looks like a case of what is known as fuel wash. A fresh coat of oil protects the cylinder walls and bearings. If that protective layer of oil washes off, it becomes susceptible to damage. Raw fuel is one thing that can wash off the cylinder's protective coat. For this reason, any unburnt fuel in the cylinders can result in fuel wash. You're left with a wet mixture of raw fuel, which washes the oil away and can cause damage to the cylinder bores, pistons, and piston rings.

The most common causes of fuel wash or wash down as it is sometimes referred to are faulty and or leak injectors and or (vacuum) leaks. A common system is also poor starting. My Spider starts fine. Marc checked the injectors and we also checked, multiple times for (vacuum) leaks.

So based on all of this, we believe the injection computer might have a problem. Remember the Spider has a very early Bosch L-Jetronic system. Two separate computers, controlling respectively the injection and the ignition. It is also a complete analogue computer. The next Bosch Model, the Motronic series, combines both functions in one fully digital package.

The Bosch L-Jetronic computers have proven themselves to be very robust and resilient. But over time, electronics age.

We discussed three options:

Repair the old computer

Install a modern electronic (race box style) computer

Convert to carburettors

To start with the carburettor conversion. It is certainly doable. But the engine compartment layout of the injection versus the carburettor version is very different. It means a look at modifications on many different parts. And then you need two new carburettors as well. So it's not going to be cheap.

I did like the idea of the new computer. But we decided to first go with the old computer. For two reasons. If we can get the computer diagnosed and it turns out it is faulty, we have found the root cause of the excessive oil consumption. If the computer can be fixed I will also retain the originality of my Spider.

However, there is a practical problem. Getting these old computers checked and repaired is becoming increasingly difficult. Marc knew somebody and he is going to check. As it so happens I have four (used) spare computers! Two injections and two ignition computers. If we find somebody that has the knowledge and the equipment to check and service these computers I will have him check my spares as well.

If we can't get the old computer checked or refurbished, we will go for the modern upgraded computer. The interesting is that inside the engine compartment, everything will remain the same. The new computer can be hooked up to all the old sensors in the Spider. All that is required is to swap the old computer for the new one, underneath the parcel shelf behind the seats! (Well, it is a bit more complex, but still)

Irrespective, with either the refurbished old computer or the new computer we will take the Spider to a facility with a Dyno, so we can do a proper engine run in combination with exhaust gas measurements. We have to make sure we are not getting raw fuel into the cylinders! The new computer needs fine-tuning on the dyno anyway.

So, we still have a way to go with this one! Should prove interesting what we find. I would love to have my Spider on the Dyno. Marc has fitted these new computers to many Alfa 105 series, with the same 2.0L as mine. He says without any further modification he can get it to crank out 150BHP easily. I am not so interested in the sheer horsepower. But a little more pulling power in the lower RPM band would be very useful.

We will see!

I had the Mini at my local garage (FNG you would say in India) for its annual MOT or APK as it is known here. They noticed the beginning of problems with one of the wheel bearings. I had them replace it because once you have a car on the lift it is dead easy. I also asked them to flush the brake fluid. My Mini was showing a "flush brake fluid" in the dash. Again, so much easier on the lift than crawling around on all fours on my concrete floor. Also, the last time I used my pressure bleeder it was leaking so I need to fix that first.

I managed to reset the "flush brake fluid" light afterwards. Only to have the "Service" light come on the day after. I knew it was coming. So I just ordered the parts. I will also replace the front discs, pads and sensors.

I also need to have another look at that pesky thermostat housing. I am still not convinced it is completely leak-free.