Pity the Poor Solex by William R Blankley

more by William Blankley

If I had an Opel Manta for every time someone had said to me "it’s the carb." I would be happy. My Boss-Lady tells me that it is unfair to compare a tired Solex with a fresh Weber, this is true, one must look to the air filter housing.

The next time you open the hood spare a glance for the single congested nostril on the air intake that the poor old Solex is being strangled by.

There is a reason for this, I am sure that it is to do with the Positive Crankcase ventilation System. One experiment I did try was to listen carefully after removing the dipstick with the engine running warm and at idle. The sump had enough oil in it to cover the end of the dipstick tube. Distinct bubbling noises could be heard. My conclusion was that sufficient depression existed, even at idle, to depressurise the crankcase and that this meant considerable resistance to the free passage of air had been designed into the system.

My next act was to try a quick blast round the block without the filter casing, interesting. The subjective effect was like a kick in the back. You should try this some time, please replace the air cleaner afterwards.

Unless there is pressing reason for change it is best to leave well alone, change one thing and it will louse up elsewhere for sure, I have seen this too many times, it usually means lots of oil dripping from places that it should not. Please remember that half measures cost time, money accomplish little and please no one. If this sounds like the rock and the hard place, so be it. Please take this as an addition to, rather than a contradiction of, the writings of Nick Webb. The Webber carb is plentiful, so are spares and jets. This is one reason for a change, being stuck for the bits, not something that has happened to me yet. It does so happen that I have a DGAV to one side.......

The Solex is very good; it does have one or two weak points.

1. Flooding, Change both float and valve. NB that the valve can stick open (I have found the needle sometimes sticks slightly sideways, this should not happen). This can be characterised by stalling at intersections and a general instability of both car and driver.

2. Rubber thing that opens second choke perished. Whip the throttle wide open for a moment. If you can manage this and look down the throttle barrel before the engine grenades..... Otherwise, or in addition to, unscrew the housing for the rubber thing, this being only two screws, wobble it up and down with and without a finger over the little hole for the air. It should be obvious; if it isn’t you got trouble. Symptoms, car does not leap forward eagerly when the throttle is floored, sluggish over 70MPH.

The poor old Solex also gets the blame for general rough running and that cutting out on right hand corner problem that Nick had (it did not happen in 1975 in our 14500mile Manta) I have had quite a battle with this. One day inspired by desperation I threw a pint of methylated spirits into the gas tank in hopes of clearing water from the system. Problem solved. Before this the ignition coil had been changed for a Lucas 12C16 from a scrap XJ6 which is the usual remedy. It was a Dr Dave Bullman who once said that 90percent of a cars troubles are electrics (C&CC TR Technique 1980). He understated the case; there is Williams extension that states that the Solex shall cop 90 percent of the blame.

I love the Solex; it is cute, technically, responding well to a little attention and a few new bits after twenty years of faithful service. I tolerate the PCV system that strangles it. How much difference opening up the airflow plus rejetting to suit would make we may never know. I can say that the car runs very well on twin Dellortos, but the brakes have to be modified, this is a problem area, also it gets oily under the hood.

What it comes down to is that it was good when it was new, after all it is an Opel, that after about 50k miles of normal neglect I would expect to be looking some hard work and expense right in the face.

I wish that I had Nick’s facility for describing things. However one day I will try to write a bit on care and feeding of the Solex. The bits are expensive, so is a S/H Webber and do you trust the jetting that you are lumbered with? What does the carb set up for a two litre pinto engine do to the performance of a CIH? Not a lot of good.

It would be a great help to establish the correct settings for the Webber, with K&N filter and with a modified to fit standard filter. When did you last see a Solex advertisement?

William R Blankley

Read more of William Blankley's Writings?

All content © OMOC. The OPEL trademark is registered to General Motors.
Click here to contact us