Up­grades, facelifts & new de­riv­a­tives

Car (South Africa) - - CONTENTS - In the in­ter­ests of pro­tect­ing him from un­wanted fame, stalk­ers and the pa­parazzi, CAR can­not re­veal the true iden­tity of the re­source­ful Garage­man.

IDLE GOS­SIP

Four gen­er­a­tions of Cron­jés had lived on the farm Kameel­dor­ing­fontein be­fore some­body no­ticed that the youngest mem­ber of the fam­ily had a face that re­sem­bled that of a camel. Camel Cronjé had a long chin, fleshy lips and small ears and was only 12 when the com­mu­nity gave him his nick­name, but he in­no­cently be­lieved the moniker was a ref­er­ence to the name of the farm – not the an­i­mal.

Camel now owns the only lo­cal se­cu­rity com­pany and his busi­ness op­er­ates a quar­tet of Nissan half-ton­ners.

Shortly af­ter the war­ranties of the bakkies had lapsed, dis­as­ter struck. One started to smoke and use a lot of oil and soon af­ter­wards it ran a big-end bear­ing.

We were asked to tow the bakkie and find out why this hap­pened on such a lowmileage ve­hi­cle. I gave the job to Au­gust, who stripped the en­gine and found that the rings had car­boned-up and were no longer func­tional. The oil looked very black and seemed to have been in the en­gine for longer than the usual 15 000 km.

Our first thought was that the bakkie wasn’t ser­viced regularly. I con­tacted Camel, told him what we found and asked him about the ser­vic­ing ar­range­ments. He said that all four bakkies re­ceived reg­u­lar ser­vices at the Nissan deal­er­ship from which he bought them, but that he would task our garage with ser­vic­ing them in fu­ture be­cause they were out of war­ranty.

We briefly en­ter­tained the thought that this ve­hi­cle had skipped a ser­vice, but then Hen­nie made the bright sug­ges­tion that we should look at the state of the other bakkies. Their driv­ers brought them in and we took com­pres­sion read­ings and sam­pled the oil. None were in as bad a state as the first one, but their com­pres­sion read­ings were low, the oil looked un­healthy and their driv­ers ad­mit­ted that they were slug­gish and started to use oil. They were cer­tainly af­fected by the same me­chan­i­cal mal­ady.

I held a meet­ing with the driv­ers and my me­chan­ics. Au­gust thought that too many short trips were to blame, but I pointed out that while the fre­quent tem­per­a­ture change as­so­ci­ated with this style of mo­tor­ing is not ideal, many cars used for com­mut­ing suf­fer the same fate, and they don’t self-de­struct in such a short time.

One of the driv­ers pointed out that the en­gines of­ten do not get a chance to cool down in spite of the short dis­tances they cover. On a cold night they’re kept run­ning to keep the heater in op­er­a­tion, and on a hot day they’re not switched-off to keep the air con­di­tion­ing blast­ing away.

The driver didn’t re­alise the im­por­tance of what he was say­ing, but my me­chan­ics cer­tainly did. Their eyes lit up and they all started to bab­ble at once. They knew we had found the an­swer to Camel’s prob­lems.

An en­gine is not de­signed to idle for hours on end. It can only do so if it gets a rich fuel/air mix­ture. The air speed in the man­i­fold is too low for all the fuel droplets to march along like obe­di­ent sol­diers. Against the man­i­fold wall some of them ac­tu­ally creep back against the flow of the stream. A rich mix­ture at the en­trance to the man­i­fold will en­sure that enough fuel reaches the com­bus­tion cham­ber to sup­port com­bus­tion.

Such a con­di­tion causes some fuel to mi­grate past the rings into the sump and also pro­motes the for­ma­tion of ex­tra car­bon that will cause the rings to stick. The oil de­graded by petrol will soon lose its lu­bri­ca­tion qual­i­ties and this will shorten the life of all en­gine com­po­nents.

The en­gines of all four bakkies were over­hauled; the driv­ers were ad­vised to find al­ter­na­tive ways to stay com­fort­able.

TWO-STROKE MOR­RIS

The pre­vi­ous story re­minded me of my un­cle Karel. In his youth he owned a twostroke DKW, which was pro­duced by the Ger­man Auto-union com­pany, which was formed in the 1930s by the com­bin­ing the DKW, Audi, Wanderer and Horch brands. I think it is quite a pity that only one of those brands sur­vived.

Oom Karel was very happy with his DKW, but it was too small for a grow­ing fam­ily, so he re­placed it with a Ply­mouth. Later, in his old age, he bought one of the first over­head valve Mor­ris Mi­nors, and this served him well – at least for the first few months of own­er­ship.

I was an ap­pren­tice at the lo­cal Mor­ris dealer at the time, and he came to see me one day. His en­gine had started to smoke and be­came very dif­fi­cult to start. I found the spark plugs had car­boned up, and the com­pres­sion read­ings were low. By then I knew that the first se­ries over­head valve en­gines were oil guz­zlers so the smok­ing didn’t bother me. I cleaned the spark plugs and ad­vised him to go away for a week­end to burn the car­bon away.

Just be­fore he left he ca­su­ally re­marked that he ex­pected this car to last him for the rest of his life. He pam­pers it by adding oil to the petrol the way he had to do it with the DKW.

Well, it took a lot of ex­plain­ing, but I even­tu­ally con­vinced him that four-stroke en­gines don’t need oil in the petrol.

Whether in the tank or the sump, petrol and oil should never mix in a four-stroke en­gine. It took a driver of a pri­vate se­cu­rity ve­hi­cle, as well as an el­derly un­cle, to re­mind Garage­man of this fact...

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