need help find a nice mechanic for my Corolla 2007 XLI Tappet Settings (Islamabad)
My problem started when my car had done around 100k kms and the idling would not remain smooth. I showed it to a couple of mechanics and everyone suggested that there was an issue with the tappets and since it has hydraulic tappets, its not simple and has to be done by kharaads. Anyway, someone suggested and referred me to this guy Naseer mechanic (i am not too sure of his name) at (near) Murreer chowk pindi who just took out the round metalish ring type tappets from the engine and got them set by some local kharaad there. The problem seem resolved to some extent however I was not too happy again firstly with the engine sound and secondly with the not so perfect idling rpm.
After a couple of months, idling problem aggravated after checking which plug/valve was not performing as per standard by taking each coil out one by one and noticing engine behaviour, it was determined by Wazir electrician (firebrigade - Islamabad) that the first one had an issue and the valve/tappet needs to be readjusted. This time round, I decided to try a different mechanic and so I took my car to Sohail Autos (Fire brigade) who changed the valve and did something, made a bill of around 20k but to my surprise, the car has gone from bad to worse. Engine sound further deteriorated and severe idling problem (lesser on petrol though than CNG). I told the mechanic that I dont think the engine is running smooth but he said itd b better when the car has run a bit. Everything will take its place.
so bascially, I have tried two mechanics, and I blv the problem lies with the head/valve/tappets... I need to know if any of you know who is the right mechanic to get the job done nicely and who knows all the knitty gritties involved and who wouldnt gouge me.
PS: dont refer me to Toyota as all they know is not to fix things but change everything. Just for tappet settings and valve changing they gave me an estimated bill of 50k. I am tired of spending money already.
When any engine is designed, it is always classified according to various methods. For example classification of the engine according to the cylinder arrangement, valve arrangement, fuel system, compression ratio, octane rating and many more. To cut the story short the engines of modern cars are designed according to the compression ratio which falls between 8:1 to 9.5:1. This ratio call for the fuel of octane rating between 87 to 91. At this octane rating the combustion temperature is approximately around 1292^F. On CNG the engine runs lean with the power loss of about 15-20% and the combustion temperature rises beyond 1800^F for which this engine is not designed. At this temperature the valves do not withstand and start getting inside the valve seats thus partially keeping the valves open. This state gives rise to weak cylinder compression which in turn affects the fuel consumption, start ability misfire and more problems.
To my opinion it is better to replace both the cylinder and head assembly with a good known one of the same configuration. In this way you could get the best results and could enjoy you car for a longer period of time. GOOD LUCK.