music box

Wednesday, April 29, 2009

Chain VS Belt

What are the advantages and disadvantages of chain and belt drive trains is terms of durability and maintenances costs? Also, the recirculating ball and nut verses rack and pinion.

Lastly, the common rail direct fuel injection versus the electrical fuel injection turbo diesel. What are their advantages in term of performance and cost of maintenance plus fuel economy?

You cannot expect a detailed reply to such technical questions and so I will only give you a brief reply to eaach:

1. To my mind, the chain drive is better than a belt drive for the camshafts. Also chains do not snap without warning and last for almost forever. However the chain is noisy and it is more complicated to keep it in good tension.

Belts on the other hand are much quieter but must be replaced at regular intervals or else you could end up with very bent valves and even a scrap engine. Belts are not cheap and usually replacing the belt also entails replacing the idlers and their bearings which can come up to quite a hefty sum.

2. The recirculating ball steering tends to be quieter and does not require as frequent adjustment as the rack and pinion. Rack and pinion steerings have very limited adjusments and once that is taken up, the rack can make all sorts of noises. Rack and pinion power steering units also have a higher tendency for leakage.

3. I think you are talking about a common rail system as opposed to a unit injector system.
I would prefer the common rail system for its efficiency and fuel consumption, although the operating pressures are much higher and there is a need to ensure that fuel used is clean.

Transmission Problem

I have a 1997 Volvo 850 T5 experiencing auto transmission problems. Lately, after draining the ATF to facilitate rep;ecement of the drive shaft, I had the transmission filled with Volvo original ATF Dextron III.

Now the reverse gear won't work at all. Other gears are working fine though. I have double checked the ATF level with the engine running and it shows sufficient fluid level at the current temperature. There is no sign of oil leak.

It appears that you did not touch the transmission at set to refill it. I think the problem may be just a stuck valve and would mean taking down the valve block and cleaning it out. It may be just dirt that has jammed a valve. I suggest hat you get someone familiar with A/Ts to have a look at it.

Oil Change

I am using Petronas Semi-Synthetic(5W-30) for my 2004 Kelisa (M). Is it ok to change the oil after 10,000km?

10,000 km is ok for the oil change but is your consuming oil. If so, it may be better to change to a more viscous mineral oil and replace it every 5,000km.

Pulley Change

I am interested in replacing my Kelisa's three-belt pulleys with the after market alloy type. I understand that it will be much lighter on acceleration compared with using the original metal type. Is it a good a idea to change?

The alloy pulleys will definitely look better but your car is not going to go any faster! I cannot see how weight you can gain by the replacement of these parts but of course, the people selling it to you will show you documents to say that this is so.

Faulty Bearing

Sound are heard when I engage the 1st and reverse gearof my Toyota KE70.

If the sound is heard when you engage the gear and the release the clutch, then it is likely that you have a worn bearing in the gearbox. The replacement of bearings in the gearbox is a reasonably straightforward job and can be done by any decent mechanic.

If it is a worn prop-shaft bearing, the noise will be there in all gears.

Thursday, March 26, 2009

Skimming The Cylinder Head

As per your advice before, true to your prediction, engine oil leaks from between the cylinder head and its gasket reappeared because nothing was done to rectify the cylinder head except changing its gasket twice. This time, the cylinder head was suspected to be faulty and the mechanic proposed that it be skimmed.

I am very wary of such a procedure and mindful of your earlier views about it because i would not want to suffer another round of workshop blues posed by different sets of problems. To use laymen, skimming seems a complicated and delicate process. What problems would arise if a hastily or not properly done skimmed head is fitted to the engine?

There are two ways to take material off the cylinder head:

1. If there is very slight uneveness, using valve grinding paste and a large flat glass, one cap lap the head until it is flat. This method takes off a very small amount of material and is usually not a problemat all.

2. The second method involves using either a shaping or milling machine to take off material from the surface of the head and this is done when there is a quite large amount of material that needs to be removed.

This procedure require quite a high degree of skill on the part of the machinist as he must know how to clamp the head in an absolutely level position in realation to the cutter and he must also know the limit of how much material can be removed.

Every cylinder head has a limit to how much can be removed because if too much is removed, the following can happen:
a) The compression ratio may get too high and you will get serve detonation resulting in piston failure.
b) The valves may hit the piston.
c) You may break into a water passage or the material may get too thin and when the head is torqued down, it may crack.
d) You may have difficulty keeping tension for the camshaft.

So my advice is to make sure that the guy doing the job knows that he is doing or else take the job to the franchisee holder who will have the right information as to what can and cannot be done.

Fuse For Horn

I wrote recently about changing my car horn which unfortunately went unanswered. However from your reply on ther column, I assume that it is possible to do so, provided the specs confirm with the electrical ratings and the installation is wired properly.

According to the fuse chart (interior fuse block) in the Owner's Manual the fuse for the horn is rated 10A. A specific fuse for horn relay is not indicated, although there is a main relay indicated in another fuse chart (engine room).

However, a fuse rating is not stated. Does this mean that there is no dedicated relay for the horn at present? I am seriuosly considering changing the feeble-sounding original horn on my Chevrolet aveo lux to something more "robust-sounding".

Please advise on the type of horn and suitable specs to comply with when replacing the existing horn, particularly on whether a dedicated relay is required and its rating.

The 10A rating for the fuse is all that you need. Most horns have relays already and you need to check if the relay has sufficient capcity for the new horn, or else you need to replace it with one with a higher capacity. Usually the suppliers of the higher capacity horns also supply a relay in the box. Check the wiring diagram in your Owner's Manual and it should tell you the location of the relay.

ABS System

I bought a new Honda Stream 2.0 i-Vtec year 2005. When I brake at low speed, it was OK but at high speed, 160km/h and above, there was steering vibration. Still under warranty, I sent my car to the Honda workshop. The disc was lathed three times but the problem still persisted.

Finally Honda changed the disc with a new one. The same problem occured. Then I changed the rear brake pads but there is no solution in sight. It is normal for the ABS system?

If the brake discs have been changed and there is no run-out on the disc, then obviously one needs to look at the wheel hubs if they are running true. Even if the car is now out of warranty, and the problem was brought to the attention of the franchisee holders during the warranty period, they are obliged to fix the problem at no cost to you.

I suggest that you make an appoinment to meet the head of the after sales division and have a chat with him about your problem.

Idling Poser

I have a 2000 Proton Waja MT which was running fine until recently when idling speed of the engine came down to less than 500 rpm after the engine had warn up. Normally it's around 750rpm. What is wrong with this car?

Have you send the car in to be checked? It could be faulty idle valve or even misfiring plug. The best is to let the people with the right test equipment check it out.

Monday, February 9, 2009

Wira Stopping With Engine Running

My Proton Wira Atomatic year 1995 has served me well despite heavy petrol consumption. Two months ago, when I was travelling along the North-South Highway at 115km per hour, there was a very loud humming sound. I later changed the automatic transmission oil, and the sound dissapeared.

But three weeks ago, the car came to a stop with the engine still running. I switched off the engine for a while, and it has not given any trouble since.

I took the car to two mechanics, but they could not find any fault. But after what I told them, they agreed that the auto gearbox is faulty and recommended that it be changed.

1. In your opinion, is the gearbox faulty?
2. Are reconditioned gear box reliable?
3. What will happen if I just leave it alone as it has not given any trouble since?

The beauty about automatic gearboxes is that they give you plenty of warning before they die. I think you have a transmission problem that is serious enough to entail a strip down because the warning signs are there. If you continue, it will fail completely and then it may cost you an arm and a leg to fix.

Personally, I do not like to use secondhand automatic transmissions unless there is some form of warranty on the used parts because one never knows the condition of theinternals. I would prefer that the transmission be stripped down and rebuilt. Overhauling an automatic is easier than doing a manual (if one know what he is doing), and if properly rebuilt, will give you many more years of good service.

RM83 A Spark Plug!

I recently bought a used Perdana V6 Year 2000. I want to change the spark plug, but to my horror, it costs RM83 each (meaning RM83 X 6). An authorised Proton service centre could not tell me how frequent should Perdana V6 spark plugs be changed, other than saying the plugs are made of titanium. A friend said the plugs can last between 5-10 years. Can a Perdana use the normal spark plug, other than titanium made?

The plugs are a specialised product, and similar plugs are used in other cars. They last about five years or more, and when they fail, the whole module needs to be replaced. Sometimes one can get used units, but like all used parts one can never be sure of the lifetime remaining.

Civic's Grinding Sound

My Honda Civic 1.5 Ferio has a gearbox problem. There's a grinding sound when I put it into "reverse", and it jerks when I put it into "drive". If I slow down to turn, I have to wait for the gears to initiate before pressing the acceleration pedal. If not, the car will jerk.

It is a second hand re-cond car of 10 years, and I bought it last year. My mechanic it is very hard to find a second hand gearboxfor this particular model. The car is still running.

I think what you are saying is that the shifting is harsh and it jerks when the gear engages. It does sound like you have a transmission problem and the best thing is to get someone who knows automatics to take the car out for a run and check it out.

I am not too familiar with this model, but I am sure that if you look around, you would be able to get a complete engine transmission unit second hand for your engine compartment. You will need to look for the guys who do such conversions as they are very familiar with this work. The average mechanic would not have the experience to do such conversion if he has not done it before.

Musky Smell

I bought an Avanza auto a month ago. Whenever I switch on the aircon, it emits a strong musky smell. The smell lasts a few second. What's wrong?

Secondly, is it usual for my car to have a "tick tick" sound after I switch off the engine? The sound last for a while.

1. Get the service technician to check if the drain hose from the aircon evaporator is clogged or the tray is not angled properly to let the water drain completely. If so, there will be water collection in the drain pan and when you start the engine/air conditioner, this gives the musky smell. After a while the water condensation dries up and the smell dissappears but when the car stops, the water condensation from the evaporator drips into the drain tray where it collects.

2. The "tick tick" sound may be just the exhaust system cooling down and as it does so, it contracts and you get the clicking noise. Nothing to woory about!

Windscreen Woes

Since getting a replacement front windscreen, I haven't been able to get water to bead on it. Water just spreads out evenly, making vision difficult. I've tried Jiff, dishwashing liquid, soap, Autosol, petrol, etc, but to no avail.

A lot depends on what caused the condition, and if it is from the wrapping plastic, either petrol or kerosene would clean it off. If that does not work, you will have to start experimenting with different solvents. Try paint thinner as that usually take off most paint-based films. Do not use Autosol or manyabrasive cleaners, as they will leave scratches on the glass.