Compression Test/ Leak Down Test Info Req,

[AsadGhumman]

compression looks ok - you might want to run your car on petrol to "carbon up the valve seats" for better sealing - also you should not be using thick oil in your engine as the lifters would not get a chance to work properly. Thin oil fills the lifters faster.

for your acceleration problem - remove the distributor and dismantle then grease up the centrifugal advance mechanism and vacuum advance breaker plate. both of these jobs will make a very big difference in engine response (i.e. if they are faulty)

Sorry for being off the topic guys...

@Xulfiqar bhai I have question that I use Havoline 20W-50W oil for my Liana-06. I feel it is too thick specially for the coming winter season. Can I switch to thinner one without harming the engine. I have heard that changing the oil grade in not recommended. Furthermore, if I can change the grade than what grade do you suggest me to o for? Car is driven about 92000Km.

[Gringo1]

@rustam54: Can u please let me know the exact location of the workshop from where u got the compression test done as my car is facing same kind of problems and would be a big help if it is tested for compression first.

[rustam54]

@Gringo1

Brother, the workshop is NEXTECH situated at Moon Market, Faisal Town. It was my first experience with those guys. The lead mechanic is Amaan-ullah.

I could'nt meet him in person but his shagird's have quite some attitude. Look for a chap named Nazim there as well. He would help you out with a bit courtesy.

[Gringo1]

@rustam54: Thanks bro would update u after paying a visit there

[Gringo1]

Experts need ur advice got a compression test done from Nextech as advised by rustam54 on my Cultus Carbi 06 and the results were not impressive at all:
C 1: 156psi
C 2: 128psi
C 3: 135psi
The test was done while the car was on CNG not on petrol. The mechanic told ur ride needs a head job and advised me to get Fuji valves reportedly best in the market so far.
Need suggestions / personal experiences from where should I get this thing done in Lahore I mean is there any expert mechanic for this u guys know of.

[Skill]

rustam,
Bro what is meant for wet and dry tests?

[fas133]

The dry and wet compression test is a standard test used to determine the condition of the pistons and rings, cylinder, valves and seats, and even the head gasket, and is carried out as follows:

1. Using an air line, blow away all dirt and debris from around the spark plugs.

2. Start the engine and allow it to warm up to operating temperature.

3. Remove all spark plugs and disable the high tension coil and the fuel pump.

4. Screw the compression tester into each cylinder in turn and crank the engine, making sure the throttle is kept fully open. Crank the engine for about four compression strokes and record the readings.

5. Check the readings. The lowest reading cylinder should not be less than 75% of the highest reading. Some manufacturers specify a minimum reading and any reading lower than that is unacceptable. You can check the vehicle service manual for these figures.

6. If all the readings are within specifications, there is no need to do the wet test but if there is variation between cylinders, then squirt about a tablespoon of lubricating oil into each cylinder and repeat the test. If the pressures increase appreciably and come up to the manufacturer's specifications, then you can be sure there is piston ring and/or cylinder and piston wear.

7. If after adding the oil, the pressure does not go up, your valves may not be seating properly and that could be for a variety of reasons. If there is no pressure rise in only one cylinder, it could be because of a blown head gasket.

Please take note that you never do a wet test with a compression ignition engine, i.e. diesel engine, because the additional oil may ignite on compression!

[fas133]

Compression and Vacuum Pressure of F8B Engine installed in Suzuki FX and Mehran.

[rustam54]

@fas133

Thanku so much sir for the detailed replies. Especially for the reference to F8B Engine. I wish you could post the G10 manual as well.

[Xulfiqar]

Sorry for being off the topic guys...

@Xulfiqar bhai I have question that I use Havoline 20W-50W oil for my Liana-06. I feel it is too thick specially for the coming winter season. Can I switch to thinner one without harming the engine. I have heard that changing the oil grade in not recommended. Furthermore, if I can change the grade than what grade do you suggest me to o for? Car is driven about 92000Km.

yep why not?

[rustam54]

@All experts.

I tried opening up the distributor myself on the weekend and succeeded. Removed upto the magnetic sensors so as to easily access the centrifugal weights. I could'nt risk the distributor further to my limited mechanic abilities. So i sort of lubricated the internals with what i had.

Please don't scold me for using the wrong items. But i first sprayed in some WD40 to just loosen up the pivots. Then dropped in a little bit engine oil at those points and at the mating outer ring of of vacuum linked plate with distributor housing. Checked for smooth weight separation and plate rotation.

I wasnt sure whether WD40 would hold up at high temps. So....

Kher the sad part is......nothing changed much except that of idling at cold start-up. I am pretty much annoyed at this stage that everything seems OK. yet the engine fails to perform OK.

Need advice

[AsadGhumman]

yep why not?

Thanks Xulfiqar bhai... So which oil grade I should go for like 20W-40W etc?????... I have absolutely no idea about oil grades.

[rustam54]

One more thing. The vaccum actuator spring seemed to have quite a tension. So i was'nt sure whether vacuum advance is acting or not. After finishing up, i took the car for a test drive with and with out vacuum hose plugged.

I could'nt feel any difference in the drive. However at idle, if start to rev up to 2k rpm and plug-> remove-> plug in the hose, i can hear a sort of click when unplugging and a nominal rise in response (between 1k to 2k) when plugged. I am not sure whether its ok or not.

As for what the electronic ignition analyzer guy said on saturday, its working fine.

[rustam54]

one last resort is to test the plug wires. I have had a bad G10 plug wire case with my Khyber in the past but the symptoms (missing under load) were far more intense than in this case.

The mechanic back then pulled the wires instead of the plug adapter during a routine tuning and it costed me a new set. Kher in this case, its only missing "At a certain rpm under load". If i ease up on the throttle (lets say in 3rd or 4th gear), it gradually climbs the 3k hill but very slow onwards.

[Xulfiqar]

does the rotor rotate and snap back to place if rotated by hand? WD40 would not help and may infact hinder distributor performance, its not meant to be used in high temperature environments, a few drops of oil are good though.

firstly check the resistances of the cables with the distributor cap connected to them, it should be within spec. Finally is your distributor rotor "sandpapered" and whats the condition of the carbon button in the distributor cap?

[rustam54]

i am sure the rotor rotates when turned manually and snaps back again. i'll retest it again tomorrow morning. Plus i'll add the snap for carbon button condition.

as for the rotor tip, yes it has been sandpapered. I hope its not something bad for it. Sir can you please mention how much are the resistance specs generally for these cars. Some spages say it should be in OHMs, some say it should be in kOhms. I am confused. As we generally check the continuity of a wire in not more than 10s of Ohms or so. And for this much length, the multimeter should read flat zero.

But since they say these plug wires are nylon core these days to avoid stray emf, i have no clue how much should their resistance be.

An optimum range of values would be greatly helpful...

[capsat]

• So far I Only see Xulfiqar a professional with the widest & broadest spectrum of knowledge on vehicles & engines. over this forum

The way he shares the tiny bit of info about cars specially mercedes clearly shows his passion for cars and the mercedes star.

Honestly i wish i'd have met him before in real in Pakistan.

am just an amature with surface knowledge out of my appetite for motor vehicles and gadgets.

My salutes to Xulfiqar for his contribution to this forum., and his occassional wity comments

[capsat]

Would you please post the picture of distributor cap innerside & the distributor without cap .

i am sure the rotor rotates when turned manually and snaps back again. i'll retest it again tomorrow morning. Plus i'll add the snap for carbon button condition.

as for the rotor tip, yes it has been sandpapered. I hope its not something bad for it. Sir can you please mention how much are the resistance specs generally for these cars. Some spages say it should be in OHMs, some say it should be in kOhms. I am confused. As we generally check the continuity of a wire in not more than 10s of Ohms or so. And for this much length, the multimeter should read flat zero.

But since they say these plug wires are nylon core these days to avoid stray emf, i have no clue how much should their resistance be.

An optimum range of values would be greatly helpful...

[Xulfiqar]

i am sure the rotor rotates when turned manually and snaps back again. i'll retest it again tomorrow morning. Plus i'll add the snap for carbon button condition.

as for the rotor tip, yes it has been sandpapered. I hope its not something bad for it. Sir can you please mention how much are the resistance specs generally for these cars. Some spages say it should be in OHMs, some say it should be in kOhms. I am confused. As we generally check the continuity of a wire in not more than 10s of Ohms or so. And for this much length, the multimeter should read flat zero.

But since they say these plug wires are nylon core these days to avoid stray emf, i have no clue how much should their resistance be.

An optimum range of values would be greatly helpful...

If the rotor edge was cleaned with sandpaper - it'll live, if the centre was rubbed with sandpaper - its garbage now, throw it away.

btw the resistance of HT leads should be about 15,000 ohms per meter in your case, test with a multimeter and calculate by the value, or look it up in the repair manual.

Lastly you should check the ignition coil too, a weak ignition coil will cause such behaviour too.

[rustam54]

@capsat. Here you go sir.

The distributor.

You may ask about the oil leaking. I guess too much oil got squirted on saturday's pseudo-service.

The rotor.

With rotor removed