Compression Test/ Leak Down Test Info Req,

[whiteangel]

Where did you buy this from and how much did it cost you?

[rustam54]

Where did you buy this from and how much did it cost you?

PM'ed you sir.

[rustam54]

@ All experts,

Any other inputs regarding compression values?? I am simply curious. While i am relaxed that the valves seem OK, i am confused at the dry to wet difference as it indicated worn rings or piston sleeve.

At one site, somebody quoted from a G10 manual that it should not be below 156psi. 195psi is of a sound engine. and the difference among cylinder should not be more than 7 psi.

[Gringo1]

@ rustam54: where did u buy this stuff and at what cost do share with everybody else as many of us are also facing compression problems and is there a good mechanic in lahore to solve this issue

[capsat]

I do not see anything wrong with the engine compression it is very much in acceptable shape, - what actually is the problem bothering you?? Gradual loss of power - did you checked the distributor, in another thread Xulfiqar mentioned, back-tracking the electricals and i believe the member isolated it to leakage in HT current when vehicle is HOT

[rustam54]

Okay here you go guyz. The location of the hardware store has been posted below.

A = Akbar Chowk
B = M. Ali Chowk
C = Hardware Store

I got the gauge for 1800. I know i could've got a hold on something cheaper. But for that i had to bear the khwari at brandreth road or elsewhere plus the fuel cost plus the time. So for me it worked.

I bought the last one in stock, but you'll be able to get it in like 4-6 days on demand from there. Best of luck.

[rustam54]

I do not see anything wrong with the engine compression it is very much in acceptable shape, - what actually is the problem bothering you?? Gradual loss of power - did you checked the distributor, in another thread Xulfiqar mentioned, back-tracking the electricals and i believe the member isolated it to leakage in HT current when vehicle is HOT

Hmm. I had been fiddling around with the distributor in past for doing minor adjustments but none of the issues popped back then. Kher I was having the same feeling about electrical system. Out of nowhere, my guess is that the mechanical advance is not working as required. e.g. the car has a reasonable torque from 1.5 to 2k rpm. It lags quite a lot from 2.5 to 3.2k. After that it starts getting back supplying power again. Also if i drive the car at 95 in 4th gear around 3.5k rpm, i don't see any power loss then.

Then again, now i am starting to doubt the carb as well. But i have also used carb cleaner on it lately and a bottle of fuel additive carb cleaner has been consumed as well like 2 months back.

I am still confused about the problem. Picks -> Lags -> Picks again on the usual rpm range . Both on petrol and CNG

[Xulfiqar]

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)

[margallar]

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)

someone told me that putting engine oil in carb is good for valve seats, is that true? if u do it occasionaly of course.

[Xulfiqar]

that helps. But most oils nowadays are detergent quality and will clean out the valve seats.

[ahmedtallal]

contact Mr Asif at Formotion Auto Clinic 03004356886 He can resolve your problem

[Gringo1]

I had the experience of putting engine oil in carbi and felt some change but for a day or two not more

@ ahmedtallal where is Formotion Auto Clinic please do give exact locations

[margallar]

maybe carb jets are worn

[shqamar]

very informatory thread poster thanks for sharing your result and experiences !!

[agm1pk]

Is there anyone who can tell the standard compresstion reading of a single cylender. (for example all of four cylender give same ratings like 180,187,185,188) as per thread you are saying that its optimal and engine is fine. but if all these are weak compression or got weak over time , then how one will judge about the standard rating ??.

[rustam54]

Mr. Xulfiqar and capsat would be the eligible people to reply that

But if i may, as far as i've read, there is no pre-determined value of a good or weak compression based on engine displacement. Its based on cylinder compression ratio PLUS cam shaft profile (cam profile determines valve overlap and thus affects max compression).

People can give general range of values for 9.5:1 engines but the correct figures are given by manufacturer service manuals.

In the case discussed above, anything below 156 psi is to be considered as weak compression. (as said by Suzuki G10 manual).

P.S. Initially you are interested in cylinder to cylinder difference. This can identify a bad valve, gasket leak or weak rings. The engine may keep on going. But a lower value across the board suggests that engine needs an overhaul.

[agm1pk]

Thanks !!! if one can elaborate it??

[rustam54]

Guys, today i went to a workshop {its "A" workshop because "The" workshop that used to provide the services has been closed in best interest of my trustworthy mechanic} for distributor service and diagnosis of the persisting issue.

The guy opened up the distributor, cleaned the contacts on the cap (that i had cleaned a week ago), had a brief overview of the mechanism conditions and said without hesitating that "no issues here. the valves are gone".

Looking at his way of diagnosis, i couldn't afford to risk forcing him to disassemble and reassemble the distributor assembly after lubricating.

However, a strange thing happened that i would like to share, that actually matches my initially diagnosis. I asked him to recheck operation of the centrifugal and vacuum advance and he played with the breaker plate rotation and the weights separation to check spring tensions.. But when he refitted that distributor back, the car started acting like its breathing again. I know you guys can say that he may have advanced the timing slightly but he didnt (double checked with distributor position marker before/after).
Driving the car around the city for like 30 kms or so, i was kind'a putting a heavy foot on it and suddenly, it came back performing as it was before. Lagging around 2.5 to 3k rpm and missing. The fault appeared in a snap. As in when you turn the AC on and the engine loads up. Just like that.

Notice: nothing except the distributor was fiddled in all this scenario. I am having a strong faith that somethings up with the ignition, not the valves.

Plus. He performed the compression test again with his tester (strange he had it in the first place) and read a 140 +/- 3 across the board. Again no big difference among the cylinders. And i can regard this reading as a gauge to gauge variation. Nothing to be alarming.

So what do you say guys, should i open up the distributor myself, and instead of disassembling it, should i drop in a couple of engine oil drops to the moving parts???? Read in a forum today that engine oil can be used to lubricate the distributor internals.

Need help.

[vyrus]

140 ? That compression is too low no ?

[rustam54]

Yeah it is......But my own tester showed the result of 178.

Gauges can vary in calibration. Even mine can be out of calibration. But not all the cylinders can drop such low (as 140) and in equal proportion. There had to be atleast 15-30% difference among them to highlight the issue. Theoretically an equal loss of compression is not possible. Unless the car has a lot of miles on the odo.

So no worries.