DIY : Compression testies :)

[bennjamin]

Its that time of the month again....DIY JOBBY !


Disclaimer: The following is provided as a GUIDE ONLY, and neither myself nor Ozhonda take any responsibility for the outcomes of someone else doing the following. You follow these steps at your own risk!


Aim: To test the compression of a engine - that is , basically see the internal condition of piston rings , valves , valve seals etc. Handy when purchasing a second hand car or if you are just paranoid like myself








Required: Car. atleast 2 hands - only one foot is needed though. Compression tester tool , and spark plug remover.



Steps:





1. Open bonnet. Pull out all spark leads , then use removing tool to take out all 4 spark plugs.



2. Open fuse box in engine bay ( upper should be right corner) - take out the fuse marked ECU ( 15a i think ?) ( to disable the fuel and ignition)




3. Place the compression tester tool into the 1st cylinder (any is ok) and tighten up. Either get a friend to hold it and read the reading OR leave it atop the engine bay. YOU MUST FOLLOW ALL STEPS IN THIS PHOTO....





4. Jump into the cabin , apply WOT ( wide open throttle/ full throttle) and turn over the engine 6 times. Jump out , and read the top reading OR get ur associate to tell you the maximum psi reached. Record down and write the cylinder number/location.



5. Simply repeat for each cylinder - once all recorded pack up in the opposite fashion , reinsert sparkplugs + leads, then reinstall the ECU fuse and away you go.



Other comments

Results of the compression test will vary engien to engine - but apparently the wanted norm is a MAXIMUM variation of 28 PSI between all 4 cylinders hot or cold .

If there is a substantial change in PSI perhaps a bent valve might be to blame - or worn piston rings or even a bad head gasket.
IF in doubt , take it to a professinal to get a leak-down test + more to find the source of crappy boost




Thats it. Go honda

[revNhevN]

Very good write up. . Do you know what the pressure should be for a B16a? like, what is good and what is bad.

[bennjamin]

Very good write up. . Do you know what the pressure should be for a B16a? like, what is good and what is bad.

i have no idea - my totally stock d16a8 - pulled 220 psi ( quite high) - while HOT ( that is , with the car warmed up properly). So , im sure your car could pull a similar number.
As long as each readout is within the 28 PSI range there shouldnt be a problem.

[egSi]

cool write up ben, i should do this

ur the diy king y0!

[ProECU]

yeah, just on this, ideally, the cyllinder pressures should not vary by greater than 5%.

Excellent writeup

[_FeRiO_]

cool write up man!! i might give it a go when i have time

[Q_ball]

LOL @ step 3

always lookin to make revenue huh bren
nice write up mate

[pgclee]

how much 12.5:1 if it were to convert to Psi?

[bennjamin]

how much 12.5:1 if it were to convert to Psi?

thats the compression ratio of an engine. This test is to judge the maximum compression in psi , to test for internal leaks etc.

[**Ghost**]

few queries

1. "turn engine over six times"... i wanan know what this means? as in rev it 6 times?

2. also another thing...where and how much does it costs to get a compression testing tool?

3. does low compression indicate a dying headgasket

[revNhevN]

1. "turn engine over six times"... i wanan know what this means? as in rev it 6 times?

I think he means to try to start the engine 6 times per cylinder.

[bennjamin]

few queries

1. "turn engine over six times"... i wanan know what this means? as in rev it 6 times?

2. also another thing...where and how much does it costs to get a compression testing tool?

3. does low compression indicate a dying headgasket

1. "6 times" means , you will hear the engine "crank" 6 times. Its an obvious noise/situation. This is to judge the maximum compression of each cylinder.

2.The tool is about $40-60. You will hardly use it so i suggest to borrow a mechanics ( like i did) or get them to do it for you. Cost = $20 or $30 i guess . It takes only 15 minutes or so.

3.Low compression could indicate a dying headgasket , or bent valves , or worn / leaking piston rings amoungst other things. The most important thing as said before - is that the compression between cylinders does not vary more than +/- 5%.