Automotive Cylinder Leak Down Test

[68ray]

What's a Ka-Burator?



[serchmarc]

iv just subbed!!!

[zambam3]

great video brother! thanks, rob

[ybafool2]

Very cool. I did not know you could do this lol Man I love YouTube :)

[hondaslave]

does it have to be on tdc of the compression stroke

[richpin06a]

@hondaslave Yes it does

[Robonza]

@hondaslave Sometimes you can have a damaged bore say an inch below TDC causing your leakage. This can only be tested when you are off TDC. Its a tricky one to do but you can rotate the engine while the test is being done. Obviously you do TDC compression stroke first.

[TheBaja274]

Make sure you check your valve clearances before this test.

[kirbstone111]

Nice vid :) Thanks for sharing.

[MrRukcus]

I know this was an how too(and an excellent one at that) I would suggest telling people to do comparative tests on other cylinders so you can better determine your expected psi loss due to wear & clearances.

[Vintageguy73]

Very good video!

I've used masking tape on the balancer to determine TDC for different cylinders. Cut a piece of masking tape the same length as the circumference of the balancer. Make three equally spaced marks on the tape, put the tape on the balancer starting at #1 TDC. Now when the marks line up with the timing pointer each piston will be at TDC compression following the firing order.

[richpin06a]

@Vintageguy73 I have done the same think to adjust the valves put four marks on the pulley for each cylinder top dead centers.

[ratrace2p51]

Nice video.

[liOVERLOADil]

How can you get a proper test if the engine has been sitting for so long and the piston isn't lubricated? Won't air just come out of everything if not properly lubricated?

[richpin06a]

@liOVERLOADil I do not think letting the engine cool down to take out the spark plugs will effect the test.

[liOVERLOADil]

@richpin06a Please re-read my comment.

[marek0086]

@richpin06a~ it will affect the test because the ring end gaps get bigger the colder the engine is.

[texturedmuffin]

Rich Pin, you are a smart person. You have my respect.

[richpin06a]

@texturedmuffin thank you

[charlieparker1234]

Excellent video, Rich Pin.

[wangbungal]

so what happens next? its leaking on the exhaust does it mean the lower part of the engine or the upper part of engine has the problem? im confused with this leak down test, what if your piston rings are damage where could be the air be heard?

[richpin06a]

@wangbungal Leaking in the exhaust tells you that your exhaust valves are not seating very good.

[wangbungal]

@richpin06a exhaust valves so its the cylinder heads right which is the upper part right?

[richpin06a]

@wangbungal yes cylinder head

[wangbungal]

@richpin06a where do you hear the air coming out if the piston rings are the one causing it so to know its the lower part of the engine is the one has a problem?

[richpin06a]

@wangbungal The dip stick tube or pcv hose all lead to the crankcase.

[green95gt]

make sure it's at tdc between the compression and power stoke. some valve overlap may exist between exhaust and intake strokes.

[darkfyre2k7]

I have a 97 dakota V6 with ring leaks, and the local garage said replace the engine... would just replacing the rings be okay? they only went out 160 miles before testing compression... readings were from cylinder 1-6, 145, 140, 100, 120, 75, 95... the guy said that something like replacing rings would blow the bottom end out because of stress attributed to power returning. is he right?

[richpin06a]

@darkfyre2k7 Hard to say you would have the measure the crank to see what condition it is in.

[darkfyre2k7]

@richpin06a well it vibrates a lot when it's cold, but that might just be from imbalanced compression, or so I'm told... would that be a sign that the crank is trash? did the leak down test and it's only rushing through the oil filler... even did a head check and a rad check, no sounds coming from those and no bubbles in the coolant resevoir

[marek0086]

@richpin06a~ dont ever quit your accent. I love your accent.

What part of US is that accent from?

[richpin06a]

@marek0086 New England (Boston)

[trayyy00cvrurface]

@darkfyre2k7 from the looks of your tests, if not replace the engine, you would have to send it in for some machine work. the bore of the cylinder is probably just as worn as the rings. A machinest would bore out the cylinders, and you always want to replace the rings on every piston, not only because they come in a set, but because replacing only one piston ring set would cause uneven compression anyways. and your test also indicates you probably need a new head gasket...

[spelunkerd]

So, I guess the reason for the pinhole is so that the regulator can't replenish air fast enough to maintain pressure when there is a significant leak. Would an instream shutoff valve accomplish the same thing? Do you think you could eliminate the second regulator and just have a shutoff valve? I find my airhoses tend to leak at those quick connections, which might confuse the readings....

[richpin06a]

@spelunkerd when pressure is applied (e.g. 100psi), what we are looking for is leakage in the cylinder as compared to the airflow through a 1mm orifice at that pressure. You could use a shut off valve.

[CARRICK6423]

Excellent.

[gst69man]

good vid thanks

[MoldyLunchBox87]

Very detailed and informative video!

[rleon1991]

great video!!

[curtis9188]

the blooper was a nice touch

[Proverbs1x26refurbed]

Love those old VW engines. I don't think I ever owned one that didn't have valve problems, so I'm not surprised it failed. They run so crudely anyway you'll never notice.

[Mulletsrokkify]

Excellent videos, well explained as usual!

[michaelovitch]

Very instructive and interesting !

[4g92mit]

Nice work Richpin.