Leak Down Test- Need Help Your Please!

[19-911-65]

Just completed a compression & leak down test on a '80 ROW 3.0. All looked pretty good except there is a air leak ( @ 70 lbs) coming from the spark plug hole on cyl. 1 & 2. You can hear air from the oil fill on all cylinders @ 35 lbs during the leak down.

The engine has been sitting for about 4 years and not run other than in the garage per the previous owner. I had the engine running prior to the test for about 30 min.

So.....what do you think I am going to have to fix on cyl. 1 & 2 concerning the air leak??

Your comments would be appreciated!

Glenn

Results of test:

Cylinder___Compression______Leak down

__1__________150_____________12%
__2__________148_____________10%
__3__________151______________8%
__4__________150_____________11%
__5__________151______________8%
__6__________160_____________11%

[kenikh]

From the spark plug hole? That's weird. I think those can be helicoiled, so it shouldn't be expensive. Cylinders 4 and 6 look pretty marginal, too. One way or the other, this motor looks like a candidate for a top end rebuild UNLESS the leaks are coming from the rings. Considering how long it has been sitting, the rings might have gone dry of oil. It's a longshot. Maybe put a teaspoon of oil in each cylinder, fire it up, let it run until the smoke clears and retest?

[19-911-65]

From the spark plug hole?

OOOPS...From the area of the spark plug hole. I don't think it was leaking at the test fitting but maybe the head/cylinder?? The other four did not leak in the area of the spark plug hole. ( I could hear the air leaking from the area of the spark plug hole)

Thanks,

Glenn

[911quest]

If you had that much leakage at one & two your compression test would show up a much less percentage unless the clyinders were wet did you use the tester at 100% thats the way I do it I find it to be much more accurate

[19-911-65]

The instructions for the "leak down" tester I have states to open the regulator untill the needle on the "% of loss" gauge goes to "0". It takes 35 lbs. of air for the gauge to go to "0".

So all these test were taken with incoming air pressure @ 35 lbs. I would then turn up the air to 80-90 lbs and that is when I could hear the air leak coming from the spark plug hole area. When I turn the pressure up to 80-90, the needle on the "% of loss" gauge pegs over below the "0" and does not show any loss of presure.

I guess at this point my concern is tracking the loss of air near/in the spark plug hole area??

Thanks again,

Glenn

[911quest]

Does the threaeded insert have a o-ring at the end? cause if you look at the plug the crush washer is what seals the spark plug to the head

[kenikh]

Does the threaeded insert have a o-ring at the end? cause if you look at the plug the crush washer is what seals the spark plug to the head

Good point; my tester has a rubber o-ring at the end of the adapter.

[19-911-65]

Does the threaeded insert have a o-ring at the end? cause if you look at the plug the crush washer is what seals the spark plug to the head

Yes it does, must be like the one Kenikh has. Could be I don't have it seated all the way down far enough?? I have a 14 mm hard line ext. on order but it has not come in yet...so all I can do at this point is screw the fitting at the end of the rubber hose down into the spark plug hole.

Here are the gauges and what they would look like during the test.

Thanks,

Glenn

[911quest]

When you set it up try to adjust the gauge to 100% then see what the reading is on the other gauge the one that has the green yellow and red If you mess around with gauge you will see that if you set it up at 35% it will show a higher reading of leakage that is why I go to 100%

[19-911-65]

When you set it up try to adjust the gauge to 100% then see what the reading is on the other gauge the one that has the green yellow and red If you mess around with gauge you will see that if you set it up at 35% it will show a higher reading of leakage that is why I go to 100%

Well my learning curve is vertical if not leaning to the left some!

Concerning the air leak on 1&2 it has to be "user error". I lubed the o-ring and tightened it up all I could. The air leak has stopped and is no more!

As far as the gauges and how they work (or at least how I think they work).....In picture #1 the reg. is turned to induce compressed air into the system. It will bring the dial hand on gauge 2 to "0" @ 36 lbs. When I increase
the incoming air pressure....even up to 100 lbs per the first gauge, the dial hand on the second gauge pegs past "0" (leakage) as shown in the second picture. As far as I know the gauges only have one adjustment and that is the reg. for the incoming air.

I am sorry to say I don't understand what else to do with the gauges and their set-up. When I increase the air pressure past 36 lbs.....say to 80 or more.....I can hear a larger volume of air coming from the oil tank and the needle stays pegged past "0" % lost.

I feel I at least now know that the engine isn't completely dead and is worth it to me to continue checking it out.

I just need to learn how to use the gauge set better!!