did a boost leak test today....

[wild_maxx]

well i have had a low vac. reading so i decided to check the system for leaks. i rigged up the same type of device that was on here and gave it a try. This is what confuses me, when i pressurize the system there is air leaking out of my oil pan seal. When i sealed it up, i used RTV to seal up the oil pan. There is a bit of oil leaking out of the pan itself so i am going to pull it off and reseal it up. I also did a compression test on it. WOT at operating temp and no fuel in the cylinders, i got a reading of about 112 across all 4 cylinders. i am thinking my rings are done for, BTW this fully rebuilt motor has 1k miles on it i broke it in the hard way and my first compression test was 130 across all 4. maybe time for a rebuild.....

[DammitBobby]

Usually when you have bad rings it is not all 4 of them and they don`t show same results. As far as the oil pan you are correct to use RTV. I had a problem with oil pan leaking myself. I had to do it twice. The second time used the same RTV black but used more of it and it didn`t leak. Make sure it isn`t your drain plug leaking. I had a leak there as well. I end up using earl fittings and I will never use anything else! Dam expensive stuff too!

Not sure about the air leaking out the oil pan?

[Structure240sx]

they also sell oil pan gaskets at parts stores that work great with a lil rtv spread on them

[Kenrik]

well i have had a low vac. reading so i decided to check the system for leaks. i rigged up the same type of device that was on here and gave it a try. This is what confuses me, when i pressurize the system there is air leaking out of my oil pan seal. When i sealed it up, i used RTV to seal up the oil pan. There is a bit of oil leaking out of the pan itself so i am going to pull it off and reseal it up. I also did a compression test on it. WOT at operating temp and no fuel in the cylinders, i got a reading of about 112 across all 4 cylinders. i am thinking my rings are done for, BTW this fully rebuilt motor has 1k miles on it i broke it in the hard way and my first compression test was 130 across all 4. maybe time for a rebuild.....

if you just rebuilt it how could it already be dead? did you clean the oil out right after the rebuild to get out the metal flakes? did you check your compression gauge it might be broken?

The numbers should not be the same on all four and be that low... things tend not to wear evenly..

[S14tat]

well since he has forged slugs, they shrink more when cold compared to the stock pistons. so if he decides to do a compression test when the engine is cold, i think it would shrink enough for the engine to have some blow by. your suppose to compression test the engine when its fully warmed up and you have to be at WOT while cranking.

[virus77]

when you pressurized the system did you do it from the turbo compressor directly or from your turbo's intake pipe.

[wild_maxx]

I changed the oil after the first 20 miles of the break-in then at 50 miles, then at 100, then at 500. I did the test with the engien at operating temperature and WOT. i was looking at the compressor blades on the turbo and there is a chip in one of the blades. I think that chip went thro my motor being ground up inside. When i did the boost leak test i hooked the tester up to the intake pipe of the turbo... should i have done it another way?

[onosqv]

Can you share the details of the device & process you did for the boost leak test?

[virus77]

^ heres the tester: zerothread?id=113785

back to the subject at hand:

If you hooked it up to the intake pipe, did you make sure to disconnect the valve cover breather from the intake pipe then pressurise the sytem. If you did not this will pressurize the crankcase aswell which is not cool. Also note im drucnk from a late night out so excuse any spelling erros, but my addvice/comments are solid.

[wild_maxx]

hahah your a pretty good drunk speller. i did have the pcv hooked up to the intake while i did the test do that may be why air is comming out of my oil pan. i will pull the oil pan off and re-seal it then do the test again.

[virus77]

There you go, thats why the sticky says to hook up the tester to the compressor inlet of the turbo, I should edit the sticky to explain that if anyone uses the intake pipe, all the fittings on it need to be blocked off like BOV recirc and PCV. Basically you were putting boost into your valve cover. Just fix you oil pan leak and do the test again with the pcv disconnected from the intake pipe and you will be cool.

[wild_maxx]

should i regulate the amount of pressure i put into the system? i used a huge compressor that has like 150 psi of pressure.

[nissanfanatic]

You shouldn't need to test past like 15psi to find any leaks. I went to 25, but its not necessary. Any leaks will show pretty well past ~10psi.

150psi=something popping. Just don't go there.

[wild_maxx]

that much air pressure will pop something? like pistons or rear main seals?

[NateDogg]

dude you might have blown a hg or something doing that. if you arent boosting more than 20psi why test it to more than 20psi. hope you didnt hurt anything!

[wild_maxx]

i didnt blow a HG. the compression was the same across all 4 cylinders and its not smoking at all. no coolant in oil or oil in coolant.

[lrb_2000]

so.. if your rings were bad, wouldn't the car produce some smoke? or what...

[wild_maxx]

yeah... thats what i was thinking. i am going to do a leakdown test and see whats going on inside. i will reaseal up the oil pan and find any leaks and fix them. do another compression test.

[C-Kwik]

It's likely that since you have the PCV hose hooked up, it blew the oil pan gasket seal. And 150 PSI is way overdoing it. I'd say at most, you'ld want to test to 150% of the pressure you actually plan to run at most. This would ensure good seal while you are actually driving the car around and leave some headroom.