oil leak test

82SC · 06-27-2005, 04:25 PM

i was just reading an interesting article in an R&T or was it a C&D

well anyways, the author went to the chevy plant and built a "trainer" mock up of the Corvette engine. It was really interesting, all the different checks and machine aided torquing, drop a bolt...it gets thrown away, balancing etc...

but what got me was that at the end of the assembly line they seal all the openings and use compressed air to see if the engine will hold the pressure. I believe in one port is was 5psi and another was 20psi. If these couldn't hold pressure for 2 min the engine was coated with soap water and the leak was sourced out.

can this feesibly be done in a 911 engine? wouldn't this help cut down on first start up after rebuild leaks and the hair tearing that ensues of having to remove your engine and take it apart???

MJ

82SC · 07-01-2005, 11:09 AM

no one........

magic930 · 07-01-2005, 12:12 PM

I did this on my 3.3 and it works. I wish I had done it before putting the engine back in! I had a leak at the outer edge of the flywheel seal and at the oil cooler, both of which where easily found with this method. You just need a few different sized rubber stoppers from the hardware store (about $3) for all the oil connections. Hold them in place with electrical tape. On the last stopper drill a small hole in it that you can push an air compresser blower fitting into. A light solution of water and dish soap will form bubbles where it leaks. You can also use a hand pump vaccumpump (Mighty Vac) with a gauge to see if it holds the vacuum.

tt_targa · 07-01-2005, 10:43 PM

I would be interested in more details like what pressure did you use for how long on what engine?

magic930 · 07-02-2005, 07:34 AM

I set the compressor at 10-15psi (1 bar). Air will leak out easier than oil so this is plenty of pressure. I just held it in the rubber plug for about 10secs and then started squirting suspect areas with soap. The bubbles show up right a way if there is a leak. You can see the bubble grow from the exact leak point. Here is a picture of the process showing a leak at the flywheel seal.
After I put in new seals I did the test again and also used the reverse of this process to verify that it was leak free. Using a Mighty Vac vacuum pump, the case held a steady vacuum for about 5 minutes.

82SC · 07-04-2005, 11:24 PM

cool....

I am sure things change since our engine do go thru alot of heat expansion...but I am sure this test will catch the big ones before installation...

MJ