View Full Version : DIY: Leakdown test for your ep3

07-31-2008, 04:22 PM
Testing procedure

--------------------------------------------------------------------------------PART # FOR GAUGE 89600. PART # FOR ADAPTOR 89602 Both are Moroso part #'s. Wrench sizes needed,
3/8 drive ratchet
and at least 6" long extention and a 5/8" spark plug socket

This post is performed using a Moroso SINGLE gauge leakdown tester. THIS STEP IS ABSOLUTLY CRITICAL BEFORE ADDING POWER!!!! DON'T WASTE YOUR MONEY! This part is available through Summit for about $100. Comes to about $109 and change with shipping. YOU WILL NEED THE ADAPTOR!
Summit is currently out of stock on this part, but you can get it from Lightning Motorsports for $19 plus shipping. The adaptor allows you to use the gauge on OHC engines. For all you dumbasses, OHC means OVERHEAD CAMSHAFT. Without the adaptor, you are screwed. Buy it. A leakdown tester allows you to see where you car is leaking from. Example: if you hear air leaking out the exhaust, you have a exhaust valve leak. Out the intake, intake valve. Out the oil cap, leaking past the rings, etc. The good news about buying this gauge is that even when you are done with it, sell it on ebay! Look them up, (if you can find a used one for sale) and look at the price they fetch! Anyway here is how to do this test. Pay close attention.

You have to have a air compressor capable of 80 psi first. Take out the plugs (while the engine is warm, not hot. Hot will make them harder to remove and the engine needs to be warm for the test) and install the adaptor. The hardest part is getting all of the valves closed and the piston at top dead center. You can do this by tapping the key with the plugs removed. You will smell a gas smell but thats because of the fuel injectors are primed for start up. Don't have anyone smoking around you, thats bad for the gas fumes. ( they don't get along well) You will have to depress the clutch to get the key to work, naturally. Zero the gauge by pressing the knob on top, or front, depending on how you are looking at it. Put your finger over the hole in the first hose coming off the adaptor. Start cranking SLOW and in intervals. When the air makes a psst sound past your finger, you should be close to TDC. Put the other hose on thats hooked up to the compressor, with the compressor on and ready to use, and it should put pressure into the cylinder. Have someone sitting in the car, its easier to feel if the crankshaft moves from there. IF IT DOES, start all over with the cranking process. YOU MAY HAVE TO DO THIS QUITE A FEW TIMES to find TDC. The test is done correct when you get a good reading (a bad one is if the gauge says you car is leaking 70%, unless your engine is blown, then the gauge is useless to you) and you do not hear the crank move, or feel it move. A good engine should leakdown less than 10%. Me and my old man did this in about 30-40 minutes. LISTEN TO SEE IF THE ENGINE MOVES WHILE AIR IS ON IT. I CANNOT STRESS THIS ENOUGH. IF IT DOES YOU HAVE NOT GOTTEN THE ENGINE AT TDC AND YOU WILL THINK YOU CAR HAS 30% LEAKAGE WHEN IT REALLY HAS 10% OR LESS. It really is easy, although it may not sound like it. I would not do the test unless you are planning on power adders, but I guess thats why we are all here isn't it? *sigh* I wish I was rich..... Have fun. BTW get the gauge that has the SINGLE GAUGE, NOT THE DUAL GAUGE. Singe gauge measures in percentage, other gauge needs a calculator.
Be very careful when screwing down the adaptor and reinstalling your plugs. Aluminium strips with very little pressure. If it starts to snag, go the other way about a 1/4 turn to loosen it up for you. Remember, anti-seize is your friend!!!
Happy modding to my friends at EPHATCH. Hope this was helpful

07-31-2008, 04:36 PM
would you add some spacing or something to make it easier to read?

07-31-2008, 04:45 PM
:lol: agreed ^