Leakdown test procedure info needed
02-06-2015, 08:43 PM
#23
I was typing as i was designing. I can verbally explain but quick posts are not my speciality.
Think of my test box as the ecu set to fire (light comes on) at 0* advance.. (tdc) #1.
If you get the box set for #1 just move the plug wire (from test box) to next plug (#8 on bbc) to fire rotate crank c-wise (std rotation)
until light just comes on there (that will be 90*) you are at tdc #8 etc, etc, etc.
If you mark your harmonic balancer at the timing mark on the block after 4 times you will not need the tool any more.
02-06-2015, 09:00 PM
#28
When actually doing the leakdown test.
If you use a cheap, i mean inexpensive, tool you will think you need to throw your motor away.
The cheap tool operates on about 12 psi for reference. They have a very bad regulator in them and your compressor also is most likely useless trying to regulate to 12 psi.
There is a youtube on how to convert the harbor freight cheap tool to work at 50 or 100 psi. (remove 1 gague and install a plug).
Remember at 12 psi a 5 psi drop is almost 45% at 50 psi that would be 10%. @ 100 psi reference = 5%you get the idea.
The regulator and gague are much more accurate at 50 or 100 psi on most of our garage style compressoers.
Also, the increased preassure will actually give you a much better test environment as it is much closer to operating paramaters.
I use 50 psi as that does not seem to try to rotate crankshaft even with all plugs removed.
If you have marked your h-ballancer position before each of the cylinder tests you can visually verify crank did not rotate.
Make sence?
If you use a cheap, i mean inexpensive, tool you will think you need to throw your motor away.
The cheap tool operates on about 12 psi for reference. They have a very bad regulator in them and your compressor also is most likely useless trying to regulate to 12 psi.
There is a youtube on how to convert the harbor freight cheap tool to work at 50 or 100 psi. (remove 1 gague and install a plug).
Remember at 12 psi a 5 psi drop is almost 45% at 50 psi that would be 10%. @ 100 psi reference = 5%you get the idea.
The regulator and gague are much more accurate at 50 or 100 psi on most of our garage style compressoers.
Also, the increased preassure will actually give you a much better test environment as it is much closer to operating paramaters.
I use 50 psi as that does not seem to try to rotate crankshaft even with all plugs removed.
If you have marked your h-ballancer position before each of the cylinder tests you can visually verify crank did not rotate.
Make sence?
02-07-2015, 10:31 AM
#29
Banned
iTrader: (9)
I have a tool that I am improving upon that screws into the spark plug hole and is spring loaded that has a measuring stick that moves when the piston moves. It is very accurate for finding TDC and on the compression stroke of course. I should have this tool completely on the market in about 3 or 4 months. Takes all the guess work out of finding true TDC.
Believe it or not a lot techs in the marine industry do leak down tests on 2 stroke outboards engines as well and you have to lock down the flywheel when filling the cylinder(s) with air. The tool I am bringing to market will be a hit for the outboard tech using it on 2 and 4 stroke engines as well..
Also I sell digital leak down testers for 200 bucks and the analog ones for 100 bucks and they are not cheap quality ones like HF or Northern tools. HF are not accurate by no means. FYI
Believe it or not a lot techs in the marine industry do leak down tests on 2 stroke outboards engines as well and you have to lock down the flywheel when filling the cylinder(s) with air. The tool I am bringing to market will be a hit for the outboard tech using it on 2 and 4 stroke engines as well..
Also I sell digital leak down testers for 200 bucks and the analog ones for 100 bucks and they are not cheap quality ones like HF or Northern tools. HF are not accurate by no means. FYI
Last edited by BUP; 02-07-2015 at 10:55 AM.
