What's the best why to test compression on an oil dry engine?
Basically my v8 has been sitting for a few years with the sump and inlet off, no cam or front cover.
Now I want to know what the comp is like before I build it back up in case I do need to remove the heads...
Flywheel and starter are on it and I'm ready to go......
I would say you could not do a compression test in this state, you would need to put the sump on and fill with oil. You could however carry out a leak down test on each cylinder by turning to TDC by hand. This would show any leakage paths in the valve train/ rings that would affect compression. I would put some oil down the bores and on the crank and let it soak before turning if it has not moved in a while
Best way woulsd be a cylinder leak-down test, you will need a compressor, old style leak-down testers work at either 100psi many chinese ones now
work at only 1bar and will work with a 12v tyre inflator compressor. The dual gauge type are best the ultra cheap chinese ones usually work Okay
--- put will need some light oil down the bores and turn the engine over a few times to getting the rings sealing before you test . Redex or
Injector Cleaner or Dexron II Transmission work even better than oil.
[Edited on 11/8/17 by britishtrident]
Youtubes from the usual suspects
Paul "ScannerDanner" Eric O at SMA and Matt at Schrodingers Box
[Edited on 11/8/17 by britishtrident]
[Edited on 11/8/17 by britishtrident]
Thanks, don't have a leak downer, all I was thinking was a sanity check to see if there was any massive callamerty waiting in one of the cylinders..
quote:
Originally posted by coozer
Thanks, don't have a leak downer, all I was thinking was a sanity check to see if there was any massive callamerty waiting in one of the cylinders..
quote:maybe also look with a borescope/endoscope. (camera on a stick)
all I was thinking was a sanity check to see if there was any massive calamity waiting in one of the cylinders..
quote:
Originally posted by gremlin1234
quote:maybe also look with a borescope/endoscope. (camera on a stick)
all I was thinking was a sanity check to see if there was any massive calamity waiting in one of the cylinders..
Thanks for the suggestions fellas, just done a bit on the bay and now waiting for a leak down kit and an endoscope..
If neither are any good yous owe me £29!
Leak down tester arrived this morning. By dinner time Id managed to break the second gauge so swapped them over...
Chucked up the need for a set of rings and 4 valves not seating correctly, 2 inlets down 30% and 2 inlets down 2%..
Heads are off now and all 8 pistons n rods are in a cardboard box unlikely to be going back in!