Compression

Post by **Onne** » Sun Mar 05, 2006 8:15 pm

I do know how to take compression sir. My equipment is calibrated and I always remove all plugs, on hot engine (I have burned my hands!) with the throttle wide open.
And it runs quite nicely be it a bit oily on startup (more like sooty actually)

Post by **rayofleamington** » Sun Mar 05, 2006 8:52 pm

It could well be the gauge/battery condition/starter condition. Test should be done on hot engine - with all plugs out and throttle wedged open - to let some air in !

Exactly.
Engine wasn't hot as I'd spent nearly an hour messing with other things and it was around 0°C in the garage - and it had only done a mile before hand. Unfortunately I didn't have time to heat it up as I had to have everything back together to meet a man in a distant layby at 6pm.... [Thanks for the gearbox WorkNiel)

If it runs well, don't worry about it!

Exactly!

Post by **NZJLY** » Sun May 07, 2006 10:23 am

bmcecosse wrote:It could well be the gauge/battery condition/starter condition. Test should be done on hot engine - with all plugs out and throttle wedged open - to let some air in ! If it runs well, don't worry about it!

What sort of numbers would be OK for a cold engine being cranked by hand? We have a 1098 that hasn't run for a while so ...

Thanks,
John

Post by **bmcecosse** » Sun May 07, 2006 4:08 pm

No idea- I doubt you will get much on the gauge by hand - the starter needs to really spin it! But - you can 'feel' the compression by hand - main thing is all should be much the same. If one feels poor - and you can hear a hissing/breathing noise - then it could be leaky rings or valves.