is there any way to perform a compression test by hand cranking the motor?
im gonna go check out a car tomorrow with a burnt wire harness so i wanna make sure that the motor is still good...i already know i have to use the same number of cranks for each cylinder but i just wanna know if hand cranking is gonna work or not

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Suck my DX &raquo;</TD></TR><TR><TD CLASS="quote">is there any way to perform a compression test by hand cranking the motor?
im gonna go check out a car tomorrow with a burnt wire harness so i wanna make sure that the motor is still good...i already know i have to use the same number of cranks for each cylinder but i just wanna know if hand cranking is gonna work or not</TD></TR></TABLE>

Maybe you can bring a battery along to work the starter.

 

really does it work that way?

 

I don't see why not. All you need is for the motor to turn over.

Hopefully somebody with more insight chimes in

 

yeah you can compression test it if you just pull all the spark plug wires, and unscrew one of the spark plugs. then you screw in the guage that reads pressure and turn it over a couple times while someone watches the guage to see what it spikes to. then put the spark plug back in and do the same on the next cylinder. i would say just bring a battery with you. much easier.

i have never tried to hand turn an engine to do a compression test, but if you put a nice long breaker bar on the crankshaft pulley bolt, you might be able to do it.. but it would be a pain in the ***..

 

The starter is very simple and all the ignition is, without spark and fuel, is starter power. You're grounding the starters 12v+ unfused circuit when you turn over the engine.
So ground the ground pole (slip on terminal) and push the 12V+ wire to the positive terminal and it'll push that starter. (wear thick rubber gloves LOL)
If you want to do it safely, get a 200 amp rated switch put that on the negative ground wire.

http://www.the12volt.com - electrical knowledge

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by sanimalp &raquo;</TD></TR><TR><TD CLASS="quote">yeah you can compression test it if you just pull all the spark plug wires, and unscrew one of the spark plugs. then you screw in the guage that reads pressure and turn it over a couple times while someone watches the guage to see what it spikes to. then put the spark plug back in and do the same on the next cylinder. i would say just bring a battery with you. much easier.

i have never tried to hand turn an engine to do a compression test, but if you put a nice long breaker bar on the crankshaft pulley bolt, you might be able to do it.. but it would be a pain in the ***..</TD></TR></TABLE>

Yep, thats how you do it. It's really not hard at all.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by NikoZai &raquo;</TD></TR><TR><TD CLASS="quote">The starter is very simple and all the ignition is, without spark and fuel, is starter power. You're grounding the starters 12v+ unfused circuit when you turn over the engine.
So ground the ground pole (slip on terminal) and push the 12V+ wire to the positive terminal and it'll push that starter. (wear thick rubber gloves LOL)
If you want to do it safely, get a 200 amp rated switch put that on the negative ground wire.

http://www.the12volt.com - electrical knowledge
</TD></TR></TABLE>
thanks...