More Compression Checking Questions

turtle1173

Chief Petty Officer
Joined
Nov 29, 2001
Messages
437
I do not have a compression guage. Can I by one at any auto parts store? Are there different types and varieties? What does one cost?<br /><br /> I have a 1976 55HP Chrysler. It has 1 carb and 2 cylinders. Can I just take the plug that is not being checked out but leave it hooked up to the spark plug wire? After I warm the engine up, do I need to crank the engine with the throttle wide open (but not in gear of course)? Anything else I need to know?<br /><br />Thanks <br /><br />Shane
 

alcan

Commander
Joined
Dec 14, 2001
Messages
2,505
Re: More Compression Checking Questions

Hi Turtle<br />I would think around $35. should get you a decent gauge w/hose and a couple adaptors for different sized holes. Don't get the cheep hold up to hole kind.<br />Pull both plugs, ground both spark plug leads,install gauge, open throtle, crank over 3-4 times. Record reading. Then repete on the next hole. Readings should be with in 10-15lbs of each other.
 

Franki

Lieutenant Junior Grade
Joined
Feb 16, 2002
Messages
1,059
Re: More Compression Checking Questions

When you say ground the spark plug leads, do you mean short them to earth so that the charge goes directly to ground?<br /><br /><br />rgds<br /><br />Frank
 

Trent

Captain
Joined
Nov 17, 2001
Messages
3,333
Re: More Compression Checking Questions

Yes thats what he meant.
 

crab bait

Captain
Joined
Feb 5, 2002
Messages
3,831
Re: More Compression Checking Questions

i got the impresson that you ground them to the motor casing ( block / motor metal)
 

petryshyn

Commander
Joined
Oct 3, 2001
Messages
2,851
Re: More Compression Checking Questions

Franki<br /><br />Ground the plug leads directly to the block... :)
 

turtle1173

Chief Petty Officer
Joined
Nov 29, 2001
Messages
437
Re: More Compression Checking Questions

How are the spark plug leads grounded to the block? I'm just having a hard time picturing this, as I've never done this before.<br /><br />Shane
 

G DANE

Commander
Joined
Nov 24, 2001
Messages
2,476
Re: More Compression Checking Questions

Hi Turtle<br /><br />I usually put the plugs in cords and lie them on the bolts beyond coils, and they will lay there sparking.
 

dixieray

Cadet
Joined
Feb 26, 2002
Messages
27
Re: More Compression Checking Questions

Why ground them? Keep high voltage off system or what just courious.
 
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