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Posted by Chris Case [75.36.40.196] on Friday, September 28, 2012 at 11:41:47 :
In Reply to: Re: Compression test? Cranking rythm? posted by CSCameron [68.228.198.56] on Friday, September 28, 2012 at 09:28:53 :
The cranking rhythm test is the simplest, easiest compression test. Simply unhook the coil wire, and crank it. You should here da-da-da-da-da-da-da-da-da-da. If you here da-da-da-oooo-da-da-da-da-da-ooo-da-da-, the 'ooo' is a weak cylinder. May be only 5 psi, inconsequential. But if there is no rhythm, there is no point in worrying about bad valves or rings. Or valve adjustment causing problems. Your problem lies elsewhere.
Mechanical timing check by using the hole over #6- It looks like a bolt headm, but is a 1/8" pipe plug. The hole underneath is probable plugged with carbon, might need to poke at it a bit. Insert a 10" lomg piece pf coat hanger wire, nad trun engine by hand until the wire is at it's highest. That is TDC of # 6, and 1 also. You can set up a dial indicator to get right to the gnats nards, or just eyeball. Best way is to measure a little low before, and same low after, and split the diff for TDC. This will check your timing marks. Maybe mismatched parts? Or maybe there is a mechanical problem, and it needs to be off 20° to ruin best?
Double check your plug wire? Firing order on ALL straight 6s in the whole world is:
15 is too young,
36 is too old,
24 is just right.
On these, #1 is usually at about 7 o'clock. But doesn't HAVE to be.
Vacuum leak? Disconnect/plug off/pinch the hose to the wipers. Further, try spraying anydamthing all over the intake and carb. Use carb spray, wd-40, spray oil is messier. Listen for changes- speeding up or slowing down.
Good luck on your trouble shooting.
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