Need help with compression test results
#1731065
01/16/15 02:03 AM
01/16/15 02:03 AM
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Joined: Jun 2013
Posts: 1,521
Tacoma, Washington USA
Adam71Charger
OP
pro stock
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OP
pro stock
Joined: Jun 2013
Posts: 1,521
Tacoma, Washington USA
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Bought a cordoba for the factory 400 it had. Was just gonna pull and store the engine, and part the rest. But, I like how comfy it is and was thinking of doing a little work to make it a daily.
So, 1st up was compression test. I could not find info on what the acceptable PSI range in a 77 400 combustion chamber should be.
Dead god, this was the WORST ASININE compression test Ive ever done. the spark plugs a hidden by high rise manifolds, and smashed up against the steering box/shaft. Getting the plugs out was a little frustrating, but nothing compared to blindly trying to screw in the compression tester... holy crap. took 3hrs to get 6 cylinders.
Here's my results. Test was done while engine cold (its been sitting a month on the side of my house.) I ranged from 120psi to 140psi between the cylinders...
Is this deference too much? Will it cause me problems? All I want to do is throw an edelbrock 1406, vacuum advance distributor, pertronix ignition and coil, new wires and plugs, and delete the A/C and emissions. Just make it a daily driver. All this stuff will cost me around 500, and thats cool with me if I get a daily driver out of it, just worried about those chamber pressures, am I worrying too much for the type of usage that I plan on getting out of it?
Just out of curiosity, what is the tuffest most PITA stock spark plug jobs? I had always thought Big Block A-bodies, but after doing this Big Block Cordoba, I've changed my mind.
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Re: Need help with compression test results
[Re: Adam71Charger]
#1731066
01/16/15 02:22 AM
01/16/15 02:22 AM
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Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
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with those readings you will be fine. EDIT Adam take another round of readings when it is warmed up/searing hot for a valid comparison 
Last edited by RapidRobert; 01/16/15 02:28 AM.
live every 24 hour block of time like it's your last day on earth
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Re: Need help with compression test results
[Re: Adam71Charger]
#1731069
01/16/15 02:23 AM
01/16/15 02:23 AM
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Joined: Mar 2003
Posts: 4,848
Memphis
HemiRick
master
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master
Joined: Mar 2003
Posts: 4,848
Memphis
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For a cold engine that hasn't run in while those numbers are fine....Compression test should be done with warm engine for best results....
Take care,
Rick
68 Coronet R/T 440 & 68 Charger 528 Hemi,and 5 Challengers! 6 cyl, 318, 360, 383, 451
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Re: Need help with compression test results
[Re: RapidRobert]
#1731070
01/16/15 02:33 AM
01/16/15 02:33 AM
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Joined: Jun 2013
Posts: 1,521
Tacoma, Washington USA
Adam71Charger
OP
pro stock
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OP
pro stock
Joined: Jun 2013
Posts: 1,521
Tacoma, Washington USA
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Quote:
with those readings you will be fine. EDIT Adam take another round of readings when it is warmed up/searing hot for a valid comparison
Is this necessary or just for a malicious good laugh?
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Re: Need help with compression test results
[Re: goldmember]
#1731073
01/16/15 02:38 AM
01/16/15 02:38 AM
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Joined: Jun 2013
Posts: 1,521
Tacoma, Washington USA
Adam71Charger
OP
pro stock
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OP
pro stock
Joined: Jun 2013
Posts: 1,521
Tacoma, Washington USA
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Quote:
Run it.Not very hard to do a plug replacement on that model,but you'll get better with practice 
Gold member you must have skinny alien fingers and the power of telekinesis. My giant sausage fingers werent happy pinned between the exhaust manifold and power steering gettin at those number 3, 5 and 7 plugs.. then installing them blindly with just the very tips of a couple fingers
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Re: Need help with compression test results
[Re: RapidRobert]
#1731074
01/16/15 02:40 AM
01/16/15 02:40 AM
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Joined: Jun 2013
Posts: 1,521
Tacoma, Washington USA
Adam71Charger
OP
pro stock
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OP
pro stock
Joined: Jun 2013
Posts: 1,521
Tacoma, Washington USA
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Quote:
Quote:
Is this necessary or just for a malicious good laugh?
You wont be laughing
I didnt think I'd be the one laughing.. just some guy I know from Nebraska
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Re: Need help with compression test results
[Re: RUNCHARGER]
#1731075
01/16/15 02:42 AM
01/16/15 02:42 AM
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Joined: Jun 2013
Posts: 1,521
Tacoma, Washington USA
Adam71Charger
OP
pro stock
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OP
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Joined: Jun 2013
Posts: 1,521
Tacoma, Washington USA
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Quote:
Those numbers sound fine for a cold 400. I would do a timing chain check and run it. I always changed some of those plugs from the top and some from the bottom, some are just ugly from the top.
Sheldon
2 hrs and several emotional outbursts later, I caught onto that
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Re: Need help with compression test results
[Re: RapidRobert]
#1731076
01/16/15 02:47 AM
01/16/15 02:47 AM
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Joined: Jan 2003
Posts: 74,978
U.S.S.A.
JohnRR
I Win
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I Win
Joined: Jan 2003
Posts: 74,978
U.S.S.A.
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Quote:
Quote:
Is this necessary or just for a malicious good laugh?
You wont be laughing
but we will ... 
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Re: Need help with compression test results
[Re: Adam71Charger]
#1731077
01/16/15 02:49 AM
01/16/15 02:49 AM
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Joined: Jan 2003
Posts: 74,978
U.S.S.A.
JohnRR
I Win
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I Win
Joined: Jan 2003
Posts: 74,978
U.S.S.A.
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Quote:
Quote:
Run it.Not very hard to do a plug replacement on that model,but you'll get better with practice
Gold member you must have skinny alien fingers and the power of telekinesis. My giant sausage fingers werent happy pinned between the exhaust manifold and power steering gettin at those number 3, 5 and 7 plugs.. then installing them blindly with just the very tips of a couple fingers
Doesn't this car have a rag joint between the firewall and the steering box ? or unbolt the engine mount and jack that side up some ?
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Re: Need help with compression test results
[Re: JohnRR]
#1731078
01/16/15 03:00 AM
01/16/15 03:00 AM
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Joined: Jun 2013
Posts: 1,521
Tacoma, Washington USA
Adam71Charger
OP
pro stock
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OP
pro stock
Joined: Jun 2013
Posts: 1,521
Tacoma, Washington USA
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Quote:
Quote:
Quote:
Run it.Not very hard to do a plug replacement on that model,but you'll get better with practice
Gold member you must have skinny alien fingers and the power of telekinesis. My giant sausage fingers werent happy pinned between the exhaust manifold and power steering gettin at those number 3, 5 and 7 plugs.. then installing them blindly with just the very tips of a couple fingers
Doesn't this car have a rag joint between the firewall and the steering box ? or unbolt the engine mount and jack that side up some ?
It's the location of the car that adds to the difficulty of working on it, soft ground full of dead needles falling from the giant cedar tree above it. Hard place to manuever all the equipment that would expediate the work. Hard parts over, just top end work to get it running, then ill bring it round to the driveway and take the front apart and change timing chain.
It's a big ugly turd but Im starting to like it...
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Re: Need help with compression test results
[Re: Adam71Charger]
#1731079
01/16/15 03:48 AM
01/16/15 03:48 AM
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Joined: Feb 2004
Posts: 4,501
Gainesville,FL
goldmember
master
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master
Joined: Feb 2004
Posts: 4,501
Gainesville,FL
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Quote:
Quote:
Run it.Not very hard to do a plug replacement on that model,but you'll get better with practice
Gold member you must have skinny alien fingers and the power of telekinesis. My giant sausage fingers werent happy pinned between the exhaust manifold and power steering gettin at those number 3, 5 and 7 plugs.. then installing them blindly with just the very tips of a couple fingers
I have had some interesting vehicles to get at the plugs and thought you could use some moral support to get you through the ordeal. My fingers are long alien sausage looking things that have X-ray vision,night vision and other freaky features unlike most "sausage" fingers. It's a family trait. You'll be ok. 
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