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360 Compression Test
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amx39068 View Drop Down
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Points: 11576 		Post Options Post Options   Thanks (0) Thanks(0)   Quote amx39068 Quote  Post ReplyReply Direct Link To This Post Posted: Jan/16/2011 at 1:11pm
Matt,
74 and later heads came with hardened seats from the factory so no issue there.  Tell me what the numbers are on your heads like 502-2 or 3384 (IIRC) in between the valve springs plus the casting date like an 8 or whatever the last digit of the year of your vehicle is.  We can do a swap for my finished heads all ready to go with positive valve seals, fresh valve job, all valve springs shimmed for correct spring pressure and freeze plugs plus the heads are resurfaced. 
 
We can just swap your old heads in need of refinishing for the same vintage from my stash of done heads plus some cash and save you a bunch of money and time.
Dan Curtis-Owner and CEO AZ AMC Restorations; Facebook: https://www.facebook.com/amcmusclecars/ & Curtis Real Estate Development
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SEdmonds View Drop Down
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Points: 8196 		Post Options Post Options   Thanks (0) Thanks(0)   Quote SEdmonds Quote  Post ReplyReply Direct Link To This Post Posted: Jan/16/2011 at 3:36pm
Cheers!Thanks for helping the number one son, guys.  No matter which way he decides to go, I really appreciate your kindness.

Edited by SEdmonds - Jan/16/2011 at 3:37pm
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Oh boy!  This just keeps getting better and better! (sarcasm)  I just removed the left side cylinder head to find a broken ring land area on #1.Hit Fan  Pics pending.  The chunk is one inch long, a quarter inch wide, and goes all the way down to the first compression ring.  From the amount of carbon on the break I am guessing this one happened long ago, before I got the Jeep.  The chunk is nowhere to be found so it probably blew out the exhaust.  Just lucky I guess that it didn't lodge between the piston and the head and break something.  The wierd thing is this cylinder had the best compression of them all-117PSI.  My poor engine.  It never gave any trouble to anyone, never broke down, was abused, made it to 122,000 miles, and ran as good as it did on six cylinders + a broken piston.  Real proof of famed AMC reliability.   This thing never gave me any indication of it's condition other than burning a small amount of oil and loping at idle.  What a good engine
                                                  Known problems to date:
Bad valve guides, bad valve guide seals, two burned valves, recessed valve seats, heavy carbon buildup, worn cam and lifters, rubber band for a timing set, scored rocker arm pivots, broken piston, sludge buildup, and I haven't even opened up the bottom end yet!  
 
A sane person would get a new engine, but just because mine has survived all this I am now completely loyal to it. bowdown


Edited by FSJunkie - Jan/16/2011 at 5:26pm
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bigbad69 View Drop Down
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Originally posted by FSJunkie FSJunkie wrote:

... I am guessing this one happened long ago, before I got the Jeep...
Sure, blame it on Mom. Smile
If your bores are in good shape, all you need is one piston. A good standard bore 360 piston shouldn't be too bad to find. With that and Dan's refurb'd heads you can still keep the costs down on your engine refresh, so don't despair just yet.
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Points: 8196 		Post Options Post Options   Thanks (0) Thanks(0)   Quote SEdmonds Quote  Post ReplyReply Direct Link To This Post Posted: Jan/16/2011 at 6:01pm
Originally posted by bigbad69 bigbad69 wrote:

Sure, blame it on Mom. Smile
If your bores are in good shape, all you need is one piston. A good standard bore 360 piston shouldn't be too bad to find. With that and Dan's refurb'd heads you can still keep the costs down on your engine refresh, so don't despair just yet.
Ain't that way it always goes?  Next think you know, we'll be on Jerry Springer...
 
Anyway, here are pictures. The damage is at the 1:00 to 2:30 spot on #1.
 
 


Edited by SEdmonds - Jan/16/2011 at 6:01pm
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69 ambassador 390 View Drop Down
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Points: 3539 		Post Options Post Options   Thanks (0) Thanks(0)   Quote 69 ambassador 390 Quote  Post ReplyReply Direct Link To This Post Posted: Jan/16/2011 at 6:16pm
Originally posted by SEdmonds SEdmonds wrote:

Originally posted by bigbad69 bigbad69 wrote:

Sure, blame it on Mom. Smile
If your bores are in good shape, all you need is one piston. A good standard bore 360 piston shouldn't be too bad to find. With that and Dan's refurb'd heads you can still keep the costs down on your engine refresh, so don't despair just yet.
Ain't that way it always goes?  Next think you know, we'll be on Jerry Springer...
 
Anyway, here are pictures. The damage is at the 1:00 to 2:30 spot on #1.
 
 
Matt,
 
     Don't worry about the bore on that one.  I have broken a few top lands and never had an issue.  That was likely caused bay a bad tune up or a chunk of carbon getting slammed in there.  Stock used pistons will work fine.  I actually broke a stocker in half and rattled the rod on the bore at 6000 rpm plus and only scratched it.  Factor spec. is .005 taper and .003 out of round.  I have been running over .008 out of round for many years so even a little over that is o.k.  Just remember that all new parts become used parts once you start using them.  If you decide on new pistons you could upgrade to forged and just hone a little extra on the stock bore to round it back out.  Forged pistons require larger bore clearance than stockers.  Someone may have a cheap set of used forged slugs out there.  More options.Wink
 
Steve Brown

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amx39068 View Drop Down
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You know now that I am thinking about it I may even have a set of new Badger 360 pistons in the private stash.  I'll check tomorrow.
Dan Curtis-Owner and CEO AZ AMC Restorations; Facebook: https://www.facebook.com/amcmusclecars/ & Curtis Real Estate Development
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fasttony View Drop Down
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Do any of you know what the compression test PSI should be for a stock 70' P code 360 10-1 compression?
 
Thanks
 
Tony
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depending on altitude and weather conditions it should be around 170 or so.  really depends on a bunch of factors.  That is why the factory gives a range spec. from highest to lowest.  if below 150 you may hve a loose chain or something.
Steve Brown

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fasttony View Drop Down
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The 70' shop manual doesn't seem to have that info, my engine runs similar to the 360 posted kind of crappy sputters at low speeds out the tail pipes and shakes a bit. I have tuned it up, cleaned the carb it tunes in good and put in fresh fuel still crappy. This car sat for a long time so I suspect the exhaust valves might not be so good? I doesn't burn oil, make any noises or have excessive blow by.
 
Thanks
 
Tony
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