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compression test  Rating:  Rating
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 Posted: 05-20-2008 08:25 pm
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rossjfox
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 Was going to do a compression test on a 74 i'm thinking of buying this weekend.  Does anybody know what reading I should expect, assuming a non-modified engine?  Are readings of 120psi expected??

Thanks in advance,

Ross
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 Posted: 05-21-2008 12:19 pm
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Lash Russell
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 Hi Ross,

     Welcome to the club!!!  On a cold compression test I am getting between 113 and 120 with a low mileage, stock "plain Jane" engine with WOT.  Note however that I live at about 7,000 feet elevation so I would be getting approx 120 to 130 at sea level.  I think what is really important is that the readings are relatively consistent across the four holes.  Hope this helps, good luck with the car.

Lash
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 Posted: 05-21-2008 12:25 pm
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rossjfox
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 Thanks.  I'll let you know how it turns out.
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 Posted: 05-22-2008 02:32 am
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Jensen Healey
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 My flat top pistons from Delta make 150 to 155psi.

Kurt
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 Posted: 05-22-2008 05:15 am
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edward_davis
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 Last time I checked my compression, cold at WOT, near sea level, I got ~125 psi in each cylinder.  This is an older engine, though.

Edward
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 Posted: 03-31-2009 11:26 pm
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Dakota123
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 10628 is on a truck heading to its new home here with me.  Should be here in two more days.  Can't wait!

The previous owner recently (well, actually 8 years but only 500 miles) had a compression test done as part of a tune-up, and came up with 155, 150, 160, 160.  (At sea level.)  That sounds high to me, and 120-130 is more what I would have expected.   She did have the heads rebuilt, including new cams and towers, 30,000 miles ago. 

Does this indicate anything to anyone, other than maybe carbon?  Is this an early enough car that it could have been non-standard? 

Thanks,

Mike

Last edited on 04-01-2009 04:48 am by Dakota123
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