is this normal compression on a .060 block

dastang2

Active Member

Dec 11, 2003

2,020

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tx

Aug 16, 2004

#1

• Aug 16, 2004

• #1

#1---123,#2---130,#3---125,#4---123,#5---123,#6---125,#7---130,#8---127

the fan belt came off a while back and this is the only time that i had to test the compression. it is a .060 over block with flattops and valve reliefs. the E7 heads have been milled a little but not enough for shorter pushrods. this worries me.

 

408stroker5.0

The world would be a better place if all males jus

Mar 10, 2004

639

0

16

Bonnyville, Alberta, CANADA

Aug 16, 2004

#2

• Aug 16, 2004

• #2

Compression is consistent but a bit low, especially for an engine with flat tops and milled heads. An average stock Bore 5.0L HO in good shape should be above 145 in my opinion. Hell, The original internally stock 5.0 I had in my GT before the 408 went in averaged 165-170 across all 8 and it had over 200,000 original KM's on her. I'd say yes, your compression should be higher then what your result's showed. How long ago was it rebuilt???

 

dartman

New Member

Mar 10, 2004

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cardboard box

Aug 16, 2004

#3

• Aug 16, 2004

• #3

what size cam you got ??? if it big it could be bleeding off some compression also....

 

dastang2

Active Member

Dec 11, 2003

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Aug 17, 2004

#4

• Aug 17, 2004

• #4

i built the motor about 1 year ago. it has less than 1000 miles. i do not drive it at all. it is a project. it has 0 blowby and i don't have the cam specs right now but it is a mellings mtf-1 cam. it is not too big but it has a lopey idle. the heads were milled just a tiny bit. the machine shop does it when they rebuild the heads. the car runs strong now and i don't think i have a head gasket leak. i am not too worried anymore but i just was wondering since my 95 v6 has numbers up in the 150-185's.

 

J

jerry beach

Founding Member

May 20, 2002

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Ocala,FL

Aug 17, 2004

#5

• Aug 17, 2004

• #5

Was this test done with the engine hot? Any chance you forgot to wire the throttle wide open? These things can make your #'s low.

 

dastang2

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Dec 11, 2003

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Aug 17, 2004

#6

• Aug 17, 2004

• #6

i did it with the engine semi warm and i have the choke wired open at all times. aren't you supposed to do it at running temperature. i have heard that, but after i warmed it up i was called to do something and by the time i got back to it, it was not as warm anymore. i could touch the plugs without getting burned. i also heard if you pour oil in the cylinders it will read a better compression. i did not do that.

 

J

jerry beach

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May 20, 2002

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Ocala,FL

Aug 17, 2004

#7

• Aug 17, 2004

• #7

Yes, if you pour a little oil in the cylinders and compression comes way up, then that is a sign that the rings are worn. I wouldnt worry about it if the car is running fine and not down on power. BTW, these cars dont have a choke, unless you are running a carb. That is the throttle blade you wired open. Good job on following the instructions for the comp test. Many folks dont.

 

dastang2

Active Member

Dec 11, 2003

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tx

Aug 17, 2004

#8

• Aug 17, 2004

• #8

if you look in my signature i converted to carb and a 5 spd. and a v8. thanks though i am feeling better now.