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Thread: compression specs?

  1. #1

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    compression specs?

    does anyone know the compression specs off hand. i have moved and cant seem to find my book.

    i think the head gasket maybe bad do to the fact i see small amount of coolant on the block behind the exhaust manifold.

    any help would be great whether directing me to another thread or??? i cant seem to find the specs on the forum. maybe im not looking in the right area.

  2. #2

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    ok i think i found the culprit. the #1 has 75#s where 2,3,4 have 170#. would this be due to valve seals? since the small amount of coolant could have been blow by, cause im not losing coolant in the radiator.

    also i put a new vacuum advance on today. now the slight miss has gone away. but it still stumbles a lil at take off. now before i did the vacuum advance i could haul it to 35 then bog out. now i have no power and it wants to backfire. and dont want to keep running.

    any ideas.

  3. #3



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    There is a manuals thread somewhere on here.

    Anyways the fsm says the limit for the 2.0 and 2.6 is 119 psi with a pressure differential of 14 between the different cylinders
    Josh
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  4. #4

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    how could i have so much in 2 3 and 4 and so little in 1 if the limit is supposed to be 119. i followed the directions on the tester. said to crank til it stops rising.

  5. #5

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    wow didnt look hard enough... thanks droppedmitsu

  6. #6

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    downloading manual now.

  7. #7

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    okay i found what im looking for. im gonna try the valve stem seals and some seafoam and see what happens. since carbon could be the culprit of high compression. the valve stem seals due to lack of compression and num 1 plug was covered in oil

  8. #8



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    Sounds like you are on the correct path.
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  9. #9



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    could be blown hg, valve seals, bent valve, cracked head, or piston rings. I dont think its gonna be valve seals sorry to say as that is a pretty low number to be leaking all out through the valve seal.
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  10. #10

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    im just hoping. but i already had ordered a head gasket. now i have to get the other gaskets and seals before i begin. but theres no loss in coolant though thats why im trying not to go that route.

    im trying to find a combustion leak tester that i can barrow from a friend. its 160 just to rent one from the parts store. im about to limp the truck up there and see if they will test on site instead of renting one. maybe that will shine some light on the subject. its worth a shot just to save a couple bucks.

  11. #11



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    Yea doing a leakdown test should help you to pinpoint the problem before pulling it apart.
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  12. #12



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    I know Pep Boys have a free tool loner program. IDK if they have a CLT tester to loan out. But they do have some tools to loan out. It's worth the call.
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  13. #13

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    i went up to advance auto parts today. they had the one that you put in place of the radiator cap and pump it with pressure. i pumped it up to about 18#s and it held pressure. i guess its not the head gasket.

    still not 100% sure though since i was looking for the tester that has the colored liquid that would change color if fuel was getting into the coolant.

    i am running it with out the thermostat so that wouldnt be messing with the test.

  14. #14



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    That was a coolant system tester. A compression leek test is what goes in the spark plug hole and then you can put compressed air in there to see where it's leaking. out the intake, exhaust pipe, crank case.
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  15. #15



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    yea that's not the right type of test/tester, as camoit said you put compressed air into each cylinder and hear where its leaking to do a leakdown test.
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  16. #16

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    well i dont think the guys at the part store knew exactly what i wanted. i was wanting a combustion leak tester like what this guy is using in his video.


    also looks like i may need to do a helicoil. the surrounding of the #1 plug is soaked in fuel i think. would that mean id have to do a helicoil? could that be the cause bad compression?

    also i think the owner before me had advanced the timing to compensate for the bad vacuum advance.

    im reading in the manual on timing but im not seeing what im looking for. is there a indicator like on a small block chevy that shows where your timing is with a timing light?

  17. #17

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    yep just confirmed they didnt know what i wanted.

  18. #18

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    heres a pic of num1

    Name:  I1348869604.jpg
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  19. #19

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    not very good but i will get a better one tomorrow during the day.

  20. #20



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    Here is a CLT tester.

    Click image for larger version. 

Name:	02-14-12_1153.jpg 
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ID:	3736
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  21. #21

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    this is the one i have

    Click image for larger version. 

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  22. #22

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    heres a slight better pic of num 1

    Click image for larger version. 

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  23. #23

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    im going to hook the hose of the tester to a compressor later today and listen for leaks.

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