351 compression test

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Jun 1, 2006 | 06:44 PM

jpjahn

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351 compression test

I have a 351 4VHO. I'm just wondering whereabouts the compression should be for the cylinders.. I took a reading back when I first got the truck last year.. I don't remember exact numbers, but i'm sure they were all between 100-110.

Thanks

Jun 1, 2006 | 07:01 PM

84-250

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From: Munroe falls, Ohio

i tested my 351w (2bbl) with 150k on a completely stock motor and got 150psi on every cylinder. as long as you have even pressure between the eight cylinders, your good, now your most likely low on power.

Jun 1, 2006 | 08:21 PM

Kemicalburns

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From: Bend,OR

if they dip below 100 its time for some work. but if they are close like 100- 110 like you said that is ok. but if one is 90 and the others are 120-130 then you got issues

Jun 1, 2006 | 09:00 PM

jpjahn

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I seem to have good power, but I had to disconnect my oil breather line (not pvc side) from the air cleaner box to keep my new filter from oiling up. I've never seen oil from the exhaust either, although my pipes are sooted even after highway driving.

Jun 1, 2006 | 11:28 PM

Kemicalburns

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From: Bend,OR

if your filter is oiling up then you either have a bad pvc valve or its time for a rebuild man. i many quarts of oil do you burn between changes?

Jun 2, 2006 | 12:18 AM

jpjahn

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I already replaced the pvc once. The first one would still rattle, but when hooked up, it pulled all the fumes through the one side. Now with the new pvc the fumes come out of the pvc and filler breather vent equally.. Is that how it should be? I don't really drive the truck that much, but I don't think it actually uses that much oil. Just enough to oil up my filter and put alittle in the secondary filter holder.