look at these compression numbers

Joined
Nov 8, 2006
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Sugarloaf, CO
its been idling poorly, so i ran the gamut of tune ups to no avail... did a compression test

145 30 122 130 136 145

dripped some oil into the number 2 spark plug hole, went up to 70...

whats yalls thinkin about this?
 
Joined
Aug 2, 2004
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San Francisco Bay Area
I hate bad compression test results too. :frown: It could be a combination of weak rings and top end on #2. When did you last check the valves? I would do a leak down test next if you have one or can borrow one.
 

Tinker

 
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Apr 15, 2004
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Larkspur, CO
X2 on NoCal: hopefully you'll diagnose a leaking valve which an adjustment will cure.

Sucks, man! I remember when my '83's head gasket went after I had done the intake manifold dance & swapped in a trick exhaust header. I was in denial for a couple weeks, trying stop-leak & chicken bones.
 
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Sugarloaf, CO
Let me know how much this sucks after the new 5.3l is nestled in and you've just got out onto the highway the first time.
Opportunity is knocking, brotha.
you read my mind... first i wanna find out what im dealin with

then i gotta find a remedy for this oil burning, black smokin itch i have
 
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Feb 21, 2006
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Winston Oregon
Just give the old girl a dry overhual with the motor still in . You can even leave the crank in. It really is easy...w can walk you through it
 
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May 25, 2008
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ST.LUCIE.FLORIDA
just saw someone going diesel in this forum last night and was selling his good running 2f dont remember where he was from but who knows ? or just start looking for a FI bowtie good luck ...by the way the rest of the numbers are all over the place how many miles you got?
 
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Nov 8, 2006
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Sugarloaf, CO
its only got about 180,000 miles... i dont know what the deal is there. im super strict about my oil changes and all...

it is what it is. time for me to start doin research. right now lookin at settin up a 2fe... cam maybe...

or i have a couple friends with 350s in need of rebuilds that they offered... although i really do have the diesel bug bad...

this kinda adds the beginning of another chapter to my upcoming rotm
 
Joined
Mar 10, 2007
Messages
991
Well, just start by taking the head off which is fairly simple. From there, you can check your valves. If you have to pull the pistons, just drop the oil pan and then push them out.
 

FJ40Jim

The Cruiser Whisperer
 
 
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Sep 26, 2003
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Lancaster, Ohio, USA
The oil in cylinder test is not real accurate. If too much oil is added, the additional displacement of the oil increases the CR, leading to inaccurate results. If not enough oil is added and distributed around the piston (more of a problem on flat engines), then results are inaccurate.

X2 on pull the head. Knock valves out and inspect. Roll crank so piston is at BDC, inspect bore.

Hopefully, it will just be a burned exh valve. 12 new stainless valves and it's better than new.
:cheers:
 

rfj62

 
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Jul 7, 2007
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Location
Downingtown, PA
Compression Test

I did a compression test on a rig that I just bought but want to verify the way I did the test to make sure I did it right. This is the guide I used. What will a compression test tell me? — Yahoo! Autos

I took the plugs out and disconnected the ignition coil, place the tester in the cylinder(s) and cranked for a few seconds. I cranked it for about 3-5 seconds. With each sec the PSI seemed to jump up until it would not go any higher. All readings were above 145psi's but occasionally I would get a reading of 180psi. I tested that cylinder again and got a reading of 150psi. Am I doing something wrong?
 
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