This is topic did a compression test today in forum Tech Talk at Northern California Ford Owners  .


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Posted by dean-93 (Member # 9401) on :
 
did a compression test on the 5.0 and got horrible numbers
1#150psi
2#127psi
3#115psi
4#95psi
5#140psi
6#130psi
7#150psi
8#135psi

that should explain why im running a 13.7 with trickflow heads cam and intake

now its time to save up for a 351 shortblock

[ September 09, 2012, 09:58 PM: Message edited by: dean-93 ]
 
Posted by turbo50 (Member # 6700) on :
 
Re adjust your rockers first....
 
Posted by Greasy (Member # 5258) on :
 
quote:
Originally posted by turbo50:
Re adjust your rockers first....
^This and how did you do your compression test?
 
Posted by dean-93 (Member # 9401) on :
 
quote:
Originally posted by Greasy:
quote:
Originally posted by turbo50:
Re adjust your rockers first....
^This and how did you do your compression test?
let it warm up for 10 min take all the plugs out then hook up the gauge let it crank over about 5 times and write down the psi
 
Posted by dean-93 (Member # 9401) on :
 
quote:
Originally posted by turbo50:
Re adjust your rockers first....
thanks for the tip ill probably try that tomorrow

but i think i only preloaded them like a 1/4 turn after u take the slack out

but shit its worth a try

[ September 10, 2012, 01:32 AM: Message edited by: dean-93 ]
 
Posted by Duncan Motors (Member # 7045) on :
 
did u disconnect the fuel, from fuel washing your cylinders while cranking? even if not that one is really low.
 
Posted by dean-93 (Member # 9401) on :
 
quote:
Originally posted by Duncan Motors:
did u disconnect the fuel, from fuel washing your cylinders while cranking? even if not that one is really low.
my fuel pump is wired to a switch and relay and it was off
 
Posted by dvuspny (Member # 10949) on :
 
Yeah....re~adjust the rockers. May have a tired set of Lifters.....the worse case could be flat cam now....depends how the initial adjustments were made. Re~check all of this. Take your time.....do it more than once if need be
 
Posted by Camara90 (Member # 134) on :
 
Like already stated I would check rockers, also what gauge did you use? I used a piece of shit harbor freight one once and it was all over the place. Then purchased a craftsman and it was all to the good.
 
Posted by turbo50 (Member # 6700) on :
 
quote:
Originally posted by Camara90:
what gauge did you use? I used a piece of shit harbor freight one once and it was all over the place. Then purchased a craftsman and it was all to the good.
I had the same issue here with a POS harbor freight comp gauge.
 
Posted by nitrous_bob (Member # 77) on :
 
did you drop some oil in the bad cylinders...redo and see if they picked up ???? just to verify ????
 
Posted by Ryn621 (Member # 11276) on :
 
quote:
Originally posted by Camara90:
Like already stated I would check rockers, also what gauge did you use? I used a piece of shit harbor freight one once and it was all over the place. Then purchased a craftsman and it was all to the good.
harbor freight specialty tools are not great
 
Posted by Secnd2nun64 (Member # 1431) on :
 
go get yourself a leak down tester. it will tell you why the compression is low.
 
Posted by dean-93 (Member # 9401) on :
 
quote:
Originally posted by nitrous_bob:
did you drop some oil in the bad cylinders...redo and see if they picked up ???? just to verify ????
does that tell you its the rings if it goes up?

ill try that
 
Posted by dean-93 (Member # 9401) on :
 
i forgot to mention my spark plugs are really really black and car always smells rich

[ September 14, 2012, 05:46 AM: Message edited by: dean-93 ]
 
Posted by lxhatch5.0 (Member # 6319) on :
 
quote:
Originally posted by dean-93:
i forgot to mention my spark plugs are really really black and car always smells rich
HHHMMMMMM worn piston rings???? IDK turbo50 might know better, he also rebuilds shortblocks. [burnout] [burnout]
 
Posted by 89foxstang (Member # 5908) on :
 
quote:
Originally posted by Secnd2nun64:
go get yourself a leak down tester. it will tell you why the compression is low.
What he said .. It will be much cheaper to buy a leak down tester in the long run than to keep throwing parts at it. You gotta have an air compressor though
 




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