N55 compression test results?

Dreyo27

Corporal
Nov 28, 2016
113
20
Sacramento
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#1
Can anyone share their N55 compression test results? About to do a compression test and would like to see how my numbers compare.
 

doublespaces

Administrator
Oct 18, 2016
6,558
1,858
AZ
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#2
Would recommend you compare compression testing equipment and method. I had wildy different results just related to those things
 

Dreyo27

Corporal
Nov 28, 2016
113
20
Sacramento
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#3
I know, best n54 results were 190, somehow the n55 is at 210ish across all 6 cyl. Is that normal?
 

Twisted Tuning

Lieutenant
Platinum
Oct 25, 2016
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#5
I would try another test set. are you the original owner?
 

Bnks334

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Dec 1, 2016
177
73
New York
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#6
@GhassanAutomotive might be a better person to ask. I am sure he has run compression tests on more than few motors. I can only speak for the results I got on my built motor which reads right around ~200-210psi. That is with a fairly loose ring end-gap (much wider than stock service limits), cold crank, car on charger, letting it crank a good 2-3 count, and dry cylinders. A little bit of oil and I got a few 230psi readings.

Maybe Ghassan can post up some info/pics of ring pack specs/thickness between both motors.

N55 compression service limits:
https://www.newtis.info/tisv2/a/en/f13-640i-cou/repair-manuals/11-engine/11-00-engine/Am0RHXdG

145psi - 232psi is within "service limits." 29psi is the max allowable deviation.
 
Last edited:
Apr 8, 2017
14
4
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0
#7
@GhassanAutomotive might be a better person to ask. I am sure he has run compression tests on more than few motors. I can only speak for the results I got on my built motor which reads right around ~200-210psi. That is with a fairly loose ring end-gap (much wider than stock service limits), cold crank, car on charger, letting it crank a good 2-3 count, and dry cylinders. A little bit of oil and I got a few 230psi readings.

Maybe Ghassan can post up some info/pics of ring pack specs/thickness between both motors.

N55 compression service limits:
https://www.newtis.info/tisv2/a/en/f13-640i-cou/repair-manuals/11-engine/11-00-engine/Am0RHXdG

145psi - 232psi is within "service limits." 29psi is the max allowable deviation.
You should see at least 180 psi on a used N55 engine, anything under that and I'd start worrying about the integrity of the engine. Sorry about the late reply.
 

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