Archived Never buy a used car without doing this first (How to do a Compression Test) (youtu.be)
submitted ago by Granite_Pill
Posted by: Granite_Pill
Posting time: 9 months ago on
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Archived on: 7/6/2020 10:00:00 AM
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Archived Never buy a used car without doing this first (How to do a Compression Test) (youtu.be)
submitted ago by Granite_Pill
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[–] CynicalBastard 0 points 2 points 2 points (+2|-0) ago
Low compression? pour a 1/2 cap or 10ml engine oil down each spark plug hole.wait a few seconds then retest.
Still low compression? your valve seats are fucked. the oil will temporarily compensate for ring wear. I would expect 140 PSI as a good value, 120 is an old or low compression level, Cars with turbos are normally under-compressed.Less than 100 PSI? crikey, get a new one. under 90 PSI good luck. If your petrol cap says 95+ DO IT as some motors are high compression (10:1) up and if you don't have the octanes it will pre ignite(damage). My bike is 12.5:1 it gets 1/2 98 and 1/2 avgas(110 RON leaded). 14:1 would be a top end motor. my Honda car commuter gets 91 and should be fucking happy with that lol.