DimaK

my 86 gxl has been running funny lately, ive changed the spark plugs, filters, **** like that and it ran fine for a week, now its not starting up again and i tried doing a compression test and i got about 70-85 psi, i was wondering if thats too low because someone told me that the normal compresiion ration is about 175 psi, but maybe thats different for rotary engines

xtremeskier97

70-85psi is time for a rebuild.

Ive never seen a rotary hit 175psi in a compression test.

ddub

This is how I look at it. With a compression tester that is known to be accurate (best thing to do if you're just using a run-of-the-mill piston compression tester is to test it on a KNOWN good running/high compression rotary engine to get a base line), engine fully warmed up, compression taken at WOT, etc.

125+ brand new
110-120 great condition
100-110 good condition
95-100 okay
90-95 starting to get tired/bad but depends on how the engine is acting
80-90 not doing so good
80 or below rebuild time

DimaK

cool thanks.....noww what do i need to rebuild exactly, and what do i start with when rebuilding the engine

DimaK

is that kind of compression for 147,000km bad, or is that normal for that much km

ddub

Check the rebuild thread in the archive for what you need to rebuild, and that compression is kinda low for 147k km but it all depends on how it was treated its whole life etc.