Hmmm - low comp all round

[RedRX]

Have an engine in my RX with a semi-unknown history. Ex-rally kinda - then some-one else had a tweak and rebuild but it sat on the bench. Before fitting had HUGE custom fuel rails and big injectors. Valve covers off show big round 30-70/70-30 cams (apparantly pretty aggressive - i have to idle about 1200rpm) and big black hi-tensile socketted head bolts rather than standard.

 

OK - the question. Tested compression during some lifter issues and have found low all round comps (ie 70-80) but pretty damn even. Now the engine does NOT blow smoke (oil use strictly thru damn lower engine leaks) and from the cleanliness on the inside has been pulled apart not so long ago. Could this be deliberately low compression in order to run higher boost? As far as drivability she is a dog off the line (unless u rev and drop it and spin wheels for 1st and 2nd) but cams and boosts up at 2500rpm and kicks u back (and sometimes starts the wheels spinning again)

 

Having said all that took her on a club day down the beach and hot soft sandy tracks (on a 38 degree C day!), UNLIFTED mind, and she climbed everything including some slopes that stopped 2.5lForresters and the like! Never above halfway on the temp either. Only bogged down once on the beach. So my little show-pony can hack the pace off-road too, SWEEEEET!

[idosubaru]

could the compression tester be dirty, clogged, or broke? i'd try it on another motor and see what you get.

 

then i'd check your timing belts alignment.

[NoahDL88]

pictures please

[rallyruss]

a turbo motor will have low compression readings due to the fact that its a turbo and has a lower compresion ratio. the cams may have made it read lower still. If you cannot idle it normaly then I think the readings are due to the cams.