so i did a compression test on my reativly new engine and the results were surprisingly and embaressingly low. highest one of the 6 is 120psi and the lowest was 110 and comsidering ive only put maybe 1500 kms on the new engine id expect it to be a lil higher.
i geuss wat im askin is is wat kind of compression pressure should i be seeing. and wat pressures do you other guys have?
my setup is this.
1985 block cast in 81 std perfect bore low miles(doesnt have the weird cam issue but still has cast fuel pump block)
stock crank and rods to the block with chrome ford "ag spec" bearings
"found them via my dad who runs a buntch of them on the farm lol"
comp 268 cam ( matching springs and lifters chromoly pushers harland sharp roller rockers monster chevy valves)
silvo lite flat top pistons perfect circle moly rings(witch i know is partly the problem as they sit 3/8 below the top of the deck which im a lil crankyy about )
stock 1bbl intake and carb (i kno i kno with this setup i need a 4 bbl im workin on it lol)
and ported efi manifolds
i would like to figure out wat i could do to incress compression with the engine in the truck. like im willing to pull the pistons from the block for a piston swap but lookin for minimal or no machining.
thanks for the advice and #s
ps i do appolijize for the terrible grammer as im currently writting the on my cell lol

 

When you did the compression test, did you open the throttle and choke all the way?
Your numbers seem a little low, but the narrow spread is good.

 

no i didnt. never heard of doing it that way before

 

What f100jim said...otherwise the cylinders are trying to draw against the restriction of a closed choke/throttle plate and thus reducing the fill on the cylinders.

 

well ill give it a shot tonight what kind of compression numbers sould i be lookin for, for a happy motor? reason im nervous is i know its not good to be below 100 psi and im gettin pretty close :s