KA24DE new rings, low compression

[borodrifter]

Granted it hasn't ran yet but the compression test shows only 64 psi all the way across.

The list:Perfect Circle Rings standard sizeCometic 1mm MLS head gasketARP head studs (torqued following Haynes manual)All machine work done by very reputable shopBottom end assembled by a separate but equally reputable shop.

[driftingmy240sx]

one problem is the head stus need to be torque per arp not the haynes manual. 2 are the piston rings installed with the end gaps all in the same position as this will cause low compression. 3 if the head gasket is thicker then the oe one it will lower compression. 4 were the cylinders bored, honed or neither? 5 are you doing a hand crank dry compression test or cranking it with the starter and if so is that dry or wet (is a tiny amout of oil put in the cylinders on top of the pistons?)

[borodrifter]

I typoed up there. I torqued it in sequenced per the manual and used the corresponding torque values from ARP.

The head gasket is 1mm and iirc the stock gasket is 1.2mm? It could be 1mm stock. I'll have to look. *edit: stock Felpro head gasket measures 1.28mm*

The cylinders where honed, not bored. I just hope they didn't hone them too aggressively and neglected to tell me.

I am checking comp wet, using the starter. No I didn't drop any oil down the cylinder but I doubt it would make much change from 64 psi.

You probably have it right that the rings are lined up at the end gap. Either way it comes down to the machine shop or the performance shop who assembled it. And apparently the engine builder at this shop was fired not long after I had it assembled. Could be a reason, yes?

I hate to be the customer who comes back bitching because my motor blew up, but it's not the "I was racing it and it blew" scenario. This is initial start-up and it's junk. IMO that comes back on them.

[driftingmy240sx]

right you are, and if they are a good machine shop the engine will show them the same story. i hope you can get everything worked out with them.

[borodrifter]

Thanks.I am going to add oil to the cylinders and do a leak down test later tonight. If that doesn't tell me what I need to know then back to the source, starting with the Performance shop who claimed that they measured all clearances first.

[jordanmullen]

checking dry and wet compression can tell you alot. another thing is cranking vacume, and timing, could be valve issue/ timing issue. some could a shop screw up all cyl, posible. all cyl screwed up the same(64psi accross) I would check timing. some times you wont get good compression till you get it to fire a few times. if you can get atlest 120psi from wet cmpression test, put some oil in all cyl then try to start.

[driftingmy240sx]

yeah i agree if the mechanical timing is incorrect you would have lower compression.