rebuild ka24de-t (wont start heres some numbers) - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

NJ3ndri · 08-21-2012, 09:26 AM

ok so i rebuild a ka . with new rings and new gaskets. starting from bottom up. what i replaced.
Rod Bearings
Piston Rings
Cometic headgasket
Laped the valves
ported intake and exhaust to match gasket.

That being said i didnt do much.

Now i rechecked my timing over multiple times and everything is right.
crank at top dead center cams facing out valves closed and distributor set at #1 mark.
I do have spark and I do have fuel. engine coolant temp sensor is fine and reading from pcm.

NOW THE ONLY OBVIOUS ISSUE I SEE.
my compression is around 90 all across (should be 130 - 150 i would assume after a rebuild) but should still somewhat start with 90?!?!!
now i could think of 2 reasons why that might be.

1. because valves were lapped now there may be a gap between the valve and the seat. i didnt shave the valve stem to compensate for laping because i dont think i took off enough to need to do that.

2. I may have put the rings upside down which i highly doubt because i checked before installing if they had a certain side up. (i may be wrong) i bought the rings at frsport.com not the oem but the other brand they have.

I cant think of anything else but since im averaging around 90 on all four it seems like something common on all 4 obviously. almost like cam might be off a tooth but like i said. timing is good . maybe my rings could be upside down.

anyone have any thoughts?? would appreciate it thanks

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08-21-2012, 09:26 AM	#1
NJ3ndri Leaky Injector Join Date: Mar 2012 Location: North NJ Age: 36 Posts: 138 Trader Rating: (4) Feedback Score: 4 reviews	rebuild ka24de-t (wont start heres some numbers) ok so i rebuild a ka . with new rings and new gaskets. starting from bottom up. what i replaced. Rod Bearings Piston Rings Cometic headgasket Laped the valves ported intake and exhaust to match gasket. That being said i didnt do much. Now i rechecked my timing over multiple times and everything is right. crank at top dead center cams facing out valves closed and distributor set at #1 mark. I do have spark and I do have fuel. engine coolant temp sensor is fine and reading from pcm. NOW THE ONLY OBVIOUS ISSUE I SEE. my compression is around 90 all across (should be 130 - 150 i would assume after a rebuild) but should still somewhat start with 90?!?!! now i could think of 2 reasons why that might be. 1. because valves were lapped now there may be a gap between the valve and the seat. i didnt shave the valve stem to compensate for laping because i dont think i took off enough to need to do that. 2. I may have put the rings upside down which i highly doubt because i checked before installing if they had a certain side up. (i may be wrong) i bought the rings at frsport.com not the oem but the other brand they have. I cant think of anything else but since im averaging around 90 on all four it seems like something common on all 4 obviously. almost like cam might be off a tooth but like i said. timing is good . maybe my rings could be upside down. anyone have any thoughts?? would appreciate it thanks