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

NJ3ndri · 08-21-2012, 02:02 PM

UPDATE: I squirted some oil in the chamber got the compression up a little. so my issue is in the compression because i cranked it after the oil was squirted and got a split second of combustion. sounded like it was going to start up but i need it to hold a little longer. i feel that once it starts i can probably hold it running a little. hopefully things will start to settle in.

NJ3ndri · 08-21-2012, 02:59 PM

Update #2. during that split second of life its getting smoke is coming from the oil dip tube on cranks.....starting to wonder if those rings were directional ...smh

NJ3ndri · 08-23-2012, 12:14 AM

UPDATE #3. PROBLEM SOLVED....BUT i may have caused some damage

...(no problem as long as i know what it is) both cams were a tooth to the left. somehow they were ligned up to the marks tho o.0. anyway moved them over and took a while but it started up barely and kinda choppy. along with a missfire from a valve i prob bent on cylinder 1. so i have a big win here and some fail.

CHECK YOUR TIMING EVEN THOUGH YOU MAY THINK ITS RIGHT

Frank_Jaeger · 08-23-2012, 09:07 PM

Sucks man. Get it straightened out! You've got this.

NJ3ndri · 08-26-2012, 10:15 PM

Quote:

Originally Posted by Frank_Jaeger

Sucks man. Get it straightened out! You've got this.

FINAL UPDATE. NOTHING BENT EVERYTHING OKAY.
On the first start I was dumping ridiculous amounts of fuel. manifold was glowing red. a day later it fixed itself. turned out to be the ecu never finished adaptive learning. So car is now running its about 25 vacuum at idle . and 7 psi feels like what 15 psi felt before.
NO Problems whatsoever.

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

08-21-2012, 02:02 PM	#2
NJ3ndri Leaky Injector Join Date: Mar 2012 Location: North NJ Age: 36 Posts: 138 Trader Rating: (4) Feedback Score: 4 reviews	UPDATE: I squirted some oil in the chamber got the compression up a little. so my issue is in the compression because i cranked it after the oil was squirted and got a split second of combustion. sounded like it was going to start up but i need it to hold a little longer. i feel that once it starts i can probably hold it running a little. hopefully things will start to settle in.

08-21-2012, 02:59 PM	#3
NJ3ndri Leaky Injector Join Date: Mar 2012 Location: North NJ Age: 36 Posts: 138 Trader Rating: (4) Feedback Score: 4 reviews	Update #2. during that split second of life its getting smoke is coming from the oil dip tube on cranks.....starting to wonder if those rings were directional ...smh

08-23-2012, 12:14 AM	#4
NJ3ndri Leaky Injector Join Date: Mar 2012 Location: North NJ Age: 36 Posts: 138 Trader Rating: (4) Feedback Score: 4 reviews	UPDATE #3. PROBLEM SOLVED....BUT i may have caused some damage ...(no problem as long as i know what it is) both cams were a tooth to the left. somehow they were ligned up to the marks tho o.0. anyway moved them over and took a while but it started up barely and kinda choppy. along with a missfire from a valve i prob bent on cylinder 1. so i have a big win here and some fail. CHECK YOUR TIMING EVEN THOUGH YOU MAY THINK ITS RIGHT

08-23-2012, 09:07 PM	#5
Frank_Jaeger Zilvia FREAK! Join Date: Jan 2012 Location: Port Charlotte, Florida Age: 33 Posts: 1,352 Trader Rating: (1) Feedback Score: 1 reviews	Sucks man. Get it straightened out! You've got this.