0 compression cylinder #4

[nismoplsr]

Yes you read correctly. Out for a highway run a week ago i pulled through 4th well mostly spun through 4th it was wet out. Shifted to 5th and start throttling then it broke up like a bad coil or plug. I thought i also might be low on fuel (tank gauge doesnt work). I filled up and still ran like a WRX. I checked for loose wires at the gas station and then drove home. I did the ol unplug one coil at a time to determine the bad cylinder. Then i replaced the coil with a spare. Same problem. Swapped the ignitor with a spare, same problem. Checked the injector with an screwdriver to the ear. Yep it was still ticking.

Some people thought it might be in the wiring. Well with the haltech i am running wasted spark so if it was the ECU or pre-ignitor i would have lost 2 cylinders.

Replaced the coil pack harness. Same problem.

No visable signs of oil in coolant or coolant in the oil.

Finally came down to a compression test. ZERO in cylinder 4. So i guessed i floated a valve revving to 8000RPM with the 8.8mm lift HKSers.

Well i just got the head off tonight and look what i found.



So basically i am looking for the Nissan part number for CA18DE exhaust valve. I like to have part numbers when i head to the dealer to make things easy. They always want a VIN , when half the time i need is not from the car i have a VIN for.

Exhaust valve part number please?

[themadscientist]

CRAP! what about your piston? Piston crowns are softer than valves.

[r34 gtr]

SWEEET! That valve got absolutely raped. I congradualte you sir, I have not seen that before.

When I replaced a few valves they were $10/ea. Dont worry, its not gonna break the bank.

[davidricardo86]

Ouch!

[nismoplsr]

This did not happen due to valve float like i thought may have happened before i pulled the head off. This happened due to one of 2 reasons.

1) Poor quality valve seat. A valve keeps cool by transferring heat through the valve seat and minimal amounts through the guides. If the seat is defective the valve cannot transfer heat effectively, causing it to "burn"

2) Not enough ignition advance. This will put the time when the combustion is at its peak temp closer to or when the exhaust valve is opening. Which puts the valve in the middle of several thousand degree temperatures causing it to burn also.

Until i take the valve out and inspect the seat i will not know which.This is still a pretty crazy thing.

Everything else in each cylinders chambers including pistons and combustion chamber face in the head look mint.

[nismoplsr]

I believe the Intake valves hit the pistons first because they are larger in diameter which puts the edge closer to the pistons.

Also it would have been the opposite side of the valve to hit the piston.

[float_6969]

So wait, are you saying the 4th piston and combustion chamber are in good shape too? How is that possible? Did you find the piece or did it go into the exhaust and fubar your turbo too?

[XTCshri2222]

valve dosn't look bent, looks like metal fetegue. maybe a bad batch of valves

[mdubc405]

well if it did break off and go out the exhaust he might have hit a stroke of luck at 8krpm, the wastegate would be open and it could've been routed around the turbo... i've seen it before, except it was the tip of a spark plug...

[boost_boy]

Got a brand new one if you still need it. Sorry about the damage.......... Dee

[Liquid_Neon]

Do they really give you a bunch of flack for no vin? Thing is, my work (chevy dealer)computer cant look up 1989 and prior vins, so i wonder how the Nissan system does it?

When you tell them your building it for a custom application.. wouldn't they get the hint?

[nismoplsr]

They just want to make sure i get the right part, well that is their purpose anyways. I can usually get around not giving them one. I have to tell them i dont have the VIN. They say you know we cant take is back if its not the right part. I am like yes i know that and you dont understand that if i gave you the VIN for my car YOU WOULD GIVE ME the wrong part. It so happen that in this case the VIN would get me the correct part.

[float_6969]

My local dealership was kind of a pain about it for a while, but once they realized that I wasn't ever going to give them a VIN, that I never tried to return parts, and that I knew WTF I was talking about, they chilled out considerably. Sometimes they'll contact me if they get a 240 in have questions about it.

Give them time, they'll ease up.

[XTCshri2222]

the nissan dealership here only works with vins, for the pure fact they are morons. I can say this because other then a body man i'm a parts pro for 4yrs. I get all my parts form a infininti dealer in California he ships me everything i need, i just tell him what i want he pulls it up and ship it, charges my account and i'm golden. I get stuff from Nissan Japan direct too. sometimes gotta deal with 3000miles to get someone who knows what they doing

[r34 gtr]

My local Nissan dealership has never once asked me for a VIN. They have never gotten me the wrong part. I guess Regal Nissan's parts dept. doesnt suck too badly after all.

[zero_gripS13]

my local delarship charges 2x the price of a normal nissan dealership so i order form everythign nissan.. only got my part wrong once...

im gona get some parts numbers and goto down to buckeye nissan and see what they charge

[silvios]

Gday, forgive me for the thread dig - but this is the exact problem i am having with my 10km old forged CA.

The symptoms are the same - WRX sounding motor and virtually no power.

this happened to me during the first run in as well!!

What could of caused such a thing to happen to a freshly built motor?


P.S again sorry for the thread dig..

[boost_boy]

Improper installation of parts is a start. Coupled with possibly failing to check clearances, etc, etc, etc. It's really hard to pin-point exactly what caused it unless I opened it up myself.

[float_6969]

Did you have the failed valve, or the symptoms?

[silvios]

Hey

My mechanic towed the car to his workshop and is going to pull the motor out again and open it up.

Then we will find out what went wrong.
Ill let you know