Jump to content

IGNORED

Spark plug reading


Recommended Posts

 

F54/P79 with .080 removed from head w/approx 150 miles driven since put back in the road. Bottom end is probably stock, but untouched by myself(no new rings, bearings etc.)

 

I'm trying to determine if my car is running rich, or if I am experiencing ring or valve stem seal failure.

 

There exists an amount of oil consumption that to me, seems high, even for an engine with a fresh head and bottom end that's been sitting for a long time.

 

It will smoke if you rev it at idle. Not under load when driving it (I had someone follow me). It won't smoke at startup either hot or cold.

 

I am pretty well colorblind, it's hard to tell if it's blue or what. It's not black, it's not blue, and it's not white. I've seen extreme cases of rich conditions produce obvious black smoke, and as early as my N42 motor I just replaced, the obvious blue hue of smoke at startup due to failed valve stem seals. It's almost as if it's a mix of blue, blackish, and white. As messed up as that sounds.

 

The plugs are difficult for me to read as well. Again, I've seen oil fouled plugs with the old motor, but the ones in my new engine seem like their on the verge of both carbon fouling and oil fouling. To me at least. What do you guys think. This one picture represents the condition of all 6 plugs with roughly 150 miles of use.

 

Edit: my TVS has not been adjusted per the FSM since installation on the new engine.

Edit #2:  A quick 6 -8 flick of the wire brush over the spark plug removes almost all of the deposits, and I'm mostly seeing powdery residue, not so much oily residue.  I'm thinking I have one of those odd situations where a rich condition is thinning out oil, making it enter the combustion process, and give symptoms of both rich condition, and oil consumption.  Perhaps someone has seen this before, and can shed light on it. 

 

bf758b37b9e6c0a441bc5d29c5639c21.jpg&key=2bb420164b6d5d29a7504fd420d9dd20b6b3d7fbe923a5ca9eb5923d2ace9ae4

 

 

 

 

 

 

Edited by Reptoid Overlords
Link to post
Share on other sites

32 minutes ago, Reptoid Overlords said:

Edit: my TVS has not been adjusted per the FSM since installation on the new engine.

Edit #2:  A quick 6 -8 flick of the wire brush over the spark plug removes almost all of the deposits, and I'm mostly seeing powdery residue, not so much oily residue.  I'm thinking I have one of those odd situations where a rich condition is thinning out oil, making it enter the combustion process, and give symptoms of both rich condition, and oil consumption. 

 

Does the exhaust smell gassy or oily?  There is a difference in odor between the two problems.  What are the oil consumption numbers?  If it's not leaking it's burning.

 

  • Thanks 1
Link to post
Share on other sites

The exhaust smells like it is a result of gas being burned, as opposed to oil being burned. I dare say it smells like a normal engine with no emissions.

 

I've been looking for leaks. I've replaced the PCV valve with Sankei one from Japan. Just to be safe. With my own prior experiences I've been keepinga watchful eye over the rear main seal area. Nothing notable yet.

 

Oil consumption is 1 quart in 150 miles.

 

I could be confused as to wether or not I have actually disabled my BCDD and if that has any correlation to anything. If I plug it off with vacuum line plugs, it will smoke upon resuming acceleration after deceleration. If I run a line from the uppermost forward large port on the BCDD to the intake manifold, then it will not smoke under those circumstances. I wonder if my manifold pressure is all jacked up? 41953d5d2bf4a073425eb1b555889a46.jpg&key=d749ac4ac53307add424a26ea8c0a5feee6ad7528724143b5ec45cb08c6a1c60

 

 

 

Link to post
Share on other sites

So rich you are washing the cylinder walls down and causing oil consumption? Gas mileage bad? 

Looks like a bit of both fuel and oil, but mostly carbon if it brushes off that easy. 

Have you checked your TPS setting? 

Might need to take a cruise somewhere and shut it off at cruise and then pull the plugs . Don’t let it idle before shutting it down. 

Everyone should invest the 200$ for a complete wideband set up. Takes a lot of the guess work out.

 

  • Thanks 1
Link to post
Share on other sites
3 hours ago, Reptoid Overlords said:

Oil consumption is 1 quart in 150 miles.

Woof. That amount of consumption ought to be pretty easy to find. Have you run a compression test?

We talked about it a little before and I mentioned that I'm getting a little oil burning and blue smoke on my broken cam engine, but it's at nuisance level... I've got a thousand miles on it and the smell is annoying, but the consumption rate isn't high enough for me to do anything about it. One quart in 150 miles would have more of my attention.

Stuck or broken ring?

Link to post
Share on other sites

The compression numbers are 178psi for cylinders 1 and 2, and 180psi for 3-6. The harbor freight checker I have is known to be about 10 or 15 psi low( I can't remember which one) when compared to a Snap On one, checked about 2 years ago. The important thing is that they are even, I guess.

Vacuum at idle is a steady 22hg with no odd fluctuation or decline at higher idle. I live 6 feet above sea level.




 

Edited by Reptoid Overlords
Link to post
Share on other sites
18 hours ago, madkaw said:

So rich you are washing the cylinder walls down and causing oil consumption? Gas mileage bad? 

 

 

I just filled up after it's maiden tank of gas after installing the engine.  131 miles took 7.5 gallons.  Which equals 17.4 MPG.  This tank of fuel has seen much idling, revving, and a lot of teething style driving, not necessarily normal operation.  Under normal circumstances I'd say 18MPG is on the low end of what I'd be getting. 

 

I'm going to go with the obvious path, and begin doing the research on how to properly set the TVS.  My copy of the FSM was wiped away when i had to erase this computer's memory due to a virus, and i can't remember what i did those many years ago.  My TVS has a riveted cover, and I believe it came off the engine that is currently in the car. 

Link to post
Share on other sites

I set my TVS finally, like I should've done all along. Also, I had a poor connection at my temp gauge. Not sure if it is connected to enrichment but I fixed it anyway.

My tach wasn't connected when I put the dash back after replacing heater core hoses. I had to replace my heater core itself just two days ago, so I had to pull the dash again. Now I have the tach hooked up.

After a test drive, I believe I have the EFI in proper working order for the first time since I've had it back on the road.

Could it be that when I filled the bone dry engine with 4.7 quarts of oil and ran it, I had to add a quart to make up for areas that normally do not drain oil under normal circumstances? Maybe that's just silly.

Sent from my Coolpad 3310A using Tapatalk

Link to post
Share on other sites

Did you check oil level after the first early start up?

If not then I wouldn't be confidant your oil consumption is as high as you think. A quart every 150 miles is a little like fogging for mosquitos! Quite noticeable

Get the oil full and on the stick where it's easy to confirm, reset the odometer and put a few more miles on it.

  • Like 1
Link to post
Share on other sites
1 hour ago, Reptoid Overlords said:

I set my TVS finally, like I should've done all along. Also, I had a poor connection at my temp gauge. 

Was it set incorrectly? Gauge or sensor?  They're not the same.

I'd recheck your oil level, go drive it for a few hundred miles, and see where you're at.

Link to post
Share on other sites

The TVS was showing no continuity at idle. I set it so that it shows continuity at idle and no continuity as soon as it senses moving the throttle away from idle.

The connection on the thermostat housing for the temperature gauge on the dashboard was not fully connected. It required some slight crimping to get a good fit. The temp gauge in the dash was giving inconsistent readings.

I have it topped up, and will drive it while monitoring oil level. It's been about 29 miles since I topoed it up today and I see no change on the dipstick. Seems like with a quart every 150 miles I'd start to see evidence of consumption pretty quick. I'll still be watching and hope I'm out of the clear in a few hundred miles.

Sent from my Coolpad 3310A using Tapatalk

  • Like 1
Link to post
Share on other sites
  • 3 weeks later...

I think it was this:

On ‎10‎/‎13‎/‎2019 at 10:00 PM, Reptoid Overlords said:

Could it be that when I filled the bone dry engine with 4.7 quarts of oil and ran it, I had to add a quart to make up for areas that normally do not drain oil under normal circumstances?

 

  • Like 1
Link to post
Share on other sites

I went and got a harbor freight leak down tester. Not sure how accurate they are, but the readings are a consistent 12% approx loss on all 6 cyl.

I can hear a faint bit of hissing through the oil filler hole, but can't feel any air through there or the dip stick.

Vacuum at hot idle is 22hg. It shoots up to about 25 if you blip the throttle. No strange movements of the needle. Nice and steady.

The plug condition has leaned out a bit too.

I'll still be keeping an eye on things.15c4a5e700370392d9dc5717d814093f.jpg

Sent from my Coolpad 3310A using Tapatalk

  • Like 1
Link to post
Share on other sites

It’s a bit contradictory that you have that high of vacuum numbers but 12% loss on leak down? My engine runs 10 at idle but only 3-5% leak down per cylinder . Plugs don’t look terrible, maybe still burning of residual oil?

Link to post
Share on other sites
2 hours ago, madkaw said:

It’s a bit contradictory that you have that high of vacuum numbers but 12% loss on leak down? My engine runs 10 at idle but only 3-5% leak down per cylinder . Plugs don’t look terrible, maybe still burning of residual oil?

Camshafts could contribute to the discrepancy

Link to post
Share on other sites
3 hours ago, madkaw said:

It’s a bit contradictory that you have that high of vacuum numbers but 12% loss on leak down? My engine runs 10 at idle but only 3-5% leak down per cylinder . Plugs don’t look terrible, maybe still burning of residual oil?

Assuming that the cam is stock, what would be an acceptable percent loss on leak down given those vacuum numbers?  I'm not arguing your comment, I just really don't know.  Most information regarding leak down test results state anything over 20% is bad news, and some say 20% is okay.  

52 minutes ago, Patcon said:

Camshafts could contribute to the discrepancy

I have no real history of this motor.  It came out of an abandoned car I got with no title.  Some PO in it's lifetime, for better or worse, certainly had it apart.  It's not entirely out of the realm of possibilities that the cam is not stock, or at least not anymore..  It's got all the OEM markings on it, but I guess it could have been ground.   That might explain why when i drove the donor car it seemed so fast.  And it might explain why is seems substantially faster than my old stock motor, and the lope at idle.  Moreover, it might explain why I'm having issues running rich.  

Today I installed an oil separator in line with the crankcase PCV system. I found excessive oil in the rubber line from the crankcase tubing to the PCV valve in the manifold.  If I'm unknowingly running a cam with longer than stock duration could the valve timing be late, causing high vacuum?

 

I have no baseline from which to judge how a new or newly rebuilt L28 "ought" to run.  Anyway, I hope I don't seem argumentative or unappreciative, I always appreciate all the fine help I get here.   

Link to post
Share on other sites

I realized after rereading the thread that this is an untouched used bottom end - so your numbers are healthy for sure . I would be happy with the vacuum readings for sure . I have a 54 block with 110k miles that I need to put a head on . I don’t plan on touching it either since the bores look perfect .

  • Thanks 1
Link to post
Share on other sites
  • 2 weeks later...

I'm not entirely out of the weeds. Whatever oil consumption issue I had, wether it be throughout the combustion process, or the PCV system is totally gone.

However, today I observed the oil level too low after another few hundred miles. According to the dipstick, after letting the hot engine sit about 30 min, about a half quart is gone.

I looked around underneath and discovered a bit of oil seeping down the bottom of the transmission that I hadn't seen until now.

So, being the reasonable person without a problem that I am, I got whatever inconvenient equipment that was in the way out, and discovered that the rear main leaks pretty good.

It's a Fel-Pro. Looks like I'll be stopping in by the Nissan dealer on the way home from work tomorrow.

One thing I didn't do, and it's no one's fault but my own, is install the trans to block brackets that came with the motor. Not sure if they are for structural support, but I'll be installing them this time. 87330424b791d1d594d4ae9701e42a8a.jpg

Sent from my Coolpad 3310A using Tapatalk

Link to post
Share on other sites

They're for "NVH" reduction, I believe.  I think that stands for Noise, Vibration, Harmonics (or  Harshness),  They stop the transmission from wobbling around on the back of the block.  Not going to help your oil leak but might make for a quieter ride.

  • Like 1
Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...

Important Information

By using this site, you agree to our Privacy Policy and Guidelines. We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.