1977 Cylinder #1 Mystery

[Zed Head]

Not really clear what cgsheen1 meant.  The cam towers have to have the ports for the spray bar.  If you run spray bar cam towers and a spray bar then oil will flow to the spray bar.  The cam towers have the passages.

As I understand things, but I haven't actually seen it, only read about it, the cam will accept oil from the cam towers if it is drilled for it.  So if you put a drilled camshaft in a spray bar head you'll get oil traveling both ways.

Can't find anything on carpartsmanual because Nissan considers the cam towers as part of the head.  You can't buy them separately.

[Captain Obvious]

Assuming you have the capacity in the oil pump, I don't see any reason why you couldn't toss an internally oiled cam into a head that previously had a spray bar system and use both oiling systems in parallel. You should get oil out of all the holes... Both out of the bar and out of the holes in the cam lobes.

[Patcon]

I believe CGsheen is saying they put gaskets under the spray bar contact points to leave it in place but eliminate flow

[cgsheen1]

On 4/20/2022 at 8:07 AM, Patcon said:

I believe CGsheen is saying they put gaskets under the spray bar contact points to leave it in place but eliminate flow

Correct.

Some might think this a "lazy" way to do this but I'm one that always tries to make modifications that can be undone if / when someone wants to return things to stock. Re-using the spray bar and covering the oil supply ports with gasket to block them off is a simple and effective way to convert to internal oiled cam. It also leaves the spray bar in a place where it won't get lost. 

My mistake was forgetting to explain that to young Curtz at the shop...

Edited April 23, 2022 by cgsheen1

[Zed Head]

Didn't realize that the car had been at Sakura Garage already.  Thought it was in the future.

Still wondering how the tuning for the cam will work out using the stock EFI parts.  Good luck.

 

[ckurtz2]

Time to confuse everyone again.

              So all things aside. I think the cam is gonna be able to be dialed in for the stock EFI. I did a little bit of work with Chuck a few weeks back and I think it's going to be doable. I'll explain that when it's all dialed in, in the future. With the tweaks done to the car it no longer runs nearly as rich (still slightly), and it doesn't seem to lean out anymore at high rpm.

             So I am 100% (bold statement) positive that the issues I am dealing with now causing the car to run rough at low rpm are still in cylinder #1. Let me explain.

So, cylinder #1 absolutely does not fire at idle. I bought a new spark plug(s) for it and let it run for about a minute cold. Pulled #1 plug and looked at it. Still looked completely new and noticed just a small amount of oily like film on it (can't confirm if it was coolant, oil, or gas. I don't have a great nose). Ok, so I installed the plug again and let it idle till warm. Pulled plug again and barely noticed a difference in the plug. Ok so I got in the drivers seat and in neutral held the car at 2000rpm and pretty much just revved the car between 2000-3000rpm. when accelerating I noticed that a thin cloud of white/grey smoke came out as well as smoke that was dark gray/black. I could distinctly see two different smoke colors. In addition, every once and a while it would pop out the exhaust.

Ok, cool, confusing. What's new..

So I disconnected the injector connector to cylinder #1 and did the same test. No more popping, no more black smoke, and only a small small amount of that white smoke. 

So after alternating this test a few times I noticed that it would only pop and display black smoke after idling for a few minutes followed by revving with cylinder #1 connected. In addition, the white smoke was much stronger when cylinder one was connected.

I never noticed the plug being covered in fuel, nor did I notice it becoming super black and carbon fouled. Looked rich, but not by much.

Now, I pulled the #1 spark plug wire while the engine was idling and noticed no difference in rpm. I also pulled the plug wire at about 2700rpm and noticed no real change in rpm, but the exhaust did sound different. So I think it's firing, but not strongly, and only at higher rpms. 

I also swapped injector connectors again and #1 connector worked on #2. 

I looked inside #1 cylinder through the spark plug hole and noticed it looked much cleaner inside on the piston top compared to other cylinders which clearly showed signs of combustion. 

Now cylinder #1 shows 150psi or so on compression. I pulled #1 and #2 injectors and turned over the car. Both show decent spray patterns with what looked to be the same flow. Spark is totally good as without even pulling the plug I can get the wire boot if pressed against the valve cover to zap it.

So I have spark, fuel, and compression at idle and no boom. If it is firing at idle it is extremely weak. What can possibly cause this.

Oil does not look milky or low, coolant looks green, pretty clear, and not low. 

 

        

 

 

 

 

[Patcon]

As a radical thought...

This is basically a big air pump that blows up. Spark, fuel and air.

So you think you have spark and fuel. What about air. Are the intake and exhaust ports on #1 totally clear. Could #1 have ingested a rag or something and be blocking up the intake valve? Just tossing it out there...

[Zed Head]

18 hours ago, ckurtz2 said:

I looked inside #1 cylinder through the spark plug hole and noticed it looked much cleaner inside on the piston top compared to other cylinders which clearly showed signs of combustion. 

Coolant passages have been known to leak in to the intake system.  Maybe you have a cracked head.  Coolant in the combustion chamber makes things clean.  Have you noticed any coolant usage?  My engine never used a drop.  It was boring.

Speaking of boring, how about a bore scope?  Take a look down the intake manifold passages and inside the cylinder.

Can't remember if you ever did a smoke test or if you just decided that you had a better idea, in past conversation.  A smoke test will show if you have any vacuum leaks, and if you remove the spark plugs and turn the engine by hand should show smoke flow through the intake ports, and, if you wait long enough, through the exhaust ports.

And, on ports - maybe you have an EGR port opened in the intake manifold and a rotted EGR valve.  Each cylinder has its own little EGR jet.  The borescope should see that if you get a good one.  They have side view now.  Here's a video from a guy that seems to know a lot.