cylinders 1 and 7 are cold

[Jim Cowden]

The push rods, it is a general comment John.
I am no familiar 100% with your eng.
Some engine don't run adjusters the rely on the lifter and push rod length.

I have had some older engine that I have had to shim rockers up because of the same problem.
As the rocker is raised of its mount it relieves the load on the lifter.
In you case rod length is important for rocker geo.

I have had some eng that have had to heavier oil cause the same problem.
The thick oil gets into the lifter and sort of goes solid.

If the specs are pull down 3/4 turn back 1 and 7 off.
I usually rotate the pushrod with my fingers when adjusting to feel when the rod and rocker meet.

It may only want 1/4 turn preload.

Jim

 

[John Milmont]

I adjust my lash the same way. I'm working on the car now. I have tested the running compression on one of the bad cylinders (7) and its checking out good. The compression for this cyl is 195psi cranking and about 100 or so running. That seems to be about right for running compression.

I also have an inline spark tester I hooked up and its pretty clear its missing. Im doing more testing and will report back later.

 

[Jim Cowden]

Post 34 1st sentence

post 82 last sentence

which one ?

 

[John Milmont]

On post 34, i was testing the spark plug by grounding it on the block. I was getting spark.

I just got this inline tester and it looks like i had it adjusted to wide. Well actually, the chart on the back of the tester says that GM HEI ignitions should be set to a certain width. At that width, i found that the spark was irregular. When i closed the gap, i had consistent spark.

Even though i have 2 different coils and the car didn't run any differently with both of them. im thinking that maybe both my coils are bad?

 

[Jim Cowden]

Is the spark testing bad in cyl 1 and 7 or all cyl.
If only 1 and 7 usually cap leads that sort of thing.

If all, check the rotor button is not shorting.

And or coil as you say.

 

[John Milmont]

I got it figured out.

And its something that I suspected all along.

Although I do believe that my coil is a little weak, it was not the problem. The problem was that the air distribution from this intake manifold creates some very confusing readings when run with a choppy cam. This really isn't a 'real' problem, because by chance, I found people on a forum talking about this issue and how it can cause wonky readings from the O2 sensor and also why some cylinders are hotter than others.

It turned out to be more of a tuning issue than anything else. The real problem was my inexperience in tuning a stand-alone fuel injection setup.

Even though my O2 sensor said I was running an a:f ratio that was near stoichiometric, the real a:f was so rich it was bogging everything and fouling the plugs. From what I understand, lumpy cams cause raw fuel to hit the o2 sensor which causes a lean read. That, combined with the poor air distribution of the intake manifold caused me to look in all the wrong places for the issue.

I always suspected something with the intake manifold. I even read that GM had to use sequential injection with it to trim out individual cylinders; but, so many people have used this intake successfully in batch fire that I threw that idea to the wayside... I guess those people are using very small cams.

 

[John Milmont]

At idle, I worked it down to about half the fuel i was putting in before. I noticed that my cold cylinders became hot and the hot cylinders became cold... The 2 banks swapped sides.

Its interesting, because every tuning guide i read said when the engine was hunting around, and the o2 sensor says its lean, to add more fuel.

 

[John Milmont]

This was such a disappointing conclusion. But I wanted to thank everyone that tried to help me through this thing.