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@Rebelyell I started a new thread just to be more on topic about the current engine.
Startup Symptoms:
Smoke out the exhaust at startup, runs rough until warm and choke is fully open, spits out some liquid that looks like water out the exhaust at startup, once warm it runs smooth and idles at 800 RPM and does not smoke or spit water out.
What I know:
I have a new Holley Street Warrior 600 CFM with electric choke on a cheap imitation intake manifold installed with hardware store random bolts. I've replaced the entire top side of the HEI distributor, wires and plugs. I put a new harmonic balancer on and set the timing using a new timing light. I do have a NIB Edelbrock Performer Intake Manifold 2107 that I got of fb for $50.
There is no serial number on the passenger front block in front of the valve cover.
The compression test surprised me! Note that the battery is not in good shape so cranking rpm may not be consistent.
#1 160
#2 160
#3 160
#4 165
#5 165
#6 160
#7 160
#8 165
The plugs are black and oily when removed after the engine has sit for a week or so. The plugs might have 30 minutes of running at idle on them.
Whenever I perform a Compression tests I like to do the following to ensure the most accurate results possible. I connect a battery charger and Fully Charge the batterybefore performing the compression test. Then while the test is being performed the charger should be connected and charging keeping the battery near full charge during the test.
The color and oil on the spark plugs would possibly indicate too much fuel? Is the accelerator pump diaphragm dumping raw fuel into the engine or just a fuel level adjustment?
Judging from the looks of the spark plugs you might want to consider performing a "Leak Down test" on your engine. The leak down would show you where the oil is coming from so you can correct the problem. The leak down is a bit tougher to do but not that much, it is a great test as it points towards problems.
Did you perform just a Dry Compression test or did you try adding a bit of oil to each cylinder to see if there was any major difference? In a situation like yours the extra information might be of use.
Usually smoking on start up is indicative of leaking valve stem seals. You can tell by the type of smoke. Oil smoke is thick, bluish, smells like burning oil, and lingers in the air. Water vapor is white, smells like exhaust, and disappears rather quickly. The condition of your plugs leads me to believe your valve stem seals need to be replaced. As far as your rough idle, I would make sure the choke is properly adjusted. Usually a car the idles smoothly once it warms up has an incorrectly adjusted choke. When the car is fully warmed up, the choke is wide open and no longer affects how the car runs, and that's why the idle smooths out. There can be other potential causes as well, but it's almost always the choke and what I would confirm first. I hope this helps.
Two things, looking at the passenger side plugs looks like it's like it's running rich and with the warrior carburetor I would say it's a choke adjustment is the most likely cause. The driver's side plugs are interesting. They're full of oil, but it get more oily towards the back of the motor. Now I could guess that the rear drain back is being obstructed on that head. But you mention you got a cheap intake manifold and maybe it isn't machined right on that side causing it to suck oil there. But with those numbers from the compression test I would say not to worry about the short block.
Whenever I perform a Compression tests I like to do the following to ensure the most accurate results possible. I connect a battery charger and Fully Charge the batterybefore performing the compression test. Then while the test is being performed the charger should be connected and charging keeping the battery near full charge during the test.
The color and oil on the spark plugs would possibly indicate too much fuel? Is the accelerator pump diaphragm dumping raw fuel into the engine or just a fuel level adjustment?
Judging from the looks of the spark plugs you might want to consider performing a "Leak Down test" on your engine. The leak down would show you where the oil is coming from so you can correct the problem. The leak down is a bit tougher to do but not that much, it is a great test as it points towards problems.
Did you perform just a Dry Compression test or did you try adding a bit of oil to each cylinder to see if there was any major difference? In a situation like yours the extra information might be of use.
The battery is shot so I had to wait a while between tests while the charger brought it back up some.
I did adjust the fuel level when I put the new carburetor on and was quite surprised how far off the new carburetor was.
The compression test was done dry with the throttle closed and the engine cold.
Two things, looking at the passenger side plugs looks like it's like it's running rich and with the warrior carburetor I would say it's a choke adjustment is the most likely cause. The driver's side plugs are interesting. They're full of oil, but it get more oily towards the back of the motor. Now I could guess that the rear drain back is being obstructed on that head. But you mention you got a cheap intake manifold and maybe it isn't machined right on that side causing it to suck oil there. But with those numbers from the compression test I would say not to worry about the short block.
Looking at the plugs under my microscope and all 8 have oil on the threads. The very tip of the center electrode on all the plugs looks good.
Usually smoking on start up is indicative of leaking valve stem seals. You can tell by the type of smoke. Oil smoke is thick, bluish, smells like burning oil, and lingers in the air. Water vapor is white, smells like exhaust, and disappears rather quickly. The condition of your plugs leads me to believe your valve stem seals need to be replaced. As far as your rough idle, I would make sure the choke is properly adjusted. Usually a car the idles smoothly once it warms up has an incorrectly adjusted choke. When the car is fully warmed up, the choke is wide open and no longer affects how the car runs, and that's why the idle smooths out. There can be other potential causes as well, but it's almost always the choke and what I would confirm first. I hope this helps.
MajD
That pretty much describes the smoke, bluish, stinks, and lingers for a while. It's not water vapor I'm seeing but drops of what looks like water on the floor behind the exhaust pipe and it's maybe 30 or so drops and that stops after a minute or less.
How would the choke cause the engine to run rough? Just trying to understand... and I did spend some time making sure the choke was set properly.
@Rebelyell I started a new thread just to be more on topic about the current engine.
Startup Symptoms:
Smoke out the exhaust at startup, runs rough until warm and choke is fully open, spits out some liquid that looks like water out the exhaust at startup, once warm it runs smooth and idles at 800 RPM and does not smoke or spit water out.
What I know:
I have a new Holley Street Warrior 600 CFM with electric choke on a cheap imitation intake manifold installed with hardware store random bolts. I've replaced the entire top side of the HEI distributor, wires and plugs. I put a new harmonic balancer on and set the timing using a new timing light. I do have a NIB Edelbrock Performer Intake Manifold 2107 that I got of fb for $50.
There is no serial number on the passenger front block in front of the valve cover.
The compression test surprised me! Note that the battery is not in good shape so cranking rpm may not be consistent.
#1 160
#2 160
#3 160
#4 165
#5 165
#6 160
#7 160
#8 165
The plugs are black and oily when removed after the engine has sit for a week or so. The plugs might have 30 minutes of running at idle on them.
JT
As before ---JT, point is: If you KNOW block's deck height, having that info empowers you. So that you can choose piston w/ best CH to work w/ your deck height AND w/ your gasket (thickness) selection. All helping to optimize quench height and set a practical static compression ratio.
When schedule permits; looking forward to completed compression tests.
----------------------------------------------------------------
tests completed:
That set of compression tests sure looks good; Very tight grouping too.
Yup, plugs are fugly
Have you ability to road test motor? burning off any oil & soot --- then visually re-assess plugs post-run ?
Perhaps you NEED Neither pistons or rings ? But again, perhaps NEED valve guide work + some carb tuning ?
JT:
have you ever cut away (lathe) Entire threaded portion of spark plugs; exposing Entire insulator ? That can disclose more than SOS. Have a Canadian carb pro acquaintance who does. He supplies-tunes some Very successful circle track teams who compete from Northeast USA, all the way to Florida. Little doubt he's either there now or expected shortly.
As before ---JT, point is: If you KNOW block's deck height, having that info empowers you. So that you can choose piston w/ best CH to work w/ your deck height AND w/ your gasket (thickness) selection. All helping to optimize quench height and set a practical static compression ratio.
When schedule permits; looking forward to completed compression tests.
----------------------------------------------------------------
tests completed:
That set of compression tests sure looks good; Very tight grouping too.
Yup, plugs are fugly
Have you ability to road test motor? burning off any oil & soot --- then visually re-assess plugs post-run ?
Perhaps you NEED Neither pistons or rings ? But again, perhaps NEED valve guide work + some carb tuning ?
I forgot to mention that the engine has been idling only while I rebuilt the rear suspension. When I mentioned that to my buddy that owns the repair shop he said it's not unusual to have black plugs from just idling if the idle mixture is a tad rich.
And maybe I didn't describe the rough running at startup well, it's not like the mixture is too rich but like not all cylinders are firing every compression stroke until a minute or so has passed then it starts to smooth out. By the time the choke is fully open it runs smooth and has good throttle response sitting on the 4 post.
I just had the battery tested and it's bad so I came home with a new 650 CCA battery. I'm sure the engine was not turning over a consistent RPM during the compression test.
I'm thinking at this point just changing the intake manifold and valve stem seals and see what happens. I also need to change the rear main seal and I'll do that before the next alignment.
Your buddy's right as rain.
Then there's those guys who band-aid their mixture issue with an MSD/CD box
I would Not skip measuring stem-to-guide clearance "wobble" --- OE sbc notorious for worn guides.
New seals May (or may not) mask significant wear; but won't mask wear for long. --- if worn; again guide-liners aka K-Liners. Another short-term band aid is new OE square O-ring seals PLUS new fluoroelastomer umbrella "shedders" which clasp onto stem and ride it up-down --- Belt and Suspenders --- But nuthin' trumps proper clearances.
Your buddy's right as rain.
Then there's those guys who band-aid their mixture issue with an MSD/CD box
I would Not skip measuring stem-to-guide clearance "wobble" --- OE sbc notorious for worn guides.
New seals May (or may not) mask significant wear; but won't mask wear for long. --- if worn; again guide-liners aka K-Liners. Another short-term band aid is new OE square O-ring seals PLUS new fluoroelastomer umbrella "shedders" which clasp onto stem and ride it up-down --- Belt and Suspenders --- But nuthin' trumps proper clearances.
If I get the valve springs off using the rope method and I feel any slop in the valve guide I'll stop right there and pull the heads off and decide if I want to have them rebuilt or just replace them with some aluminum heads. It's surprising how small of a movement you can feel with your hands and being a machinist among other trades you learn to feel clearances.
I feel much better about the lower end after the compression test... and the inside is looking much better not to mention the under side too.
JT
Last edited by jthornton; Feb 5, 2026 at 05:01 PM.
JT:
have you ever cut away (lathe) Entire threaded portion of spark plugs; exposing Entire insulator ? That can disclose more than SOS. Have a Canadian carb pro acquaintance who does. He supplies-tunes some Very successful circle track teams who compete from Northeast USA, all the way to Florida. Little doubt he's either there now or expected shortly.
I bored one out once and welded a quick disconnect to the base of a spark plug to do something to my 81 Custom Deluxe C10... it must have had something to do with removing valve springs because I still have the tool to remove the springs and the modified spark plug. You could almost stand up inside the engine compartment on that truck.
After reading the rest of your post and getting a better understanding of the idle symptoms, I don't wonder if your plugs are fouled with oil on start up. If all of the threads on the plugs have oil on them, that's coming from either the oil entering the combustion chamber or a leaking valve cover gasket that lets oil seep onto the plugs. Initially, this contamination could cause a plug to misfire until the oil burns off the plugs and the idle smooths out. Just a thought. It will be interesting to see what you find out.
yup, I can see that possibility.
also, what if heads' drain-backs are partially-clogged; then heads fill w/ oil & quickly over-top guides>into chambers ?
Especially so if a HV pump's installed? Dunno ???
After reading the rest of your post and getting a better understanding of the idle symptoms, I don't wonder if your plugs are fouled with oil on start up. If all of the threads on the plugs have oil on them, that's coming from either the oil entering the combustion chamber or a leaking valve cover gasket that lets oil seep onto the plugs. Initially, this contamination could cause a plug to misfire until the oil burns off the plugs and the idle smooths out. Just a thought. It will be interesting to see what you find out.
MajD
I don't have any oil on the outside of the heads so the valve cover gaskets are doing their job. It does leak from the rear main seal but that's another project.
One thing that came to mind this morning was I noticed something coming out of the breather on the passenger side valve cover last time I ran the engine so I'm thinking the PCV valve probably needs to be replaced.
One thing that came to mind this morning was I noticed something coming out of the breather on the passenger side valve cover last time I ran the engine so I'm thinking the PCV valve probably needs to be replaced.
JT
Yup, PCV valves are cheap n easy.
Don't recall seeing any pics of top of your motor OR if the OE PCV System is intact; routed properly to ensure a flow-thru breathing loop ?
When I got the C3 the passenger side valve cover just had a hose going no where in particular, just hanging in space so I added the Mr. Gasket breather cover.
JT
Last edited by jthornton; Feb 6, 2026 at 04:40 PM.
82 L83 Engine Diagnostics
