# What did I do to my poor engine?



## Stereolab42 (Apr 6, 2018)

1. Engine (numbers 400 on base 68 GTO) was completely rebuilt summer 2018.
2. Problem-free until two weeks ago, when I noticed a ticking.
3. With a stethoscope I isolated the ticking to the passenger valve cover.
4. Using a timing light I noticed the ticking was synced with the light, not half-speed, which from what I read is further evidence for a valve train issue (versus bottom end).
5. After poking around I then discovered the #4 spark plug wire was disconnected at the distributor! I certainly did not disconnect it, and have no idea how it happened. I do not know how long the engine was running down a cylinder, could have been months and hundreds of miles.
6. There was carbon buildup in the metal plug of that wire. I pulled a few other wires and they were clean. I'm not sure what this implies... could there have been a huge spark or some other event that forced out the wire?
7. After cleaning and reconnecting the wire, the car runs and drives fine, and the wire stays in place. However, the ticking is not gone.
8. I pulled the valve cover and can see nothing obviously wrong, but the oil shield is in place. Can that just be unbolted to expose the rockers or is it more complicated than that? I really don't have an experience poking around in engines and I have an appointment with my mechanic in a week, so I'll probably just leave it alone.

So there are a couple mysteries that need answers:

1. Why did the #4 wire come loose from the distributor? Was it accidentally knocked loose? If so, why the carbon buildup?
2. Did running down a cylinder cause whatever valve train trouble that is causing the (now permanent) ticking?
3. What are the chances the bottom end has been affected? I am not keen on dropping another 5 grand on another rebuild.


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## BLK69JUDGE (Jun 10, 2010)

I will dive in ...........

the drippers are held on by nuts on the top of the head bolts.see em between the rockers ?
its ok to pull em
go slow dont drop the nuts ..
the wire was probably arcing for a while until the wire dropped
change your oil NOW
that cylinder has had NO spark and hax been full of fuel only and it has more than likely
thinned your oil ... new napa gold or WIX filter too

Scott

is your mechanic coming to you ?


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## Stereolab42 (Apr 6, 2018)

BLK69JUDGE said:


> I will dive in ...........
> 
> the drippers are held on by nuts on the top of the head bolts.see em between the rockers ?
> its ok to pull em
> ...


Good suggestion regarding the oil. They are about 5 miles away. Aside from the ticking, the car feels fine, so I'll just wing it on the assumption that any damage there was to do has already been done. I did check lash, all rods and rockers are tight with no up-and-down slack at TDC. I really hope the camshaft isn't bad, did some reading and it looks like on a 400 taking it out or even just getting a peek requires removing half the engine and engine bay. After reading up on what happens when a V8 runs down a cylinder it seems unlikely that would have been the cause of damage, and it may be a coincidence. Probably was just knocked/pulled loose, possibly very recently, and arced out as you say.


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## PontiacJim (Dec 29, 2012)

*Stereolab42: "I did check lash, all rods and rockers are tight with no up-and-down slack at TDC." 

PJ: Checking lash on a hydraulic cam doesn't mean anything. The rocker arms get torqued down to 20ft pounds. The rocker arm nut could have backed off slightly. You would not know this as a hydraulic lifter is designed to take up the slack and provide a zero lash.

You can also check the engine with it running with the drippers on. You should see the pushrods rotating. If that one ticking rocker/lifter is not rotating, this could be a problem and indicate a worn cam lobe or lifter base.

Oil choice can cause a problem with lifters. As BLK69JUDGE stated, without the plug firing, you may have diluted the oil down and it is now too thin. Changing the oil may quiet the lifter right up. Too heavy an oil, like the 20W-50 can be too thick and not allow the lifter to operate correctly.

I would check the torque on the rocker arm nuts, reinstall the oil dripper, change oil & filter, and fire it up and watch the pushrods for rotation. Sometimes they don't spin so well as idle, so you may have work the carb by hand to bring the RPM's up just a little. Have a few rags handy as the oil may splash out the engine. Run the engine just long enough to scan all the pushrods for rotation, so it won't be run long at all.*


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## Stereolab42 (Apr 6, 2018)

Thanks Jim. Here's what I've done now:

1. Changed oil/oil filter with no issues. Ran car, sound unchanged.

2. Popped valve cover and oil shield. The rocker nuts are the OEM nuts and seemed to be torqued correctly. I re-torqued to 20 ft/pd and ran car again, sound unchanged. From what I read elsewhere, rebuilt Pontiac 400s might actually call for a different torque value on those nuts due to a changed geometry, and therefore rebuilders usually install adjustable poly nuts. That wasn't done here. I'm not sure if that was a mistake or just that my rebuilder decided it wasn't necessary for some reason.

3. Popped valve cover and left oil shield in place. Ran car. The pushrods all seem to be rotating, although it's hard to tell on some. I can run the car like this for about 5 minutes before oil starts leaking from the corners. (It's obvious if I ran without the shield oil would be going everywhere immediately, though.) I was able to reach the nut for each rocker stud (under the rocker) with my stethescope. Surprisingly enough, there was no difference in sound between any rocker.

Surely an issue with a particular rocker, spring, pushrod, or lifter would have been audible with the scope on the rocker stud nut? And as I tested earlier, it seems unlikely to be bottom-end related due to the timing of the sound. Playing around more with the scope, it might be the case that the sound is more centered on the exhaust manifold. Maybe it is the heat riser? My manifolds were replaced with repros in 2018 and the heat riser hardware is present and functional... maybe it is bouncing around, although the sound is unchanged if I hold the external flap in one position. I suppose an exhaust leak could be a possibility, although it really does sound more like metal-on-metal.


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## PontiacJim (Dec 29, 2012)

Stereolab42 said:


> Thanks Jim. Here's what I've done now:
> 
> 1. Changed oil/oil filter with no issues. Ran car, sound unchanged.
> 
> ...



OK, you did the checks. Yes, sometimes hard to see the pushrods spin even when they are. I read a trick is to put a white marker pen line on them to see the rotation better.

Yes, the ticking could be an exhaust leak as this has come up before and it could be the butterfly valve flopping around inside the manifold seeing you did not seem to find anything else with the rocker arms. But.....

Next up, you can continue to check the valvetrain and pull each pushrod and roll it on a flat piece of glass. You could have a bent pushrod - which could be due to wrong rocker arm geometry from the rebuild. Geometry of the valve train can change due to machining, or aftermarket parts that have differing measurements over stock OEM parts. The factory 1.5 rockers do not have "long slots" where the rocker pivots on the bottleneck stud. If the cam lift is too high, it can force the rocker arm up against the stud which acts as a stop......and something has to give - either a bent pushrod or worse, the bottleneck stud snaps off. I had a rocker arm nut back off and the rocker arm go sideways but not before the pushrod jammed into the rocker arm and bent it like an "S". No damage, just installed a new pushrod and put it all back together.

When you pull the pushrods (remember what direction they came out as you want the same ends to mate with the corresponding lifter/rocker arm cup), examine each rocker arm & ball. Look for anything out of the ordinary or a "blued" color indicating an overheating problem from poor lubrication. If me, I would at this time replace them with the Comp Cams stamped rocker arms which are stronger, have a more accurate ratio, are "long slot", and have the much improved rocker arm balls with the oil grooves to retain oil for better lubrication and heat dissipation. COMP Cams High Energy Rocker Arms 1251-16

So at least check all your pushrods - just a slight bend could be a problem.

The rocker nut gets torqued to 20 ft lbs, period. Now it the nut has been off and on a couple times, it is possible that they won't hold. But if you checked them and they are all good, then that's it. The poly locks will make a non adjustable valve train like the Pontiac, an adjustable valve train. It allows you to "zero lash" the lifters for additional RPM's before the llifter pumps up. They can also be used as a fix/crutch if the rocker arm geometry is off slightly.

Poly locks can be made to work IF you purchase the correct ones in your instance. What you may need to do is tighten down further on the rocker arm ball to take up any slack - IF that is the problem. The down side here is that you may have to give up the factory oil drippers. But, I recall another member using this set-up and he installed some washers under the legs of the oil drippers to raise them up enough for the needed clearance. 

Purchase a set of these 3/8" poly locks. They have a hollowed shoulder at the base which will fit over the 7/16" base of the bottleneck stud so you can adjust the rocker arm. Many are flat/even where they sit on the rocker arm ball and if so, would stop at the shoulder of the bottleneck stud just like the factory nut, and be of no use to you in needed adjustment. Mr. Gasket Sure-Lock Rocker Arm Nuts - For Stock Rocker Arms - Fits SB Chevy : 920G

Purchase a set of rocker arm oil splash clips to keep the oil down without the factory drippers for adjusting. One set will only do one side, so you will want to adjust only one side at a time with the engine running to "zero lash" the lifters. Keep the rocker cover on the other side snugged down until ready to swap over to that side. Mr. Gasket Rocker Arm Oil Deflector Clips 1015

You can install all of your poly locks on the engine with both valve covers off, then reinstall just one valve cover to keep oil off the engine, and work on one side at a time with your oil splash clips installed.

To use the poly locks:

You back out the center allen lock screw of the poly lock so that it will not touch the top of the rocker arm stud until after you screw the outer nut down far enough to remove all the slack from the tip of the pushrod to the rocker arm.

Rotate the engine until the #1 piston is at TDC on its COMPRESSION stroke - both rocker arms will be even and your timing mark on the harmonic balancer will line up with the "0" on your timing cover scale.Then tighten the poly lock using the nut until the slack is removed from the pushrod/rocker arm - you should be able to spin the pushrod with your forefinger and thumb with a little bit of resistance to it. Adjust both valves like this. Then tighten the inner lock screw of the poly lock down onto the rocker arm stud to get it near where it needs to be, and then back it out 1 full turn - you will do a final adjustment/tightening later.

After adjusting both valves on #1, I'd rotate the crank 90 degrees to the next cylinder in the firing order, which is #8, adjust both valves then rotate 90 more degrees to the next cylinder in the firing order, which is #4, and so on, thru the firing order til both valves on all 8 cylinders are adjusted. 

Now put one valve cover on one side - just snug should do it. With the clip-on oil shields installed, some rags to help catch some of the spill oil, and your allen wrench and open end wrench ready, start the engine.

Now beginning with the first cylinder of the bank you are working on, you are going to "zero lash" each rocker arm. Slowly back the poly lock off until clicking is heard - you will know it. Stop at that point. Now slowly tighten the poly lock until the clicking stops. Wait about 30 seconds for the lifter to pump down and adjust itself. If it begins to click again, tight down just enough to stop the clicking and wait 30 seconds. Repeat if needed until the clicking stops completely. Once the clicking has stopped, holding the wrench on the poly lock, tighten the set-screw with your allen wrench. Snug it down tight, but not killer tight as you can strip it out. Once it is tight, fairly snug but not enough force to strip it, then with the wrench still on the nut, turn it about 1/8 of a turn to give it its final clamping force to hold it in place. Do each rocker arm this way and go down the row of cylinders until done.

If you feel there is too much oil dripping off the engine, you can stop at any time, let the engine cool a bit, and clean it up. You'll probably get some smoke from the oil if it gets on the exhaust manifolds.

That will "zero lash" all the lifters/rocker arms and you should not have any ticking. If you still have ticking, it could be a collapsed/bad lifter or even a cam lobe wearing down and not being able to hold lifter adjustment IF it is in the valvetrain and not something else missed.

Now some will say this is the time to pull the bottleneck rocker arm studs and replace with the stronger ARP Big Block 7/16" rocker arm studs. You could. But this will mean a little more work and money. And, you will need matching 7/16" poly locks. If you don't have a big cam, the factory studs will be fine. If you get into a big cam, then now would b the time to swap.

The factory 3/8" bottle neck studs will have a slight convex curve on the tops of the studs - ie they are not perfectly flat. The 7/16" ARM studs are flat. The poly locks are said to work better and hold in place better with the flat top studs. I have used the 3/8" poly locks on several cars with little issue. I would periodically check them, maybe 1 time a year to make sure all is well if you don't put a lot of miles on your car. Should you develop any ticking noise, then you will know right away what it is - a poly lock has loosened up on you and needs a little attention. I usually keep tools & a few spare parts in my trunk anyway, so keep an allen wrench, box wrench, and socket set should you need to do a roadside check/fix if it ever happens.


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## LATECH (Jul 18, 2018)

Cut the oil filter open (The used one you removed ) .
Check the paper /pleats for metal which would indicate engine damage. If you see some, run a small magnet across it to see if it is ferrous. That will indicate Iron parts like lifter face,or cam lobe, etc. , non ferous will likely indicate bearing material.

Do you know the proper way to cut a filter open? 
I am suprised this was not mentioned in this thread.


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## Stereolab42 (Apr 6, 2018)

Thanks for the big reply Jim. Since I think it's now more likely not to be valvetrain related I'll wait to see what the mechanic says on Monday. Exhaust leak/heat riser should be a simple fix, or maybe he'll just say it's normal or "I can't hear it". (I have a 440 Mopar with what I swear is a light ticking noise from the driver's side... three different mechanics said they couldn't hear it specifically and everything they could hear was normal, so perhaps I just have oddball ears.) If he says he does need to dig into the valvetrain, I'm now much more educated.

LATECH, good idea about the oil filter. I just ordered one of those oil filter cutters, which apparently must be used if you don't want to contaminate the crime scene with (perhaps additional) shavings. I did check the old oil carefully as it came out and didn't see a speck of anything foreign so currently I'm optimistic.


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## Stereolab42 (Apr 6, 2018)

Really looks to be the heat riser hardware. (Repop exhaust manifolds.) It gets quiet when I hold the "stub" up during a cold start. Going to leave it alone for now since it's not really that noticeable.


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