The Cutlass Get’s an Engine Tick!

Diagnosing an engine tick is probably the most annoying part of building or maintaining a car. The sounds can be hidden and masked in a number of different ways, and are almost always caused by a problem that you can’t see.

Here I’ll walk you through the symptoms, diagnosis, and inspection of the engine tick that recently started on my freshly rebuilt Olds 455.

I find that this is also a good place to plug my book Troubleshooting With Your Senses for the more casual owner/driver, since it focuses on diagnosing issues on the road!

Background

This engine has only ~600 miles on it since it’s original build (by someone else). The engine made good power, but over those 600 miles a number of issues surfaced.

Discoveries include:

• The harmonic balancer had been “modified” to include a timing mark 40 degrees advanced from the proper location. I can only assume this was done because it was used on a block with a different timing pointer location? But who knows…
• The new high torque mini starter had weakness and sometimes improper tooth engagement. I discovered why, and the short story is DON’T buy Powermaster starters.
• One rocker arm had improper valve lash. But this could also be caused by lifter/cam lobe wear and perhaps was correct initially.
• NASTY coolant. Some sort of brown/clay color, but seemed to be something other than rust, almost as if the block had been buried?
• Dirty oil with metal everywhere, even after 2 oil changes.
• THE TICK.

Engine details can be seen in This Timelapse Video of the frame off restoration.

It has also been struggling with detonation since first startup and 93 AKI octane. The first issue was the harmonic balancer inaccuracy causing over advanced timing. Second was EFI tuning issues causing lean tip in. After fixing both, detonation only occured when very hot, but still occurred. My theory was that the heads and block were overly decked + flat top pistons, causing overly high compression. Solutions without buying new pistons?

Symptoms

The Cutlass would occasionally have a banging sounds when starting. I originally attributed this to the defective starter, although after working on the starter it still had an issue. This would turn out to NOT be related to the engine tick.

The ticking came from the exhaust leak on the driver’s side header gasket, yes, but there was also another tick. It sounded like it was coming from the top end, although couldn’t be positively identified. To my ear, it sounded like lifter ticking, but not exactly.

Diagnosing

So, I finally got some free time over a weekend to begin diagnosing the issue. This was around 9/17.Using a stethoscope, I tried to find the source of the ticking. It seemed loudest near the lifters when listening through the intake manifold, but just barely. It also seemed louder under the engine near the oil pan. More or less, the stethoscope didn’t help.

I checked the flex plate for cracks and checked the flex plate and torque converter bolts for tightness. All tight. I also check the accessory pulleys and bolts for tightness, all good.

I went deeper and removed the valve covers to check valve lash. I had just checked valve lash 300 miles earlier, so I didn’t expect or find any loose rocker arms. I decided to run the engine with the covers off to check for oil flow. All rockers had oil flow, although the oil did have metal sparkle in it. Still nothing.

Next was checking for a wrist pin issue by pulling spark plugs one at a time with the engine off. I pulled cylinder #3 and NO CHANGE to how the engine ran. Pulling a spark plug wire off should cause the engine to stumble or RPM’s to drop.

CRAP.

Spark on Cylinder #3 checked out good. I shocked myself by accident through rubber gloves and boots. The plug was new and also didn’t have any concerns. If you haven’t guessed by now the worste case scenario would be compression. The compression was 0 psi. Not “Near 0”, actually 0.

I removed the rocker arms and checked again. 20 psi. It probably went up slightly because there wouldn’t be valve overlap with the big cam. Next I added a cap of 10w40 oil to the piston and compression went up to 120 psi. Other cylinders are consistently 170-180 psi. There is definitely an issue with this cylinder. I also saw light scoring on the cylinder walls after only 600 miles.

Given this problem, and all the other problems noted above, this engine was getting pulled out of the car.

“That’s Not Gone Well” – Jeremy Clarkson

Tear Down

The engine was pulled on Friday. By Saturday it was stripped to a bare block.

 The Good:

• The block and pistons were 0.060 over. This was one question that couldn’t be answered by the seller. Not really a plus or minus, depending on your preference.
• The block has oil resistors correctly installed in the cam bearing oil passages, correct internal oil passage block plugs and oiling holes for the cam and timing gear.
• The block had oil return passages in the cam and heads properly enlarged to help with oil return flow. Nice plus.
• Bearings seem to have been correctly installed, and there was no obvious signs of binding.
• The pistons matched and were the same size. I have seen this not be the case on other used engines.
• All bolts and gaskets seemed to be torqued and installed correctly.
• All the goodies were there, including main girdles, windage tray, etc.
• There were no obvious signs of a wiped cam lobe or lifter.
• Cam timing was set correctly. I was concerned about this earlier with some run-ability issues.
• It seemed like the engine was assembled well, except for filth everywhere. Not sure if this was from assembly or while running. I expected a clean engine after only a few hundred miles, and you should too.
• The engine seems to have been externally balanced. It will be internally balanced when I’m done however.
• No obvious head/valve damage. They will be disassembled and checked.
• Crank journal oil passages were chamfered well.

The Bad:

• Flex plate has a broken tooth. This was probably the cause of the “Bang” occasionally heard when starting. This may have been caused by the defective starter, or perhaps defective flex plate.
• Deep scoring was found in cylinders 2 and 4. These will need to be sleeved. The other cylinder walls looked OK and will be fine after a light hone. No serious issues were found with cylinder #3 however, which was the no compression cylinder.
• The cylinder’s were not chamfered at the bottom after boring, which probably caused metal to reach the piston skirts and cause scoring.
• There is some wear on the rear facing thrust surface of the main journal bearing. This requires more investigating.
• In general, all bearing surfaces had some scoring, which was probably caused by oil contamination.

The Ugly:

• Oil pan had some crap in it. There is water from the teardown making it difficult to see, however this water is not from when the engine was running.
• The coolant passages were so nasty from brown crap that the coolant in the lower parts of the block wasn’t even slightly clear. The lower drain plugs were completely blocked off with debris.
• Oil had alot of magnetic metal after only a couple hundred miles.
• The pistons/rings were covered in crap, mostly carbon. But so much carbon after such a short time?
• Metal, metal, and more metal particles.

*Update after further disassembly*

• Piston to wall clearance of .007-.009, or about triple the recommended spec of .003′. This probably contributed to the excessive oil found in each cylinder (poor ring seal).
• Broken #3 cam bearing. It was split at the top, which wasn’t done during removal.
• Lots of rust/scale/garbage in the coolant passages of the block. It was probably stored full of water.

The problem is: What caused the tick and no compression in #3?!?!?!?  😥

Since I didn’t find obvious cylinder or head damage on #3, I’m leaning towards a lifter or valve seat issue, but it must not be obvious. Worst case scenario would be a cracked head or block. Both will be cleaned/dipped and checked for cracks before rebuilding. I won’t have this answer until the machine shop finished their work.

After all of this, people are starting to call the car “Bad Betty”

*UPDATE*

After cleaning the pushrods and adjusting their length during assembly of the rebuilt engine, one pushrod for #3 cylinder was bent. This was probably either a lifter problem or mis-adjusted lifter pre-load. These are also adjustable pushrods, which aren’t the strongest. Whatever the cause, this lifter/pushrod/rocker arm combo was probably the compression issue and ticking issue. With a visual look, there may be a couple others that are a bit tweaked. Looks like new pushrods are on the menu to accompany the new roller cam and roller lifters.

Also the piston rings were 1/16″ thickness, while the pistons were designed for 3/32″ clearance, leading to excessive side clearance and if not caught eventual failure. This likely caused the oil in the cylinders that I was seeing and possibly compression issues.

For the records, as found:

Main Bearing ID: 9/97 .020 Lower MB-2362 P Clevite 77 B-01

Cam: Engle JM 22 25 Hyd 10 0

Pistons appear to be from Mondello. Marked SPD 2060 060.

For Reference, Stock 455 specs are: (All shared with the SBO 350,  except main bearing journal diameter)

If you have an idea which I haven’t though of, please leave a comment!

Happy Building.

LEFTLANEBRAIN