Sludge. What did I expect?
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| Not my motor. Mine was worse! |
It wasn't just a bad lifter, it was a burnt valve. I decided to tear down the engine and do a valve job. I pulled the rocker arm covers and saw what was going to be a problem. The motor was full of thick, black, gritty, sludge. I filled an entire coffee can with the sludge that I scraped off the inside of that motor!
Extreme sludge build up is not a common problem with modern engines, for several reasons. First of all, the adoption of emission control equipment has required that engines run at a much higher average temperature. Engines are designed to achieve this temperature more quickly to fire off the catalytic converters. The engine has to quickly warm up enough to "get off the choke"and run off of a leaner fuel mixture.
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| photo source: quora.com Many times a stream of water is also spilling out. |
I'm sure that you have observed steam streaming out of a car's exhaust pipe when it been started on a cold morning. That's because of the water that forms within the combustion chamber. The same thing happens when we breathe out on a cold morning. It condenses in the cold atmosphere. This moisture soon evaporates as the motor and exhaust system heat up to cause evaporation.
Unfortunately this period would last a lot longer prior to the mid 1970s. Water actually would condense in the crankcase of the motor. Moisture laden combustion blow by would collect in there also. This would mix with the churned up oil in the crankcase. After achieving proper operating temperatures the moisture could evaporate and be removed by the crankcase ventilation system.
Now if this car was owned by the proverbial "little old lady" who only drove it six blocks to Church on Sunday, then it never was driven enough to get it hot enough to boil out the oil. Instead all that moisture was whipped up in the spinning works until it resembled carbon fouled mayonnaise. Without proper maintenance, which would be frequent oil changes, this mixture coats the engine internals and forms a thick layer over time. The sludge traps the carbon grit and holds it in suspension, occasionally releasing a chunk into the oil stream where it circulates to the detriment of the engines's life.
Luckily the same efforts that auto manufacturers have made to clean up our air have also contributed to the longevity of our engines. Manufactures were required to provide a 50,000 mile warranty on emission control systems and equipment. This lead to use of higher quality materials and manufacturing practices. Long term reliability has been achieved in this area.
There have been major improvements in fuel control systems. Electronic fuel injection, electronic engine control modules, positive crankcase ventilation, catalytic converters and more. Not to mention improvements in oil and gasoline formulations.
Also, our modern long commutes really help keep our engines clean. Our cars are at optimum operating temperatures for extended periods of time. All that, in a nut shell, is why modern cars have such a long life. Back in the Day, cars needed a valve job at around 40-50,000 miles and a total engine rebuild at 90-100,000 miles. (If you were lucky!)
A well exercised car is a happy car. Back to the Riviera.
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Mistake number One:
After removing the heads I took them to a "random" machine shop to have a valve job done. I actually mean random. I had seen the shop while wandering around industrial San Jose. I didn't even think to ask the guys at my local auto parts store for a recommendation. The guys at the shop didn't seem to be familiar with old time American V8s, there were mostly small four cylinder motors lying around. So I dropped off the heads and hoped for the best. Who wouldn't know how to perform a routine valve job?
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| image source: DC comics. This kind of described the inside of my motor. There could have been a skeleton buried in all that sludge! |
While the heads were out I decided to change the cam chain/sprockets and oil and water pumps. On the Nailhead motor both of these things attach to the aluminum timing chain case cover.
This was obviously a motor that hadn't received much care over the years. The attachment bolts had literally welded themselves to the cover. When I attempted to remove the timing chain cover four bolts snapped off and stayed in the block. Oh, how I fiddled with those broken bolts. I was able to remove the two that were sticking out of the block with a pair of vise grips. The other two were broken off below the surface of the block. There was no way to access these bolts with the motor in the car, so the motor had to come out. I just had to buy a cherry picker first.
I stripped it down to the bare block so that I could stand it upright. I placed a couple of two by fours under the bell housing mounting surface. Lot's of drilling, picking, soaking, and swearing followed. After a long time the broken bolts were removed. At first I had thought to just clean the parts up and reassemble, but after seeing that mess I had a great idea, "why not rebuild the entire motor?"
Mistake number Two: ( It will become clear later)
I had picked up the heads from the shop and they looked good. Clean and shiny and painted. I certainly didn't want to bolt them onto that crappy mess in the garage!
This time I got a recommendation for a machine shop. I dragged the whole filthy wretched mess to the shop in the back of my New Honda Civic. A couple of weeks later I hauled the newly machined block and new components back home. Of course I reassembled all these parts myself. This is called the short block in the rebuilt motor business. Why shouldn't I get a share of the glory?
Rebuilt heads, rebuilt short block. What could go wrong? Believe it or not, Plenty!
I installed the motor in the car and was anxiously awaiting the moment of truth. Like an airplane passenger that only cares about the landing, I was looking forward to this most sacred gearhead moment. Wrenching don't mean nothing if the motor don't fire up. Why shouldn't I get a share of the glory?
All fluids in, wires and hoses hooked up, initial timing set, a little gas poured down the carb. Turn the key and it catches. Roaring to life! I stood vindicated! blah blah blah. Except... What was that steady tapping noise? It had sounded like that before I tore down and rebuilt the motor. What was up with that?
Maybe the lifters just had to fill up with oil, then they would quiet down.
I'll just let it run until it warms up completely, that should do it. Right? No, not right. Maybe, just maybe, one of the lifters picked up a particle of dirt that prevent it from filling properly with oil. Sure, that could be it.
I pulled all the lifters out to inspect them. I even filled them manually with an oil can, then I let them "soak" in a can of oil. Did I think that they were some kind of metallic sponges?
Reassemble and repeat. Experience extreme disappointment. Again.
I was running out of ideas, what could it be? Maybe the rocker arm assemblies are worn enough to cause the clattering sound. I'll order a new set, they were only around 300.00!
Things are starting to get (more) expensive.
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| photo source:centervilleauto.com Boy, are they pretty when new. |
Little did I know that it was going to get even more expensive.
Okay, I'll just reassemble all these new parts. It seemed to me that I had rebuilt just about everything in that motor. Connect all hoses, fittings and wires. Prime the carb, turn the key. It roars to life. I was almost ready to pat myself on the back when that dreaded tapping started again. What COULD that be? I shut it down and walked into the house, time to gain a little distance. The car could wait, and it did, for several months.
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