Valvetrain noise and start up smoke

[rfoll]

The car is a 1984 El Camino with a 305. The engine is original to the car and has 100 K on the odometer. The Computer Command Control is gone, replaced with a Performer, a QJ and Street Fire HEI. The timing gears have likely been changed, because it has a chrome timing cover that no one it their right mind would install because it looks pretty. Cranking compression is 180, and the car uses about 1/2 qt. of oil in 2000 miles. It runs like a top and gets 19 mpg freeway. It doesn't smoke visibly at idle, but when restarting hot, it produces a very visible, stinky cloud of oil smoke. In addition, at any rpm over 2000, it makes noise like a loose rocker. At first I thought it might have one of the noisy cheap solid roller timing chains, but I am now guessing maybe one or more really sloppy valve guides. If that is the case, do I really need to worry about it getting ugly and destroying the engine? I don't want to dive into an otherwise perfect running daily driver. Thanks, Rick

[travis]

I would pull the valve covers and roll the engine over by hand to make sure all the lobes are still there. This era of 305 was well known for cams going flat. This would also be a good time to roll the engine back and forth and watch the valvetrain and the distributor to see how much slack is in the timing chain. It may need valve seals also...very common issue with these as well especially with some age on them. Valve guides were more of an issue with the earlier 305 heads but always a possibility.

One quick way to check for timing chain noise is to use something like a cut down wooden broom handle or dowel rod, hold it against the timing cover with the engine running and put your ear against the other end. A timing chain that is slapping or rubbing on the inside of the timing cover will be quite audible testing this way. This is also very useful to isolate noises to valvetrain, water pumps, alternators, etc.

A flattened intake lobe can cause oil to be pulled up past the rings and make them smoke on startup. A flat exhaust lobe usually makes them pop out the carb.

[rfoll]

I should pull the plugs and see if I can find out if the problem is on a particular cylinder. Repairs are not in the cards right now. My wife is recovering from a full knee replacement, and I have my hands full.

[rfoll]

Pulled the plugs and none had any evidence of oil fouling. However, some had oil on the threads. The engine runs really strong for a stock 305. For whatever reason, the trans,(from a 1980 wagon), upshifts about 500 rpm too late, about 5500. It barks the tires in second gear.

[bigfoot584]

Pulled the plugs and none had any evidence of oil fouling. However, some had oil on the threads. The engine runs really strong for a stock 305. For whatever reason, the trans,(from a 1980 wagon), upshifts about 500 rpm too late, about 5500. It barks the tires in second gear.

With what you just said here, I'd look into a ruptured vacuum modulator diaphragm
on the transmission, sucking oil into the engine and hard shifts, if it's not shift kitted to do that.

[rfoll]

The trans is newly rebuilt with a shift kit. The vacuum modulator is new.

[ProPower engines]

Adjust the kick down cable a little longer to ad some slack to it that will speed the shift in a TH350 also adjust the modulator to speed the shift. If the cable is tight when the throttle is wide open then adjust the cable on the bracket by popping up the stop lock and let the cable go slack at WOT then push in the stop lock and try it.

I believe you unscrew the small adjuster screw in the center of where the vacuum line attaches but be careful as 1/2 turn is a big swing depending on what regulator spring is in the V/body.
You can also check the governor springs just pop off the bale cap on the side of the trans and pop of the cap. It will have a bit of fluid in it but jack up the right side of the car to do it and you will be fine.

[rfoll]

My experiments with adjusting slack in the cable have dropped the shift point to under 4000 rpm. I have been holding about 1/4" of cable, and releasing the adjuster and re-setting it. I may just convince myself to crawl under the car and swap out the governor. It's always been my understanding that the vacuum modulator primarily controlled part throttle shifts.

[PRH]

It’s not that uncommon to have one or more of the pushrod slots in the heads start to get “bigger”, which allows the rocker to move around more from side to side...... which can produce some of that “clackity” sound under the covers.

I’ve seen situations where the rocker is riding off to one side and the bottom of the rocker is “sawing” the stud off too.