What is that knocking?? HELP!

[frez]

OK, guys so I have been have a good time tooling around and cleaning this thing up. It is shifting great (changed the shift Coupler and Pin). I added the electric ignition from clarks to get rid of the points, that went fine. I changed the distributor cap (the old one had a chip in it (i did that). I changed all the plugs and wires (those plugs looked old. I took out the old retarder (i don't think it was working) and swapped out for the advance/retard from Clarks and i adjusted the timing to 18 (per clarks based on the new A/R). Now i set the timing with the A/R on not tube pulled and plugged as the manual states it is not neccisary for the turbo engine. With all that said i have always heard a slight clicking but now it has gotten louder over the last week (before I did all this work the clicking was just as loud but louder since i bought it a few weeks ago), i thought setting the timing would help, but it does not go away no matter which way i turn it. It sounds like it is coming from the top of the engine if i was to pick a cylinder i would say by #6. I speed up it speeds up I slow down it slows down. In idle and in gear. The car is running great otherwise I have to pump the gas a bit to get it to start but I assume that is not out of the ordinary. The only thing I have done is added a few tanks of regular gas that is what is in it now, before i read that premium would be best for the corvair. So with all that here are my questions:
1) What the hell is that knocking
2) Could it be the gas
3) Did i set the timing right
4) i set the idle screw to 850rpm before i set the timing per the book, and now it is about 950 at idle, if i back it out trying to get back to 850 the engine dies as that is almost all the way out, did i set something wrong

[frez]

just an update, i re-read what clarks told me and they said to set timing to 18 with the a/r tubed pulled and plugged so i did that setting to 850rpm and timing @18 then put the a/r tube back in which brought it up to 950rpm and over 24 on timing. still all the same questions

[frez]

oh and the knocking might be the bottom, i hear it from that side above and under the car

[bbodie52]

There are two common forms of "knocking" on a Corvair...

(1) The rattling, pinging form of knocking associated with detonation. This can be caused by a vacuum leak and resulting lean fuel/air mixture. It can be caused by low-octane fuel, when Premium fuel is called for. It can also be caused by incorrect ignition timing. Detonation usually occurs under load, and not at idle. It is a rattling sound you might hear as you accelerate or climb an uphill grade, but would decrease or stop when coasting.

(2) The constant knocking associated with a defective hydraulic lifter that is failing to pump up and close the gap between the rocker arm and the valve inside the valve cover. This sound is common on Corvairs when one or more hydraulic lifters has drained its oil with the engine off. (The lifters sit horizontally inside the engine, and they rotate slowly within their bore as the engine runs. There is an oil hole in the side of the lifter, and if the rotating lifter happens to stop with the oil hole facing down when the engine shuts off, gravity may pull the oil out of that lifter, which causes it to rattle with excessive valve to rocker arm clearance until the lifter refills when the engine starts. This rattling sound usually clears on its own as the engine warms and the oil gradually pumps up the lifter to close the clearance between the rocker arm and valve. If the lifter is defective, or if the rocker arm has not been adjusted properly, or if there is a defect such as a bent push rod, the knocking sound from the valve train defect may not clear on its own until the mechanical defect has been corrected.

An inexpensive mechanic's stethoscope may help you to localize the source of the knocking sound you hear. If it is a loose rocker arm you may have to remove the valve cover to determine the cause.

The worst knocking sound is an internal mechanical failure, such as a failed connecting rod bearing. Such a sound can indicate a serious problem with a damaged crankshaft and bearing. It is a more-distinct mechanical banging sound from within the crankcase. Since these sounds can be carried through "telegraphing" through the metal engine components, they may be more difficult to localize to determine the cause. Again, a mechanic's stethoscope may help to locate the source.

[frez]

thanks brad could #2 have happened when i changed the oil/filter/pan? i did that all before the noise got this loud.

[frez]

ok i got a stethoscope and it is not coming from the engine it is a rocker arm. Does that mean it is an adjustment as per the Rafman website

"install your oil catchers on both sides and follow these steps:

1- let the engine warm up.

2- starting at either end, loosen the nut until the rocker arm starts clattering/ knocking/ ticking & let it do its thing for at least 15 seconds.

3- re-tighten until the clatter goes away & go 1/4 to 1/2 turn. Proceed in that manner until all valves are adjusted, and you are done."

[miniman82]

#3 would be a rattling flywheel that goes away when you depress the clutch pedal.

[bbodie52]

If you identify a specific rocker arm that is banging away because of clearance between the rocker arm and the valve, you need to determine the cause. You might look at the exposed threads above the rocker arm adjusting nut. The number of exposed threads usually appear about the same on the array of properly adjusted valves. A bent or damaged push rod or a damaged rocker could account for excess clearance, as could a stuck or collapsed lifter. A sticking valve or a damaged valve seat might cause the valve train clatter, since the valve would never fully close (this condition might be revealed by a low compression test in the bad cylinder). The adjustment procedure has you adjusting the rocker for zero clearance, and then adding an additional turn that pushes the plunger into the lifter about half-way. The properly functioning hydraulic lifter then automatically compensates for expansion of the valve train and engine components as the engine warms after starting. This maintains zero clearance in the valve train components as temperatures and expansion varies with temperature. A damaged component, a stud that pulls out of the engine cases, a bent push rod, or a stuck hydraulic lifter internal component could all explain a noisy valve train. Over-tightening the adjuster nut could push the internal lifter components all the way to the bottom -- making it like a solid lifter. But then the valve train might be too tight as the engine components heat, and the 'solid " lifter might cause the valve to remain partially open and never fully close, which could cause low compression and a burned valve or damaged valve seat as hot gases leak past the valve when is supposed to be closed. An excessive number of exposed threads above the adjuster nut might reveal a rocker that has been over-tightened.

Again, if you identify a specific noisy valve, you need to determine why that particular valve became noisy. If the adjustment nut is in about the same position as all of the others, something else in the chain of components between the cam lobe and the valve has changed to make it noisy. The trick is to identify the faulty component so that you can correct the fault.

[64powerglide]

[frez]

Hah!

[1949chevy]

The way I was taught by my super mechanic as applied to my corvair vs my two chevy v-8's, my 283 and 327-350hp in my vette.

I drop the mufflers down so they stay working, otherwise you will never hear the clacking. Remove the valve cover, put on cut down valve cover to keep some oil off the floor. I then start the car and let it warm up. Then I back off each nut until I hear clacking. I SLOWLY tighten down the nut until the clacking stops. I then move to the next lifter and repeat what I just typed until all are done as I stated. I then TURN THE ENGINE OFF and turn each nut down 1/4 to 1/2 turn. My method makes sure you do NO damage to your valves which you can do by turning them down while the engine is running and with the engine off, adjusting the valves is much easier and faster.

If the clacking/noise does not stop...you may need a new lifter or you might have a bent push rod.

I bought one used valve cover and cut it into 2 pieces and made the oil catcher for both sides.

[frez]

Thanks all i will get it up on the blocks this weekend and see how the adjustment goes. I have to put in new lower shroud thermostats as those are both failed open anyway. I can do it all at once