ticking valves?

[Amsterdam]

my 1964 Monza Spider seems to have developed a nasty tick in its engine.....No drama when engine cold but after some time when the engine warms up the ticking starts. I have ruled out the electronic fuelpump because that is a noisy bugger too. Will do an oil-change tomorrow with a higher viscosity , I don't know what is in there at the moment.
I have a video of the engine running but I can's seem to upload it (attachment too big?)
The more I work on it the more noises I start hearing so I like to get a second opinion...what kind of noise is acceptable of this engine?
Rob

[bbodie52]

If you do not have the rocker arms adjusted properly, that could be the reason that the ticking noise you hear only begins once the engine is warm. The shop manual procedure basically has you adjusting the valvetrain for zero clearance. THEN... the rocker arm nut is turned an additional ½ turn tighter to center the piston inside the hydraulic lifter. There is a significant amount of cast iron and aluminum components between the camshaft and the intake or exhaust valve. The aluminum and cast iron components expand differently as normal engine heat increases. The properly adjusted hydraulic lifter automatically maintains a zero clearance within the valve train while allowing the valves to fully close. You may also have a defective or gummed-up hydraulic lifter. If the lifter piston is sticking. The mechanic's stethoscope may help you to locate the specific noise source. If it is valve train noise, you may have to remove the valve cover to permit inspection of each individual valve and rocker to determine the source of the noise. Once you find the source, you may be able to determine what corrective action is needed.

The engine hydraulic lifters can make a sound that is similar to the sound you described. Since the lifters lie on their side (unlike those in a Chevy V8) the oil in the lifter can drain if the lifter (which rotates in its bore) oil hole happens to be facing down when the engine stops. This type of noise is somewhat softer than a connecting rod knock, and usually quiets down as the engine warms up and the lifter refills with oil.

I actually did have a connecting rod bearing failure one time in a 1963 Corvair. It had a more=distinct sound and requires some tender loving engine teardown!

The manual transmission Corvair flywheel is a two-piece affair with a flex plate riveted to the flywheel. The rattling noise from the bell housing are usually quiets when you depress the clutch pedal enough where the throw-out bearing comes into contact with the pressure plate diaphragm spring. The noise will return when you take your foot off of the clutch pedal.

Although I have never seen this, I suppose it is possible for the three bolts that hold the automatic transmission flex plate to the torque converter to come loose.

A really bad cooling fan bearing can fail and cause a lot of noise.

The three piece harmonic balancer can separate and loosen the outer ring. The inner hub and outer ring are pressed together with a rubber damper component in between.

Running the engine very briefly with the fan belt off can help to identify a fault there.

A mechanic's stethoscope can sometimes help in localizing thee source of the noise.



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[Frank DuVal]

Just to rule out a dropped seat, do a compression test. See if one is way out of line.

If one is out of line, or all are reasonable, next take a valve cover off and check do not do a valve adjustment. What? Set the crank pulley on the spots found in the shop manual for doing a valve adjustment. Then see if there is zero lash on those valves (tight rockers). Rotate crank and check the others. Yes you can do this cold. This is looking for a valve that may be out of adjustment. If one is, see why. Do not do the rest, they are fine.

10W-30 is a fine oil viscosity for Corvairs, especially upper Europe weather. If it takes 40 single weight or more to quiet the noise, there are issues!

A worn valve guide can tick. That stethoscope can help pin-point. So can a long screwdriver, handle held to your ear. And there can be a tick from an exhaust leak. Head gasket failure starts as a squeak, not a tick usually.

If you put down enough paper you can run the engine without valve covers to see if you can hear the tick. Be warned, there is a lot of noise there, so it may be hard to hear. And you will loose maybe a quart of oil depending on how long you run it. I used to adjust valves hot after o-rings and sometimes didn't use the cut down covers. Hot oil treatment for the arms I called it. Those half (third, whatever) valve covers are nice for this . I do cold valve adjusting these days, unless it is a high miles worn motor.

[vairmech]

LOL, I agree with Frank this time!!!! But we generally think pretty much alike.

10W-30 is sufficient for the Corvair as long as it has enough zinc in it. Most diesel oils have enough. See this web site, [url][https://www.widman.biz/Corvair/English/ ... l.html/url]

[Amsterdam]

thank you guys, enough to work on!

[66vairguy]

I know this is a "touchy" subject so take it as just what I've learned and what works for me. Feel free to do your own thing.

If you are not going racing or driving in extreme cold or hot, the 10W30 works well in the Corvair engine.

About ZDDP - After reading Richard Widmark's oil comments and looking at the history of zinc in oil I found any of today's 10W30 motor oils work well up to about 1,000 miles. Old cars used little zinc (ZDDP was 400PPM or 0.4%) in the oil until GM and Ford extended oil changes to "Save the customer money on maintenance". This is when camshaft failure increased dramatically on cars under warranty so ZDDP was increased to about 850PPM. Then the high output big cam engines of the 60's saw performance oils with up to 1200PPM ZDDP. The engineers found the optimal amount of ZDDP (1200ppm, 1.2%) stopped camshaft/lifter scuffing when oil got old and the film failed.

NOTE!!!! When ZDDP levels approach 2,000ppm bearing and journal surfaces exhibit corrosive damage!!!! Yes too much is bad for the engine.

ZDDP was reduced because it "plugged up" catalytic converters. Meanwhile diesel motor oil ZDDP has also been reduced due to emission regulations, BUT other additives are used now that reduced engine wear. So the level of ZDDP isn't a good reference now.

Put another way --- change the oil before it wears out and ZDDP function isn't needed with today's quality motor oils. As Richard Widmark pointed out - today's oils are superior to the oils sold in the 1950's and 1960's even without higher levels of ZDDP.

Considering the few miles I put on my hobby cars, changing the oil at 1,000 miles isn't a problem. IF you drive your Corvair daily then a motor oil with more ZDDP (or other additives) for longer oil change intervals is worth it. Since most of use don't run our cars often and trips tend to be short (which adds a lot of contaminants to oil) - oil changes at 1,000 miles make sense.