[pippintook]

Thanks for the replies - this had made my troubleshooting better.
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Note, I have not yet taken the oil filter off and inspected. Plan to do that soon.
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So, today (Mar17) I started the engine. Temperature around 50F and valve covers still off. I used my ex-wifes nail polish and drew a small line at top of each pushrod. When the engine was started I could see all the pushrods were spinning. A few pushrods were spinning slower. I could maybe hear a light tapping. As engine warmed, I could not really hear the tapping. If I leaned my ear real close - just maybe light/faint tapping.
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After 20 minutes or so the engine was fully warm. Idle was around 750-800 rpm. Engine oil pressure and engine water temperature looked normal (via gauges). Still no tapping ! All the pushrods were spinning pretty fast except for
exhaust on cylinder 4 - it was spinning but pretty slow. I also noticed that oil would periodically shot out pretty far from one of either cylinder 3 or 5's pushrods (like triple what any other pushrod did). This powerful shot of oil was happening intermittently.
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I let the engine idle for another 10-15minutes. I added the the remaining 8oz of my Marvel Mystery Oil (MMO) bottle. Note, I had previously (about 2-3? weeks ago) added about 6oz of Seafoam and 8oz of marvel mystery oil.
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Schurkey's tip for shorting the ignition wires is great Using small copper wires in the HEI seems pretty safe and easy way to short cylinders from firing. When I had engine running , I attached my testlight to a ground and then
bring the test light tip very close to copper wires on the HEI cap (for cylinders 1-3-5-7). When shorting each a cylinder via the copper wire in the HEI cap, I can see the spark jumping to my test light. (will upload a video). The engine just seems to die a little - but I see the vacuum gauge drop about 1.5" of vacuum and become a bit more erratic.
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Tapping / clacking seems strange...
One day, pretty heavy tapping - tapping happened when engine started - this was on a cold day with temperature around freezing (32F). Another day, tapping when engine was cold and warm - but, then tapping stopped after engine ran for about 25minutes. Now today, really minimal or no tapping on cold or warm engine. One thing I do notice is that the vacuum gauge reading at idle is around 19" - but it is a bit erratic. I will upload a video of this.

It is possible the noise was a sticky lifter? And maybe the seaform/MMO has helped to free it up? If not a sticky lifter , what else could have been making what appears to be an intermittent tapping / clacking noise ? At idle, can it be normal to have a slightly erratic vacuum reading of around 19"?

I was kinda getting ready to tear down and inspect the cam lobes and lifters. Not sure now what to do? Any advice on best way to proceed ?

[Schurkey]

Originally Posted by pippintook

I have not yet taken the oil filter off and inspected. Plan to do that soon.

Worthwhile.

Originally Posted by pippintook

I used my ex-wifes nail polish and drew a small line at top of each pushrod. When the engine was started I could see all the pushrods were spinning.

Good news.

Originally Posted by pippintook

A few pushrods were spinning slower.

Not unusual.

Originally Posted by pippintook

All the pushrods were spinning pretty fast except for
exhaust on cylinder 4 - it was spinning but pretty slow. I also noticed that oil would periodically shot out pretty far from one of either cylinder 3 or 5's pushrods (like triple what any other pushrod did). This powerful shot of oil was happening intermittently...

...It is possible the noise was a sticky lifter? And maybe the seaform/MMO has helped to free it up? If not a sticky lifter , what else could have been making what appears to be an intermittent tapping / clacking noise ?

I was kinda getting ready to tear down and inspect the cam lobes and lifters. Not sure now what to do? Any advice on best way to proceed ?

I have the sense that you won't feel right until you inspect the lifters and cam lobes. I suggest you remove and disassemble them one at a time for cleaning and inspection. Hydraulic lifters are essentially miniature oil filters. The oil pathway into the lifter is relatively huge, the oil pathway out of the lifter is microscopic. Sludge gets in, can't get out.

[steve25]

The excess oil spray out of some of the push rods is indicative of lifters that are bleeding down faster then others .
This can easily be the source of your temperature related noise.

With such lifters investing the time to take them apart and cleaning them out may or may not help.

I would not waste time in trying that cure especially since you have seen some push rods spinning noticeably slower then others.

This is a sure fire sign that those lobes and or lifters are on there way south.

In short, to me it’s cam and lifter time.

When you got things apart and before reassembly check the underside of all the rocker arm nuts, as a few times I have seen them displaying radial cracks out from the center from being over torqued passed 25 ft lbs.

These will never hold a valve adjustment for long, in fact from what I have see maybe only one or two heat up and cool down sessions and rpm is always a factor in that.

[pippintook]

Schurkey , steve25 and the other guys that have posted - thank you for the replies. It has really helped me in troubleshooting

Here is short video clip using Schurkey's great tip on shorting the ignition wires. Makes it easy to short the ignition wires https://youtube.com/shorts/u8cwepyTOcU

This is a video clip of the idle vacuum (engine warm and idling around 750-800rmp). 19" of vacuum looks decent, I think. But, vacuum is bit erratic. Maybe? that can also be a sign of sticky lifters. https://youtu.be/KPF_T-Tz0Cs

So, I guess the most likely cause of the intermittent clacking/tapping is sticky lifter(s)? Maybe the Seafoam or Marvel Mystery Oil helped free a sticky lifter(s) a bit? And that is why the clacking/tapping is becoming more intermittent/stopping or maybe tiny pieces of sludge are moving inside the lifters?

I tend to agree, it is likely a good idea to tear down a bit and inspect the cam lobes and lifters (rocker arms, valve tips, pushrods too).

[pippintook]

Strangely, the one pushrod that I see turning much slower is cylinder 4 exhaust. It seems to turn - but very slow. But, there has been really no noise from cyl 2-4-6-8. Most of the clacking/tapping noise was from driver's cylinders (primarily 1 and 3, it seems). The pushrods on cylinder 1 and cylinder 3 and all others (other than cyl 4 exhaust) appear to be spinning pretty fast.
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There was very little to no noise on the last start from any cylinder. Cyl 5 (which had intermittent - larger spurts of oil out pushrod) seemed much better.
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So I guess the diagnosis could be sticky lifers / maybe some internal grit/sludge is getting into lifters (or was in the lifters?). The sticky lifters / grit then causes the intermittent issues I am seeing ? Like intermittent clacking-tapping/slower spinning pushrod/intermittent larger spurts of oil from one pushrod. Perhaps, the marvel mystery oil and seafoam I added has helped dissolve or clean the lifters a bit and this made the issue better (or more intermittent?).
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It sounds like the best approach is to pull intake and inspect the cam lobes/lifters/pushrods/rockers and drain oil and check oil filter pleats

[track73]

Throw in some Marvel Mystery Oil and drive it few mies and see if it quiets down.

[78w72]

Hydraulic lifters definitely can be sticky or get debris in them, there are products designed to free sticky lifters, MMO & seafoam can work but rislone makes or made a product specifically for this. Might be worth a try if you are seeing/hearing improvements to the ticking as mentioned in the last couple replies.

Ticking/tapping noise is a very common thing with most of the hyd roller lifters, especially the older ones like the original comps, I had a set of those that were noisy and the 1st suggestion I got from SD performance & comp was to add seafoam to the oil at the suggested amount or a little stronger for a sort time to see if it helped, not just 20 min idling, actually driving for 50-100 miles, it seemed to help a little but the lifters were defective or a few were loose tolerances and just noisy.

Does rotella have a 10/40 oil? Always thought it was 15/40 or more recently they have a 5/40 synthetic or 10/30. I would use a good 10/30 synthetic if you have a roller cam, or conventional if not, up to you on brand but with a mostly stock size broken in cam you dont need race oil like VR1 etc, or super thick oil, especially in canada or starting it at freezing temps.

Try a strong dose of MMO or regular dose of seafoam & drive it for awhile to see if the noise improves then go to more drastic measures if it doesnt.

[steve25]

It may take “ more then a few miles “ to get a product like marvel to work as the motor needs to get to the point of having the oil temp darn close to what the normal water temp is.

Next time you are or other are washing dishes try doing it with cold water! :-)

[hobbygto65]

Have you tried checking the torque on the rocker nuts. If it's a stock engine they should be at 20 ft lbs.

[65madgoat]

Oh, you have HEI? Not a fan. Never was. I'd get rid of that to eliminate ignition.


https://www.youtube.com/watch?v=0ze4TpyHURw


FMG had similar symptoms you are experiencing due to his HEI failing.

[Schurkey]

Originally Posted by 65madgoat

https://www.youtube.com/watch?v=0ze4TpyHURw

Several errors and outright omissions in that video, none of which really matter. Kinda torques my jowls, though.

Also some good tips--using a spark tester in addition to an ohmmeter to test ignition coils; assuring that there's some kind of heat-transfer compound between module and distributor housing, and, of course, verifying the wire harness ESPECIALLY on cheap-junk knockoff distributors.

In the end, the HEI is THE most-reliable electronic ignition system on Planet Earth. Any downsides in the original design were handled after the first few years of production; and most of the failures of lower-mileage HEI systems now are the direct result of crappy imported parts made to be cheap instead of being made to be good. This situation is likely to get worse as HEI distributors become more and more niche instead of mainstream. The world revolves around distributorless ignition systems, and has for decades.

[PDC]

Originally Posted by Schurkey

Several errors and outright omissions in that video, none of which really matter. Kinda torques my jowls, though.

Also some good tips--using a spark tester in addition to an ohmmeter to test ignition coils; assuring that there's some kind of heat-transfer compound between module and distributor housing, and, of course, verifying the wire harness ESPECIALLY on cheap-junk knockoff distributors.

In the end, the HEI is THE most-reliable electronic ignition system on Planet Earth. Any downsides in the original design were handled after the first few years of production; and most of the failures of lower-mileage HEI systems now are the direct result of crappy imported parts made to be cheap instead of being made to be good. This situation is likely to get worse as HEI distributors become more and more niche instead of mainstream. The world revolves around distributorless ignition systems, and has for decades.

FWIW -I had Davis Unified HEIs in both of my Poncho powered TAs and they were nothing but rock-solid reliable every day I had the pleasure of enjoying both cars. The curve I requested was dead-nutz ‘on’ in the car once fired up. One of my Davis HEIs replaced an MSD ready to run and a Spark Box that gave me nothing but troubles. And zero issues after dropping in the Davis HEI unit.