Ugly engine noise, please help me diagnose. 1966 Austin-Healey 3000. (slo-mo video) - PeachParts Mercedes-Benz Forum

Shortsguy1 · #1 11-30-2015, 01:28 PM

Hi-
I have posted these videos over on a Healey forum, but I respect the amount of engine knowledge on PP very much. So perhaps someone here has a few thoughts.

The engine of my mom's 1966 Austin-Healey 3000 BJ8 makes a ticking sound which is troubling me very much. The sound is most noticeable at idle. It is a ticking or clicking sound, at the same speed as the engine. I have adjusted the valves twice (0.015 inches cold the first time and 0.012 inches cold the second time) and it hasn't changed the noise. I have filmed the engine with the valve cover off, so I am hoping someone can help me figure out the problem.

Both videos are at idle, although I don't recall if the RPM was slightly elevated because the engine wasn't very warm. I think the loud clack is pretty obvious, but let me know if you aren't sure what noise I am worried about:
https://youtu.be/nAYgH7i2atQ

This second video used the iphone's slo-mo feature. It is actually pretty cool because you can align the noise (now muffled, but clearly louder than the other noises) with the valve movements. At 0:24, you can see that the noise aligns with valve 1 and 3 starting to open. At 1:45, the same noise aligns with valve 8 and 11 closing up. I have no idea if these sorts of noises are more commonly associated with opening or closing of a valve.
https://youtu.be/Cfv1scOIiwk

Before I filmed any of this, I used a mechanic's stethoscope to try to find the problem. If I had to guess, I think the noise was towards the back of the engine. I had trouble getting any more specific than that. But this does make me think that valve 8 or 11 are more likely the culprit than 1 and 3.

Nothing else looked awry in the engine, but I am not very experienced with these cars. I checked the pushrods by rotating them and they all seemed straight. There seemed to be plenty of oil pooling up there, but I guess I don't know for sure. British cars do have less oil up here than some other vehicles, I believe.

The engine was rebuilt 4000 miles ago (17 years ago), but the car has only been driven 200 miles in the last 10 years. So it may have developed some problems due to lack of use.

Also, when I received the car, it had a lot of rust on the underside of the valve cover. The valve cover rust was worst at the back of the engine. It was flaking off and small chunks were landing on the valve train. Clearly this could cause damage which might cause the noise. I tried my best to clean off all the rust and wipe away any chunks, but who knows what happened before I ever touched the car.

Anyway, sorry for all the background info, but I wanted to provide it in case it is helpful. I guess my main request is for someone to watch the videos and let me know if you recognize that noise. Thanks so much for any assistance you can provide. I really need your help with this one.

kerry · #2 11-30-2015, 01:42 PM

It does sound like something in the valve train to me. How does oil get to the valve train? Is it possible some portion of the valvetrain isn't getting oil? i couldn't detect the noise on the slo-mo version.

Jorn · #3 11-30-2015, 01:43 PM

Piston slap? try some thicker oil and see if it changes the sound.

Idle · #4 11-30-2015, 02:42 PM

Quote:

Originally Posted by Jorn

Piston slap? try some thicker oil and see if it changes the sound.

That's what I was thinking. The connecting rods on these cars are not the strongest in the world and any play between then and the wrist pins could cause a noise like this.

But I would keep chasing the valve train since it would be the easiest to repair.

But if you put the scope on it again and the noise sounds like it is coming from the area of the cylinders then piston slap is about all it could be.

barry12345 · #5 11-30-2015, 04:14 PM

Got a mechanicaL fuel pump? If so try to listen closely to it.

Idle · #6 11-30-2015, 04:32 PM

It is possible that it is a cam bearing.

You would need to put a gauge on it to see if the cam is running true but these are easy to find on Ebay for around $40. These gauges are also handy when determining brake rotor run out.

Shortsguy1 · #7 12-01-2015, 08:14 AM

Hi Guys
Thanks for all the suggestions. As some of you surmised, the valve train is apparently not getting the amount of oil it is supposed to. On top of the rocker arms are holes which are used to drill an oil hole through the rocker bushing. For some reason at some prior time, somebody brazed those closed (incorrectly), so no oil can come out of them. So I still don't know what the noise is, but I do now know that whoever worked on this engine at some point didn't exactly know what they were doing.

I am already using 20/50 oil, so if it is piston slap, is there anything I can do about it (other than a complete rebuild)?

I didn't understand Barry's question about the fuel pump. I believe the car has an electro-mechanical fuel pump located near the fuel tank. You can hear it click a few times when you first turn on the car. The noise in the video is not the same as the clicking of the fuel pump, if I am understanding your suggestion correctly.

Thanks for the help. I sadly think this engine is going to need some sort of major overhaul, only 4000 miles after it had a prior overhaul.

barry12345 · #8 12-01-2015, 10:20 AM

The engine was so old I thought it may have a mechanical fuel pump. They run off a cam lobe and can make similar noises to what you have if the pivot arm or it's spring is worn on occasion. Obviously you describe an electric fuel pump.

I might go to an English car site and ask about the brazed holes in the rocker arms before much else. They may also have some helpful information. There may be typical problems with these engines that our site members are not aware of.

Air&Road · #9 12-01-2015, 02:40 PM

I was surprised at how well the sound came through on the video, but it is still not like being there. It sounds like it is not comin from deep inside. Did you say you have already set the lash?

link · #10 12-01-2015, 03:08 PM

Try listening to some similar noises recorded on other youtube video/audio recordings. There are some very clear examples of valve, piston and rocker arm slap related noises.

To my ear your video sounds like 2 ticks in quick succession and comparatively loud, as if coming from a bigger part. Due to that I guess piston rings, or maybe the big end bearings. But only a guess…

You may try removing one spark plug at a time to see if the problem persists. If it is due to a piston there will be far less force on the piston if it is not getting compression or detonation and so the noise will diminish. If due to a rocker or sticky valve the noise will be about the same. At least that is a working theory...

optimusprime · #11 12-01-2015, 03:13 PM

I would find the one i thought was the culprit and remove the pushrods .Some times the tappet as a step in the base ,in the place you put the guage in to find and set the gap.You need to remove them and inspect all the top end ,push rods tappets also inspect top of the valve stems were they contact the adjuster and the valve top .My car as the same engine as your car .I have the Ausyin 3 Litre 1970 six in line .Another check is to put a thin feeler guage under the tappet as its running ,short time only , and use old feeler guage ,it may damage it ,the guage that is.. .You will find which one it is .

Mxfrank · #12 12-01-2015, 04:10 PM

I dont think you'll identify this without some diassembly. I'd be looking for a bent pushrod, bent valve stem, bad lifter, flattenened cam lobe, or a problem with the rocker arm, related to poor oiling. AH engines sound a bit agricultural, but this is a bit much. At least we can eliminate your SU fuel pump as a suspect.

Air&Road · #13 12-01-2015, 04:13 PM

For the most part, killing a cylider would only change the knock if its something like a rod bearing, piston pin or something weird with a piston. It would be helpful though to kill each cylinder in turn and see if you hear a change.

kerry · #14 12-01-2015, 04:26 PM

If it's an oiling problem, perhaps it can be confirmed by pouring a bunch of oil over the valvetrain in the suspected area. If the noise diminishes with the excess oil it might at least narrow it down. Take a quart of oil and pour some over each rocker/valve/pushrod/pushrod tube in turn to see if the sound changes. Maybe even take an oil squirt bottle and squirt oil onto the rocker/valve/pushrod interface to see if it changes the sound. Not sure this is a reliable diagnostic method but it's worth a shot before going any further.

optimusprime · #15 12-02-2015, 06:16 AM

Quote:

Originally Posted by kerry

If it's an oiling problem, perhaps it can be confirmed by pouring a bunch of oil over the valvetrain in the suspected area. If the noise diminishes with the excess oil it might at least narrow it down. Take a quart of oil and pour some over each rocker/valve/pushrod/pushrod tube in turn to see if the sound changes. Maybe even take an oil squirt bottle and squirt oil onto the rocker/valve/pushrod interface to see if it changes the sound. Not sure this is a reliable diagnostic method but it's worth a shot before going any further.

Kerry very good idea