Engine noise

[Moises]

Could noisy engine operation be due to excessive slack in the timing chain?

[David Morris]

Hi Moises, good to hear from you! Yes, the simple answer is that yes, a worn timing chain could cause excessive engine noise.

I usually check whether a timing chain is worn by comparing the one in use with a new one. Hold the chains in your hand horizontally and see how much they 'droop'. The worn one will show a more pronounced 'droop', with the free end hanging further down. I don't know why Jowett's didn't fit some form of tensioner? Even the Austin 'A' series engines have a rubber insert in the larger timing wheel. I did find one Jowett front cover where someone had fitted a 'slipper' type of spring-loaded tensioner, but I am sure this wasn't a factory modification.

The camshaft gear teeth themselves can also get worn. Have a look at them and see if they look too sharp and pointed, compared with others, or better still new ones?

I can see in your video that you are moving the oil pump/distributor drive gear with your finger. This looks a bit 'slack', and could cause the timing to be erratic? The bronze drive gear fitted to the crankshaft might be worn? Are the crests of the bronze teeth looking sharp and worn? If you are working in this area of the engine, it's worth checking that the oil spray nozzle, fitted to the top of the oil pump is open and not blocked? I had one blocked once and the bronze gear wheel soon became scrap. It relies on the constant jet of oil from the nozzle.

All the best,

David

[Keith Clements]

viewtopic.php?p=46696#p46696

Also:
viewtopic.php?p=45995#p45995

. One thing new learnt today is that two widths of Oil Pump Drive Gear 50648 were used the wider one fitted here with the neck point outwards.

viewtopic.php?p=44327#p44327

And sprockets
viewtopic.php?p=23650#p23650

[Moises]

Thanks David, I took this video a long time ago. I will remove the front cover and check the condition of the chain and drives.
All the best

[Moises]

vlc-record-2025-02-27-19h19m08s-MVI_4404.MP4-.mp4

[Keith Clements]

Difficult to say. Location of the sound is the best indicator, a piece of 15mm hose to the ear and a large screwdriver to the ear can help. The sound to me could be from exhaust or perhaps piston slap as it appears worse on overrun.

[Moises]

Keith, do you think the noise could be due to a faulty exhaust system? I have a new stainless steel silencer fitted supplied by Paul Beaumont.

[Moises]

What is "slap piston"?

[Nick Webster]

Sometimes web video sound gets out of sync with the image, so I cannot be sure, but the noise is there even before the shaft starts to turn. In that case I would be looking around the clutch. Could be bolt has fallen out, or a bit of broken spring. Sounds like something very tinny rattling round, perhaps banging on the clutch cover. One last suggestion and perhaps a bit silly, but I have heard similar strange noises from an exhaust silencer box when the internal parts broke loose.

Nick

[Moises]

Thanks Nick. I have disassembled the clutch several times and replaced the disc and have not noticed anything unusual. As for the exhaust silencer, it is a new stainless steel unit supplied by Jowett Car Spares. It is really quite annoying to drive with this noise.

[David Morris]

Hi Moises,

Thanks for the video and salutations on the first day of Spring!

No, this noise is not normal and sounds 'tinny', like something light vibrating. Is it there when the car is stationary, but with the engine running?

If it remains, I would suggest taking off the fan belt as a first step. The fan assembly is prone to vibration, and this might be the cause?

Best wishes,

David

[Forumadmin]

My first impression was an exhaust rattle. So if it is a new exhaust then it is the likely culprit.

Piston slap is a knocking or tapping sound that occurs when there's too much space between a piston and the cylinder wall in an engine.

Unlikely I think but a similar sound might occur with clutch issues but then this should change when the pedal is depressed.

[Moises]

Hi David, thanks for your comments. I installed a plastic fan to avoid vibrations. However, following your instructions I have removed the fan belt and the engine sounds like this. Best wishes

MVI_4411.MP4

[Moises]

Thanks Keith for your help. I rule out slap piston. The pistons are new and correctly fitted.
Is it possible for a new silencer box supplied by Jowett Car Spares to be faulty?

[Moises]

Thanks Keith for your help. I rule out slap piston. The pistons are new and correctly fitted.
Is it possible for a new silencer box supplied by Jowett Car Spares to be faulty?