Hectic rattling noise in the front of engine

[Chris Van]

Hi Boffins

Hope this finds you well?

I use my A as a daily driver and she really does work hard in the commuting traffic and on the highways. She has given zero mechanical trouble for 20 000 miles since I did the engine rebuild fifteen years ago.

However, last week a rattle in the engine started... and has gotten louder and louder and now it is overwhelmingly loud. I thought it was the water pump (which leaks) but I took off the genny and the fan belt and the noise is still there. There is no problem with the performance - she goes like a bat out of hell but I have now stopped using the car as the noise is clearly serious.

I have no idea what it is... hence my posting this thread. Best way I can describe it is a very loud rattle, as though there is a loose bolt flying around in the engine.

Any ideas please? The noise is definitely in the front part of the engine.

Many thanks...

Chris

[Y-Blockhead]

Timing gear(s)??

[johnbuckley]

Loose timing gear? Usually noisier on the overrun as the engine tries to throw the wheel out of mesh, and quieter when engine pulling as it pulls the wheel back in fully. sometimes possible to confirm by removing timing pin and applying slight pressure to the timing wheel.
Absolute visual confirmation by removing the timing wheel inspection cover on the right side of the engine

[MikeK]

Likely the thrust spring and plunger in the timing gear cover. Remove the cover and check it. Stuck plunger or collapsed spring.

[Chris Van]

Ah thanks... that sounds convincing. So to remove the cover I must remove the radiator and work from the front?

[Bulligen]

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It is easier to remove the radiator however I have replaced timing gears without doing that. The Timing gear can make a horrible racket !!

[Bulligen]

Of course the big issue is making sure the timing marks line up when you install the new gear !!

[Chris Van]

Can I drive the car like this or am I looking for trouble?

[Chris Van]

Okay thanks... yes noted.

[FL&WVMIKE]

Have you inspected the front pulley ?
Take off the belt and see if it is loose.
MIKE (mikeburch)

[Bulligen]

I would plan on taking care of it right away. If it is a fiber gear the back and forth motion might cause the teeth to strip, and then you have a bigger mess. Before you take anything apart match up the timing pin to the gear so you know you have it in the right spot when you are reassembling it!! There is a special tool to take off the large nut that holds the assembly together ( I did make my own). If you are all ready to do the job, it shouldnt take you more than a couple hours. Remember you want to replace the gaskets on the fron and side covers so that it wont leak afterward. You will have to support the motor, as the cover is also how the front motor mount is attached! It really is not hard, just take your time!

[Chris Van]

Hi Mike... yes the front pulley is still tight as anything, unfortunately...!

[Chris Van]

Thanks Bulligen... okay will do it myself (well actually with a gearhead mate) but remember I have to order the new parts from the Land of the Free and the Brave which takes about a week or so.... but at least it sounds doable.

[Patrick L.]

I would recommend trying to pinpoint the noise a little closer.
I'd first check for a loose or broken front pulley before moving on to the timing gear. When checking the timing gear, before removing the cover reverse the timing pin and apply a bit of pressure against the gear while the engine is running. Go very gently at first and increase the pressure slowly. If the dimple is shallow this will work, if its been drilled deep then it may not.

[Chris Van]

What I don't understand is how the thing running and still going like a boeing if the timing gear is bust. Is MikeK's theory that is the thrust spring and plunger in the timing gear cover thus not the likely cause of this diabolical noise the engine is making?

[Chris Van]

Thanks Patrick... will do.... I need to pluck up courage to start even the simplest job but usually prevail so will at least start with that suggestion of yours.

[SteveB31]

They can make a lot of noise, and still run fine. We had one in the shop last week like that. Ran great, HUGE noise. Turns out the nut that holds the timing gear on was about to fall off.

Replaced the timing gear, tightened the nut, and all is great.

Steve

[George Miller]

You need to find out what is wrong. Short out one plug at a time and see if it goes away. What kind of noise and when is it the loudest.
My guess is center main.

[Chris Van]

George it is more a rattle than a knock... so I will first try the (optimistic) option of the timing gear... then if it does not go away will pull the motor.... ouch...

[Patrick L.]

Don't get hung up on the gear, check the pulley first.
Actually first, work to better locate the problem/noise.
Don't jerk out the engine without talking to us again.