Slight knocking after oil change

[andyhay]

Hi all.

I just did the first oil change of my Elan plus 2 in my ownership. I used a ryco z9 filter as recommended by a club member. The car started and ran perfectly but after a 15 minute run I went to park it for the night and noticed a knocking sound from the engine at idle. Not loud but noticeable. Particularly noticeable as the car was turned off. Could this be related to the oil filter? It fitted fine but was a large diameter than the one that came off. Dip stick is reading full.

I'll try fitting a new oil filter as a first step.

Thanks for any assistance.

[Davidb]

What weight oil did you put in?

[andyhay]

20/50

[rgh0]

The correct filter is a Ryco Z62. Is the larger diameter Z9 hitting on something when the engine moves?

cheers
Rohan

[andyhay]

That is probably the issue! There is only about 1 mm between the filter and the sump. Thanks Rohan.

[andyhay]

I won't have a chance to change the filter until next weekend but I started the car this morning and noted the following:

No knocking sound when cold. My engine vibrates less at idle when cold for some reason

Knocking started when the engine was warm. But only at idle. As soon as I applied any throttle and the engine smoothed out there was no sign of the knocking.

Car is driving perfectly. Oil pressure good.

I think the above supports Rohan's theory.

I did notice a strange vibration rattle noise at idle from well under the car prior to changing the oil while it was warming up. This was intermittent and didn't happen while driving. This happened again when I started the car this morning. Sounded like something might be loose.

Thanks.

Andy

[Bud English]

...except it won't be knocking against the sump. That 1mm distance is fixed as the oil pump with filter and sump are both bolted to the block. Might be hitting the frame or something else though.

[billwill]

Knocking is often due to part of the exhaust system tapping on the gearbox.

But it could merely be that you put in thinner oil so the big-ends are making more noise than before.

While you are right to suspect the last item you changed, it is extremely unlikely that an oil filter can cause any knocking noise.

[nmauduit]

No knocking sound when cold. My engine vibrates less at idle when cold for some reason

Andy

for investigating that kind of vibration I would first check/clean or swap the spark plugs...

[2cams70]

The Ryco Z9 is for an Australian 6 cylinder Ford Falcon. In the Falcon it sits horizontally therefore it is fitted with an internal anti drain back valve. On the Lotus (Ford Kent) engine the filter sits at an angle of about 60 degrees so there is no need for an anti drain back valve. Maybe the anti drain back valve is having an undesirable effect??
The correct filter is a Ryco Z62 (or direct equivalent) Why use something else? Bigger is not necessarily better.