Whirriing noise when running over 1500RPM

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Zaphod
Senior Poster
Posts: 243
Joined: Mon Aug 23, 2021 21:38
Model: Excel SE
Colour: Blue
Year: 1990
Location: Uffington

Whirriing noise when running over 1500RPM

Post by Zaphod »

Now I have oil pressure I seem to have a new problem.
The engine displays the symptoms of a cam belt that is too tight and make a loud whirring noise when the revs go much above idle. I have run it with both the alternator belt and PAS belt removed, and that makes no change. My Burroughs guage shows the belt to be tensioned at somewhere between 90 and 95 (Crank at 30 degrees BTDC) which I believe is within the factory range. The frequency test gives a results in the range of 103-108hz using the gates belt app on the phone. I did change the tensioner bearing which was a 'Breda Lorett' item for a new Flennor bearing in case that was a problem, however it has not solved the issue. There is a very low volume high pitched whine at idle, but this could just be air entering the carbs? I do know the plastic cover under the distributor cap is missing, the noise seems to be more central than at the front of the engine. It reminds me of a dry ball race
Of all the things I have lost I think I miss my mind the most...

1952 MG TD
1957 MGA 1500
1959 Austin Healey Sprite
1975 MG Midget 1500
1990 Lotus Excel

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rbgosling
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Joined: Sun Jul 04, 2010 22:55
Model: Lotus Excel SE
Colour: Midnight Blue
Year: 1990
Location: Rugby

Re: Whirriing noise when running over 1500RPM

Post by rbgosling »

You definitely have the correct cam belt, with either the trapezoidal or semi-circular teeth profile to match the pulleys?
"Farmer" Richard

1990 Lotus Excel SE (Lilith)
2022 MG MG5 EV (not due to be a classic for quite a few years...)
2011 Nissan Leaf (Ragly - EV pioneer, must be due to be a classic one day)

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