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Kennomini
 Post subject: Engine knock....
PostPosted: Tue Apr 06, 2021 11:05 am 
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Location: Yandina,Sunshine Coast,QLD
Well I think I have a problem.
My A+ 1275 seems to have developed a loud "rattle". I thought is was bad engine stabilisers/mounts but having a closer look the sound appears to be mid internal (below head height). It dose seem to go away in higher revs 2k+ but it's really loud at idle and power output seems the same.
What things can I check to try and rule out any other possible sources before I pull the engine out and split the box off?

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Steam
 Post subject: Re: Engine knock....
PostPosted: Tue Apr 06, 2021 2:42 pm 
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Tappets would be the first possibility.

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gtogreen1969
 Post subject: Re: Engine knock....
PostPosted: Tue Apr 06, 2021 4:21 pm 
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Drop gears can rattle at low revs / low oil pressure
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TK
 Post subject: Re: Engine knock....
PostPosted: Tue Apr 06, 2021 8:01 pm 
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Joined: Wed Jan 19, 2005 1:52 pm
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Location: Brisbane
idler gear rattle

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Kennomini
 Post subject: Re: Engine knock....
PostPosted: Wed Apr 07, 2021 11:15 am 
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What would cause the idler gears to rattle?
Oil pressure seems to be good 40-60psi at idle (hot and cold)

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drmini in aust
 Post subject: Re: Engine knock....
PostPosted: Wed Apr 07, 2021 12:28 pm 
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Location: near Baulkham Hills, NSW
Idler + primary gears can rattle if engine is idling at low speed, particularly with a lightened or race flywheel and a sporty cam.
But that's a rattle, not a knock.
I would pull spark plug leads off, 1 at a time, if it goes away it's something related to that cylinder like a worn big end bearing.
If knock is there under load regardless of rpm it could be a broken crank, I've had a couple go.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R. :mrgreen:
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Kennomini
 Post subject: Re: Engine knock....
PostPosted: Thu Apr 08, 2021 7:00 am 
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The engine has been in the car for over 5 years so it means something is broke........I'll try the leads and see what happens.

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9YaTaH
 Post subject: Re: Engine knock....
PostPosted: Thu Apr 08, 2021 8:02 am 
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Joined: Sun Apr 11, 2004 11:32 am
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Location: Sthrn HiLoLands, NSW, Australia
What sort of driveshaft to engine type couplings?

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Kennomini
 Post subject: Re: Engine knock....
PostPosted: Sat Apr 10, 2021 11:55 pm 
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Pot joint/cv's but the noise happens at idle when not moving.

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drmini in aust
 Post subject: Re: Engine knock....
PostPosted: Sun Apr 11, 2021 5:10 am 
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Does it go away when you push clutch in? And what is idling speed?

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R. :mrgreen:
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Kennomini
 Post subject: Re: Engine knock....
PostPosted: Sun Apr 11, 2021 8:43 pm 
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Location: Yandina,Sunshine Coast,QLD
Idle is around 800.
I havn't noticed the clutch affecting it, I'll try to check soon.

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sitnlo62
 Post subject: Re: Engine knock....
PostPosted: Wed Apr 14, 2021 4:20 pm 
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Is it Crank speed or Cam speed knock.
Possibly broken cam follower or perhaps Bad piston or wrist pin.

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