Aircooled Knock under load.
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- Davegrohl99
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Aircooled Knock under load.
Hey everyone,
Just back from a 900km trip around “Sunny south east” of Ireland.
I have noticed taking on some very steep hills under harsh acceleration uphill there is a audible ticking noise. When I change down gears the knocking seems to disappear. It’s a bit worrying but seem to be okay when in the correct gear.
Am I not changing down early enough and not holding it in 3rd for long enough.
2.0 CU engine for reference.
Cheers
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Just back from a 900km trip around “Sunny south east” of Ireland.
I have noticed taking on some very steep hills under harsh acceleration uphill there is a audible ticking noise. When I change down gears the knocking seems to disappear. It’s a bit worrying but seem to be okay when in the correct gear.
Am I not changing down early enough and not holding it in 3rd for long enough.
2.0 CU engine for reference.
Cheers
Sent from my iPhone using Tapatalk
1981 Westfalia 2.0 CU engine.
1971 Early Bay Microbus.
1971 Early Bay Microbus.
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Re: Aircooled Knock under load.
Sounds like bottom end knock
- Davegrohl99
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Re: Aircooled Knock under load.
"pooh".
Rebuilt the top end this time last year to the day.
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Rebuilt the top end this time last year to the day.
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1981 Westfalia 2.0 CU engine.
1971 Early Bay Microbus.
1971 Early Bay Microbus.
- Davegrohl99
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- Posts: 190
- Joined: 10 Jan 2019, 14:57
- 80-90 Mem No: 16802
- Location: Offaly, Ireland
Re: Aircooled Knock under load.
Maybe it could be pinking? I’m hoping that might be it. The only thing I haven’t looked at since ownership and rebuild is the carbs. Maybe a retune of the carbs and balancing them and maybe run it slightly richer might solve the issue.
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1981 Westfalia 2.0 CU engine.
1971 Early Bay Microbus.
1971 Early Bay Microbus.
- tobydog
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Re: Aircooled Knock under load.
I would check that the ignition timing is not advanced
My Moto Gucci is meant to run on the old 5 star fuel. If you open it up too much at low revs under load it pinks which sounds like a metalic pinging.
My Moto Gucci is meant to run on the old 5 star fuel. If you open it up too much at low revs under load it pinks which sounds like a metalic pinging.
Knowledge is power
1970 CU
1970 CU
- Davegrohl99
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Re: Aircooled Knock under load.
Okay will do.
We only have 95 Ron at best here in Ireland. I religiously use Dipetane as an additive to help keep the engine clean. Maybe I should consider octane booster also?
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We only have 95 Ron at best here in Ireland. I religiously use Dipetane as an additive to help keep the engine clean. Maybe I should consider octane booster also?
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1981 Westfalia 2.0 CU engine.
1971 Early Bay Microbus.
1971 Early Bay Microbus.
-
- Trader
- Posts: 2593
- Joined: 27 May 2009, 18:56
- 80-90 Mem No: 16628
- Location: hayling island
Re: Aircooled Knock under load.
Davegrohl99 wrote: ↑11 Jul 2021, 16:43 "pooh".
Rebuilt the top end this time last year to the day.
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did you do the big end bearings too?
- Davegrohl99
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Re: Aircooled Knock under load.
No never split the case. Problem was top end related at the time. I’d be very disappointed if that was the problem as the engine is really performing well. Other than in that situation. I might try what’s been said above before I get really worried.
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1981 Westfalia 2.0 CU engine.
1971 Early Bay Microbus.
1971 Early Bay Microbus.
-
- Trader
- Posts: 2593
- Joined: 27 May 2009, 18:56
- 80-90 Mem No: 16628
- Location: hayling island
Re: Aircooled Knock under load.
Davegrohl99 wrote: ↑11 Jul 2021, 19:25 No never split the case. Problem was top end related at the time. I’d be very disappointed if that was the problem as the engine is really performing well. Other than in that situation. I might try what’s been said above before I get really worried.
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You can do the big ends without splitting the case , it’s not uncommon for the big ends to fail after a top end rebuild , I could be wrong
- T25Convert
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Re: Aircooled Knock under load.
It’s pretty common to develop bottom end issues after a full top end refresh.
I watched a great video (which I can’t find again) of an American changing the big end bearing shells. It went like this:
Remove heads, withdraw barrels but leave them just over the piston so the rings stay compressed. Thin walled socket on a wobble bar between base of barrel and case to undo con rod and cap. Piston and barrel removed complete with con rod and half the bearing. Hand in through the now present hole to retrieve con rod cap. New shells and back together again. Did a whole set of big ends in a matter of minutes.
If it were me I’d want to look at crank and car bearings, but if you are confident of the issue and don’t fancy splitting the case there is another viable alternative!
I watched a great video (which I can’t find again) of an American changing the big end bearing shells. It went like this:
Remove heads, withdraw barrels but leave them just over the piston so the rings stay compressed. Thin walled socket on a wobble bar between base of barrel and case to undo con rod and cap. Piston and barrel removed complete with con rod and half the bearing. Hand in through the now present hole to retrieve con rod cap. New shells and back together again. Did a whole set of big ends in a matter of minutes.
If it were me I’d want to look at crank and car bearings, but if you are confident of the issue and don’t fancy splitting the case there is another viable alternative!
RIP - George - 1.9DG '85 AutoSleeper Trident - rusted away
George Second - 1.9DG '89 Caravelle
George Second - 1.9DG '89 Caravelle
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Re: Aircooled Knock under load.
When the revs are low, and gear is high, there's a lot of torque going through the transmission. If a cv is dodgy it could make a clonking noise. Does your knocking keep time with engine revs or road speed (wheel revs)?
1982 Holdsworth poptop. 2L CU Aircooled.
1982 Danbury tintop Caravelle. 2L CU Aircooled.
1982 Danbury tintop Caravelle. 2L CU Aircooled.
- Davegrohl99
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Re: Aircooled Knock under load.
No the noise is sporadic and isn’t in the same time as the engine. I wrought it was my exhaust rattling but doesn’t seem to be that either.
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1981 Westfalia 2.0 CU engine.
1971 Early Bay Microbus.
1971 Early Bay Microbus.
- sarran1955
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Re: Aircooled Knock under load.
Hello,
Ticking noise under load...Hmmm
When did you last check/grease/change your CV joints...
Cordialement,
Ticking noise under load...Hmmm
When did you last check/grease/change your CV joints...
Cordialement,
- Davegrohl99
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- Posts: 190
- Joined: 10 Jan 2019, 14:57
- 80-90 Mem No: 16802
- Location: Offaly, Ireland
Re: Aircooled Knock under load.
I checked CV bolts were tight before my strip. The CVs themselves I haven’t checked perhaps a rebuild is in order?sarran1955 wrote:Hello,
Ticking noise under load...Hmmm
When did you last check/grease/change your CV joints...
Cordialement,
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1981 Westfalia 2.0 CU engine.
1971 Early Bay Microbus.
1971 Early Bay Microbus.
- Robsey
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Re: Aircooled Knock under load.
I think it is the type of sound that matters..
In my " very generic" understanding -
A worn CV joint is more likely to be a ticking or crackling sound.
A worn crank bearing would be a more rumbling type sound.
A more metallic pinking / tinking noise could indicate timing being too advanced by a couple of degrees.
A general rule for me is start out and rule out the easy stuff, and go through the options until you hopefully find the source of the noise.
So in simple terms -
Basic service with timing check etc.
Strip, clean and repack the cv joints.
And last resort, look at the bearing shells.
In my " very generic" understanding -
A worn CV joint is more likely to be a ticking or crackling sound.
A worn crank bearing would be a more rumbling type sound.
A more metallic pinking / tinking noise could indicate timing being too advanced by a couple of degrees.
A general rule for me is start out and rule out the easy stuff, and go through the options until you hopefully find the source of the noise.
So in simple terms -
Basic service with timing check etc.
Strip, clean and repack the cv joints.
And last resort, look at the bearing shells.
1983 Tin Top with a poorly DF and 4 speed DT box.
1987 Electrics and a DJ engine.
Maybe one day I might get it finished
1987 Electrics and a DJ engine.
Maybe one day I might get it finished