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Pinking on 2nd Choke
http://international2cvfriends.com/forum/viewtopic.php?f=7&t=2456		 Page 1 of 5
Author:  Nelsthebass [ November 20th, 2010, 6:29 pm ]
Post subject:  Pinking on 2nd Choke
I have a strange problem on the Beige Beast - it pinks only on the second choke - you can travel along nicely at around 65mph on the first choke but put your foot down and open the 2nd choke it starts to pink...its timed right, doesnt look to run too lean by looking at the plugs any ideas?
Author:  ken [ November 20th, 2010, 6:43 pm ]
Post subject:  Re: Pinking on 2nd Choke
Nels,
by definition, the engine's intake is 'throttled down' when the carburettor is on anything less than 'wide open throttle', at which setting any tendency to pink is minimised because of reduced cylinder filling.

So, if it's pinking on full throttle, it's the timing which is incorrect.

Reducing the amount of total ignition advance will cure the problem, although rejetting and using colder plugs will help as well...

ken

Nelsthebass wrote:
I have a strange problem on the Beige Beast - it pinks only on the second choke - you can travel along nicely at around 65mph on the first choke but put your foot down and open the 2nd choke it starts to pink...its timed right, doesnt look to run too lean by looking at the plugs any ideas?
Author:  Rhythm Thief [ November 20th, 2010, 6:48 pm ]
Post subject:  Re: Pinking on 2nd Choke
Might also be worth having a look at the advance weights and points cam (all the bits behind the points box). The weights do wear and they tend to be forgotten about.
Author:  2CViking [ November 20th, 2010, 6:53 pm ]
Post subject:  Re: Pinking on 2nd Choke
Rhythm Thief wrote:
Might also be worth having a look at the advance weights and points cam (all the bits behind the points box). The weights do wear and they tend to be forgotten about.


Gee, that is wonderful to read, that someone understandings the whole senario
regarding pinging. Good on you mate.
Author:  Nelsthebass [ November 20th, 2010, 7:07 pm ]
Post subject:  Re: Pinking on 2nd Choke
Thanks for the responses - I will double check the timing again - what cold plugs does anyone recommend? It's unlikely the advance weights are screwed as the engine has only done a genuine 11,000 miles. Someone has also suggested that, as it blows a lot of smoke on start up, the rings may have become damaged with standing idle for 30 years and that the oil coming through them is causing the pinking?
Author:  ken [ November 20th, 2010, 8:24 pm ]
Post subject:  Re: Pinking on 2nd Choke
Nels,
when you set the timing, did you use a method which allows you to know how many degrees total advance there is (i.e. a strobe), or did you use the 'pin in hole' method and hope that the centrifugal advance was somewhere in the right field?

If it's the latter, the links below should help you with the more scientific method, but note that a 9.0:1 engine will need less advance, maybe 31 degrees/6.5 teeth on the flywheel ...

< http://www.flickr.com/photos/30132857@N ... otostream/ >

< http://www.flickr.com/photos/30132857@N06/4313805292/ >

< http://www.flickr.com/photos/30132857@N06/4498470220/ >

If you keep on thrashing it with too much ignition advance, the problem with smoking will probably increase, rather then diminish.

Is your carb a 21-24, or an 18/26 version?
Check the numbers cast into the offside float bowl to find out.
For the 21-24, you'll probably need a 125 primary jet instead of the 120 that's fitted, whereas for the 18-26, it needs increasing from the 102.5 (or 105) to a 110 jet.

B8HS plugs, if you're regularly going to be seeing the speedo in the range that you posted in another thread. :lol:

ken

Nelsthebass wrote:
Thanks for the responses - I will double check the timing again - what cold plugs does anyone recommend? It's unlikely the advance weights are screwed as the engine has only done a genuine 11,000 miles. Someone has also suggested that, as it blows a lot of smoke on start up, the rings may have become damaged with standing idle for 30 years and that the oil coming through them is causing the pinking?
Author:  Sean [ November 20th, 2010, 10:47 pm ]
Post subject:  Re: Pinking on 2nd Choke
Nelsthebass wrote:
Someone has also suggested that, as it blows a lot of smoke on start up, the rings may have become damaged with standing idle for 30 years and that the oil coming through them is causing the pinking?


what so its acting like a diesel or something? sounds a bit shonky advice to me, stuck, or pitted rings would reduce compression and therfore reduce the tendancy to pink.
perhaps the pinking has been the cause of the smoke?

compression test will put your mind to rest

it does it on second throttle because the pinking occurs under max load ie WOT
Id say timing!

bear in mind that the last time it ran was on very diffrent petrol to that we have now.

so NGK b 7 (or 8) and reduce the advance slightly.

(and the factory manual suggested that on setting the timing you use their tool ,1692-T, to check the maximum advance and ajust that before setting the timing.
using a strobe kind of kills 2 birds with one stone- lets you see what the timing advance is doing and set the timing in one go! simply saying change the weights is like saying change the tyre if you get a flat...it may be a puncture in which case your right ...it may be the valve ..or rim, stick it in a bath and find out whats actually wrong!)

Sean
Author:  J-dub [ November 20th, 2010, 10:49 pm ]
Post subject:  Re: Pinking on 2nd Choke
ive always felt it difficult to know what pinking sounds like personally.
russ said it sounds like walking on rice crispies,
however in a cab noisy engine, i cant hear myself think,,,,,

cant seem to find a video on tubeyou to help :(
Author:  rebel2cv [ November 20th, 2010, 11:01 pm ]
Post subject:  Re: Pinking on 2nd Choke
'it does it on second throttle because the pinking occurs under max load ie WOT'

Mine is as good as gold, unless I'm sitting at 40, that's the only time mine pinks. Worrying thing is she blew a huuuuge ploom of smoke out yesterday on start up, first time it's done that
Author:  J-dub [ November 20th, 2010, 11:04 pm ]
Post subject:  Re: Pinking on 2nd Choke
mine smokes when the atmosphere is cold, but all cars do that
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