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Re: Popping sound today

Posted: 10 Aug 2009, 07:47
by toomanytoys
Its not pinking on overun.... it will be an air leak, most likely on the exhaust or poss the carbs need tightening as the gaskets will have settled since re installation (who fitted them?)
No casings on heat exchangers means very rotten... and yes thats why it doesnt have any heat....

Has it been fully serviced and set up yet (by someone that knows about them??)

Re: Popping sound today

Posted: 10 Aug 2009, 09:32
by cygnak
Thanks Mark

I'll get under tonight and check the manifold back to the backbox, which i replaced with a twin empi. ( I know i've read the stories)
Anybody got any ideas what the best timing setting. Tried it at between 7 & 8 BTDC ( Haynes setting) and completely lost power.

Thanks for your advice

Re: Popping sound today

Posted: 10 Aug 2009, 11:01
by ghost123uk
Popping on the overrun is almost always a leak somewhere in the exhaust system, though it can be an air leak in either the carb base to manifold join or the manifold to head join.

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Re: Popping sound today

Posted: 10 Aug 2009, 14:47
by toomanytoys
cygnak wrote:Thanks Mark

I'll get under tonight and check the manifold back to the backbox, which i replaced with a twin empi. ( I know i've read the stories)
Anybody got any ideas what the best timing setting. Tried it at between 7 & 8 BTDC ( Haynes setting) and completely lost power.

Thanks for your advice

This ought to be i your own tech thread really... :wink:

Its not a "1.9" Aircooled I am afraid.. its either a 1.6 or 2L... so if its a 1.6 thats been bored and stroked to 1915cc (costly and not worth the effort frankly), we need to know that... :wink:

What distributor are you using? a
re you dissconecting the vac pipes when setting the timing?
vac pipes on the right way round? (I dont remember the webber having 2 vac ports, but it has been a while since I set one up...)
Correct timing for a dual vac dizzy according to Haynes is 4-6 deg ATDC (After tod dead centre) with both vac connections made...

If the carb has only 1 vac conection and botht he vac lines from the dizzy are connected to it, the vac advance wont work.. discconect the side nearest the dizzy, DO NOT blank the pipe on the vac unit.. set timing to 7.5 BTDC with no vac on it... reconect vac only to outer pipe..

12 BTDC sounds about where an 009 needs to be at idle to give the correct total advance at 3000 rpm (where inccorect timing will do most damage...)

You should be looking for a total advance of around 32-34 degrees at 3000rpm IIRC...

Re: Popping sound today

Posted: 10 Aug 2009, 18:25
by cygnak
Thought about starting a new thread but as there was no resolution to the initial issue and had the same problem it seemed to make sence to continue this one.

You are correct 2l (1970cc).
Will get dist. no.
Defenitely has 2 vac ports, will take pic tonight. Both are going to there own connection.
I don't have a rev counter so doing it by ear and guess work on that at the moment, not ideal but will get set up properly after rebuild during winter.

Thanks for help and advice

Re: Popping sound today

Posted: 10 Aug 2009, 22:07
by cygnak
Setting at 4 deg BTDC with advance and retard seems to be the most stable on idle.

I'm getting no difference in engine speed when either pipes are disconnected. Could this mean faulty distributor or carb?

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