Tuning a Carb Engine
Discussion
Chaps,
I was reading a post about a catasrophic engine failure caused by a carb being out of balance. I.e. the overall output of the engine was not lean or rich, but 1 cylinder was obviously running way too lean and it burnt out!
My question is...
Can anyone give me some advice on tuning my engine with respect to timing/carbuerretion?
I've got a 2 litre V8 with 4 twin choke Carbs and 2 distributors (so no more complex than 2 minis!).
I'd like to make sure everything's in balance and hopefully cure a lack of throttle response when it's been idling for a while.
Can you recommend any books or courses for tuning such an engine? Or give any advice at all about techniques or tools required.
Thanks in advance.
Dan
I was reading a post about a catasrophic engine failure caused by a carb being out of balance. I.e. the overall output of the engine was not lean or rich, but 1 cylinder was obviously running way too lean and it burnt out!
My question is...
Can anyone give me some advice on tuning my engine with respect to timing/carbuerretion?
I've got a 2 litre V8 with 4 twin choke Carbs and 2 distributors (so no more complex than 2 minis!).
I'd like to make sure everything's in balance and hopefully cure a lack of throttle response when it's been idling for a while.
Can you recommend any books or courses for tuning such an engine? Or give any advice at all about techniques or tools required.
Thanks in advance.
Dan
A few of useful tools:
Mixture plug (you put it in like a spark plug and the colour tells you the temp/mixture)
You can also get a pressure/flow guage you stick in your air intake (I've not got one of these as all my cars in the past has had one carb so not needed) but evidently good for balancing multiple carbs.
For timing I like using a multimeter and using dwel angle (although this may be dated as I used to tune an old points system, would have to look up if the same is true for pointless systems) Someone on this forum I'm sure will advise.
You didn't say what the V8 was (make) I had a A series engine and I found "tuning an A series engine" by David Vizard to be extremely useful. I know he does other books so may be worth a look.
Hope that helps.
>> Edited by smeagol on Wednesday 5th February 01:49
Mixture plug (you put it in like a spark plug and the colour tells you the temp/mixture)
You can also get a pressure/flow guage you stick in your air intake (I've not got one of these as all my cars in the past has had one carb so not needed) but evidently good for balancing multiple carbs.
For timing I like using a multimeter and using dwel angle (although this may be dated as I used to tune an old points system, would have to look up if the same is true for pointless systems) Someone on this forum I'm sure will advise.
You didn't say what the V8 was (make) I had a A series engine and I found "tuning an A series engine" by David Vizard to be extremely useful. I know he does other books so may be worth a look.
Hope that helps.
>> Edited by smeagol on Wednesday 5th February 01:49
danhay : first of all you will definately need a synchometer (about 20 or 30 quid from superformance). I once had a go at setting up the 308's 4 carbs. Made what I thought was a reasonable attempt, and car certainly ran okay. A couple of weeks later the car was in the shop for another matter, and I got them to tune the carbs properly. The difference was amazing ! Much better response.
You can see my second attempt at tuning twin carbs (the Westfields X flow) in little bits on the floor. Now, assuming it WAS out of balance carbs and not one of a 100 other reasons a) I could swear that the carbs were balanced. b) apparently highly tuned X flows are prone to being susceptable to this problem on cyl. no. 4, so shouldn't get such a catastrophic failure on what is a relatively much less stressed engine (I believe).
Going from my experiences above, from now on I'm going to leave ALL of that stuff to the professionals.
And anyway, to get the BEST out of the engine it would be worth spending 100 quid on a rolling road session, which you can't do at home anyway.
Just my 2p
You can see my second attempt at tuning twin carbs (the Westfields X flow) in little bits on the floor. Now, assuming it WAS out of balance carbs and not one of a 100 other reasons a) I could swear that the carbs were balanced. b) apparently highly tuned X flows are prone to being susceptable to this problem on cyl. no. 4, so shouldn't get such a catastrophic failure on what is a relatively much less stressed engine (I believe).
Going from my experiences above, from now on I'm going to leave ALL of that stuff to the professionals.
And anyway, to get the BEST out of the engine it would be worth spending 100 quid on a rolling road session, which you can't do at home anyway.
Just my 2p
p.s. there's various online "how to tune" descrptions of the x08 engines, for example ...
www.r-design.net/308/index_e.html
... which was written by my mate Carl from Australia. BTW he says it's "easy", he lies !
(edited coz I can't spell "how")
(or "descrption")
>> Edited by nevpugh308 on Wednesday 5th February 09:17
>> Edited by nevpugh308 on Wednesday 5th February 09:18
www.r-design.net/308/index_e.html
... which was written by my mate Carl from Australia. BTW he says it's "easy", he lies !
(edited coz I can't spell "how")
(or "descrption")
>> Edited by nevpugh308 on Wednesday 5th February 09:17
>> Edited by nevpugh308 on Wednesday 5th February 09:18
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