Pinking under load!

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John H
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Re: Pinking under load!

Post by John H »

So the good news is I no longer have pinking! So here is what I think happened!
1. Noise begins on the motorway under load.
2. Cleaned very dirty fuel filter and flushed tank
3. Checked timing and reset to engine spec 15Deg BTDC -- no change
4. Adjusted timing to 32Deg at 3000 rpm with vacuum on variable not full -- no change
5. Thanks to Ian found 2 loose passenger side exhaust manifold bolts! One very very loose! -- improved but still there on high load
6. Removed vacuum advance completely. set at 15 Deg initial, which results in around 34 at 3000 rpm. Ran out of fuel but noise no longer there.
7. Drive 60 odd miles with fresh VPower all good!

Next steps - do I try with vacuum again or not! I will monitor fuel consumption this week but it feels back to normal!
So I think I caused the pinking - the original noise were the loose bolts! Lesson learnt on what to check and not to make assumptions quite so quickly!
Thanks for all the input especially Ian for pointing out the manifold can sound very similar!
Cheers John
Built St Piran Hawk289FIA in Scotland!
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Fireball
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Re: Pinking under load!

Post by Fireball »

My engine builder told me to set the ignition to no more than 32 degrees at 4000rpm, this gave me about 10 degrees at tickover, which increased when I added the vacuum line. (Ford 302)
I also had a glass filter which deformed due to a blocked fuel line and the mechanical fuel pump was still sucking. The heat from the headers must have radiated to the filter and it collapsed due to the vacuum. And it was glass! I use a cheap plastic filter now and replace it every year.
Finally sorted Dax 'AC 289' after 4 years in the wilderness.
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Migge
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Re: Pinking under load!

Post by Migge »

I never used the vacuum pipe at all, for what? It is on "normal" cars to optimize fuel consume and smooth running.

I have 4 Dellortos DRLA on the RV 3.5 and the average consumption (believe it or not) of 11.5 Ltr. per 100 km. I was just driving in Germany, Netherlands, Belgium, France and England approx. 70-80 miles/h. That's 20.5 miles per gallon!
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clive
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Re: Pinking under load!

Post by clive »

You need to get a hood Migge. 18 mpg without hood, 27 mpg with hood!
Cheers, Clive.

(If I'm not here I'm in my workshop or on the golf course!)
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peterc
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Re: Pinking under load!

Post by peterc »

Migge,
I think your average of 11.5 L/ 100km is around 24.5 mpg and 20.5 mpg is around 13.8 L/100km. Not bad for a Quad carb set up.
The best I have seen for motorway driving is around 23 mpg and more generally 17- 22 from a 4.6 Rover on a single Weber 4 barrel and 270 BHP.
I have not investigated with or without the hood but could understand that there ought to be an improvement. Of course driving with the hood up tends to be slightly slower.
I think the only way of improving that would be to go to fuel injection.
Peter C
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clive
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Re: Pinking under load!

Post by clive »

peterc wrote: Thu Sep 06, 2018 8:10 am Of course driving with the hood up tends to be slightly slower.
That's never been the case with me Peter!

The most economical 289 I ever came across was Allan Tunstall's Rover powered car. I can't remember the actual figures, but it was well into the 30s. He uses his car for extensive touring, having driven all over Europe, as far as Finland. Bill Telford's 289 is also fairly economic (Surprisingly due to how he drives it!), but as Peter alludes to, it is a Rover with EFI.
Cheers, Clive.

(If I'm not here I'm in my workshop or on the golf course!)
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Migge
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Re: Pinking under load!

Post by Migge »

The 11.5 Ltr. per 100 km are correct. May I have the wrong internet calculation tool for mpg.
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