Measuring distributor max timing advance

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Brit01
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Re: Measuring distributor max timing advance

Post by Brit01 » February 26th, 2013, 8:14 pm

If the mains were very rich could I still get a tan colour like this (could be hot enough to burn off all excess carbon)?

Brit01
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Re: Measuring distributor max timing advance

Post by Brit01 » March 1st, 2013, 2:35 pm

Do you think I've gone oversize on the mains? (no loss of power though)

A long fast drive on the motorway on the mains circuit resulted in an oil pressure drop of about 3psi. (this did not occur on the smaller mains) oil temp 95c

A long drive yesterday but lower revs (mostly idle circuit), mainly town driving, the oil pressure was back to normal. oil temp 90c

I'm concerned about bore wash (or is this mainly when engine is cold?), is 3 psi is anything to worry about? Only happened on the motorway, engine was hot so should be burning off excess fuel I believe.

Brit01
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Re: Measuring distributor max timing advance

Post by Brit01 » March 10th, 2013, 9:48 pm

I was running with half a tank of fuel and 1 litre of Toluene added.
Increased timing to just above 8 degrees static. (it was knocking like unacceptable at 7 degrees before).

Good run on some city streets and highway driving up to about 130 km/hr, overtaking in different gears etc.

Very smooth and all sounded great.
Very happy with the progress I've made.
I will add 2-3 litres of Toluene per tank now and keep the static timing a little higher 8-9 degrees.

I may even try a little acetone. It is supposedly help to atomize the fuel better and clean the combustion chambers. Not too much to damage anything but just enough to have a benefit.

Regards

TomLouwrier
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Re: Measuring distributor max timing advance

Post by TomLouwrier » March 10th, 2013, 10:37 pm

As you're going to play alchemy, please take care with your health. Read up on handling the stuff and ventilate well.

regards
Tom
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Urbancamo
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Re: Measuring distributor max timing advance

Post by Urbancamo » March 10th, 2013, 11:30 pm

Nice to hear results. This clearly shows how much difference only the fuel makes...

T
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Guy Croft
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Re: Measuring distributor max timing advance

Post by Guy Croft » March 11th, 2013, 11:29 am

you will notice the oil pressure dropping as the oil temp increases.

You need to get it down to 85 deg C

G
Guy Croft, owner

Brit01
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Re: Measuring distributor max timing advance

Post by Brit01 » March 11th, 2013, 2:05 pm

Guy Croft wrote:you will notice the oil pressure dropping as the oil temp increases.

You need to get it down to 85 deg C

G
Hi Guy,

I can't rely on the readings as being true as the sensor is taken from the oil channel on top of the block. It could well be soaking up heat from the block.
But I've had feedback from other Alfa owners and most of them do have higher oil temps than 85.
Is it dependent on the engine design?

The only other viable option is to use a special dipstick but they are out of my price range at the moment.
Thought about a sensor in the drain plug but they drop too low to the ground due to the design of the boxer engine.

Oil pressure is still good though. around 12 psi now at 900 rpm hot idle.
4000 rpm gives about 55-60 psi when very hot after cruising on the motorway at 140 km/hr for extended periods.


Regards

Chris

Brit01
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Re: Measuring distributor max timing advance

Post by Brit01 » March 21st, 2013, 5:58 pm

No wonder!

Just been confirmed in a main newspaper article that Uruguay had the worst quality petrol in the whole of Latin America!

Brit01
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Re: Measuring distributor max timing advance

Post by Brit01 » June 1st, 2013, 4:40 pm

Great. Bosch advance springs finally arrived! Good mixture of tensions. 20 springs in total!
They were sent tp Venezuela. 6 months wait.

Brit01
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Re: Measuring distributor max timing advance

Post by Brit01 » June 2nd, 2013, 4:42 am

Photo of the springs. I imagine the primary one needs replacing.
Attachments
springs.jpg
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Brit01
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Re: Measuring distributor max timing advance

Post by Brit01 » June 9th, 2013, 8:54 pm

New primary spring in. Timing adjusted.

9 degrees static, full throttle in 2nd and third - smooth and no pinging.
Opening the throttle fast felt much better with the static at 9 and the new spring in.
I need to do some further testing on the highway when I get the chance but I feel it is going to perform much better.

The old primary advance spring felt very weak indeed compared to the replacements. I am confident the firmer spring will be much more suitable for the low octane fuel we have here.

Had a few mishaps while replacing it though. Very unlucky day.

First circlip off the distributor shaft, small holding pin out (most tiny part that can get lost easily), plate off, then second circlip off.

I had carefully placed the tiny pin on a cloth.
The circlip catapulted out of the special pliers and hit the small pin which flew off behind the sofa somewhere!! 1 in a million chances of ricocheting the pin with the circlip.

After 1 hour of frantically searching for it appeared! phewww (its only 3mm long and 1mm wide!)

Then putting the small 10mm bolt back on the distributor onto the block - the bolt fell down the flywheel timing hole (wasn't sure though). Nooooo!
Removed the bottom plate underneath to see if anything fell out. nothing!
Moved the engine forward in gear to see if the flywheel was catching on it - all ok.

Ok I used a bolt from the flywheel cover from underneath to re-attach the distributor.

Started her up and all ok. A big relief.

But a few metres down the road I heard a small rattle for a second - scared the salami out of me thinking it was going to get lodged or something.

After that all ok.
Maybe it fell out down the road, anyway I couldn't find the thing.

TomLouwrier
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Re: Measuring distributor max timing advance

Post by TomLouwrier » June 9th, 2013, 9:56 pm

Sounds like a bad case of Murphy's law...

greetz
Tom
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Brit01
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Re: Measuring distributor max timing advance

Post by Brit01 » June 12th, 2013, 5:19 pm

hmmm appears that the static idle of 9/10 was too much.

Was in heavy traffic with a hot engine last night and accelerating fast hearing pinging above 3000 rpm again.

Got home, lowered it back to 8 degrees as factory specs. Was a bit sluggish off acceleration but didn't get to try at higher speeds due to the traffic conditions.

This is proving to be tricky.
I hope is not the secondary spring that needs replacing.
I believe its the sum of both of them that control the advance at higher revs.
So if I put a thicker primary spring in then it should lower the total advance but may also have an adverse effect on power at lower revs.

May also try without the vacuum advance again at 9/10 degrees static.

News: Purchased a new Bosch LSU4.9 wideband so hopefully I will get my AFR gauge kit up and running again in the next week or so to rule out mixture issues. Actually I'm hoping it is a mixture issue as this will be easier to fix apparently.

Brit01
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Joined: June 28th, 2011, 4:54 pm
Location: Uruguay

Re: Measuring distributor max timing advance

Post by Brit01 » June 14th, 2013, 5:31 pm

Thought I might have bitten off more than I can chew but still persevering with trial and error.

Considering sending the distributor to be refurbished and re-mapped in the UK.

Looking for a donor piece to keep the car running in the meantime.
There are some old ones from 1.3 and 1.5 boxer engines here but with points.

My Bosch has the standard 2 wire output from the amplifier (electronic pick up).

Does anyone know how to wire up a points distributor to a set up that was used with an electronic distributor?

Thanks

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