Can Lead additive affect/alter engine timing?

[libellav15]

Hi again guys,

has anyone ver heard of engine timing being affected by adding too much lead additive to the petrol?

it was running really nicely - now i've over done the additive a bit and its pinking, missing, bogging etc.

i am going to add more fuel to dilute to the correct ratio (i know how much i added over the amount required)

i'm sure i can get it running nicely again - just wondered if the extra lead additive could affect the engine so abruptly?

cheers

adam

 

[zbnutcase]

Re: Can Lead additive affect/alter engine timing?

Yes. Fuel tanks and crankcases are no place for snake oils....

 

[Bifflefan]

Re: Can Lead additive affect/alter engine timing?

My fisrt question is where did you get lead additive these days?
And what are you running it in?

The lead was added to act as a cushion for exhaust valves.
To much will collect on the spark plugs and cause fouling.

 

[libellav15]

Re: Can Lead additive affect/alter engine timing?

1972 mercruiser 120.

I am in the UK so red-x is everywhere - every garage and car parts shop.

Loads of other brands too - can you not get any out there - not even valvemaster?

Cheers for the answers - excuse my ignorance - but what is snake oil zbnutcase??

 

[Tig]

Re: Can Lead additive affect/alter engine timing?

Just a detail but, it's not that the additive changes the timing of your engine. It changes the characteristics of your fuel.
Too much additive could cause less power by slowing the burn of the fuel. Pinging is normally associated with not enough additive. (ignition by compression, pre-ignition)
I've never played with additives so I can't say for certain easy it is to cause problems.
How much did you over mix this?

 

[libellav15]

Re: Can Lead additive affect/alter engine timing?

I put 30ml in a 20 litre gerry can - the 250ml bottle has 5 markings on the outside - and you are supposed to add 50ml to 50 litres

ie 1 ml per 1 litre

but it was a new bottle - so the first 2 marks are spanned over the skinny bottle neck and the main bottle width - if that makes sense.

got paranoid so emptied the rest of the bottle into a sterile measuring jug and discovered only 220ml left when it should be 230ml

so only 10ml's over - but really thats a 50% overload.

 

[libellav15]

Re: Can Lead additive affect/alter engine timing?

if you can't get lead booster out there what do you all run your old mercs on - pre-unleaded engines

or do you just change for unleaded heads/ or harder valve seats

is additive even required in my engine? it came with a half empty bottle of it in the boat - so i have just been adding it to protect the valve seats - as you would with an old car etc

 

[Tig]

Re: Can Lead additive affect/alter engine timing?

I did a bit of reading on a classic car site. Seems there is no consensus on the use of lead additive. Many do not use additives at all and say that it is only required on engines that are worked long and hard. Other say they fear the consequence of not using it.

 

[John_S]

Re: Can Lead additive affect/alter engine timing?

Cars switched to the hardened valve seats around that time. Don't know how you can find out by casting/part number. I think lead will increase octane slightly. With a "double" dose, suspect lead fouling of plugs, as was mentioned. Pull a couple of them and check.

 

[Tig]

Re: Can Lead additive affect/alter engine timing?

You bring up a good point John. I just posted a Ford head casting code link the other day. I'm sure that info is available for any manufacturer. Just need to do a bit of research on when hardened seats came in to see if you made the cut.

 

[libellav15]

Re: Can Lead additive affect/alter engine timing?

been reading as well - usual story - some sy use it, some say don't bother, and of course the occasional horror story from someone who wished they had used it - could easily be a red-x employee though

 

[Bifflefan]

Re: Can Lead additive affect/alter engine timing?

but what is snake oil

"Snake oil" is second cousin to "Blood from a turnup".

In the old west people used to sell elixers that did nothing, but the salesman told the customer that it was a cure all. These were called snake oil after people found out they did not do as claimed.

Have you ever seen blood from a turnup or oil from a snake?

As for the question where did you get it, I didnt realise that you are on the metric system.
We in the states have not had lead in fuels for many years.

 

[John_S]

Re: Can Lead additive affect/alter engine timing?

We in the states have not had lead in fuels for many years.

I haven't looked for it in many years. Has it been outlawed here? or just lack of demand? I would have thought it would be still available for all those classic cars: pre-70.

 

[libellav15]

Re: Can Lead additive affect/alter engine timing?

Cheers Biff lol

I feel pretty stupid now - knowing that - but to give you all a laugh, I will admit that I spent a good half hour yesterday on Google - searching for snake oil D'OH!!!!

cheers to all for the inputs - fab as usual.

Adam