Fast Marina Magazine

i have an MGB/GT which i put lead replacment in, i know own a marina 1.8 both have same engine, i have heard that some marina owners with 1.3 engine dont bother with lead replacment. the mg club say i must use lead replacment in my mg, so im a bit confused.

I always put it in mine. For years my car was run on unleaded with no additive, the valve seats were the worst my dad has ever seen in over 30 years of being an engineer.

Some of the additive has an octane boost too, useful with low octane modern petrols.

thanks josh, so i take it then that 1.8 owners need to use it but not 1.3 owners

I always thought you were meant to on the 1.3 A series as well...I know Paul Utting doesn't but unless he checks his valve seats he wont know for sure

Ah the unleaded debate again.

Its a question of mileage versus cost and whether to convert the cylinder head to unleaded.

Biggest problem IMHO is the change in octane rating of fuels. The old ignition advance curves, designed for 4star, are not ideal for the Ethanol containing unleaded fuels we have now. You can do more damage with a badly tuned pinking engine than with a lack of lead.
Additives give peace of mind, but given the costs, I would drive without any additives and if I have any future problems, have the head reworked with bigger valves, new seats, and gas flowed.


viewtopic.php?f=13&t=4669&p=42080&hilit=unleaded#p42080

what about the 2 ltr o series? i have been told that due to the ally head they have hardened seats fitted as standard so no need for lead replacement is that right or have i been given a bum steer
trev

Thats what i have been told too trev and ran the 2ltr with no additive and also run my 1700 with no additive either .

read this article down near the bottom tells you was desinged with unleaded in mind

http://www.aronline.co.uk/blogs/2011/08 ... -o-series/

In the 4 years that I owned my 1.3 coupe I never used an additive. I did have occasion to remove the head on it as we thought that the head gasket had gone. The valves and seats were in perfect condition. On the other hand the 1.8 that I have now has a lot of problems with running on. Not sure if this is down to the fuel not having any additive or whether I have other problems but I will get to the bottom of it at some point. Mumford first, eh

Gary.

just what i suspected the 1.3s dont need lead replacment but 1.8s do. im glad that is cleared up i shall continue putting replacment in my 1.8 which so far has not caused any problems, but then again ive not had car long

Good thinking mate, it would be a shame to have such a beautiful body with jiggered engine wouldn't it. Oh, how does it handle with those 185 section tyres?

When the FBHVC tested "unleaded additives" for valve seat erosion protection, they used A-series engines specifically because - as a cylinder head design - it is especially prone to valve seat erosion. Then again, the 'test' was arduous, involving prolonged very high speed running under load - the sort of use 'our' cars wouldn't generally see - perhaps the closest experience on the road would be towing a caravan on the motorway flat out while the car is also full of people and luggage for a few days...

In day-to-day use, 'our' engines may well be fine sans aditif (and the O-series definitely will be - there was an article on the internet confirming this in connection with the MG Maestro/Montego engines but I can't find it now). I seem to recall that only exceeding 3,000rpm for extended periods of time on a longer motorway journey present the conditions when valve seat erosion is perhaps more likely to occur - driving round town and at slower motorway speeds there won't be a problem at all.

I use an additive in my E-series-engined MG Maestro 1600, but then the car often sees motorway cruising at 3,500rpm or so and it's not the most robust of engines either.

Glad I got mine done as I was 4000rpm at 70MPH + back from Yorkshire 8)

cdk343v wrote:When the FBHVC tested "unleaded additives" for valve seat erosion protection, they used A-series engines specifically because - as a cylinder head design - it is especially prone to valve seat erosion. Then again, the 'test' was arduous, involving prolonged very high speed running under load - the sort of use 'our' cars wouldn't generally see - perhaps the closest experience on the road would be towing a caravan on the motorway flat out while the car is also full of people and luggage for a few days...

In day-to-day use, 'our' engines may well be fine sans aditif (and the O-series definitely will be - there was an article on the internet confirming this in connection with the MG Maestro/Montego engines but I can't find it now). I seem to recall that only exceeding 3,000rpm for extended periods of time on a longer motorway journey present the conditions when valve seat erosion is perhaps more likely to occur - driving round town and at slower motorway speeds there won't be a problem at all.

I use an additive in my E-series-engined MG Maestro 1600, but then the car often sees motorway cruising at 3,500rpm or so and it's not the most robust of engines either.

Which goes to support my supposition.
The valve seats do not fail suddenly, it's a very gradual process, and only shows with reduced performance.
The ultimate cure is a converted head, it only needs doing once. A head can be individually prepared and modified over an extended period of time to an ideal personalised condition, crack tested, gas flowed, new seats and big valves fitted, tufrided rocker shaft, etc etc. and when the need is complete, do the swap at a time that is convenient.

Additives can give you an octane boost and help avoid pinking, but a small adjustment to the timing will sort that out.
I think there are some further issues that may arise as the fuels are made with gradually higher and higher ethanol content over the coming years, with fuel system components, piping, seats, seals etc in pumps and carbs deal with a chemical they were not designed to handle.

I read in Classic Cars Weekly recently that it looks like the introduction of higher ethanol content in petrol has been posponed for the time being.
As far as uneaded additives go I find Castrol Valvemaster Plus is a good option as you don't have to empty the whole lot in to the tank in one go, you can measure out enough to treat as little as 10 litres at a time if that is all you want to put in. It also boosts the octane from 95 to 97. I use my Marina all year round and I'm sure i only use three or four bottles all year.

one bottle of valvemaster will last me about 1,000 miles, sounds like im using to much