Unleaded

[ColinJack]

Can anybody advise in what would need to be done to enable a Mk1 V4 to run on unleaded?
Is the compression a problem (i.e. spacer required) or okay and just needs timing adjusting slightly?

[fortyeight]

i put lead replacement in the petrol in my mk2; i had a vw 1600 beetle engine trike and took it to a beetle workshop and was told it wern,t just a case of ajustment it was a new head etc,just use lead replacement

[FredTransit]

yup another vote for lead replacement here. One reason being to preserve valve stem seals. That having said, if you are not doing a lot of miles in a Mk2 its not worth the bother. I do put it in the Mk1s though

[ColinJack]

Many thanks.
This is a Mk1 (1976) I take the point with the erosion of the valve seats and seal damage. LRP is no longer available so are you using additives? If so what?

Of course I could drop a Di & MT75 in

[whitemice]

The 'millenium' from the Shell garages is fine and economical at just under a fiver for 250 liters of petrol, i use it and their high octane petrol in the V6 and with todays fuel find the timing needs to be a few more degrees advanced than of old.

Set the mixture and timing with a vacuum gauge.

[baconsdozen]

I use an additive in my modded V4 and have had no problems running on unleaded.
I;ve heard the millinium stuff is OK but the only place near me that seems to have it is Tesco and then its very hit and miss like the printer for dishing out receipts.

[whitemice]

I've done @50,000miles with the Minellium stuff Bacon, one thing that concensus suggests is that it is advantageous to stick with a particular brand as they vary in elements such as phosphorous, zinc and sulphur etc. and constantly switching will have a mishmash of chemical reaction going on which can't be a good thing.

[baconsdozen]

Sorry misred your post I thought you meant the Millenium 2000 petrol

[whitemice]

Sorry misred your post I thought you meant the Millenium 2000 petrol

ha, just to clarify as i'm sure you know, i mean the lead replacement additive in Shell petrol stations called Millenium along with their red label petrol.

[robbie.cee]

I have never ever used leaded or lead replacement in any of the 5 cars i had that were built for leaded fuel.
never burnt out a valve seal etc and all got thrashed daily.

even the pinto and essex in my van now get unleaded. not super tho its wasted on carbed engines of this age in a van.

if your really bothered, i got some lead flashing, cut into strips 2 inch by 6 inch, stabbed loads of tiny holes in them, then rolled into tubes around a 1/4 inch rod. will eventually remember to drop one or two into fuel tank.

lead will be replaced as 2 or 3 rolls will bash about in the tank, so its better than nothing...

[baconsdozen]

The 'lead' in leaded petrol is lead tetra ethyll,putting a lump of lead in the tank will do absolutely nothing.
You can buy some air gun pellets wrapped up in wire netting on ebay for £25 or so and they do bugger all as well (other than stirring all the crap up in the bottom of the tank and eventually wearing a hole in it.

[robbie.cee]

The 'lead' in leaded petrol is lead tetra ethyll,putting a lump of lead in the tank will do absolutely nothing.
You can buy some air gun pellets wrapped up in wire netting on ebay for £25 or so and they do bugger all as well (other than stirring all the crap up in the bottom of the tank and eventually wearing a hole in it.

Cheers for heads up I won't bother then

[bortaf]

TBH it depends on what you use the engine in and for, i killed 3 pintos in a heavyly laden Mk3 by using unleaded in it on mainly motorways, only cured it by fitting an unleaded head (after testing lead pellets and even a magnet over 30K and each head lasted about 10K before the seats resessed and it started to run shite), whereas in a car doing mainly round town i got years of use with no problem( well over 40K and still going), heat and high revs do the damage.
Additive will only protect the valve seat and will do nothing at all for the vavle seals the fuel gets nowhere near the seal or at least it dam well shouldn't
An old engine thats ben run on leaded for years will have some lead mnemory (IE deposits) on the seat but how long that will last if entierly down to prev use/miles coverd/fuel used ect, a freshly built head will last no where near as long as a well used one.

[baconsdozen]

Dead right Bortaf. It's the temperatures of the exhaust valve and seats that determine if recession will take place (and how fast). At very high temperatures,which increase with load and speed micro welding of the valve to seat takes place causing metal to be pulled off and blown out of the exhaust.
None of the so called boosters on ebay make any difference what so ever and it's one of the few places that permits adverts for these and other things like ignition boosters and the like.
The unleaded memory helps but most engines driven carefully will survive without lead in the fuel and we should all be happy that as a result of the non use of lead we'll all live forever in those lovely care homes that so often feature on the telly.

[robbie.cee]

so should i be using additives then?

guess i should!

top info gents!