How safe is it to use unleaded in an engine without hardened valve seats?

I know that it can cause valve seat recession OVER TIME, but what if I was to use a few litres just to get a car from one place to another before putting the right fuel in it?

The reason I ask is: I have about 4 litres of premium in my 5L jerry can that needs to be used before I can refill it. I can sqeeze some flashlube in there later, but need to get it running NOW....

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[NATHAN] -- Sold everything mini related and am back in big beautiful BMWs

You're not going to notice it on an engine as old as it is

Do it.
Won't hurt at all in the short term.
Long term, yes it will- I have pics and a buggered 202 head to prove it.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

the engine isnt old, it was rebuilt a couple years ago.... not smokey, some kind of speccy cam in it, no oil leaks. Its the kind of engine that doesnt need to be pulled apart (for a change)

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[NATHAN] -- Sold everything mini related and am back in big beautiful BMWs

Your valve guides are probably that worn that they leak oil into the bore and lubricate it for you.
Therefore eliminating the need for the additives

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Miniworx Centre 0883741299
Sooperdooperminicooperexpertengineering
Online BMW Mini Shop

Ah thats good.... cos I already did....

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[NATHAN] -- Sold everything mini related and am back in big beautiful BMWs

I have been running my Morris 1100 as a daily driver for about 5 years on regular unleaded without any additive at all and the head has not been off in 40 years.

If you were to give it a heap of revs on a freeway on a hot day it could die in hours but for cruising around town it will last forever.

I add Flashlube every 2nd or 3rd tank full. Engine runs fine. No dramas.

i dont use flashlube additives anything above 95 octane rating in unleaded should be ok anything below is not ok because of valve damage will occur overtime 10 years ago octane ratings were around 91 flashlube was essential many engines were damaged nowadays higher octane ratings have compensated for this factor thus the increase in higher octane ratings which reduces engine detonation whereas before a lead sustitute had to be added to increase the octane rating so to speak of 91 unleaded.minis are so to be run on 100 octane lead substitute how do you do that.well now you know why petrol is so expensive these days arent you glad you dont drive a v8.Fact leaded petrol is actuaaully less toxic than unleaded.the reason for the change i here you ask,lead goes into the the ground and causes learning defects up until the age of 18 but unleaded contains benzine which goes into the atmosphere and some genius realised theres more surface area up there then on the ground so its a case of out of mind out of sight.By the way benzine is 10 times more toxic than lead.sorry to through a spanner in the works.please reply to my comments if you agree or disagree some body who doesnt know it all backyard mechanic.Bulla.

yeah, really hard to unnerstand

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Crazy Minimad

Anyway doesn't valve seat reccesion occur because of a lack of lubrication for the valves? I don't think flashlube raises the octane rating of petrol - its added in such small ammounts, and never advertised as an octane increasing additive, only as an upper cylinder lubricant.

And the statement "benzine is 10 times more toxic than lead", what do you mean? In what cases? How do you derive this 10/1 ratio?

Bulla is right, running old cars on unleaded with no cat converter puts lots of carcinogens into the air fron the benzene (toluene) and other solvents in it. A fact conveniently ignored by the people who pushed for unleaded.
Most lead in the air & environment is caused by things other than petrol- eg lead in paint and lead pipes etc.

re the Flashlube, it was designed to eliminate valve recession in taxis etc with cast iron heads, using LPG which is also a dry fuel.
I got bad valve seat recession in 6 months on a 998 daily driver, after a head recondition. I ran it on 91 unleaded with no additives just to see.
Whether you use 91, 85 or 98 octane unleaded, NONE has anything in it to prevent valve seat recession.

I've since proved to my satisfaction Flashlube works, the valves and seats in my 1310/1360 have never looked better.
IMO if you want it to last, it's Flashlube, or unleaded seats- take yer pick.
Jury is still out on those Fuelstar etc tin pellet things... whether they work, or are about as useful as a Peter Brock Polariser thingy.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

I'll let you know in 50,000 miles when I pull the head Stay Tuned

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Lillee - 1969 Morris Mini K

Not trying to start an argument Morris1100 but just wondering on some points.

When you say daily driver and recognising you are in Goulburn. What is the average kilometres of your individaul trips. Are you in town ? Are we talking trips of say 1.5 - 2 kilometres ?

We know that recession occurs for a couple of reasons and heat is a major reason. Although your car may reach operating temperature, if its only for a few minutes then the factors causing recession would be quite different to someone in the city who spends an hour each way in traffic and at variable speeds.

As you know, we are 27 km from a major shopping cente (Mudgee) and 16 km from a minor shopping centre (Gulgong). Both are 100 kmh from the front gate to the town boundaries. I have now also seen enough heads from older cars to instantly know which are using flash lube and which are not. The differences in wear are very noticable.

I dont doubt you in any way, I am just trying to be a bit analytical about the whole issue.

so...... what about using a few mL of 2 stroke oil instead????

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[NATHAN] -- Sold everything mini related and am back in big beautiful BMWs