31 replies to this topic

[Nikko]

So I want to convert my 998 mini to run on unleaded. Can anyone please advise on best course of action? Do I just buy an unleaded head and have it fitted or have mine done? My car has only done 38000 miles so keen to keep the original engine as is. What is the difference cost wise? Also can anyone recommend somewhere to do the work either in Berkshire or London?

[gazza82]

You will need to have hardened valve seats fitted to the exhaust valves and you may need new exhaust valves ... For an idea of pricing find Rob Walker Engineering in Oxford on web.

Small machine/engineering shop in High Wycombe, CMK, can probably do the work. Should come up on google.

[dyshipfakta]

Cheaper to put additive in to be fair. What year is your mini?

[maccers]

Where in London are you? I can highly recommend a place just south of London near Kingston Upon Thames. With the cylinder head off you could take the opportunity to replace valve stem seals and valve springs as well as have the head skimmed if there is some meat left on it.

[Nikko]

It's an 87 Park Lane. I'm in Fulham so Kingston is not far for me.

[Nikko]

£400 quoted so far? Sounds expensive to me but really don't have much clue.

[dyshipfakta]

Honestly if it runs well don't bother. Just get loads of additive if you have a problem or something down the line by all means do it but to dismantle a well running engine to fit valve seats is just not worth it. Even running the odd tank of untreated when in a pinch won't hurt it.

[hhhh]

I remember the hype when they first took lead out of gas. I haven't converted any of my many vehicles and I'm not noticing valve seat recession in any of them.

[kezzkitkat]

£400 ? i assume thats for everything ? not just valve seat 

if your on a tight budget then source a second hand head with it done 

to be honest on a 998 not to sure if i would personal do it but each to there own 

[Dusky]

Running without additive is unwise. Your own call, but very unwise.

[hhhh]

If the vehicle in question has done many miles with leaded gas, the seats have become somewhat impregnated, not to mentioned work-hardened, and therefore are somewhat immune to damage from lack of lead in the gas.

[Cooperman]

Just add Castrol Valvemaster in the correct quantity each time you fill up. It is all you need and not expensive.

[MRA]

Ricardo an engine development company that is used by if not all definitely most engine companies in the UK and elsewhere did some development for Rover, they concluded that running a standard A series on unleaded without any modification or additive the valve regression rate was outside of required limits.

 

To put this in short hand, the valves regressed by over 1mm per 10,000 miles, this test was concluded on brand new engines and medium mileage development mules that had run with leaded fuel for some time, the minimum mileage on the mule engines was 15000.....  additive will certainly help even if you rev the nuts off it, the best way ?

 

Well you have 2 choices,

 

1) additive,

2) valve seat inserts,

 

Both have their negatives and positives, but as above, if it is a perfectly running engine just use additive, keep enough with you in the boot though.

[gazza82]

If the vehicle in question has done many miles with leaded gas, the seats have become somewhat impregnated, not to mentioned work-hardened, and therefore are somewhat immune to damage from lack of lead in the gas.

They aren't immune ... Just less immune ... And that depends how they are driven ...

[jabos7]

Hope to bump this up to get an idea of how to tell If my head is already set up for unleaded..

It's a 1973 Mk3 with 998, and has the bypass installed to the water pump.  -Is that indicative or totally

unrelated? I can't recall years timing as to whether mine was built for unleaded.  So many other surprises on this one

as I tear it down that unless there are some serial/part number clues I'm lost.  Hate to waste machine

shop $$$ if this one is good to go, and I get the impression that even looking at the seats straight on you

can't tell if they are hardened or not.   

 

Any direction/advice will be greatly appreciated!  --J