14 replies to this topic

[imabitnaughtyxx]

Righto, a while ago i asked forum members if they thought my car ran on unleaded.
I checked the engine numbers and it appeared the car was built running 4 star. Ok i thought, problem solved...but no
the previous owner emailed me and said the car ran on unleaded for all the 4 years she owned it. she never had a conversion but maybe the last owner did before her she had no idea... she was told at purchase it was unleaded.


so folks what do i look for to check its unleaded and if it was not converted and should be on 4 star... how in hell is it still alive. the engine ran pretty well once the choke is off and no knocks or bangs and no smoke????

HELP!!!

[Udo]

The only way to be sure if it has been converted is to remove the cylinder head and have a look to see if it has had hardened inserts fitted in the valve seats

[imabitnaughtyxx]

The only way to be sure if it has been converted is to remove the cylinder head and have a look to see if it has had hardened inserts fitted in the valve seats

ok and if it hasnt, what damage has been done?

[Ethel]

If it doesn't have unleaded valve seats it can run on unleaded perfectly fine but you'll be slowly eroding them and the day will come when it won't run very well on any petrol. The only way to be absolutely certain is to take the head off and look at the valve seats.

If it was me I'd use it as an excuse to fit a flowed head

[imabitnaughtyxx]

If it doesn't have unleaded valve seats it can run on unleaded perfectly fine but you'll be slowly eroding them and the day will come when it won't run very well on any petrol. The only way to be absolutely certain is to take the head off and look at the valve seats.

If it was me I'd use it as an excuse to fit a flowed head

O dear, well ive no idea what a flowed head is... as im still learning about all this and to be honest exactly how easy is it for the novice to attempt head removal and replace, armed with haynes manual of course?
is it as simple as remove have a look and replace using new gasket and studs???

[Matt]

well apparently the head removal is quite easy.. but its not something i would be armed with taking on.
have you tried running it with leaded petrol? i know seems the obvious but if it runs better then perhaps its that?
i dunno im a novice

[imabitnaughtyxx]

well apparently the head removal is quite easy.. but its not something i would be armed with taking on.
have you tried running it with leaded petrol? i know seems the obvious but if it runs better then perhaps its that?
i dunno im a novice

we only drove it 1 mile, it drove ok considering it had not been serviced in 4 years!!!
seemed fine. apparently it wont do any harm using lead additive anyway is this true.

[Matt]

cant see it doing any damage as if its not used it will just burn through to the exhaust.

[imabitnaughtyxx]

cant see it doing any damage as if its not used it will just burn through to the exhaust.

might just do that then until we get round to doing more with the engine, going for re-spray later on so concentrating on that for now...

[Mephiston]

Yer not harm putting lead additive in even if it is unleaded - you will be doing more harm by not giving it a proper service - do that now and it will run much better

[Ethel]

Taking the head off is one of the simplest things you can do on a Mini. You'll just need to replace the head and manifold gaskets. My suspicion would be that it is unleaded if it's set up to run on unleaded and the previous owner really used unleaded for years, but as we say only one way to be absolutely sure.

[HARBER07]

The only way to be sure if it has been converted is to remove the cylinder head and have a look to see if it has had hardened inserts fitted in the valve seats

This may be obvious to some but how would i know if they are hardened or not ( ie. how are they different?)
thanks

[Se7enS1ns]

You can usually see a ring around the valve where the hardened seats have been pressed in place. you'll have to have a good scrub to remove all the carbon to be able to see it, if theyre there.

[998dave]

The only way to be sure if it has been converted is to remove the cylinder head and have a look to see if it has had hardened inserts fitted in the valve seats

ok and if it hasnt, what damage has been done?

No lasting damage except to valve seats, which will be ground out and covered if you change to unleaded, though as mentioned is a good chance to fit an unleaded head anyway, theyr'e cheap to buy.

If it doesn't have unleaded valve seats it can run on unleaded perfectly fine but you'll be slowly eroding them and the day will come when it won't run very well on any petrol. The only way to be absolutely certain is to take the head off and look at the valve seats.

If it was me I'd use it as an excuse to fit a flowed head

O dear, well ive no idea what a flowed head is... as im still learning about all this and to be honest exactly how easy is it for the novice to attempt head removal and replace, armed with haynes manual of course?
is it as simple as remove have a look and replace using new gasket and studs???

Flowed head, or large valve head will give more power, best to buy from a trusted source if your not that confident, but that aside...

Head change is relatively easy, you can check if it's flat too, and decoke while you've got it off, (scrub the soot deposits away), which will help, especially if your car tends to over run on switch off. Good chance to check valve clearances too, and general service never goes amiss...

D

[Millers Mini]

I had my head converted about 2 months ago by minikel and it really improved the performance so if yours isn’t running as well as you would like check to see if has been converted and if not get it done, you will certainly see the difference.