7 replies to this topic

[robmillar_121]

I have an austin mini city 1997 998cc

 

just got it up and running as it was sold a non runner, fresh fuel, played with the timing, carb and boom up she started.

 

ive heard that these engines were built to run on leaded fuel, and that obviously now petrol is all unleaded and combusts at a higher temperature than leaded fuel does and can damage the valve seats?

 

im probably going to take it all apart and do it anyway because why the ******* not? never done it before so it will be a good experience. 

 

obviously going to change head gasket etc etc whilst im there, just wanted to know if it was actually true or not? or just one of them things that is technically true but doesnt actually do anything 

 

 

many thanks 

 

 

rob

[HarrysMini]

If it's 1997, it should be unleaded as standard. 

 

I think it was around the mid to late 80s they stopped making the leaded engines. 

 

Hold on, if it's 97, it shouldn't be a 998 as they were discontinued in '92.

Edited by HarrysMini, 20 January 2014 - 09:47 PM.

[Cooperman]

A 1997 will have hardened valve seats for unleaded.

And 'Yes,' as above, all 1997 Minis were 1275.

Edited by Cooperman, 20 January 2014 - 09:48 PM.

[robminibcy]

I guess its a typo and is actually a 1987 mini city since 998s stopped being made in the early 90s. I think as standard it will still be a leaded head but I know it was around that era that the change over to unleaded heads was made. If it is in need if a refurb then yes go for the conversion. If it seems ok then put it back together and use castrol valve master which is readily available from garages and motorfactors. It will run ok on unleaded but there will be accelerated wear on the seats as you said. The conversion is something a machine shop will need to do unless you have access to tools and skills to machine the head and fit the hardned seats

Edited by robminibcy, 20 January 2014 - 09:54 PM.

[robmillar_121]

I have an austin mini city 1997 998cc

 

just got it up and running as it was sold a non runner, fresh fuel, played with the timing, carb and boom up she started.

 

ive heard that these engines were built to run on leaded fuel, and that obviously now petrol is all unleaded and combusts at a higher temperature than leaded fuel does and can damage the valve seats?

 

im probably going to take it all apart and do it anyway because why the ******* not? never done it before so it will be a good experience. 

 

obviously going to change head gasket etc etc whilst im there, just wanted to know if it was actually true or not? or just one of them things that is technically true but doesnt actually do anything 

 

 

many thanks 

 

 

rob

 

A 1997 will have hardened valve seats for unleaded.

And 'Yes,' as above, all 1997 Minis were 1275.

 

I guess its a typo and is actually a 1987 mini city since 998s stopped being made in the early 90s. I think as standard it will still be a leaded head but I know it was around that era that the change over to unleaded heads was made. If it is in need if a refurb then yes go for the conversion. If it seems ok then put it back together and use castrol valve master which is readily available from garages and motorfactors. It will run ok on unleaded but there will be accelerated wear on the seats as you said. The conversion is something a machine shop will need to do unless you have access to tools and skills to machine the head and fit the hardned seats

sorry yes it was a typo its a 1987 lol in new to this stuff so please forgive me 

[robmillar_121]

I guess its a typo and is actually a 1987 mini city since 998s stopped being made in the early 90s. I think as standard it will still be a leaded head but I know it was around that era that the change over to unleaded heads was made. If it is in need if a refurb then yes go for the conversion. If it seems ok then put it back together and use castrol valve master which is readily available from garages and motorfactors. It will run ok on unleaded but there will be accelerated wear on the seats as you said. The conversion is something a machine shop will need to do unless you have access to tools and skills to machine the head and fit the hardned seats

 

 

Yeah im going to strip it all out and then give it to an enginering company that it litterally round the corner from where i work, coincidentally where one of my classmates works, so yeah im going to go for it!!

 

 

thankyou very much for the info i do appreciate it, its nice to prove the reason for what im doing.

 

 

rob 

[Fast Ivan]

AC Dodd has written up how to do the conversion in the latest mini world magazine, worth having a read of that. It has the sizes and tolerances in that might be usefull to the engineering firm you use.

[Rog46]

I think it depends on how Mitch you want to use it! Yes it will slowly destroy the exhaust valve seats but it will take quite a few thousand miles to do it! If it's a hobby car with just a few thousand miles a year use forget it until the compression drops!