Morris Minor Owners Club

How much does it cost to convert a morris to run on unleaded petrol?

Any advice would be greatly appreciated.

Would pay for a garage to do this.

If you strip the head, rebuild it and refit it yourself it should cost about £50 for the machining. Look at about £150 if you want a garage to do all the work....

how easy is it to run on leaded petrol? or is it better to convert it to run on unleaded?

and is there much difference in price / running it?

also another quick question how much is it to convert breaks to servo?

thanks

Unless you do lots of high speed motorway miles just leave it as it is until such a time as valve seat recessions demands you fix it - Probably last forever just pottering about.... Servos cost around £60 new but why would you want to?

PSL184 wrote:If you strip the head, rebuild it and refit it yourself it should cost about £50 for the machining.

I think it comes to something like £120 including the cost of the exhaust seats and the hardened exhaust valves. A reconditioned exchange head from ESM costs £139+VAT (plus whatever it costs to post your old head to them).

you can put lead additive in with the fuel when you fill up.i used to use valve master

Use a local machine shop like I do and it's much cheaper.....

No need to go unleaded - unless doing long hard miles. If really worried - get some Tetra-boost additive. It's the ONLY one that puts tetra-ethyl lead in the petrol effectively converting it to leaded fuel! The others are of doubtful benefit - mixtures of sodium/potassium and hocus-pocus !
No need for a servo either - assuming you have reasonable leg power. These cars were made for little old ladies! If the brakes are heavy - they need overhauling. New shoes and cylinders all round is cheap and easy to do.

Here in the US, we haven't had leaded gas in years. Lots of Morris' around and don't think all of them have been modified.

If you're planning to do more than 50,000 miles then it's worth having the head conversion, otherwise an additive works out cheaper.
If you're planning to do the head conversion anyway or not likely to do a lot of miles (especially with hard driving) then you may want to try running without any additive and see how long the valves last - some can last a very long time!

i have run my 1100 on unleaded 91 for three years now with no problems. i did put a bit of valvoline in it initally but never bothered after that.

ive heard that avgas is really good. put a litre of it in about every 5 tanks. i was told that lead has good memory so it doenst need to be put in every tankful.

I was on the industry technical committee which over saw the introduction of unleaded petrol in New Zealand.

Valve recession is a fact, but was almost totally limited to the gasoline powered tractors in the US Mid West and a few other examples of highly loaded high speed petrol engines with cast iron heads and no hardened valve seats. Those American tractors had high engine speeds and high loading factors. You will be able to run your Morry on unleaded with no fear of valve recession, unless you constantly tow a caravan at over 100 km/h on the motorway.

The fear of valve recession (and the fear of higher benzene levels in unleaded petrol) could probably be attributed to the manufacturers of the lead anti-knock additives.

I'd tend to agree. I know of two minors, one a 1098 th eother a 948 that have both done large mileages, including long distance otherseas jaunts over the last 6 years or so with no problems. The 948 alledgedly had and unleaded head supplied by a Minor specialist, though when inspected recently following a head gasket failure was found to be just standard (which may not be the fault of the Minor specialist, but their supplier).
Anyway the point is that Minors seem to stand up to unleaded pretty well, and I'd be tempted to leave it unless you have to take the head off for something then have the exhaust valveseats done for £60-£80
I've never heard of anyone who has suffered valve seat recession, but plenty of folk who have said that their favorite brand of additive / unleaded head has been ok. But would it have caused probelms otherwise?

Likely not - I don't use any - and drive my car hard when driven, although admittedly it's not that often. The important thing is to set the exhaust valve gaps to 15 thou - and keep an eye on the gaps. If they start to close up - just adjust them open again.

i may have a unleaded head in the garages some were will have to have a look

My 'conversion' cost nothing - I just chucked the fuel in the tank and it went.
I was doing around 12k a year, maybe more, with several sustained 'long distance' trips inbetween.
They built them tough in the old days.