Tech Tips:
Unleaded Fuel

From: Miles Family [milesfamily(at)telus.net]
Sent: Monday, March 31, 2003 1:37 PM
To: hillman@can-inc.com
Subject: "Hillman – " gas question

Hi, I've got a question about gas ( no, not that kind ).  Is there any problem running older cars from the 50's and 60's on unleaded gas ?


From: alkon [alkon(at)bigpond.com]
Sent: Monday, March 31, 2003 7:20 PM
To: hillmanlist
Subject: Re: "Hillman – " gas question

The unleaded gas question has been knocked about a fair bit.
However my feeling is that it will do no harm to our Rootesmobiles.
With my 55 model the compression ratio is low enough for it to run quite happily on the standard unleaded.  If a higher compression engine was used then using the premium unleaded would be advantageous.
The alloy headed models should be OK with the unleaded as they already have valve seat inserts.
In addition to the unleaded fuel I use a lead replacer additive.  This is basically an upper cylinder lubricant.
It is worthwhile to keep an eye on the valve clearances but no more than is typical for a solid lifter engine.  

I will not use the lead replacement fuel.
Different suppliers use different additives and they are not totally compatable, and I feel not benificial to the long term reliability of the engine.
Having said that there has been some noise in Australia recently about the use of contaminants mixed in with the fuel (to maximise profits) so in some areas what you get from the pump is perhaps not what you think you are getting.  This can cause all sorts of problems with poor engine performance and premature engine wear.  

I have been running my Californian on unleaded for two years with no problems. 
There have been a few links to sites discussing the ULP and LRP saga.
I unfortunately lost the addresses when my computer fell over.
I am sure minimania.com was one of them.  The Rolls Royce club also had a file on the use of ULP in their vehicles.  

55 Californian

From: Adrian Higgs [adrian_p_higgs(at)yahoo.co.uk]
Sent: Monday, March 31, 2003 8:01 PM
To: hillmanlist
Subject: Re: "Hillman – " gas question

This message forwarded by the Hillman List.

As I understand it there are 2 principal issues with reference to unleaded in older cars.

1) The lead (actually a lead based compound, tera-ethyl lead) raises the octane of the fuel, discouraging pre-ignition – "pinking" under load and "knocking" at higer engine speeds, both of which over a period can seriously damage pistons.  The same effect can be achieved by retarding the ignition timing a small amount (the exact amount is a matter of trial and error – keep retarding it till the pinking goes away, and, "bingo")

2) Some of the lead in the fuel leaves a protective film on the valve seats.  When the engine runs fast or under heavy load for more than a short while, the exhaust valve seats can get very hot indeed, to the extent that without that protective film of lead, the opening valve can pull small blobs of metal away from the seat.  The result over a period of time is valve seat erosion, which you will see evidence in the exhaust valve clearances closing up, hence Keith's comment about watching them.

So, what qualifies as "fast" or "under heavy load"?  Generally the accepted wisdom seems to be that if you tow or habitually run at over 3000 rpm then your engine qualifies.

Solutions to the problem?

If you only potter around town and out to the odd classic car meet a couple of times a year, retard your ignition to sort out the pinking and don't worry about valve seat recession.

If you're at the other end of the spectrum, running a daily driver at high cruising speeds and you go caravanning every year then you need to consider valve seat recession.

There are a number of solutions to that:

1. Use LRP or unleaded with a lead replacement compound.  I personally would only use a compound approved by the FHBVC (Federation of British Historic Vehicle Clubs) as these seem to be the only ones that have been adequately tested.  However, choice of lead replacement compound is an absolute minefield with all sorts of opinions generally very strongly held.  Discussions on the relative merits of the competing products usually end up in minor wars.  My advice would be to get the facts from the people who know, ignore the opinions however strongly held and make your decision.

2. Have hardened valve seats fitted, or fit a cylinder head with them already in place.  This sorts the problem "properly" by replacing the seats with metal hard enough not to suffer from the valve seat erosion in the first place.  Engines with alloy heads have always (I believe) had inserted valve seats but these are not always hard enough to deal with the problem – not sure about the Rootes engines in this respect as my Rootes is iron headed.

You can of course run the car on unleaded without lead replacement compound, watching the valve seat clearances and at some point in the future do a full head overhaul, having hardened valve seats fitted at the same time.  That gives you the time to save your pennies up for the job and to plan the work; maybe important if the car is a daily driver.

One last comment – different manufacturers used different qualities of materials in their engines as much as in any other part of their vehicles.  BMC's "A" series engine is known to suffer greatly from valve seat recession, presumably down to poor grade iron in the head.  Rootes engines on the other hand were built to a very high quality (Jan Eyerman can wax lyrical on that topic so I won't steal his thunder!) and the iron in the heads was good stuff, so Rootes engines don't tend to suffer so much from valve seat recession.

Sorry, that turned out to be *really long*.  If you're still alive, I hope it was useful!  :–)


From: Will Owen [nashwill912(at)earthlink.net]
Sent: Tuesday, April 01, 2003 2:35 AM
To: Miles Family
Cc: hillman@can-inc.com
Subject: Re: "Hillman – " gas question

This message forwarded by the Hillman List.

> Miles Family wrote:
> Hi, I've got a question about gas ( no, not that kind ).  Is there any
> problem running older cars from the 50's and 60's on unleaded gas ?
They need to have hardened valve seats.  Most cars with alloy heads (Alfas, for instance) had hardened seat inserts already.  I know that the heads on the old BMC A and B block engines are reported to suffer valve-seat erosion, and replacement heads are now offered with hardened seats.  Don't know about Rootesmobiles, but I suspect it's the same story there.

Easiest fix is to use a lead-replacement additive.  "Car" magazine did an article on this a few years ago, and mentioned that MIRA had run tests on all the additives then on the market.  I'm sure the results are in an accessible database somewhere.


A new thread begins :

From: Penelope King [penny_allen(at)yahoo.com]
Sent: Thursday, February 10, 2005 5:08 PM
To: HillmanCars@yahoogroups.com
Subject: [HillmanCars] Conversion to ULP

Does anyone know what is involved in converting a Series 3A Minx to ULP?
Rumour is they are going to start to phase out lead replacement petrol in Australia, and besides...it is awful stuff anyway.  My Minx has never been the same since they got rid of the "poisonous" stuff.  Not that it was a speed demon, but now it just doesn't run the same...

Penelope King
{address & phone numbers supplied}

From: Peter Chadbund [peter(at)thecopshop.co.uk]
Sent: Friday, February 11, 2005 12:30 AM
To: HillmanCars@yahoogroups.com
Subject: Re: [HillmanCars] Conversion to ULP

The same as with most cars – harder valve seats for the exhaust valves and new valve guides


From: Evan Hillman [hillmancars(at)comcast.net]
Sent: Friday, February 11, 2005 4:26 AM
To: HillmanCars@yahoogroups.com
Subject: RE: [HillmanCars] Conversion to ULP


The whole leaded/unleaded thing approaches a religion.  Much of what is said must be taken on faith.  You can search on "leaded fuel valve problems" and read for hours.  In reading about the issue over the years I have noticed some consist opinions, though:

– Engines that have been run on leaded fuel in the past continue to see the benefit of the lead for some time after switching to leaded.

– Engines that are gently used are at less risk of problems.  Engines that are run at high RPM or under heavy load are at greater risk.  If they are even at risk in the first place...see the next point:

– Not all heads are made of the same alloy; some alloys are tougher than others.  I don't know how this applies to Rootes heads, but for some manufacturers engines happened to have been made of strong enough materials that there are no worries about using unleaded.

– The makers of fuel additives are hardly benevolent.  They are in the business of making money, and fear mongering is one tool they use to make money.  I would hardly consider the makers of a fuel additive the best source of information.

I have never talked with anyone who has had a valve problem due to the use of unleaded fuel, but I have talked to a mechanic who has found that some of the additives clog up the carburetor.

Here are a couple of mildly interesting web sites that take the point of view I subscribe to:


http://www.carolinahealeys.com/Technical Pages/Engine/unleaded fuel.htm


Now, all of the above is about the effects of unleaded fuel on valve wear.  I don't find much said about unleaded causing the engine to run differently, which is what I understand you concern to be.  Lead was originally added to reduce pre-ignition ("pinking"), and serendipitously, it helped with valve wear (once they figured out how to design the valves to keep the lead itself from killing valves).

I would guess that if your engine is running poorly, you would want to first make sure that the valve clearances are OK, make sure your carburetor isn't gummed up, then perhaps adjust the timing a bit to maximize power with the octane rating of fuel you are currently using.  Remember, octane rating is not a measurement of the energy stored in the fuel; it is a measure of the anti-pinking qualities of the fuel.  Higher octane = more resistance to pinking = greater spark advance is possible (or greater compression possible) = more power.  So you don't get more power from higher octane fuel without other engine changes.  Interesting, huh?



From: Jan Eyerman [jan.eyerman(at)usa.net]
Sent: Friday, February 11, 2005 8:40 AM
To: HillmanCars@yahoogroups.com; HillmanCars@yahoogroups.com
Subject: RE: [HillmanCars] Conversion to ULP

Being in the USA and having had experience with unleaded fuel for 20+ years, I think I can shed some light on the subject....

1) Lack of lead of the fuel will hurt some engines – problem is "valve recession" where the valve seats wear away.  From what I"ve read in English publications, Rover 4 cylinder engines are the most effected by this (as used in the Rover 2000, etc.).

2) A good additive helps – BUT since the various additives are different chemically, you must choose one and stick with it.  Redline 2000 seems to be one of the best (but also quite expensive).  I use Alemite (as they have been around for years and years).

3) Higher octane gases are both harder to ignite and burn slower – this can cause burned valves if you have not adjusted the timing (advanced it) for the higher octane fuel.

4) Formulations of gasoline have changed since the sixties – so a Hillman will run differently.  You will need to make sure all of your settings are right for the "new" fuels.

My Hillmans have run fine on no-lead but I have been using 4 ounces of Alemite lead substitute with every tankful.

Jan Eyerman in cold New Jersey (actually we are just coming off of a "warm" spell with temps of about 50 degrees F).  Most of the snow has melted.

From: Wendy or Glen Davies [wlwk_11(at)hotmail.com]
Sent: Friday, February 11, 2005 8:51 AM
To: HillmanCars@yahoogroups.com
Subject: RE: [HillmanCars] Conversion to ULP

"3) Higher octane gases are both harder to ignite and burn slower – this can cause burned valves if you have not adjusted the timing (advanced it) for the higher octane fuel."

I guess I'm "missing" something here.  I've always known higher octane fuels burn slower.  So, why advance the timing?? Seems a retard (like me) is in order, no??


From: Evan Hillman [hillmancars(at)comcast.net]
Sent: Friday, February 11, 2005 9:11 AM
To: HillmanCars@yahoogroups.com
Subject: RE: [HillmanCars] Conversion to ULP


If the fuel burns slower, you must start the combustion process sooner, thus you must advance the timing in order to start the process sooner.

Note also that an engine will advance the timing as RPM goes up, to try to keep the combustion event happening at the correct point in the cycle to produce maximum power.  If it happens too far after top dead center, power is wasted.  If it (the combustion event, not the spark) happens before TDC, then pre-ignition.

The realization that time passes between the spark and when the, uh, "explosion," explains some of the weirdness of how spark timing is handled.


From: vklemans [rhughes(at)actewagl.net.au]
Sent: Friday, February 11, 2005 10:33 AM
To: HillmanCars@yahoogroups.com
Subject: [HillmanCars] Re: Conversion to ULP

Pete (and Penny)

The poor running that Penny is referring to is from Lead Replacement Petrol (LRP) which was introduced downunder about 5 (?) years ago when leaded petrol was phased out.  There was some discussion about LRP a couple of years back and I remember Keith saying that some of the chemicals used in it were incompatible with some fuel system components and the general concensus was that one was better off switching to unleaded and using an additive.

My own experience (in my V8 Commodore) was that LRP is/was indeed crap.  I switched from low-leaded to LRP and immediately noticed running issues (less power, rougher running and running on) with some brands of fuel, although Shell LRP seemed OK.  Other 'classics' owners have noted the same thing.  About 2 years ago I got a really bad tank of the stuff in Sydney (Maybe because of a fuel substitution racket) – 40 km later on the freeway I noticed a lack of power and pinging under load and it was running hotter than normal.  This incident appears to have resulted in a fine crack in the head – the car always used a little coolant afterwards.  After that I changed to Premium (high octane) unleaded plus additive and the car ran better.

Last year I converted to run on straight unleaded.  Since that conversion, the car is running better than it has for years.

So, Penny, yes it's true that LRP is being phased out – I haven't seen it in ACT/NSW since the beginning of 2004 (I think).  You have a choice for your iron head Minx:

First, you can run your car on unleaded and use an additive.  Select one brand and stick to it – I used Morleys for 2 years with no problems.  The cheapest way to buy additives is in large (about 1 litre) bottles at places like "Super Cheap Auto" You have to add a small quantity each time you fill up.

Second, you can convert the Minx by having the valve seats and guides replaced as Evan has said.  After that you can just run on straight unleaded.

Cheers, Vic

From: Brian Vogt [brian-vogt(at)netspace.net.au]
Sent: Friday, February 11, 2005 11:11 PM
To: HillmanCars@yahoogroups.com
Subject: Re: [HillmanCars] Re: Conversion to ULP

Vic wrote:

> I used Morleys ...

That should be Morey's Upper Cylinder Lubricant.  It's made in New Zealand and seems to be readily available in Australia.
Cost was $15 for a 1 litre bottle the last time I bought it.
http://www.moreyoil.co.nz/oil_cylinder.htm   (they moved their web page – Ed)
Some useless clown has removed the 2nd page which gave more info.  On the bottle it says
"OLDER VEHICLES:  MOREY'S UCL is a valve seat protector and replaces the need for LEAD in Unleaded Fuel."

At the recommended ratio of 1:650 it adds 2.3 cents/litre to the price of petrol.

Several 1970s-80s BMW motorcycles in the local club (including my brother's) utterly refused to start with LRP.  All who tried Morey's UCL were happy with it.  My bike had no trouble either way.  The same goes for the very worn Minx engine in my Gazelle.

Brian Vogt.

From: Graham Robinson.Aust. [Leslie3008(at)bigpond.com]
Sent: Friday, February 11, 2005 1:43 PM
To: HillmanCars
Subject: Re: [HillmanCars] Conversion to ULP

All Evan tells us is mostly correct but there is always someone out there that wants to sell you something that makes the car go better – even snake oil.
A well 'tuned, breathing' motor wont be affected by fuel changes to a great extent and an additive is always a safe thing to use – irrespective of 'religious' stories.  If you drive the Hillman it will be fine but if you putter along it may suffer in some performance areas.  My 1725 alloy head twin CD150 engine does hiccup with some of these fuels but it still goes when you push the pedal, some pinking does occur unless you use the Premium grade fuel and it is probably cheaper than the Super or LRP crap we find in Aust.  A compression test would determine if you need new valves or valve guides but this could also show the rings are worn as well so this is not gospel.
Slow burn fuels are common and this is why they have those little expensive black boxes 'ECUs' to manage the engine ignition and breathing (and boost) in modern cars.  So for fuel and environment changes one has to change the computer management chip – expensive.

From: rhughes(at)actewagl.net.au
Sent: Friday, February 11, 2005 3:47 PM
To: HillmanCars@yahoogroups.com
Subject: Re: [HillmanCars] Conversion to ULP

>A compression test would determine if you need new valves or valve guides
>but this could also show the rings are worn as well so this is not gospel.

You can isolate valve/guide wear from piston ring wear by doing 2 compression tests.  Do the first, record the readings, then put some oil in each cylinder.  Then do the next compression test.  If compression increases on second test, you have worn rings.


From: Penelope King [penny_allen(at)yahoo.com]
Sent: Friday, February 11, 2005 2:03 PM
To: HillmanCars@yahoogroups.com
Subject: Re: [HillmanCars] Re: Conversion to ULP

Thanks all.  I thought it might be just the valves and guides but just wanted to be sure.  I have been using the LRP and the Moreys additive for a while, previously just using the LRP.  The additive has made an improvement, but might try the premium to see what happens.  The engine is due for a good overhaul anyway after being garaged for the best part of 10 years.

From: Robin [ordrazz(at)yahoo.com.au]
Sent: Friday, February 11, 2005 8:39 PM
To: HillmanCars@yahoogroups.com
Subject: [HillmanCars] Re: Conversion to ULP

I use Shell optimax in my Humber Hawk, I had the head done with hardened seats & new valve guides 4 years ago, I switched from cheap (crap) run of the mill regular unleaded last year & havent looked back.  My engine doesn't carry on like a pork chop when I switch off, I have more power than I have ever noticed, there is no more bad unleaded smell around, & I get way better milage (I can go from Colac to Albury on 56 litres now & still have a little to drive around, over 400 miles, never could do that before on the one tank).
Shell optimax is 98 octane, that's the best one I have found, Caltex's vortex I like too, I think thats 96 or 97 octane, dont like the rest, esp.  BP gold, as that is only 95 octane like LRP, & they sell it for the same price as optimax... until I started using it, I couldn't belive the difference it would make, you notice it after the first tank of it has gone through the engine, also keeps everything cleaner (carby etc), only costs about $3 more per tank but worth it in my opinion....

I even use it on my 1954 Hillman Minx side valve (with an additive) it makes it tick along well too, & i get better mileage out it than LRP.

I think its worth getting your head/valves done, & kick that crappy petrol out of your Hillman anyway...

thus ends my two cents

Back to my shed full of Hillmans, Humbers & Rovers

Cheers for now,

Robin, Leanne & Jeremy

From: Vic & Rosalie Hughes [rhughes(at)actewagl.net.au]
Sent: Friday, February 11, 2005 11:34 PM
To: HillmanCars@yahoogroups.com
Subject: Re: [HillmanCars] Re: Conversion to ULP

I also find Optimax to be the best;  in the (1984) V8 Commodore I sometimes get running-on and pinging with others, even Vortex.  The Alpine runs OK on most premium unleaded petrol (surprising, as it has a radically shaved head – the "quarter moons" are completely gone – goodness knows what the compression ratio is, probably > 10:1).  The Hunter runs OK on most premium ULP but pings like mad on regular ULP.

Cheers, Vic

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(Choosing the Fuel Type and tuning your engine to suit)

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