can B201 8-valve engines run on unleaded fuel?

My 900-S has an 8-valve B201 engine and runs fine, but here in Australia, leaded-replacement fuel (called 'LRP') is considerably more expensive than standard unleaded fuel. The price difference is generally between 3 to five cents per litre.

I've asked a few people but nobody seems to have a conclusive answer... Has anyone successfully run a B201 engine with unleaded fuel?

If not with standard unleaded fuel, how about with higher-octane 'premium' unleaded? I've got no idea what the octane ratings of our fuels are here in Oz, but they'd probably be similar to what's available in the US and Europe, with differences in whether or not LRP and premium fuels are available.

I'm tempted to try the engine with mixture of half-LRP and half-unleaded (standard ULP) to see what happens, and move on from there.

Craig.

-- Craig Ian Dewick ( snipped-for-privacy@lios.apana.org.au).

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APANA Sydney Regional Co-ordinator. Operator of Jedi (an APANA Sydney POP). Always striving for a secure long-term future in an insecure short-term world Have you exported a crypto system today? Do your bit to undermine the NSA.

Reply to
Craig Ian Dewick
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If you're worried about valve seats then don't - you won't have a problem running unleaded.

As far as engine performance goes, you'll just have to suck it and see. Try a tank full of whatever standard unleaded is available to you, and see how it runs. If you get any pinking, you may be able to get rid of it by adjusting the timing.

If it pinks and you can't stop the pinking, you'll need to use a higher octane fuel.

Reply to
Grunff

Craig Ian Dewick wrote: :: My 900-S has an 8-valve B201 engine and runs fine, but here in :: Australia, leaded-replacement fuel (called 'LRP') is considerably :: more expensive than standard unleaded fuel. The price difference is :: generally between 3 to five cents per litre. :: :: I've asked a few people but nobody seems to have a conclusive :: answer... Has anyone successfully run a B201 engine with unleaded :: fuel?

How old is the car? If it's newer than 1980, then no problems.

Cheers!

Reply to
Henrik B.

Yes. Built in late 1982, sold from the dealer in early 1983.

Craig.

-- Craig Ian Dewick ( snipped-for-privacy@lios.apana.org.au).

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APANA Sydney Regional Co-ordinator. Operator of Jedi (an APANA Sydney POP). Always striving for a secure long-term future in an insecure short-term world Have you exported a crypto system today? Do your bit to undermine the NSA.

Reply to
Craig Ian Dewick

You should check that it has hardened valve seats. Unleaded petrol was introduced at different times in different countries; the UK was one of the last. I had a Fiat Croma from 1987, this car wasn't adapted for unleaded. The octane rating is just one aspect. If the car doesn't need premium fuel, it might well run normally for 10k miles or so before excessive valve seat wear becomes apparent if it doesn't have the hardened valve seats that is required for running unleaded.

Reply to
Johannes H Andersen

This only applies to engines with cast iron heads. Engines will alloy heads (*all* 900 engines) have always had valve seat inserts - an alloy head wouldn't last more than a couple of thousand miles without them.

Reply to
Grunff

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Never happy to loose an argument :) I found a page that suggest that Saab 99 Turbo *and* early Saab 900 Turbo had soft valve seats, unsuitable for unleaded. There is no MY on the page, so more research is required.

Johannes

Reply to
Johannes H Andersen

It does seem to imply that the inserts fitted to the earlier heads were soft. This sounds like madness, but in the absence of more evidence, I will concede. Looks like I was wrong.

Reply to
Grunff

I wish they would say what Early is?

My '84/85 is a 16v. You would assume that they didn't make the same mistake twice.

It also had a green filler cap which would suggest unleaded (does on other Marques anyway from arround the transition period), and the APC which will allow it to run on lower Octane fuels without pinking.

Reply to
MeatballTurbo

FWIW I've been running my 86 T16 on unleaded for years. I replaced the head gasket a couple of weeks ago, and the head + valves were in immaculate condition.

Reply to
Grunff

Hi Craig,

LRP is made from premium unleaded (95 RON) with a valve saver added, regular unleaded is only 91 RON that's why LRP is more expensive. BP Ultimate and Shell Optimax are 98 RON.

More info can be found at oil companies' web sites. I think some oil companies have a hotline you can phone to find out if your car will run on unleaded fuel. John Hudson Brisbane AU.

Reply to
John Hudson

Loverly.

Reply to
MeatballTurbo

I like the Optimax for my 9000 CSE. It gives clean acceleration without hick-ups or flat spots. There are naturally many factors to consider and this petrol may not give any benefit if you're trundling around in city traffic.

Reply to
Johannes H Andersen

MeatballTurbo wrote: ::: FWIW I've been running my 86 T16 on unleaded for years. I ::: replaced the head gasket a couple of weeks ago, and the head + ::: valves were in immaculate condition. ::: :: Loverly.

ALL Saab 16-valve engines are made for unleaded fuel.

I ran my old 99L '78, for over two years on unleaded, without any probs.

Cheers!

Reply to
Henrik B.

John Hudson wrote: :: Hi Craig, :: :: LRP is made from premium unleaded (95 RON) with a valve saver added, :: regular unleaded is only 91 RON that's why LRP is more expensive. BP :: Ultimate and Shell Optimax are 98 RON.

Can't that that as a generel rule. Here i Denmark, we have 92, 95 and a few places 98 octane unleaded. And the we have the "red" gas, which is 95 octane.

Cheers!

Reply to
Henrik B.

Excellent. One less thing to worry about.

Reply to
MeatballTurbo

Thanks for the comments. I've had some other people mention Optimax as well when I suggested I'll try running the car on something other than straight LRP to try it out. Is Optimax significantly different in any way to the other 'labelled' types of premium ULP?

I would rather not take the head apart on the engine to determine the type and condition of the valve seats, etc. while I'm lacking some important tools (mainly a proper torque wrench, etc.), so I might try first of all running with a mixture of half-LRP and half-Optimax or another type of premium ULP and see how it goes. Since the car is from the pre-ECU era I don't know what different it'll make not having an ECU to manipulate engine management settings when running on alternate fuel, so I'll see what happens. 8-)

Pricing for LRP and premimum unleaded fuels is around the same at most places in the part of Sydney where I live. Since fuel pricing for ULP hovers between the low 80 cent per litre mark (that's A$0.80) at the start of the week, rising up to almost 1 dollar per litre by the end of the week, it's impossible to get better pricing without driving a long way to cheaper fuel suppliers, and/or always making sure I fill the tank on low-priced days (Monday to Wednesday normally).

Craig.

-- Craig Ian Dewick ( snipped-for-privacy@lios.apana.org.au).

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APANA Sydney Regional Co-ordinator. Operator of Jedi (an APANA Sydney POP). Always striving for a secure long-term future in an insecure short-term world Have you exported a crypto system today? Do your bit to undermine the NSA.

Reply to
Craig Ian Dewick

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