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Location:
queensland
Registered:
May 2002
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18RC leaded or unleaded?
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Mon, 07 April 2003 21:00
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when i bought my 'other' car the owner said
he runs it off unleaded but then others have told me
dont be stupid its leaded..
how can i find out which fuel my car takes?
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Location:
Mornington Peninsula
Registered:
September 2002
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Re: 18RC leaded or unleaded?
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Mon, 07 April 2003 22:36
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Trust me, use leaded! These cars were designed to use leaded petrol. They can still run on unleaded but they don't run as well and can damage your engine. I know some one who once ran their car on two stroke and another time on diesle! Not good for the engine at all.
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Location:
Canberra
Registered:
December 2002
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Re: 18RC leaded or unleaded?
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Mon, 07 April 2003 23:41
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You mean lead replacement because the only fuel that i know of that has lead in it is AVGAS and if you get caught using this  you will aquire big fines.
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Location:
Brisbane
Registered:
May 2002
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Re: 18RC leaded or unleaded?
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Mon, 07 April 2003 23:55
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This thread seems to pop up once a fortnight, but I'll go over it again...
Back in the good old days, lead existed in petrol for two separate reasons:
1. Anti-VSR (valve seat recession) agent.
2. Octane booster.
Note that a tiny amount of lead is required for 1, so most of the lead was actually for 2 as it's a cheap and very effective octane booster.
Now, in the mid-70's Japan switched to unleaded fuel (as did most of the developed world), so ever since then Japanese engines have been designed to run without lead in the fuel - that means they have hardened exhaust valve seats. People in this country assume that anything built before 1986 (when unleaded was introduced here) can't handle unleaded fuel, but that only applies to local engines; almost anything else, including the humble 18R-C, is designed for unleaded fuel.
So while it's true the 18R-C doesn't need lead, the other issue to consider is octane. Leaded fuel used to be 96 RON, but regular ULP is only 91 RON. That's why some engines complain when you chuck unleaded in them - it's nothing to do with the lead, it's the low octane which is causing the problem! Of course that's an easy fix - just fill it up with premium and everything is OK again.
I hope that all makes sense. Can this be made into a tech article, if one doesn't already exist?
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I supported Toymods
Location:
I renounced punctuation
Registered:
May 2002
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Re: 18RC leaded or unleaded?
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Mon, 07 April 2003 23:59
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It should be added there is no such thing as 'leaded' fuel available at pumps on the roadside for cars anymore.
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Location:
queensland
Registered:
May 2002
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Re: 18RC leaded or unleaded?
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Tue, 08 April 2003 01:28
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Thanks heaps that made perfect sense
i remember reading a discussion maybe a year and a half ago
that was about fuel. but couldnt remember what was specifically said
yeh i meant to say LRP, just cut it down to the point where it meant something else
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Location:
Mornington Peninsula
Registered:
September 2002
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Re: 18RC leaded or unleaded?
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Tue, 08 April 2003 01:51
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When my head was replace all my valve seats were burnt out cause the previous owner used unleaded petrol.
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Location:
Melbourne
Registered:
May 2002
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Re: 18RC leaded or unleaded?
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Tue, 08 April 2003 08:33
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ra23celicachick - U will find that ur valve seats were burned out because the fact there was lower octance in in ULP and hence cause detonation giving the burnt valve seats. Anyways running ULP in a car without that was desinged to run leaded would wear out the valve seats because they r not hardned. Just out of interest u said u knew some1 who ran a car on diesel. I think who ever told u this was pulling your leg a bit as the combustion process between a pertol and a deisel engine are completly different and and swaping fuel between engines would render eitheir inoprable.
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I supported Toymods
Location:
Berowra-Sydney
Registered:
July 2002
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Re: 18RC leaded or unleaded?
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Tue, 08 April 2003 10:52
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in my 18-RC i ran a mix of LRP "leaded" fuel and premium unleaded, never had a problem, and when i say mix, i mean i would run a tank of leaded then maybe 3 tanks of unleaded than some more leaded ect,
i've contacted both shell and mobil on this matter and they both gave me the same answer, if a car is made to run on leaded to cushion the valve seats than you can use one tank of leaded per two tanks of unleaded as the lead "or whatever they use now" would stay around protecting the valve seats while unleaded was being used, just remember one thing, LRP "leaded" is of higher octane than normal unleaded, so if you wish to use unleaded fuel then make sure its a premium mix so your engine is getting the same if not more octane as it was designed for.
18-RC is a tough engine and mine sure got a work out, did the trip between melbourne and sydney 4 times all running on premium unleaded and the engine never got a rest the whole way down and it never showed any problems from using unleaded fuel. only thing that killed it in the end was me writing it off but hey the engine still ran afterwards and still got me home 
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Location:
Adelaide
Registered:
February 2003
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Re: 18RC leaded or unleaded?
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Tue, 08 April 2003 11:11
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when i got my ra23 the dude said unleaded but he wasnt sure, but it runs fine on u/l...
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Location:
Brisbane
Registered:
May 2002
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Re: 18RC leaded or unleaded?
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Tue, 08 April 2003 13:09
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OK let's be clear about this: by the time RA23's started rolling off the production line in Japan, leaded fuel did not exist in Japan. Can you imagine Toyota building engines which won't run properly on the available fuel? Me either. 18R-C's do not require lead in the fuel.
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Location:
Sydney
Registered:
May 2002
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Re: 18RC leaded or unleaded?
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Tue, 08 April 2003 13:33
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I think 18r-c's would run ok on metho..
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Location:
Mornington Peninsula
Registered:
September 2002
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Re: 18RC leaded or unleaded?
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Tue, 08 April 2003 22:38
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My friend ran either his early 90's ford falcon or 85 nissan pulsar (that i know have in my back yard) on diesle. He ran out of petrol and the only fuel he had on hand was diesle. He said it ran like a complete dog but it still just got him to the petrol station
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Location:
Canberra
Registered:
December 2002
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Re: 18RC leaded or unleaded?
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Tue, 08 April 2003 23:21
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But when the cars were brought here in the 70's did we have unleaded petrol? If we didnt, would the engines have been detuned to run on leaded? Just curious 
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Location:
Brisbane
Registered:
May 2002
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Re: 18RC leaded or unleaded?
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Wed, 09 April 2003 00:58
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Leaded petrol was introduced in 1986 in this country. We usually got the crappy engines in the early 80's because of this - for example, the Supra got the asthmatic 5M-E while the rest of the world got the 5M-GE which was equipped with an oxygen sensor and a cat (hence not lead-friendly). Also we never got the high-performance twincam engines in the Celica for much the same reason, and let's not forget the 4A-C in the Sprinter.
Post-86 all this changed - say hello to the 4A-GE (Corolla), the 3S-GE (Celica) and the 7M-GE (Supra)!
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Location:
Canberra
Registered:
December 2002
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Re: 18RC leaded or unleaded?
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Wed, 09 April 2003 04:27
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Is that why we got the 18R-C instead of the 18R-G? Or did we get the 18R-G? Cause when the celicas were brought over in the lte 70's they didnt have a cat so that means they were made to run leaded doesnt it?
I understand where you are coming from in regards to PULP I am just curious. Besides if its an older engine wont the valve seats have receded a little anyway? My 18r-c was recond 30,000km ago apparently but I will still run LRP i think. Gota get it goin first
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Location:
Adelaide
Registered:
February 2003
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Re: 18RC leaded or unleaded?
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Wed, 09 April 2003 09:54
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so the 18r-c is ment to run on u/l??? an easy way to tell is to go to the petty station and try to put the nozzle of lrp in, if its u/l then the nozzle SHOULDNT fit... but yer thats all i got.
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I supported Toymods
Location:
Berowra-Sydney
Registered:
July 2002
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Re: 18RC leaded or unleaded?
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Wed, 09 April 2003 11:16
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what wouldn't fit into the filler hole on a ra23 or 28 ect? fact is that new lead replacement crap is meant to be worse for your engine, than normal leaded fuel, so i'd prefer to not go near it if possible and fact is no one has ever had a problem with running there 18rc on unleaded so i suggest you run unleaded but if you are going to i'd suggest premium unleaded as there is no point in going down in octane,
also i don't see why you would think the engines were de-tunned to run on leaded, leaded has a higher octane rating than normal unleaded.
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