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Location:
Brisbane
Registered:
October 2002
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18 rgu tech questions
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Sun, 20 April 2003 10:33
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ok, what is the ignition timing on an 18rgu {points dizzy} supposed to be at full tilt, i know its 12 btdc at idle, but what advance should i be getting up high.
as 18rg owners know u can change the timing of the cams somewhat, what does retarding or advancing it do in relation to power-band ect ect.
does an 18RC dizzy fit into a 18RGU, what are the jaycar electronic dizzy kits like
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Location:
Puckapunyal
Registered:
April 2003
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 Re: 18 rgu tech questions
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Sun, 20 April 2003 11:59
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Hmm, i'm interested in the answers to these mighty fine questions myself - Anyone?
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Location:
Brisbane
Registered:
December 2002
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Re: 18 rgu tech questions
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Sun, 20 April 2003 23:03
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Just to let you know I, I am getting an 18rgeu ready to replace an 18RC. The new engine has an electronic dizzy so I thought I might as well swap it into the 18RC and see how it goes. Will I'll tell you it is not a straight swap. The tightening bolt on the adjuster is about 5mm out. I did not try it the other way around, but why would I seeing I already have the electronic dizzy? Just a thought.
One more thing. the electronic dizzy's adjusting arm is a part of the housing of the dizzy as the 18rc's has the clamp type. this might have caused the problem I had. But it never hurts to try. (unless you put it in 180 degrees) BIG BACK FIRE!! 
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Location:
brisbane
Registered:
March 2003
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Re: 18 rgu tech questions
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Mon, 21 April 2003 10:34
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oi blaze where did you get that fine looking ra23 from? it looks alot like my old one. anyway the dizzy will fit but as blaze said its got a different mounting point...the 18rg dizzy has a clamp that bolts onto the timing cover and the 18rc has one moulded onto the dizzy otherwise it goes straight into the timing cover ont he 18rg...
the points gap and timing is the same as 18rc
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Location:
Brisbane
Registered:
December 2002
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Re: 18 rgu tech questions
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Mon, 21 April 2003 22:09
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Hey Celicaboy, you didn't happen to sell your old one to a Canadian by any chance?  if so it might be it.
If it was I have a few questions for you.
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Toymods Social Secretary
Location:
Sydney
Registered:
July 2002
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Re: 18 rgu tech questions
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Tue, 22 April 2003 01:44
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the Jaycar High Energy Ignition kit is not too bad a little kit at all!
Basically it uses the points from you original dizzy as a kind of switch to control when to spark, and takes care of all the spark load itself - rather than put that large load on the points in the dizzy, which wears them out. It also give better spark performance since the points only have to work on a small load. and its $52.95, cheap!
Ill be building myself one or splashing out on an expensive electronic dizzy
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Location:
Puckapunyal
Registered:
April 2003
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Re: 18 rgu tech questions
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Tue, 22 April 2003 10:04
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Isnt the electronic kit from Jaycar just over $60, and $52 if you buy in lots of 5 or more?
Does look good tho doesnt it, the 18RG's chew through points like nothing else, methinks it would be a good investment :0) If I wasnt throwing my engagement party early may I would get me one :0)
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Location:
brisbane
Registered:
March 2003
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Re: 18 rgu tech questions
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Wed, 23 April 2003 12:07
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na dunno mate.. it got sold to some guy out at beaudesert blaze. weather or not its been sold again i dont know
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Location:
Adelaide
Registered:
June 2003
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Re: 18 rgu tech questions
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Thu, 19 June 2003 04:51
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Ignition timing at idle (1000RPM) is supposed to be 5 degrees BTDC.
Once the coolant temp is over 60 deg C the timing should be 5 degrees BTDC/1000RPM
Sourced from the engine manual.
The only celica engine that had timing of 12deg BTDC was the 2t-b so I don't know where your info came from.
The 18RG distributor has a different part number to the 18r-c and so is engine specific. (it actaully has 18rg marked on the label)
18R-c points do not fit in a 18rgu dizzy either, they bolt in differently.
18rg engines also have different advance weights in them to cope with a higher revving engine and the different behaviour characteristics.
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Toymods Social Secretary
Location:
Sydney
Registered:
July 2002
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Re: 18 rgu tech questions
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Thu, 19 June 2003 11:44
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dude - many people bolt in 18R-C dizzy's into 18R-G's. So i have no idea about the different in advance weights....
as for ignition advance - from the GREEN BOOK (18R toyota repair manual) it states the ignition timing at idle to be 12 deg BTDC. I'm assuming this is with vacuum advance connected.
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Location:
Rocky Mountains, Canada
Registered:
May 2002
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Location:
Adelaide
Registered:
June 2003
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Re: 18 rgu tech questions
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Fri, 20 June 2003 03:19
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Witzl,
The green Toyota repair manual is where I got the info from, they must have a few different versions.
My info came from the 1977 edition engine repair manual and the 1976 toyota celica owners nmanual.
What year is your book?
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Toymods Social Secretary
Location:
Sydney
Registered:
July 2002
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Re: 18 rgu tech questions
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Fri, 20 June 2003 03:38
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mine's copyright 1992!
1st prining 1977.
Anyway, thats just what this book says. I have seen in an RA60 celica repair manual state that the 18R-G ignition timing to be 5deg BTDC, but i am running 12 deg, without an issue. So ill stick to my higher advance thanks!
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Location:
Brisbane
Registered:
December 2002
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Re: 18 rgu tech questions
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Fri, 20 June 2003 06:31
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I have the green book too. it also says 12 deg btdc. the 18r-c was 7 deg. When I first put in the 18rgeu it was running really bad. I check the timing and it was a complete 90 deg advanced. thats what you get if you take the dizzy off to look at it and put it back wrong. about the 12 deg. there are 2 markings on the bottom pully, one is 12 and the other I guess would be the 5 deg. Try both and see what you'd rather.
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Location:
On your mum!
Registered:
May 2002
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Re: 18 rgu tech questions
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Fri, 20 June 2003 07:29
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Usually 1 mark is TDC and the other is the xx BTDC which is where you set it with the timing light. I.E I think in your case 1 will be 12deg BTDC and the other TDC.
Advancing or retarding the cams will offer little in power gains, (cylinder fill would most likely be adversely affected) as would bringing the lobe centrelines closer (inlet in relation to exhaust). Generally speaking - the more overlap (inlet and exhaust open at the same time briefly) the lower the cylinder fill will be at low RPM. This is traded off with better performance at high RPM, but you need raise the comp ratio accordingly to realise the benefits.
The way Toyota has done it is most likely correct. They probably used more cam grinds and timing changes to to get to that point than we will ever see. If you were to change the bottom end (big compression) then there could be benefits in playing with the cam timing.
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Location:
Adelaide
Registered:
June 2003
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Re: 18 rgu tech questions
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Mon, 23 June 2003 17:11
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None of the timing marks on the 18rgu pulley are 5 degrees.
I reckon I've figured out why the books suggest different timing.
The book I've read is, due to its age and the compression reading in the back of it, for the high compression 18rg.
If you ran 12 degrees in a 9.7:1 CR engine I am guessing that it would ping really badly, would I be correct. However in an engine with only an 8.7:1 or and 8.3:1 CR it would be about right.
We have an 18rgu with 9.7:1 pistons so we will stick with the 5 degrees.
One suggestion to sort out any confusion could be to advance it until it is just pinging and then retard it until it doesn't ping anymore. This worked really well with the old 18r-c we had.
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