Dizzy advance degrees 18rg

[maurice c]

Hi guys, I've been playing around with dizzys and looking at my old 18r dizzy, one side gives 11.5 degrees advance mechanical and the other gives 13.5 degrees, the amount of mechanical advance you get is governed by which side you put the pole between,Now looking at my Rg which has a ra40 dizzy with an electronic ignition installed, I only have 11 degrees of advance. The other side of the plate gives exactly the same reading on a verniers and is not stamped, so basically anybody that has changed over their dizzy to elecronic using 21 r internals is running less mechanical advance.

Now the question is, can somebody that has an 18rg 250 or older dizzy read the degrees of advance on the dizzy plate on both sides, then if I file the advance side of the plate out a bit to replicate the extra degrees will I end up with extra mechanical advance if needed? Thanks.

[Rodger]

Yep that is how Toyota can use the same dizzy and parts on several engines and variants on engines.

Maurice there would be something in either River's 18R-G specs thread or in the Mega 18R-G thread that lists various timing set ups for this motor. Half the mechanical advance shown in the tables and that will show how the plate slots relate.

Good info.

Regards

Rodger

[GA61XX]

[QUOTE=maurice c]"Now looking at my Rg which has a ra40 dizzy with an electronic ignition installed, I only have 11 degrees of advance. The other side of the plate gives exactly the same reading on a verniers and is not stamped, so basically anybody that has changed over their dizzy to elecronic using 21 r internals is running less mechanical advance. "

QUOTE]

So use the 22RE elecronic internals, to convert your 18R dizzy.. The 22RE, has a larger mechanical advance, & lighter weight's, & springs..
But you would need a Dyno to set it up propper...

[The Witzl]

i wouldnt make it advance too much.
I used the 13* side of the plate on my 18RGEU, and it pinged. I never got around to changing it to the 11* side to see if it fixed it.... becuase i went to a Megasquirt instead.

[maurice c]

When I originally got the engine it was runnign 13.5 but the dizzy was trashed by d-head transporting and sons. I'm confident that that amount of advance wont be a problem. So exactly what is stamped on the 22re plate?

[maurice c]

Just in case anybody is going to start filling their dizzy plate make sure that your filling away the left hand side not the right, this is a mistake you'll only make one time.

[Steve M]

From the 1977 book, 18RG 88250 and earlier engines (read 9.7:1 and the larger of the stock cams) were supposed to have
13.5 degrees of distributor mechanical advance and a
static timing of 5^.
vacuum advance of 7.5^ @ 105mm.Hg,
4.3^ @ 75mmHg and
vacuum advance beginning at 45mmHg.

My 18RGU points dizzy has a 15 degree option. I thiknk the other option was 13.5 or something like that.

The 88231 (I think) and earlier, small cap, distributors used a different design of advance mechanism and so the swap to electronic pick up is not doable. They are also not marked with their advance degrees.

[maurice c]

Thanks Steve,
Well now i'm going to try and modify the plate to get that 13.5 degrees of advance, when I have some time of work, i'll measure the weights compare springs and see whats achieveable. So to wrap it up putting an electronic guts from a 21 R dizzy will rob you of 5 degrees of mechanical advance! Anybody like to make a contribution about the 22re advance plate?

[Steve M]

You could worry about all that, or you could just advance your static timing to make up for whatever you're losing in mechanical advance and get a smoother idle and a little better response from the engine.

[maurice c]

I've thought about that but its the easy way out for someone as particular as I am. I just have to take my rat tail file to another advance plate. This time a spare.

[GA61XX]

When I originally got the engine it was runnign 13.5 but the dizzy was trashed by d-head transporting and sons. I'm confident that that amount of advance wont be a problem. So exactly what is stamped on the 22re plate?

21R-c = 11

22RE = 12.5

..

[maurice c]

Thats a bit better, whats a degree between friends.

[Omegaman]

i know this is an old thread, But.
When rebuilding an 18rgeu dizzy, how do you know what side the 13.5 weight and the 11 deg weight goes on.
Is there a difference, how do you look and the plate and verify what side either should be on??