For the love of a tractor engine: The life and times of the 18R-G

[floppy]

So many variations to these 18R/RG blocks.

The one that came in the yellow celica I thought was an original 18RG until i bought this other one and the oil dipstick is on the exhaust side.

I also have an 18R (not r-c) if that makes any difference plus the 18r-c I got from you mr rad28.

Dave

[The Witzl]

weeelll.... lets throw my experience on the engine's i've played with in here
so far to date, i've toyed with at least 8 different blocks.

But, citing River's mammoth Diagram thread.....

Note the following 18R-G block:
... see the breather thing is fully blocked up on the exhaust side. This is synonymous with the TWO genuine 18R-G blocks i have in my garage.




Now note the following 18R block:
... see the breeather on the exh side is actually open, suggesting a breather pipe is fitted to it. This would make complete sense on an 18R where the intake is also on the exhaust side (non-crossflow). It would make NO sense on an 18R-G cos the intake is on the other side of the engine.





Some further evidence.......


see these 18R-G diagrams... the crankcase breather is on the exhaust side. This is correct with ALL the 18R-Gs i've played with.




Compare that with the 18R block below
... see how the crankcase breather normally found on the intake side of an 18RG is blanked off......







And now for some annecdotal shit

• 18R-GEU engines have the crankcase breather blocked off on the intake side of the engine too.
• later 18R-G blocks that have come from KNOWN '77 engines do not have the lump on the exhaust side as shown in the diagrams above. These blocks have always had the 8.7:1 pistons.
• The two blocks ive pulled apart with the lumps on the exhaust side have had 9.7:1 pistons.

.. this tends to make me think that the lump on the exhaust side of the block indicates the block to be an 18R-G item, and the lump was ditched when they became the 18R-GU.


I think it's also pretty darn same to assume that the "U" in 18R-GU is indicative of Exhaust Gas Recirculation (EGR), as shown by diagrams 55 and 56.
Also looking at diagrams nearby to that, you can see all the EGR stuff is ONLY on the "u" designated engines.

Mammoth diagram thread is here: http://www.toymods.net/forums/showthread.php?t=22911

[thechuckster]

Karl - am pretty sure my 18RC doesn't have that lump either... will go out with torch now and re-check.

nope - nothing at all on that side of the block for a breather port.

[Major Clod]

Okay...

So about to get my '23 RWC... 18RGEU with Electronic Ignition has been running sweet for the last few weeks on the small trips I've taken it on. Idled fine etc etc...

Anyway last night went to take it for a run, again started it up, let it idle for about 10 mins while cleaning up a few things getting ready to back it out of the shed.

Got to the top of my street, and it stalled on me.... Okay fair enough I thought, started it again took it for a drive... it was running OK... but not really.. misfiring occasionally, stalling whenever I let the motor drop in revs... Got it back home and the bastard won't idle at all anymore, and its running really rough.

Now I've checked all my EFI stuff, the injectors are firing, there is fuel pressure, etc. etc..

Putting the timing light on just to double check the timing I notice my first issue.... When on Lead #1, the light will flash only occasionally... very randomly, sometimes go for 5-10 seconds at a time without a flash.

Stick on a couple of other leads, does the same deal, however it flashes most of the time when on Lead #4.


So I stick Mr Timing light on the Coil Lead... He's flashing all the time, so no problems with Him...

Weird thing is plugs appear to be sparking regularly..

Anyone got any ideas...

I'm thinking perhaps a dizzy issue, even though we have just cleaned it only a few weeks ago, making sure all the weights work perfectly etc etc...

Before I go pulling stuff apart, I'd just like to hear any thoughts on the matter.


Also, if anyone has a working 18RG Electronic dizzy in Brisbane they might like to loan me, I'd appreciate it. Likewise if anyone has a standard 18R dizzy with a normal Coil, I wouldn't mind borrowing that too.

Cheers,

Ryan


***EDIT***

Could someone also confirm with me the massive screw on the top of the throttle body is an IDLE SPEED adjuster and not a mixture adjustment? (The big one that has the spring underneath it, sits just in front of the vacuum advance connection.

[The Witzl]

i can confirm the massive screw on top of the throttle body IS indeed the idle SPEED screw.

The idle mixture screw is in the AFM, and is recessed to avoid accidental tamperage.


Chuckie.

I forgot to mention in my posts that I believe the lump to be on pre-1975 blocks only, it was something that was in the casting initially, and then the lump was completely removed off the casting at a later date.

I was trying to say that IF the block has the lump there... you can identify if the block was 18R-G or not by seeing if the lump is factory sealed, as the 18R has that lump used as a PCV.

[crowncustom]

The screw you are talking about is IDLE only.
Mixture srew if it has one would be on the AFM.
Cheers Brett.

[o_man_ra23]

Sounds like a weak spark Mr Clod. Try cleaning your dizzy cap and rotor button... how old are they, how old are the leads, etc etc.

Cheers, Owen

[The Witzl]

Just get a new dissy cap and rotor button from Supercheap.... they are cheap enough to just buy to rule that out as the problem.

[river]

Hi,

Can you still buy 18R-G leads?

seeyuz
river

[The Witzl]

Well... you sorta can, but they are homo.
I would recommend getting a set made by Top Gun or someone similar (who custom makes leads).

You really want them with the 90* top so that the leads arent poking up to rub on the bonnet and look gheyer than Elton John at mardi gras. The ones off the shelf dont have the 90* top.

[Major Clod]

Yeah I went down to the shed this morning to check out the spark... Pulled out the plug and grounded it, was very weak spark and wasn't actually jumping the gap, it was to the side. Gap is fine (~1mm based on the 18RG green book). Leads are brand new Top Gun... Tried a sparkplug i found on the floor and it was sparking fine, so I'll make a trip today and grab some new plugs see how that goes.

Plugs aren't that old at all, however the 1st cylinder I checked was fairly black (ie carbon, conductive, causing my spark to run down the electrode rather than jump the gap) which would indicate that the engine is running rich yes? Perhaps its an issue with the injectors, or maybe the plugs are too cold? I've been running BP6ES as recommended previously.

I'll be able to grab a better idea tonight when I take all the plugs out and look at them.

[o_man_ra23]

NGK Platinum might be the go... bit exxy tho

Cheers, Owen

[The Witzl]

i stick with BPR6ES or BPR6EY.

I run about a 0.9mm gap.

[RAd28]

about the only thing i have to add re that lump (and valve) on the exhaust side is that the pipe running from the lump (and valve) to the intake side is definatly a hard steel pipe which looks genuine enough, if someone had modified an 18R, or R-C block, then they almost certainly wouldn't have gone to the trouble of making up a steel pipe to do the trick...


after all is said and done, is there any reason i can't block off the lump valve, and modify the intake side pipe to do the trick? send that to atmo via a catch can?

Ryan - i have a bosch points dizzy you could borrow... PM me if your interested...

cheers

[GRUMPIRA28]

River.....Spark plug leads are available (well they were last year) made by NGK. They are listed on their website www.ngkspark.com.au - part No. RC-TE94. Listed under Toyota Import. They are the correct shape (90 deg. at spark plug) & only come in blue. Fit perfectly.

You have to buy from a distributor (Bursons I think). Best to call them (see website for details) and ask who is the closest distributor to you. That's what I did. Once contact was made they were sent overnight.

Good luck.