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

[RT104GT]

I seem to remember way back when 18RG stuff was n/a I used a different top guide (single or double sided) and it came off an Australia single cam R engine and was quite acceptable and worked OK. The lower curved 18RG guide and the slipper are also interchangeable with 8RG and 9RG and possibly 2TG stuff you just have to redrill mounting hole and there is less friction material (teflon). It may not suit the fast and furious but it will work on the street engines OK.

[RT104GT]

Re GEARS.

The lower gears are all 18RC 8RB
The upper gears can be bolted onto early 210 camshafts and are from the 8RB 18RC camshaft. 3 bolts and a Dowell.
All Dowelled gears off the Yamaha head later series are a different matter they actually fit on the opposite way to the bolted gears off the single cam.
I am sure it is possible to find old 210 type camshafts aftermarket or you drill them out and use the single bolt and one dowell in the later camshaft.
I am told you can get two 8RB or 18RC cams and grind off the unwanted lobes leaving the inlet lobes and exhaust lobes and they match up, dont know if this is an old wives tale.
The lower chain guide although smaller from the 18R will fit across the top and guide the twin cam chain ok.

[The Witzl]

i dont need the upper middle guide, as i have a brand new one already and they are still available from Toyota.
I really only want the two curved upper chain guides (the hinged and the fixed) if they are new or bloody close to new, because they will be going onto a pretty serious turbo 18R-GTE.

NZ and japan both nill stock, USA is priced through the anus, and europe aint worth the freight costs.

[Steve M]

Ok, here's what I found.

No. 2 tensioner
O rings are replaceable, I just used two smaller ones from a standard red box o-ring kit (sprint auto parts store). They won't last as long, but they are a shitload easier to get in than the thicker ones and they seal just as well (haven't tested under pressure yet)
I didn't have any issues putting the little ball and spring arangement together in my no. 2 tensioner, just balance it all vertically and slide it in. That works fine with small o-rings.

Some smart cookie fixed a leak in their tensioner by brazing up the back-stroke hole.
I fixed that while I has changing the o-rings.

Guides
I got some brand spankers for the top centre and the fixed curved one last year while they were available.
I tried going through Toysport with Jeffro but they were a pain in the arse apparently.

There is a Jag item that looks like it may be similar in curvature, but I have only seen an internet photo. I think it was used in XJ6s around 1990.

I ended up buying a $24 18RC one from Sprint Auto parts and bending shaping it in places. With a lot of dummy assemblies and monor tweaking, it actually lines up better than the original. I don't reckon there was too much distortion in the compound as a result.
I did get some new plungers made up for the tensioner though, they are basically the same as the 3TGTE or late 18RGEU plunger poker things with the mushroom heads.

The reason behind the new plungers was that the 18RC slipper has a rubber lump on the back of it, not a cast steel lump.
The late model 18RGEU slippers also had a rubber lump.

I couldn't find anyone who was interested in making a small number of guides, but I have heared that a nut in Adelaide has ordered a batch of 100 of each type.

Someone mentioned chains.
My engine machinist has highly recommended checking that all timing chains you buy have solid or tube rollers. Some cheaper brands have split rollers (made from steel tape, not tubes). These split rollers have been known to deform and let go after a while

Does that shed any light?

[The Witzl]

yes it does... thanks

[RT104GT]

By the way as a last thought in the microfiche the 2TG and 18RG tensioners are the same part number in the engine section.
The curve slipper is rare and costly but you can use a different type and just cut the bolt so it clears the timing cover, Crown I think.
If I get a chance I will scroll all the engines in the fiche to see what suits. 2TG would modify to fit but is as hard to get.

Try USA I think.

[Steve M]

One afternoon with a vice, a hammer, a shifter and a $24 18RC slipper and I've now got a brand new japanese made slipper.

I tried to get a slipper brand new through a guy who is really good at sourcing hard to find genuine parts for 18RGs but he couldn't find one in Japan, Australia or in Europe.
The one place the We tried in the States was a PITA to deal with and didn't appear to want overseas business.

[RT104GT]

One afternoon with a vice, a hammer, a shifter and a $24 18RC slipper and I've now got a brand new japanese made slipper.

I tried to get a slipper brand new through a guy who is really good at sourcing hard to find genuine parts for 18RGs but he couldn't find one in Japan, Australia or in Europe.
The one place the We tried in the States was a PITA to deal with and didn't appear to want overseas business.

How about a few photos, the part number of the 18RC unit and how you did it thanks we would all be grateful.

Is this left or right? The flapper or the guide?

Step by step remember we are TOY heads.


Also as a thought any curved guide is ok up to a certain radius as I have been experimenting and providing you dont go too sharp the length is not an issue. The aim is mainly to keep the chain clear of any metal protrusions and smoothly change its direction. It goes around the crank pulley which is a 180 degree reversal in 2 inches so it will find its own radius and tension based on the curve of the guide you make.

Just run really really good oil not kmart crap maybe 10w-60 with detergent and you have a really slippery environment with low friction. My 100,000 k chain in the GT was nosiy until I threw out the 10 year old oil and put in Federal-Mogul which is now a quiet engine. Maybe a Moly additive would assist. Something about the angle of the dangle equals the slip of the chain?

[Steve M]

The part I modified was the tensioner slipper, the single bolt flapping thing from the inlet side of the timing case.

I could take pics but it just looks like a late model 18RGEU tensioner slipper now.

There was no great technical method that I used.
I got a work out damper from an 18RC that we had lying around and had a go at bending it into shape to see if it could be done. It was successful, so I bought a new 18RC tensioner from an ACL book.
What made it easy was that the ACL supplied ones are made from rolled steel rather than cast iron, so they're easy to shape.
Hand pressure was enough to curve it for most areas. A hammer did the rest.
I set the guide in the vice (wood lined of course) and added small amounts of extra curve at many points along the guide.
Before I started modifying it, I checked where the most worn points on the 18RG slipper were and made sure that when I altered the 18RC slipper those area were altered such that less pressure was applied to those sections.

I reckon I had the 18RC slipper in and out of my dummy assembled engine about ten times while I was fine tuning the shape and checking for twist.
I think I had to adjust the bushing a little too, but that was just a press in tube that they'd stuck in the wrong place.

I can't really give too much info, as I just made it up as I went along.

Summary:
18RC aftermarket damper + curve where needed = 18RG damper
18RG tensioner + custom made mushroom headed plunger/piston = suitable for 18RC/G hybrid tensioner (rubber lump for contact with tensioner, not cast iron like early twin cam tensioners)

Notes:
Have a spare 18RG damper
Have a crap 18RC damper for test runs (don't want to waste $24)
Start with small bends, lots of small bends to spread the stress.
Make it better than the original, not the same. The original took most of the pressure at the base and about 1" from the tip. I changed the curvature to even this out with the 18R-C slipper.
Test fit lots on times to make sure the curvatures right.

Check for slipper twist as you're bending and chech for slack in the bushing, they're not that great in that department.

Most importantly, HAVE FUN.

[pilot]

What is the oval shape cap in the front of the engine for? I removed mine the other day and could´n´t realize what can be done through that hole.

[The Witzl]

it allows access to the oil control nozzle and the bolts that hold the fixed curved chain guide

[pilot]

That oil control nozzle would be the long hex head that can be seen in the middle of the opening? What is it for?

[Sigmeister]

yes the oil control nozzle...the nut needs to be put in in the head so that the 'face' of it is facing horizontal (there is a line on the face of the nut).
one would assume that this nut controls oil going onto the chain on the inside face to lubricate it going around the gears.

[pilot]

Thanks guys.

Here there´s a pic where it can be roughly seen:

[tricky]

yes the oil control nozzle...the nut needs to be put in in the head so that the 'face' of it is facing horizontal (there is a line on the face of the nut).
one would assume that this nut controls oil going onto the chain on the inside face to lubricate it going around the gears.

yep, it's just a jet to lube the chain.... Keeping those valuable guides in one piece