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

[The Witzl]

Just thought i might add a couple of items of interest to this thread.....

Here we have a genuine Toyota 18R-G head gasket. $58 retail!!! (will advise p/s later)



Here's another pics that really shows the difference between the 18RG and 18R-C/18R-GEU rods..... note the small end sizes.... and the busted 9.7:1 piston



And here's something i found that threw me off a little.... check out these different cam gears!!

[Mr DOHC]

whats the PN's for the rods

[The Witzl]

i've posted them earlier in this thread... on page 1.
but cos you're from qld i'll forgive you for being slow

[The Witzl]

p.s. you should know how toyota part numbers work, and thus why it doesnt matter that i've only given you half of the part numbers

[Screamn_Sleeka]

That genuine Head Gasket looks great, waiting for buying details

Re: those cam gears, the left one if a 250, what is the right one off? Does the right one give decent adjustment?

[Steve M]

I wouldn't mind betting that the cam gear of the right is either a Tosco original or Sean Maloney redrilled it with to match the Tosco original pattern. He had a pattern for the 8 hole ones Toyota used in their rally engines.
I was going to buy a set off him but it appears he finally retired right before I could.

Witzl, I'd love to get an accurate pattern from that there cam gear, what are the chances you could get someone with a rotary table or other similarly usefull tool to measure up the hole offsets? I think there would be a lot of people interested in those details!

I'm sure if I could get my brain to work I could figure out the spacing, but it would be good to know for sure.

[The Witzl]

Steve,
I'll see what i can do for you mate. I've had to remove that gear as it has a chipped tooth, so it's available for measuring and shit.

TOSCO,
Just call up your local Toyota parts dealer and ask for the headgasket from an 18R-G engine.... all they should need is the model car it came from, ie. RA28!! Unfortunately i think i threw out the p/n sticker from it when i cleaned up the garage a couple of nights ago

[The Witzl]

Some Invaluable Information for the 18R-GEU guys...

I've been trying to work out for a while now just how the water lines, vacuum lines etc etc are all hooked up from the factory.
I finally found a couple of pictures that gives enough of an explanation, but i still have queries about whether or not I am correct...



1. Comes from the water pump, joined to the water cross-over pipe that takes water from water pump to the thermostat housing. Other end to 5. the forward of the two water outlets on the throttle body.

2. Notice the little side feed that goes from this short rubber water line off to the left and to 6. the vacuum valve thingy? Well i've never seen this before nor in the flesh!! I'm guessing it supplies water to the vacuum temp valve thingy???

3. Vacuum line for vac. advance. Connects to 6.- vacuum valve thingy

4. Vacuum line for charcoal can, runs around the back of the engine...

5. The two water outlets on the throttle body. The rearmost one connects to an outlet on the intake manifold flange that mates with the head, and yes - IT GETS WATER!! The forward most one goes to 1. water crossover pipe. The function of this is still slightly unknown to me.... is it part of an idle control system that increases air passing thru idle valve when the water is cold, then restricting it a little when it warms up? I have it connected as per the diagram above, but i do also have the AUX. AIR VALVE connected, so i cant tell. Theories anyone? Does it need to be there?

6. Vacuum temp valve thingy. It's attached to the thermostat housing, and appears to have a water line too.... my guess is that it opens/blocks vacuum passing between the two ports depending on coolant temp - obviously to control the vacuum advance. My question is - would it turn vacuum advance ON or OFF when it reaches operating temp?

[Steve M]

My theory on 5. is that it is to heat the throttle body so that it doesn't freeze open in cold climates.

Just a guess, but I reckon you'd need more advance when the engine is cold, as it would generally idle lower in that state.

[YelloRolla]

I think that throttles freezing open is an issue when fuel and air are pouring over them - not the case with a MPI engine.

I think that the water through the throttle is for emissions - if you heat the air more, the closer you will get the fuel to vapour - increasing its surface area improves its ability to burn. It is not the best for power though.

[barned01]

Just a question that you would never thought would ever be asked...
Is it possible to put an 18rc head onto an 18rg Block with 18rg pistons?
I am aware the timing cover, and the dummy drive shaft and gears would need to be changed to 18rc items (and a couple of extra things) but would the 18rc head physically fit without hitting the 18rg pistons?

[ra_28]

No 18rc have hardley any combustion chamber in the head.

Alex

[RA23]

Some Invaluable Information for the 18R-GEU guys...

I've been trying to work out for a while now just how the water lines, vacuum lines etc etc are all hooked up from the factory.
I finally found a couple of pictures that gives enough of an explanation, but i still have queries about whether or not I am correct...

If you don't already have it, here is a pdf with some exploded views of the 18RGEU, it may help with your questions:
http://www.se-technology.com/18RGEU.pdf

[crowncustom]

Just a question that you would never thought would ever be asked...
Is it possible to put an 18rc head onto an 18rg Block with 18rg pistons?
I am aware the timing cover, and the dummy drive shaft and gears would need to be changed to 18rc items (and a couple of extra things) but would the 18rc head physically fit without hitting the 18rg pistons?

I don't even reckon the head would even sit on the block.It would be sitting on top of the pistons with quite a bit of clearance between head face and the block.Seeing as the RG pistons sit above the block.No harm in asking but the answer is no it wont fit with RG pistons.
Cheers Brett.

[thechuckster]

Just a question that you would never thought would ever be asked...
Is it possible to put an 18rc head onto an 18rg Block with 18rg pistons?
I am aware the timing cover, and the dummy drive shaft and gears would need to be changed to 18rc items (and a couple of extra things) but would the 18rc head physically fit without hitting the 18rg pistons?

no - you need flat-top pistons for 18RC - the combustion chamber isn't hemispherical.

fwiw: the flat top piston would give you uber-low compression with an 18RG head - but it would probably be a sloth to drive and you might have pinging/detonation issues as you would have removed the squish areas (from the 18RG head) that control flame propogation and burn speed.