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

[The Witzl]

OK... time for some PICS!

This pic shows the differences in the 88230 and 88250 cams. Note the thickness at the front where the cam gear is attached!!



the following two pics show the cam gear differences, 88210 and then 88250





this is the valve bucket, with the shim still inside.... just in case you didnt know



one and a half blocks.....list of parts:
1/ oil pump drive shaft. This is the 88250 one, with the fuel pump cam and dissy gear
2/ the oil pump, complete and assembled (and dirty)
3/ 88250 8.7:1 pistons and rods
4/ 88250 cam gear...
5/ head bolts
6/ 9.7:1 pistons from a previously rebuilt engine, broken..
7/ gudgeon pin (piston pin)



close up of one of the broken 9.7:1 pistons. They were 0.5mm oversize, and a couple had managed to blow BOTH ring lands for about 1/3 of the circumfrence. 3 of them also had busted skirts

You can see the broken ring lands here



Those broken ring lands came straight out. Even more interesting was that whoever rebuilt that engine used 18R-C rods! Look at the 18R-G rod to the right!!





Now here is a mind boggler - look at the part number for this 0.5mm oversize 9.7:1 piston!!!!

[The Witzl]

more pics....

This is a COMPLETELY original 18R-G from River's RA25 GT. Cant remember if it's 88230 or 88210.... i think its 88210.















This is the Toyota Genuine oil filter - USE IT!



Just an 18R-GEU, for reference



My busted 88253 in pieces...

[The Witzl]

Here we have a completely disassembled and cleaned oil pump. NOTE the spacer at the bottom left - this is what makes the 18R-G pump different to an 18R-C one.



Here we have the 18R-G vs 18R rod comparison. Interestingly, the 18R-GEU lists the same part number for a rod as an 18R



a valve assembly. wow



valve guide on 88250 head



with the exhaust valve removed, here is the view of the exhaust port looking from combustion chamber on an 88250 head.

[Gleno28]

Great work Witzl! you get more rep!
Another thing i noticed is that on my 88210 head, there was no yamaha logo compared to all other 18RG's??? maybe didn't want to advertise yet??

Also, (i'm sure it's been mentioned before) there are a few sorts of tappet covers, depending on the head with writing and oil cap on different sides.
Cheers
Glen.

[The Witzl]

yeah thats right, this is why some people refer to the later model 18RGs as the "yamaha head" version - when in fact they are all Yamaha heads (as is every toyota "G" head)

[river]

Hi,

Nice pics. Good visual info. Damn it, my engine needs a new paint job - that'll be done very soon. I don't like that brown gunk under that thing in the oil filter pic. I'm gonna have have a look at that next time I'm home.

seeyuzz
river

[The Witzl]

dont worry about that too much - its the carbies leaking a little fuel and then leaving a residue once the petrol evapourates, allowing shit to stick to it good. Mine do it too

[jeffro ra28]

Its photo time!? well this photo has been posted before, but it will make it easy future reference.

[jeffro ra28]

These can also be very helpfull.

[ta22gt]

If someone in bris would like to come round to take some photos of my head and piston it will give some more ref. material for those interested in the 2.2l option. I have had heaps of head work done and it is running 12.5:1 comp forged pistons

Nev











;

[Mr DOHC]

what area u in nev

[Steve M]

What fuel set up are you running too, Nev? We've got some 12:1 pistons but are hesitant to use them for detonation reasons.

[ta22gt]

Am in eight mile plains.
As for fuel i run optimax with a splash of tolulene or avgas

[Steve M]

We've got some 0.5mm OS 9.7 pistons with the 88252 part number too. I reckon they were made as the standard replacement item for all 18RG's before that time.

An interesting point about the two different cam types: the 88231 fixed gear cams have an almost identical profile to the 88250 adjustable gear cams. Both sets were used before testing, so it could be wear that made the differences, they are so close.
So for all those people chasing the early model cams, you can have them in adjustable form of you get 88250s. We haven't profiled the 88210s yet though, there may be a difference yet.
I'll get some photos of the difference between the early an late model timing cases for you too Witzl.

[ta22gt]

Has anyone had any success getting hold of decent adj. cam gears to suit aftermarket high lift 18rg cams