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

[RA35GT]

Fark I'm trying very hard not to turbo this thing :/

Stop fighting.

[Shifty]

It's supposed to be my cheap engine! Maybe a budget turbo setup might be on the cards. T28BB etc, go for a lazy 200rwhp and leave it at that.

So, who wants a cheap set of 44mm mikuni EFI throttles (with injectors, rail, tps, etc)?

[lilcrash]

Price? 10char

[Rodger]

Added missing diagram to my reply #3592 about manifold stud spacing

Regards

Rodger

[RA35GT]

Shifty

If no one measures during today I can post up dimensions when I get home from work this evening and I find a manifold.

I'll measure the sidedraught bolt pattern, the centre spacing of the two carbs on the 18R-G manifold and a distance between throttle shaft ends.

Finally got to a computer that could allow me to download a picture.




Regards
Rodger

Nice work mate,

17111-88231 is also pretty much the same dimensions as that, but has different design vacuum balancing.

[RT104GT]

Nice work mate,

17111-88231 is also pretty much the same dimensions as that, but has different design vacuum balancing.

Bottom is Corona GT water heated

Top Celica GT not heated short ram.

There is another variation much longer ram and water heated. will see if I still have it here.

I have full micro fish drawings.

[RT104GT]

I hope I notice a difference from an 18rg in an rt104 to an 18rg in a ta22

They are different what do you need to measure?

I have original 18RG Corona GT gasket set but its too big to scan in scale.

[RA35GT]

Bottom is Corona GT water heated

Top Celica GT not heated short ram.

There is another variation much longer ram and water heated. will see if I still have it here.

I have full micro fish drawings.

I think you have that the wrong way around dood?

The 231 has coolant and the 251 has no coolant.

Also my gt celica came with the 251 manifold also. (assuming its original)

[Shifty]

Rodger, thanks for your info!

I now have my motor (I should more correctly say "pile of bits") in the garage and have had the opportunity to compare a few things. Doesn't look to be too hard a job to adapt the Mikuni EFI setup (from a mechanical perspective at least) so I can fairly happily shelve that part of the project for now and concentrate on the bodywork and physically fitting the long motor.

When I get to doing the EFI stuff, if it turns out to be a good result I'll post details on how/what/where so that others can put the same setup to use. That is, if I don't end up turboing it instead.

[Shifty]

Oh as a side note is there anywhere you can get a bolt-up single carb manifold to suit an 18RG? I wouldn't mind running a 40mm weber as a stopgap, to run the engine in.

[o_man_ra23]

Shifty, I have never heard of such an animal. I think you may be shit outta luck on that.

[Steve M]

RT104GT,

There are two versions of the long manifold.

I want to get my hands on an 88211 manifold as that's what best suits my plans.




If anyone has an 88211 manifold, please let me know. It is long and water heated.
I would be willing to swap for one of my shorter manifolds if need be (which fit better in Celica engine bays).

[Shifty]

For anyone interested there are a couple of 18rg manifolds on yahoo japan presently

[Shifty]

Shifty, I have never heard of such an animal. I think you may be shit outta luck on that.

Shame, you can get them for 18R/RC.

All good, I might just bite the bullet and go EFI straight up :/

[Shifty]

Ok enough quasi-topical stuff & back into serious business

Ok so I'm learning about motors here, forgive me if there are any dumb comments as this is all based on a small degree of knowledge-in-passing rather than any real knowledge... but I guess that's why I'm posting.

So it's generally agreed to take it out to 92mm for a 2.2lt capacity. Unless I'm mistaken it's not really 2.2 litres though, which shows you how "accurate" the internet is. Based off my understanding:

89mm = 1990cc
92mm = 2127cc
92.5mm = 2150cc

Unless my maths is wrong, it's a bit of a stretch to call it 2.2 litres even at 92.5mm (apparently maximum "guaranteed safe" bore). Anyway unless my maths is wrong, I'm all over this part of it and it's a bit of a no-brainer, so I'll definitely be going 92mm.

What I probably won't be doing, but am interested in purely to learn more, is that from 2127cc / 2150cc you can then fit a modified 22R crank. Information is scarce (and again it's from the internet so it's questionable at best) but apparently an offset-ground 22R crank (89mm stroke stock) gives a capacity of circa 2.4 litres.

My limited understanding (from my time liking bogan motors when I was younger) is that as the crank is ground to a smaller circle RETAINING the outermost part of the circle you should actually end up with a LARGER stroke than the crank originally had. That being the case it wouldn't only be an increase from the 18RG's 80mm to the 89mm stroke as per the 22R, but something like (for example, depending on how much it is ground) 91mm? Given the 22R isn't the highest revving motor out there I'm not convinced this is necessarily the best option... but depending on where it ends up it should be just about square... which based on my understanding is a reasonable place to be.

Also that's assuming that the 'offset grind' in this case is a traditional 'stroker' type offset rather than a 'de-stroke' offset grind that would actually reduce the stroke. Interested to know if anyone can nut this out for me.

Also I take that you'd need to shorter rods to make up for the extra stroke... but then what the hell happens to static CR?!?