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

[JustenGT8]

The 18RG is oversquare ie bore larger than stroke. This makes is quite a revvy engine (for a truck motor). An engine with stroke larger than bore is undersquare, and will be a lot less revvy. A 3SGTE just outta interest, is a 'square' engine ie bore = stroke.

So, by doing just either bore or stroke to an 18RG you will change the nature of the engine. Having done the 2.4 capacity upgrade, i can say the resulting (still oversquare) engine still revs very nicely. Went well with a stonking TO4 hanging off the side too

A simple bore would be cheaper than the 22R crank conversion, but either requires a reasonable amount of machining and neither would be 'cheap'.

You are talking a full engine build and attempting this on the cheap is a sure fire recipe for disappointment.

[JadeEstevez]

I'm rebuilding the engine completely =) Was contemplating 18RGTE but now I think just a nice 18RG with a little work done to it will be fine for a nice daily. I'll 1GGTE the other RA40 for a fun car =P

But yes, I'm keen on boring it and upping the compression to maybe 10.0:1... I'll have to get Cams to suit wouldn't I? I don't know much about the cams but I was thinking of hunting for some off of a 210 head. I have an 88250 head just to clarify.

[Taff]

Can someone give me a starting point for jetting an 18rg, 40mm solex, ~9cr, 251 cams, GEU head.

[roadkill]

Hi,

18rg and 20r/21r/22r crank is alot of work. From memory you need to machine the block, do some machining of the crank for both clearance in the block as well as balancer etc etc, you've also gotta think about rods getting them shorter. Unless you're a machinist or can get machining work done really cheap (or you're loaded and don't care) then it would really be a very hard thing to justify doing. Just keep it 2l, get good rods and pistons and let the turbo do the rest of the work. Or go something that was made for more power from standard.

I have a mate that did the stroke/bore combo and was going to turbo it. But decided to just go a jz engine. And he's a machinist for stones brothers racing.........

bEn

[river]

Hi,

I'm rebuilding the engine completely =) Was contemplating 18RGTE but now I think just a nice 18RG with a little work done to it will be fine for a nice daily. I'll 1GGTE the other RA40 for a fun car =P

But yes, I'm keen on boring it and upping the compression to maybe 10.0:1... I'll have to get Cams to suit wouldn't I? I don't know much about the cams but I was thinking of hunting for some off of a 210 head. I have an 88250 head just to clarify.

A "little work" would be higher compression pistons and maybe some cams, and that's about it. To do a complete engine rebuild and boring it out is a bit more extensive than a little work.

What is your definition of a daily driver? Sure you can get some good high end power out of modded cams, but it can become tiresome to drive each day. Lambo had a lovely sounding NA modded 18R-G and it pumped out some good power. Was a great engine for some serious fun, but as a daily it sucked as it had too little power down low and made daily driving annoying.

For a nice daily there is nothing wrong with the stock 18R-G. It has a good power band, revvy and fun, reliable and is configured to operate across the rev range and driving conditions for normal road/street use. Save your money and leave the 18R-G as it is and spend it on your 1GGTE powered fun car.

seeyuzz
river

[JadeEstevez]

But I still want the daily to have some balls, just so people go "Oh shit". IF I just upped the compression and chucked some cams in would it give it a little more or is it really not worth buying the pistons and cams without doing a heap of other things?

[o_man_ra23]

You are all missing a vital bit of knowledge in this argument. The stock pistons and bores will almost definitely be flogged out by now, so new pistons should be in order anyway. It doesn't matter if you bore it .5 or 3.5mm, the cost won't significantly change. If you go new lumpy forged pistons, get the bores matched to the pistons and the rings matched to the bores, then have the rotating assembly balanced, some stock 210 or 230 cams will respond well and improve torque across the board. This should make the motor more driveable, and give more oomph.

Adding a lightweight flywheel will also help free up some go, but will make takeoff slightly more difficult. Shouldn't be detrimental though. Remember that the flywheel and front pulley are needed for a proper balance. You may also need the main tunnel line bored to stop the bearings rubbing, and it is a good idea to put good main studs, head studs and rod bolts in.

It won't be über cheap, but if you want a good, lasting engine, expect it to cost.

[JadeEstevez]

It's alright, I'm not too worried about the cost's, more so the drivability as a daily: I don't want a race/track car but still wanna give people a run every now and then ;P I think it will need a little bore, the engine has been flogged! If there isn't much change in the price I'll go for the 2.2litre bore, I think it was 92mm?? I can't remember O__o I'm also rebuilding the gearbox and diff in the car, along with suspension and steering components... Try to make a nice daily while I fix up the rusty RA40 I drive now =P

If I took it to a good engine builder, would they get me the correct pistons and rings for the bore, or is it something I have to work out myself?

[Omegaman]

I would consider not going for the 2.2ltr bore and spending the cash on .05 over high comp pistons, bore to suit. 210 cams or similiar profile regrounds, then spend some cash on slight head porting and matching. 4 kg Fly wheel. Keep new cams to a good usable rev range. let the tractor breath....
changing the total engine characteristics would not make it reliable and as said above somewhere, for the cost of yr 2.2 ltr job, different engine would be easier.

[o_man_ra23]

I am afraid I disagree Omegaman. The cheapest pistons I could find were Arias forged units, which have no change in cost between NA or FI capable, bore diameter, or compression ratio. Cometic make a head gasket to suit the 92mm bore, and I haven't come across a machine shop yet which charges more than a few dollars per bore difference when going from a .5 oversize to a 3.5 oversize. The difference in cost between .5 and 3.5 overbore when we are talking about a build like this is very minimal, and for the extra torque, you would be mad not to go the 92mm items (unless you have a very specific race class which requires you to remain sub 2000cc). Also, it has been proven by several people on here that the 18R-G is still reliable at a 92mm bore. I do agree with your spec on cams and the porting and matching.

I would source the pistons and flywheel myself before taking the bottom end to a machinist, as these can turn into long lead time items, and they are not usually in regular catalogues. My pistons came from Paradise Racing in the US, however there are several suppliers for those pistons, so may be viable to shop around. You should also take the opportunity to get both the deck and head skimmed. If your valves are rooted, stainless items can be had new along with bronze guides from Stewart Wilkins Motorsport. Precision Shims can supply new shims in a range of sizes also to ensure your clearances are good.

Once she is all back together, head to a good carby specialist and get your carbies re-jetted and tuned to suit the new arrangement. From there... once it's run in, enjoy!!

Yup, not cheap, but what would it cost to rebuild another donk, then go through all the engineering? Cheap if you don't rebuild the engine, but then are you back to square 1 regarding reliability?

[timbosaurus]

I'm getting a bottom end fully rebuilt, and I have already got some stock 0.5mm oversize 9.7:1's. I'm trying to work out if I should spend the extra to get some new high-comp slugs.

If you guys were to rebuild a streetable 18rg, what comp would you choose?

92 or 92.5mm bore?
10.5 or 11 comp?

Got limited time to decide, because I've already dropped the stuff off.

Also, what price were the arias from paradise Oman? Is there any difference in quality between arias and wiseco?

Cheers, Timbo.

[o_man_ra23]

Timbo, they were under $700 delivered. I would go 92 bore, gives scope for one more oversize at a later date. 10.5 is fairly safe on good pump fuel, but if you have E85 regularly available, I would consider more compression and make it run E85 only. If you have an absolute gun tuner handy, or are going EFI, then consider that modern engines are running well over 12:1 on 95RON fuel.

Can't comment on the difference in quality between wiseco and arias as I haven't seen the 2 side by side, but the arias units were extremely tight on tolerances when mine were measured, balanced etc.

[timbosaurus]

Yeah, I don't wanna sail too close to the wind with comp... I know you can't compare an old 18RG to a 12:1 beams motor, but I though maybe 11:1 is as high as you'd want to go on premium. Am I way off?

Anything less than 10.5:1, and I may as well stick with my 9.7's.

I wonder what postage is worth... because joel from toysport is saying around $550+postage (incl rings/pins).

[JustenGT8]

We ran something like 11:1 Timbo and then we still turbo'd it no dramas and the torque!!

[SilverRA23]

Mine is 92mm and 10.5 comp Timbo. Nice and streetable

Don't forget to get the cometic head gasket to suit when you are buying your bits out of the USA.