3R to 18R-G

**Casino Kid** · 02-04-2007, 09:14 PM

Hi just wondering if anyone knows wether a 18rg is a direct bolt in replacment for a 3r. The car im planing the conversion in is a 1965 crown (RS41) it has a 3 spd man with elec over drive. if any one has done this conver any help would be great

**crowncustom** · 02-04-2007, 09:43 PM

It won't be a direct bolt in but it should fit with a few minor mods.
I did a 18RG conversion in an old RT 40 1600S Corona years ago which basically ran the same type engine as the 3R but it ran a 4R originally.
Cheers Brett.

**gianttomato** · 03-04-2007, 12:48 PM

Mounting points are quite different. RS40/3R mounts are located on the middle of the block but the 18R ones are right at the front - you'll have to weld new mount points on to the chassis. You'll need a mid sump - I think the RT104 has this arrangement.

Then you come to the issue of the gearbox - the 3 mains R series motors (like your 3R) have a totally different bellhousing bolt pattern to the 5 mains R series motors (like the 18RG) so running your 3 speed with overdrive behind the 18RG means you'll need to make an adaptor ring to adapt one to the other.

Personally I wouldn't bother - a slightly worked 18RG with a bith of spirited driving will blow the shit out of the planetary gears in the electric overdrive unit quick smart. I would opt for a W50 but you'll need to relocate the gearbox crossmember mounts on the chassis and make a new crossmember. The tunnel will need slight modification too and the gearstick wants to hit the bench seat in gears 2,4 and reverse. You'll also need to make a new tailshaft - the gearboxes have different output shaft splines.

Now to be honest, I don't know if you have enough room to fit the twin carbs between the motor and clutch master. You may need to use a slightly lower profile one like RT81 or possibly MS65.

As for brakes, I suggest you look at Hiace RH40 disc brakes - use the whole assembly and be sure to use the RH40 lower ball joint - it's bigger than the RS40 one. The upper one is the same. Swap the steering arms over.

**barned01** · 03-04-2007, 05:19 PM

rt104 is midsump? i thought it was front sump

**gianttomato** · 03-04-2007, 05:53 PM

Whatever. Just get a midsump.

**WDE_BDY** · 04-04-2007, 08:20 AM

Originally Posted by gianttomato

Mounting points are quite different. RS40/3R mounts are located on the middle of the block but the 18R ones are right at the front - you'll have to weld new mount points on to the chassis. You'll need a mid sump - I think the RT104 has this arrangement.

Just curious, the later 18RG blocks run a third engine mount boss more rearward compared to the early blocks, would this be closer to the 3R setup?

Callum

**Casino Kid** · 04-04-2007, 08:13 PM

thanks guys for all your help. the 18rg seems like more work than I was hopein.are there any motor/gear box swaps I could do that would need less work I dont want a power house just a bit more than the old 3r to make it more driveable. and if i could keep it collum shift that would be great.oh and a motor you can get parts for would be good cuz when i ask a parts store for 3r parts they just giggle and say no

**OSJ** · 05-04-2007, 07:55 AM

You could get a 5R,2litre 105hp,from a hilux.Parts are still available,run some extractors and a good exhaust,should be fun.

**gianttomato** · 05-04-2007, 11:10 AM

Just be careful with that. There are 2 5Rs - 3 mains and 5 mains. The three mains 5R will bolt up but you'll only find of these in a 50 series Crown, ancient Stout and possibly a really old Hilux (although I think they came out with a 12R). They share the same bellhousing bolt pattern as your 3R.
Later 5Rs have a 5 mains bottom end. Totally different bellhousing bolt pattern.

Wasn't aware the 18RGs had another mounting boss that was located further rearward - this would facilitate mounting greatly.

Originally Posted by Casino Kid

when i ask a parts store for 3r parts they just giggle and say no

I suggest you change to a better quality auto parts store. Most service items are readily available- you just have to wait.

**WDE_BDY** · 05-04-2007, 12:21 PM

Originally Posted by gianttomato

Wasn't aware the 18RGs had another mounting boss that was located further rearward - this would facilitate mounting greatly.

My 18RGEU from an RA63 has a third mounting boss in the block, unlike my early model 18RG carbed motor which only has two. Will try to get some pics up, but to give you an idea the mounts in my KE70 are very similar to the T series mounts from a TE71 (T18) in terms of placement on the crossmember and the block.

Callum