Ren's 18R-G Rebuild

[Ren_RG28]

Welcome.

As some of you might know, my 18R-G is getting the full rebuild due to another blown headgasket thanks to a split radiator hose on a stinking hot day. After weighing up all the options, this is what my mechanic has come up with:

• NEW Matched pair of Weber 45mm DCOE 152's running 38mm chokes
• Extensive Head Work
• Tighe cams: 412 lift, 243 duration @ 50
• 9.7 comp, 92mm Pistons
• Fully Balanced
• ARP Rod Bolts
• Lightened Flywheel
• 5 Puck Button Clutch

Apparently the Pistons he's sourced are, "The last quality pistons in captivity in Australia for an 18R-G". Sounds good, I'd be keen to find out what brand they are. I think they're somewhere around the 10:1 comp mark.

I'm pretty damn excited - especially coming from a virtually stock low-comp 18R-GEU! Engine will be pulled apart within the next couple of weeks and work will commence. I'll be sure to keep all you RG nuts informed and up to date. I'll try to get photos if I can manage to find the time.

Possible Further Modifications:

• Rods shot-peened and magnafluxed
• Knife-edged Crankshaft

I know for a street engine it might be a little overkill, but has anyone had experiences with knife-edged Cranks? Also If anyone has any suggestions on further mods I'd love to hear them (except for more EFI lectures from Witzl & Norbie )

[The Witzl]

dont bother shot-peening the rods.... for not much more money you can buy billet ones. The stock 18R-G rods (not the 18R-C / 18R-GEU rods) are pretty beefy, and will be up to the task i think.

This should be a good motor! With good tuning it will be reasonably drivable.


oh......EFI lectures are for your own good!!

[thechuckster]

is this car a daily driver? was just wondering how unpleasant that cam+big carbs would be driving around 50 zones in the burbs (unless you stayed in 2nd gear)


otherwise - this car is very neat up close, adding a twitchy 18RG will only give it more street cred

[ra23celica]

Tell us more about these magical pistons when you can please mate...
Thanks.

[Rodger]

Good thread Ren (subscribed ),

Drivability could simply come down to jetting of those Webers.

The full comp spec of my 2T (now in my green thing) had the full 100 degree TRD cam, 11mm lift etc, etc. I ran two sets of jetting with the #36 venturis/chokes.

If I ran the road race jetting it was a pig when I went to run motorkhanas. I dropped back several sizes in jetting to pick up a good drivable set up. Of course this drivable set up did not let it rev on the track.

A better Venturi/choke would be #34.

Regards

Rodger

[Ren_RG28]

Witzl: Ok cool I won't worry about shot-peening then. I'll have ARP rod bolts holding it together so that should be suffice.

Chuckster: Yes this will be a daily driver. I hope it won't be too rough to drive myself.. The mechanic said, "You don't have a problem with idle quality now do you?" Thanks for the compliment mate, at least now it'll be able to kick some Poosar butt!

RA23Celica: Will give Piston details as soon as I find out myself. They weren't cheap (around $850 @ his trade price) so I'm pretty confident they'll be nice.

Rodger: Yeah I agree. A lot of the drivability will come down to the tuning of the Webers. My mechanic said straight off he'll throw in some #38 Venturis to start, then go from there. Cheers for subscribing, I'll do my best to make it as informal and interesting as possible!

So, where I'm up to right now is finalising quotes from Weber dealers in the USA. Cheapest quote for a new 45 DCOE 152 (Spanish made) Weber is $450 our money including postage with insurance. How cheap is that? Redline/Hardiman in Aus quoted me $795 ea, and Carbtech $875 ea. Hopefully that might make it a little easier for some of you to understand why I'm going down the carby road.

Don't get me wrong - I know EFI would help tame it's wild character, but having a pretty limited knowledge of what I'll need for a decent EFI setup makes it all very overwhelming.. So if anyone's really convinced that I should go EFI, I'd appreciate a parts list with quotes so I know what I'd be looking at.

Speak now, or forever hold your peace.
Ren.

[Norbie]

EFI hardware: 18R-GEU inlet manifold, plenum, throttle body, injectors, thermostat housing.

EFI electronics: take your pick of ECU (Microtech, Haltech, MS etc), hook it up to all the sensors, take it to someone who can tune it.

On an engine like the 18R-G it's actually a very simple process, and there are any number of people here who can talk you through it if you get stuck. It's hardly new-fangled technology any more!

[TA23 Racer]

I agree with Norbie, EFI would be a real + having fiddled with chockes, jets, dissy curves, pump jets, pump duration, lean top end,rich bottom end juggle juggle it goes on just plug in and change without going to the tool box it saves lots of time and you don't have to live with compromise and that EFI manifold with longer runners and plenum will give the old 18rg great driveability down low. Just my opinion.
Sounding good though, that rev range would be alright on the street as long as the gearing isn't to tall I would've thought.

Best of luck with it Cheers.

[Sagluren]

(subscribed) going to be doing a build soon and this will be a much visited tread

sam.

[Roscos]

I think webers come standard with #36 chokes, which is to big for the street, you will have trouble with jets and you will find you have to have a petrol tanker following you.

Put #32 chokes in and rejet it that way, you will still get the power.
Get your mechanic to blue print the carbys to the manifold, you will find there is a big difference in the size and do the manifold to the head.

Make sure you get the ram tubes with the carbys because they are all designed into the one package and they all work accordingly.


Roscos

[ra_28]

36mm chokes will be ok we ran 39mm for a while that was a bit rough.

What number is stamped into the end of those cams they sound like the same tighe cams i used. Loved those cams made good power.

Oh yeah will the head work include match porting of the manifolds??

Cheers
Alex

[Ren_RG28]

Thanks for the advice guys, but I just don't think I could bring myself to go EFI. And it's just a lot less hassle (and cost) for me to just order in the Weber's from the states. I know there will be a lot of compromise involved, but I'm happy to cop the good with the bad for the authenticity factor.

Yes the Weber 45's come out factory with 36mm chokes. My mechanic is planning to throw in 38mm chokes straight up and jet it from there. By the sounds of things he is aiming for a high HP setup rather than a 'street friendly' setup right? Thankfully I have an MSD 6A - which does wonders for efficiency, so fingers crossed it shouldn't be too much of a pig down low.

clubagreenie Thanks for the advice in your PM. I know - $450 for a new Weber is a bargain! There's a pair for sale locally in Brisbane for around $1,200 second hand. My mechanic was originally planning to source some second hand Italian made Weber's, but once I enlightened him with the possibility of importing them from the US, he was happy to go down that path.

TA23 Racer: Cheers for the advice, will keep it in mind. Thing is, I kinda enjoy pulling over on the side of the road and whipping out the screwdriver to make some fine adjustments. I like the 'realness' about carbs.

ra_28: I haven't actually got the cams ground yet, but when I do I'll let you know. What grind were yours? Good to here other people have had good experiences with Tighe cams. I'm pretty sure they will be match-porting the intake manifold as well, but I'll have to double check on that one.

Sagluren: Thanks for subscribing mate. Good luck planning the build and I hope this thread helps. Let me know what you have planned.

[infotechplus]

Good luck with this build - sounds mucho interesting. Plenty of photos too, please so we can see the good work.

Cheers,

Peter

[ra23celica]

There is obviously a number of combinations of carby set-up, jetting etc and cam profiles that can 'wake-up' the 18RG. Can people shed some light on their experiences with this please? At what point(s) to you loose your idle and low down street driving friendly torque and then realise the most power at highest revs? Thanks.

[Steve M]

[QUOTE=Ren_RG28]
By the sounds of things he is aiming for a high RPM setup rather than a 'street friendly' setup right? Thankfully I have an MSD 6A - which does wonders for efficiency, so fingers crossed it shouldn't be too much of a pig down low.
QUOTE]
Fixed it for you.

The MSD might help, but if the fuel/air mixture is too slow through big cams and big venturis then you won't have much going on down low, where, as a daily driver, it will spend 80-90% of its time.

We're running [email protected]" and we had to change from 37mm venturis to 34s for the daily driver RA28. (keep in mind it hasn't been properly tuned)
It's totally cactus below 2000RPM, not too bad from 2-3000, very lazy from 3000-4000 and only really starts to kick on from 4500RPM.
We set the idle to 1250-1300RPM and it's still crap in the morning, I've gotten really good at left foot braking so that I can keep it from stalling in neutral while slowing down. The idle is actually very well tuned and very smooth for 298^ cams, but only after it's warm.
We need trumpets really badly and short ones just won't cut out that dead spot.

When we had the [email protected]" cams in they idled like shit (poorly ground) but were usable from 1500RPM. At 3000-3200 they started to come to life and by 3500 they were kicking hard. Aside from the idle and a little bit less on the top end, these cams were much better to drive and a lot more fun as we didn't have to wait for them to wind up.