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

[o_man_ra23]

Jusepi, get the motor to No.1 TDC, take out the spark plug and shine a torch down to the top of the piston. If the crown is raised, then its 18R-G pistons, if they are flat, they are 18R-C pistons. From the compression readings you have, I would hazzard a guess that they are proper raised dome pistons.

[RAd28]

Need some advice...

I installed a shorty manifold on my RG so i could fit ram tubes on the webers. trouble is that the old long manifold had outlets for water (from the head). but the new manifold doesn't. as a result the engine now runs warmer, which in turn causes it to "run on" alot more when i turn the car off... this thing has always run on a bit... or when i get it really hot, but now it does it all the time.. i've tried all the tricks suggested previously, spraying water through the carbies when it's running, changing the timing etc... only thing i haven't tried is different carby jets (smaller 'cause it's running rich already).

my questions is this, how can i recover some of the watre flow from the head? the heatre hose at the back is connected directly to the water pump... i can't help but get the feeling that this is just immediatly re-circulated through the engine, would it help if i fed this back into the top of the radiator?

the only other solutoin i've come up with is to have the new manifold modified so it allows water flow as well... but i can see that being rather exxy due to the limited room..

off topic... anyone know any reason why RA2x seat belts can't be fitted to a TA22?

[o_man_ra23]

Back of the motor outlet (behind the exhaust manifold) should run through to your heater, and then the outlet of the pump goes through the heater tap to the heater. So yeah, recirculating like this will definitely hurt your cooling system. Not sure on the water outlet of the long manifold.

Seat belts... they are interchangeable... but I don't think the early TA22s are completely setup for the retractables, they may need a locating hole drilled above the bolt hole.

[Steve M]

I wouldn't have thought that the water ports in th long manifold would have any bearing on heating/cooling issues at all.
Were the water hoses going from your long manifold to the thermostat bypass tube, or just back into the head?

If the thermostat is working properly, then your engine shouldn't run warmer when swapping the manifold over.
What spark plugs are you using? we are running NGK BP7ES cause they are suppossed to be a litttle cooler and were recommended for reducing the running over issue, they worked a bit.
Cam timing and fuel idle tuning make a much bigger difference in whether the engine turns off well, as does idling the engine for a while before turning it off. That worked on my brothers engine.

[RAd28]

Back of the motor outlet (behind the exhaust manifold) should run through to your heater, ... ... Not sure on the water outlet of the long manifold..

yeah, the hose from the outlet at the back of the head SHOULD go through the heater core, but since the heater core is leaking, it's been bypassed.

Seat belts... they are interchangeable... ...may need a locating hole drilled above the bolt hole.

sounds easy enough for me.

I wouldn't have thought that the water ports in th long manifold would have any bearing on heating/cooling issues at all... ...If the thermostat is working properly, then your engine shouldn't run warmer when swapping the manifold over.

There was a very definate difference in the temp the engine ran at, with the long manifold the needle was just below the 1/3rd marker (or is it 1/4) on the temp gauge, but now it runs just above it... not hugely significant, but enough to cause trouble.

What spark plugs are you using?... ...they worked a bit.

Prett sure i'm using NGK BP5ES

Cam timing and fuel idle tuning make a much bigger difference in whether the engine turns off well, as does idling the engine for a while before turning it off. That worked on my brothers engine.

with the idleing mixtures, i'm in a bit of a catch 22 here... because of the shorty manifold i also lost my chokes, i've had to remove them so the carbies would fit on the manifold. so in order to get SOME reasonable cold start abilities i've had to richen up the idle mixtures (compare with what's recommended in the manual, with the shorty manifold they were richer still ). now though, i notice the fuel smell at idle alot more, and the plugs were alot more sooty when i last pulled them out. (had been idleing for a while before hand)

[o_man_ra23]

your running rich...

Where you just bypassed the heater core... block the ends off. The bypass hose you have just put in is bypassing your radiator, which will help you heat up.

Also, what timing do you have set?? Too much timing will make you run hot.

[RAd28]

your running rich...

Where you just bypassed the heater core... block the ends off. The bypass hose you have just put in is bypassing your radiator, which will help you heat up.

Also, what timing do you have set?? Too much timing will make you run hot.

i'm well aware of how it's running, but the idle mixtures are set rich for a reason, primary and secondary jets are rich because that's the way they've always been and i haven't bothered to change them yet.

the hose bypassing the heater core doesn't bypass the radiator anymore then what it would do if the heater tap was closed on a normally functioning setup, ergo, doesn't change anything.

anyways, going to have to investigate modifying the shorty manifold, and get around to tuning the carbies.

[o_man_ra23]

If there is a heater hose directly from the pump to the back of the head, then it is bypassing. If the heater system were hooked up properly and the heater tap open, then water is going through the heater core with heat being dissappated through there also.

Also, it has been covered that running too rich can cause overheating just as much as running lean. So you need to look into getting that fixed up.

Again, check the timing, if it is too far advanced, it can cause overheating.

[roadkill]

Hi,

I think it might also be worth noting that the difference between 1/4 and 1/2 on most temp guages may only be 1 deg C or less. Not really that much to worry about i would think. Might be a good idea to get a decent guage from superthief etc to get a more accurate reading on what the actual temp is.

For the "run on" it is possible that it is then engine running backwards (yeah, crazy i know) but if the idle is too rich then as the engine is coming to a stop, the fuel can fire BTC and spin in reverse. Check this by taking your foot off the clutch next time it does it to see if it rolls forwards or backwards. My dads old 60series cruiser did it a bit unless you let it idle for a bit. Also, does it start easily - always a easy way to tell if your timing is out.

bEn

[bnicho]

Hi,
Now that I have an 18RG in my RT112 I have read right through this thread.

One think that confuses me. Why does everyone go for a cable-throttle conversion. Why not use a linkage like Toyota fitted to these motors as new?

I'm keen to keep my car as original-looking under the bonnet as possible, which means using a linkage!

Cheers,

[roadkill]

Hi,

I think that the reason would be cables are easier to get and put in. Most cars have a cable which can be fitted easily to just about any setup. Try finding a good set of old linkages then you might change your mind. My old 28 had linkages for the 18rg but over time everything had loosened a little bit and about 1/4 of the pedal movement did nothing on the carbs. I had a fiddle with it all but sold it not much after.

bEn

[RA35GT]

Cable is alot better IMO. Its not jerky like linkages could be at times, especially if they are poorly maintained, cables require very little maintenance.

The other reason is, its alot easier to adapt a throttle cable in conversions.

[o_man_ra23]

It is also difficult at the best of times to find the linkages. Mostly due to the 18R-Cs having the carby on the wrong side. If you do find a set, you should be able to refurbish it if you are after true originality. Once this is done, that gets rid of the dreaded pedal slop, and if well maintained they are smoother than cable and more resistant to unexpected wear. Linkages were often used in racing.

But in saying that, you will probably tear your hair out trying to find a correct linkage set, and it would be much easier to build a factory looking cable setup.

[bnicho]

I WAS happy with the setup I had, which is a modified 18R setup with shortened rods relocated to the other side of the firewall. Until this morning when I realised that because the linkage worked on the REAR carby first (closest to firewall) the carbs were not synchronised above idle. The front carby (closest to radiator) has to be "pulled" for the carbs to work in sync. Otherwise the rear carb has to take up the slack in the little spring under the balance screw before the front carby even moves. The only way I can see around this is to fabricate a linkage or use a cable that pulls the front carby first, from the factory position between the carbs. Am I correct?

I don't suppose anyone has the proper linkages lying around do they? Otherwise I might have to buy some Weber ones and make them work. Call me a fashion victim if you want, but I don't really want to go cable cos it just doesn't look right, in my opinion.

EDIT:

THis is what I need, that sodding rod lying across the top of the carbies and the bit that joins from there to the frontmost carby (not in shot) . I've got everything else.



At least this proves such a part exists!

[Roscos]

Hi,
Now that I have an 18RG in my RT112 I have read right through this thread.

One think that confuses me. Why does everyone go for a cable-throttle conversion. Why not use a linkage like Toyota fitted to these motors as new?

I'm keen to keep my car as original-looking under the bonnet as possible, which means using a linkage!

Cheers,

You get better response from a cable and it is easier to adopt. Linkages wear and get sloppy....forget about them.


Roscos