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

  1. #1
    MR 18RG Chief Engine Builder The Witzl's Avatar
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    Default For the love of a tractor engine: The life and times of the 18R-G

    Please feel free to add info, refute info, give argument, share pics, comparisons, etc etc..... All of this will go into the FAQ and then one day onto the website's Tech Library.....

    I will continually update with any new info and pics that come to hand.

    Toyota's Dependable 18R-G

    The Early 18R-G, number 88210 and 88230

    These were the most powerful of the 18R-G engines, with a boasted 140hp from the factory and running a pair of Mikuni Solex DCOE carburettors.
    Compression was a high 9.7:1, there was no pollution/emission control gear, and the cam profiles are the most aggressive of all the 18R-G engines.
    The heads are commonly considered the worst of all the 18R-G heads - rumoured to have smaller valves, and definitely having smaller ports, their overall design is improved upon as the engine went through its phases.

    The 18R-GU, number 8825*

    These are the most commonly found today, and from all accounts were produced in the most numbers back in their day. Again using Solex carbies, the biggest change moving into this phase of the 18RG was the addition of emission controls (EGR etc), shorter cam duration and lower compression pistons (down to 8.7:1). Of course this brought the rated power down to around 120hp.
    There were improvements with this new generation of 18RGs though - the head received a little bit of a working over, receiving larger porting, better casting design and larger valves (now 45mm intake and 38.5mm exhaust).
    The very last of the 18R-GUs was the 88253. Virtually the same as previous 18R-GU's except that the head was yet again updated with dual valve springs, larger ports again, better casting, larger exhaust studs, and other little improvements.
    There are also differences in the intake manifold and Solex DCOE carbies, but as yes i have yet to identify the differences in any real detail.

    The 18R-GEU, number 88270

    Carburetion has been ditched in favour of a simple analogue EFI fuelling sytem on the most modern version of the 18RG. Compression was yet again reduced to 8.3:1, cam profiles were further reduced, but the addition of EFI along with electronic ignition (still with mechanical advance) made up for the losses associated with the EGR and other emission control systems implemented on the 18R-GU, such that the rated power was virtually unchanged.
    The head is virtually the same as the 88253, save for reliefs cut in the intake ports for the injectors and the cams.

    ********************************
    Further information to come, including comparisons of carbies, head castings, pistons, and other stuff.....
    ********************************
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  2. #2
    Toymods V8 Member Too Much Toyota CrUZida's Avatar
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    Default Re: For the love of a tractor engine: The life and times of the 18R-G

    So would the best setup to be to use the late head and efi, with the early cams and block?
    Or is that not possible?
    Peewee
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    MR 18RG Chief Engine Builder The Witzl's Avatar
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    Default Re: For the love of a tractor engine: The life and times of the 18R-G

    yes that is the perfect setup of stock bits. The Solexs will give the most power, but the EFI will give the best useable power and far superior fuel economy.
    I have close to this setup in the '28 right now.... 9.7:1 pistons, 88253 head, but 88250 cams..

    The next trick is finding some of the rare 44 Solexs.... me being the carbie moron that i am i have no idea if the two different sets i have here are 44s, ones a set from an 88210, the other from an 88253.
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    Aerial Superpony Domestic Engineer SeptemberSquall's Avatar
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    Default Re: For the love of a tractor engine: The life and times of the 18R-G

    Correction: The Mikuni Solex carburettors aren't DCOEs, the designation is PHH. DCOE is a Weber carb.

    As for your sizing question, 18R-G was not specced from factory with 44mm carbs, or any other carb than a 40PHH (reference: Wayne Stephenson, per a plethora of Toyota microfiche and hard copy manuals). A common misconception is that the 18R-G carbs 'should be' 44s as the engine is 'bigger than a 2T-G'.

    To ID your carbs, check the back of the throttle vanes. '165' indicates 40PHH, '175' indicates 44PHH. Or just run a vernier over the manifold side of the carb throat? More info here .

  5. #5
    Toymods Net Nazi Too Much Toyota river's Avatar
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    Default Re: For the love of a tractor engine: The life and times of the 18R-G

    Hi,

    18RG models and power output.

    Model----------C/Ratio---------HP
    18RG -----------9.7:1------------145
    18RGR ---------9.2:1------------135
    18RGRU--------9.2:1------------130
    18RGU--------- 8.7:1------------125
    18RGEU------ 8.3:1------------125

    seeyuzz
    river
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    Toymods Net Nazi Too Much Toyota river's Avatar
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    Default Re: For the love of a tractor engine: The life and times of the 18R-G

    Hi,

    So, what sort of HP would I be looking at by bore/stroke an 18RG out to 2.4litres, get it ported/polished and balanced, and run a custom EFI, and using the more aggressive cams of the older 88210 engine?

    seeyuzz
    river
    The thinking man's clown and the drinking woman's sex symbol
    RA25GT - There is no substitute | 18R-G - Toyota's Dependable Masterpiece
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    MR 18RG Chief Engine Builder The Witzl's Avatar
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    Default Re: For the love of a tractor engine: The life and times of the 18R-G

    one would only be guestimating.... maybe 160-170hp?
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    MR 18RG Chief Engine Builder The Witzl's Avatar
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    Default Re: For the love of a tractor engine: The life and times of the 18R-G

    here's little more comparison data....

    check out the difference in carbies and manifolds from an 88210 and an 8825*






    And for reference, this is the crown of a 9.7:1 piston...

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  9. #9
    nothin' doin Grease Monkey
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    Default Re: For the love of a tractor engine: The life and times of the 18R-G

    damn...when i saw the thread title 'for the love of a tractor' i thought you were talking about SR20's
    Quote Originally Posted by Rex_Kelway
    i am of no speech

  10. #10
    MR 18RG Chief Engine Builder The Witzl's Avatar
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    Default Re: For the love of a tractor engine: The life and times of the 18R-G

    i said tractor motor, not wheel chock.
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  11. #11
    Junior Member Too Much Toyota RONA's Avatar
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    Default Re: For the love of a tractor engine: The life and times of the 18R-G

    Quote Originally Posted by Steve-AE86
    damn...when i saw the thread title 'for the love of a tractor' i thought you were talking about SR20's
    Lol the sound very much like tractors

  12. #12
    MR 18RG Chief Engine Builder The Witzl's Avatar
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    Default Re: For the love of a tractor engine: The life and times of the 18R-G

    Ok, please dont let this topic go waywards!!

    Now... refering back to the pictures above of the 88210 manifold + carbies vs the 88250 manifold + carbies - you can see that the 88210 manifold is substantially longer, and thus places the carbies further outwards. This to me tends to suggest that this early model was used in a car that didnt have the same brake booster and master cylinder setup as the RA25-RA35 celicas, since on these models the carbies are VERY close to the master cylinder.

    I also have some pictures of River's intake manifold on his 88230 18R-G in the RA25, and this engine has a similar manifold to the 88210, but it is shorter like the later 88250 manifold.

    The major diferences in these 18R-G vs 18R-GU manifolds is the balance chamber design and the water jacketing.

    The 88210 and 88230 manifolds (18R-G) have what is quite literally a metal pipe acting as a manifold balancing chamber, with a couple of fittings coming off it for various ancillaries, and is attached to the manifold by rubber hoses. You can see where the outlets are on the pics above - they are the largish (my guess - 5/8") outlets on the carby side of the manifold, in between no.1&2 runners and between no.3&4 runners.
    Also note on the 88210 manifold that there is engine coolant present in the areas between 1&2 and 3&4 runners! You can see where the coolant comes from on the mounting flange to the head, and the rubber line (going off to the right in pics above) which is attached to fittings on the underside of the manifold. I can only guess what the purpose of this was....

    On the 88250 manifold pictured above, you can see the balance chamber is a nice cast item that is bolted to the manifold via a couple of mounting flange faces where 5/8" ports were before. There is also no engine coolant present in the manifold, unlike the earlier versions.

    I am yet to disassemble and compare the differences in the two types of solex carburettors pictured above, but i will get to this one day soon.
    ...... butt scratcher?!


  13. #13
    Aerial Superpony Domestic Engineer SeptemberSquall's Avatar
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    Default Re: For the love of a tractor engine: The life and times of the 18R-G

    I am yet to disassemble and compare the differences in the two types of solex carburettors pictured above, but i will get to this one day soon.
    http://www.wolfcreekracing.com/carbid.html

    The carbs on the left are Type S4 carbs, among the most common of the Mikuni Solex PHH carbs. These carbs in 40mm size were most commonly used on the 2T-G. Did come in 44s too, check the back of the butterflies.

    The carbs on the right are Mikuni manufactured Solex carbs built OEM for Toyota 18R-G. Parts for these carbs are interchangable and they take the same kits. I've got a set of these carbs disassembled and a digicam if you really want to see inside.

  14. #14
    Forum Member Grease Monkey scootaphill's Avatar
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    Default Re: For the love of a tractor engine: The life and times of the 18R-G

    as a side note on the runners.
    i believe that teh 210 motor would have more torque due to the longer runners *however* im not sure how much more. its my understanding that the torque will rise with the length of the runners. in turn your top end improves with shorter runners.

    cheers
    phill
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    RIP Scott Kalitta Automotive Encyclopaedia Mr DOHC's Avatar
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    Default Re: For the love of a tractor engine: The life and times of the 18R-G

    once i find my 18RG tech article {on one of 10 dvd's ATM} i'll post it

    or is SteveM has his copy still, he can post it

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