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

[jeffro ra28]

I love your work River. Im glad there is someone that could be bothered to spend the time to enlarge and edit these so that they are forum freindly.

[Steve M]

Those photo's are always good to look at, but in true toyota fashion the forget some of the details.

For parts identification:
- That's an 18R-C water pump, the little side tube is too small for an 18RG one.
- I'm not too sure about those conrods, they look like the 18R-C ones drawn in the green book. I've never seen a set of 18RG rods looking like that.

River, would you happen to have an exploded diagram of the top tensioner? With part numbers?
I'm rebuilding mine with a some changes and part numbers would be great to know.

[river]

Hi,

I have more detailed diagrams of the water pump and they 18RC and 18RG water pumps are the same. The only difference I can see is the off-shoot pipe on the 18RG bends backwards a bit, while the 18R engine shoots off straight.

The 18RG water pump has twin pulleys whereas the 18R has one pulley. The actual pump, pump housing, fan assembly are the same between the two engines.

Remember, I'm talking about the early build 18R-G, 18R-GR and 18R engine here. So, maybe there was a difference with the 18R-C, 18R-GU and 18R-GUE engines. I'll need to check my RA23/28 info to get that information and see if these variants have a different pump assembly.

The 18R pistons are a different shape on the top as opposed to the 18RG pistons. Don't forget, these pics are from an EPC and are presentative as opposed to being superbly detailed engineering blueprints.

I can get the part numbers, but I have no further exploded diagrams on the engines for the chain tensioner.

seeyuzz
river

[Steve M]

it's the little offshute pipe for the thermostat bypass that I think is different to the water pumps I have. Mine have a larger diameter one than is shown.

Also a quick question for anyone who has an early model block, what is that two-bolt + big hole flange on the exhaust side for. The one right near the coolant drain boss.
I don't reckon any of our blocks have that.
That block also uses a different bottom timing chain guide to the later model ones that I've seen. One of those early model guides came in a timing kit for my brother's old 18R-C but wouldn't fit anywhere as the block was too new.
That top chain damper is also a different design from the later ones. They are interchangeable but they have a different shape adjustment cap on the end.

[barned01]

i was looking at those pics when it occurred to me.
has anyone tried modifying the bottom dampener that connects to the block (the flat one) to fit on the upper timing chain dampner between the 2 cam gears (in the head).
the bottom dampeners are readily available and cheap from parts suppliers like sprint autoparts.
that would just leave a way to find a replacement dampener for the curved one that goes from the head to the block and for the tensioner dampener

[Steve M]

I reckon you'd have to weld onto the bottom damper to get it to fit on the top as there is not enough metal there to do the job. The welding would screw up the nitrile.

I have found that with a little careful bending work the $23 18R-C tensioner dampener (slipper) can actually line up better than the original 18RG ones.
I've had some new tensioner plunger parts made up with big wide mushroom heads so that it won't dig into the rubber lump on the back of the slipper.
I haven't run it in the engine but I have test fitted it and it looks to be quite good.

Price of my conversion:
$ 24 for chain dampener/slipper
$ 60-70ea for the new tensioner piece (that's what it will cost next time)
$ 9 for a bag of new circlips (couldn't source the original style in the right size so using more normal design)
$ bugger all for the o-ring I might as well replace while I have got it apart.

Total <$110
Saving $100 on the last quote I got in Adelaide (that's if it were still available)

Verdict: worth a shot I reckon

[The Witzl]

nice work steve..... now get some pics!!!!

[classiccelica1]

quick querey for the witzl
i bought a ta23 couple of months ago, with 18RGEU
read your post on the different models of 18RGs I am a bit confused because mine has
88270 head but twin mikuni solex carbs on the side.
your post states that on the 18RGEU carbs were ditched in favour of fuel injection
what engine do I have?
Rick

[TA-022]

efi has been ditched for that horny carby sound many a time.

[Steve M]

Another thing that happens regularly is head swapping and rebuilding from multiple engines.
My engine came with an 18R-C block and oil pump, Mid-era 18RG conrods, 18RGEU pistons and head, thermostat housing, cams and timing case, Early-era 18RG manifold, 18RGU carbies and tappet cover.

[thechuckster]

query about timing marks on twin pulley 18R/18RG crank pulleys...

would this be a fair assumption of what they mean?
TDC - ?? degrees - 12 degrees

See picture for what i'm looking at:


Is a close up of this pulley/trigger setup:


cheers and tia,
Charles.

update: On the basis of witzel's suggestion i'll take it as:
-TDC - ?? - 12 degrees and ignore the middle mark
it's not like i'd need to refer to a mark at 5 degrees...

[The Witzl]

chuck.... dunno about the 18R-C crank pulley, but on the 18R-G crank pulleys, those marks are 12deg BTDC and 5deg BTDC.



Onto things in my garage...... turns out the lack of compression on cylinder 4 was thanks to a slightly bent exhaust valve.
Word to the wise - dont rest your head on the ground with any valves open, they bend REAL easy....

I'll get some pics up in a few minutes of what's happening...

[river]

Hi,

Did you really do that? Rest the head down in a way that bent a valve?

That's almost a -ve rep!!!!!

I hope Toobs gave you a bit of a slap for that. I know I will when I see you next.

seeyuzz
river

[The Witzl]

meh - i got spares.... lots of spares.

and new valves too

If you are bored right now River, come over... you can see the insides of a couple of 18R-Gs. I'm rebuilding one now with 9.7:1 pistons.
.. you can get your books too

[river]

Hi,

Should of told me a few hours ago. I got a belly full of wine now and, coupled with my advanced years, sleep beckons.

However, if you need a hand during the week to get your Yellow Power Ranger (I think her name was Trini ) ready for Dubbo, then let me know.

seeyuzz
river

[tricky]

Word to the wise - dont rest your head on the ground with any valves open, they bend REAL easy....

Oops! When I rebuilt mine, I made a point of having the cams out whenever the head was off the block. For an extra 10 nuts to undo, it's cheap insurance! I also made a point of not resting the head on the gasket surface after I got it ground. I accidentally knocked it over at one stage. I can tell you know, expletives weren't enough to vent my rage!

The only good point is at least now you have the priviledge of pulling it apart. They really are a good engine to work on, except for the removel valve collets that is.

Karl, in this pic:



It looks like you have done away with the corrosion prone circulation pipe in favour of a piece of rubber hose... I wish I thought of that when my reconditioned engine started pissing coolant out of a rusted pin hole... I used silicone goo and thoughtfully placed hose and clamps

Chuck, with your ms trigger wheel, did you retrofit one from another car, or did you have it machined up? If so, how did you go about this? ...I'm gonna go and read your members rides section!

[The Witzl]

Tricky,

yeah you are right - i too had the metal pipe corrode on me, so i got the shits and threw it out!
A couple of quick points with my water hoses there though - that water pump housing is different to all the others i have, in that the "off to the side" outlet (for the corrosion-prone metal pipe to thermostat bypass) is heaps smaller (around 5-7mm diam).
All the other water pump housings i have have a side feed line the same diam as the corrosion pipe (~12mm IIRC)...
... hence why i have used the wee 5mm line for the TB coolant thingy (im yet to work out it's purpose in life) and then used a heater hose T-piece to supply the thermostat bypass line.

Hope that explains that.......



Now... some pics as promised!


i make garage big mess!





.... mmm, doesnt look to be seated right....



Have a guess which one is bent??



old engine block... not really that old, or in bad shape....



.... new engine needs some work, like maybe some assembly.



........ and why am i rebuilding the bottom end?
-> to use these phat puppies!!!

[Steve M]

Back on the topic of 18RG Harmonic Balancer timing marks.
The tri-pulley 18RGU one we've got has a TDC mark and one of the other two marks is actually about 9.8 degrees.
I imagine that every version of the engine would have had different timing to suit different compression and cams.

The best way is to calculate it. (I knew there was a reason we did Pi in school).
Take the circumference (mm) of the pully where the marks are and divide that by 360 and them times that by the distance between the TDC mark and the other marks (also in mm).

I realise most people would know how to work that out, but I put my bit in there anyway.
If the answer doesn't look right, it probably isn't. I did comprehensively fail year 12 maths in 2001 and have rarely done maths in the five years following that.

[TA-022]

I did comprehensively fail year 12 maths in 2001 and have rarely done maths in the five years following that.

^^^ here here!

[The Witzl]

Steve - you'll actually find that the 9.8deg you calculated was an error of measurement of the circumfrence and spacing of the marks (perhaps due to the length of an arc vs a straight line)..... that mark should be 10deg BTDC exactly.

I have both types of 3-belt crank pulleys at home.... the tripple timing mark and dual timing marked, and have worked out the timing marks for them both.

Dual Marked - TDC and 10deg BTDC
Tri-market - TDC, 5deg BTDC, 12deg BTDC.


.... i comprehensively aced 3 unit and 2 unit maths in 1999, then followed it up with distinction average in 1st year engineering maths and physics at uni.

Now i play with toys and push buttons on a computer.