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

[wal_ra40]

So, I present, for lazy people (like me)...

The one stop shop (post) for 18RG ARP fastener info!

Rod bolts: Use [203-6002] - same as 22R and 3SGTE
Flywheel bolts: Use [203-2802] - same as 4AG, and you get 2 extra to lose!
Main studs: Use [203-5402] - from a 7M-GE, and you'll get 2 spare that aren't able to be used
Head stud option #1: [???-????] Shortened 22R - Rumour to be confirmed
Head stud option #2: [207-4202] From a Mitsubishi 2600cc Astron, need to mill down head posts by ~19mm - Suggested by YelloRolla (see stidnam's 2TG mod in the pic below)
Head stud option #3: [???-????] From an Escort (flipped upside down to match threads - suggested by UnderPresha)
Head stud option #4: [???-????] Custom made ARP studs that are floating around in limited numbers (group buy was organised by YelloRolla)

If I need to correct or update, please let me know.

Stidnam's 2TG head mod to use head stud option #2

Head gaskets keep failing on the 92mm 10.5 CR engine, and was wondering if replacement head studs might fix it.

Has anyone got any more information on head stud options 1, 3 & 4? If possible would prefer not to modify the head for option #2.
Part number for option #3 is [203-4201].

[73GTV]

Head gaskets keep failing on the 92mm 10.5 CR engine, and was wondering if replacement head studs might fix it.

Has anyone got any more information on head stud options 1, 3 & 4? If possible would prefer not to modify the head for option #2.
Part number for option #3 is [203-4201].

Option 3: is a no go due to the thread pitch M12 x 1.00 and the required pitch is M12 x 1.25


Option 1: was completed By Bollox on 1stgencelica:
Borrowed from his post, please give him the credit! He stated:

5"9/16" is the max height from the block to the top of the stud, you could leave it at 5,1/2" and you would still be fine, you still have to allow at least 3/4" to an inch in the block.

Here is what I did.

Using a lathe we cut 1/2" off of the bottom of the Stud
Then we turned down above the ARP thread about half an inch to allow the stud to go below the deck of the block.
When measured, the entire stud to 6, 9/16" after we again using the lathe to cut them to this length.
We then used a special die that allows you to alter the cut of the thread, i.e. you can tighten it down or open it up!
This allowed us to bypass the ARP threads without damage and then using the lathe, cut into the stud with several passes to thread below the original ARP thread, works fine.

I then used RED threadlock and cut a rod to get the right height, its a lot of work but if you have the time its way cheaper than ARP making you a set

[RA40peter]

With the recent down time, I have finally been able drag out the old wiring loom from an 18R-GEU.
Unfortunately the loom has been hacked up a bit and the relays have been just cut off all together.
I have a manual on the engine but nothing on the wiring and ECU.
Looking through the forums, I found old links to the wiring but they are all dead now.
Can someone provide the full ECU wiring details at all?

[Omegaman]

There are 2 to 3 wiring diagrams floating around. Slightly different. I have them lying around. Will check.

[73GTV]

http://www.retrojdm.com/ScanViewPage...0-%20Index.jpg

[RA40peter]

Great info, Thanks for the link.
However what I have doesn't quite match up unfortunately.

[73GTV]

Great info, Thanks for the link.
However what I have doesn't quite match up unfortunately.

https://page.auctions.yahoo.co.jp/jp/auction/g289151363
https://page.auctions.yahoo.co.jp/jp/auction/m326121392

Sorry, I thought that I had a link to the TA40 and RA40 models but that proved to be nothing. Best I could do was point you towards the place that I had collected most of my hard documents an CD's which are now restricted!

[virus-zn]

hi guys.
i am currently building up an 18rg to fit into my rn20 hilux.
im currently stumped at the 2 holes on the top of the block. timing chain side.
cant seem to find any info online. does it take an oil squirter like the 18rc ones or can it be blanked off?

[73GTV]

hi guys.
i am currently building up an 18rg to fit into my rn20 hilux.
im currently stumped at the 2 holes on the top of the block. timing chain side.
cant seem to find any info online. does it take an oil squirter like the 18rc ones or can it be blanked off?

Please provide a good photo of the item in question, someone would be happy to give you an answer. Also this is not like the 18rc. Here is a link to the engine manual which should help with your question.

http://www.retrojdm.com/ScanView.asp?ScanID=25

[virus-zn]

Please provide a good photo of the item in question, someone would be happy to give you an answer. Also this is not like the 18rc. Here is a link to the engine manual which should help with your question.

http://www.retrojdm.com/ScanView.asp?ScanID=25

thanks for the response. i for some strange reason cannot upload pics here.
according to the manual if one looks at image 5-117 i am querying the very top bolt in the pic just above the timing gear.
so on the image for the 18r-g there is a bolt that blanks off the oil gallery, but on the 18r-c there is an oil squirter in that location.
my query is this, has anyone put the oil squirter in a g block to aid lubrication for the bottom chain and would it affect oil pressure.
or should i just stick to what the book says and blank it off with a bolt?
any advice?

there is a thread that comes up on google search thats on 1stgen celica forum, but i cannot seem to register there.

[73GTV]

You do know that the Oil squirter nozzle is within the head assembly of the 18RG head directed at the timing chain assembly. Look at chapter 6 Lubrication system, around page two or three and look for the nozzle and the list for that number is on the next page.
http://www.retrojdm.com/ScanViewPage...0-%2018R-G.jpg

Pg 5-3 shows it connected by side view to the oil system...
http://www.retrojdm.com/ScanViewPage...way%20View.jpg

http://www.retrojdm.com/ScanViewPage...20Assembly.jpg

http://www.retrojdm.com/ScanViewPage...20Assembly.jpg

[virus-zn]

You do know that the Oil squirter nozzle is within the head assembly of the 18RG head directed at the timing chain assembly. Look at chapter 6 Lubrication system, around page two or three and look for the nozzle and the list for that number is on the next page.
http://www.retrojdm.com/ScanViewPage...0-%2018R-G.jpg

Pg 5-3 shows it connected by side view to the oil system...
http://www.retrojdm.com/ScanViewPage...way%20View.jpg

http://www.retrojdm.com/ScanViewPage...20Assembly.jpg

http://www.retrojdm.com/ScanViewPage...20Assembly.jpg

Thanks.
this helps.

http://www.retrojdm.com/ScanViewPage...20Assembly.jpg

got my ans on the above page.
item no 7 - oil jet. listed for 18r-c and not 18r-g. both blocks have allowance for it.
im just wondering if adding a 2nd oil sprayer will drop the oil pressure much.

[73GTV]

The 18Rg and 2TG heads have enough of a problem with delivering to much oil to the head assembly and it takes a while to drain back to the sump. Removing the casting flash and smoothing down those edges will aid in the oil return to the sump. That said, If you want to add a additional oil squirt noozle to your system, That may help you, Give it a try!

The reason for that statement above was from a conversation, post or article of someone adding a restriction to the 18rc block (Not the 18RG) to reduce the amount of oil being supplied because of the size of the oil supply port that was drilled at the factory. I never thought about that info until you asked this question.

You will have to ask someone who has access to both types of block (Same Block in my mind) to check that rumor out.

Are you adding a larger capacity oil pan or making modifications to your stock pan for more oil capacity, windage tray or baffling the sump to direct more oil back to the pump?

Stock or Racing application. What are your goals? Are you adding an addition oil pressure guage to monitor the difference?

Remember this, It is your engine, build it as you please!!

[Dalerous]

Hi guys. I've been absorbing info on this thread for years, I hope there are still a few lurking around to answer a question. I have an 18rg, very earliest motor with 9.7 pistons in a lotus 7 kit. I've blown the head gasket so it's coming out to get a refresh and I'll mate it to the spare 88253 head I have (I'm hoping the head is serviceable). I'm hoping the bottom end is still in tolerance so I can hone the block and put in new rings and all new bearings. What's the experience with these motors changing to ARP rod bolts? Do you think I need to get the rods resized if I do? Am I safe to reuse the old rod bolts?? I know the originals have been untorqued and retorqued at least once as bearings were changed some years ago.
Thanks Dale

[Omegaman]

I've changed heads. skimmed heads, changed rings etc. used the same rod bolts, with no issues. Note, this is a NA motor so no boost to need ARP extra clamping force.
Im sure the piston clearance on skimmed head is still within spec, there are guides on the head showing max spec.
Honing should not make bored oversized. See when dissembled condition of bores.
No issues with freshening up these motors, rings, bearings, gaskets.
Maybe check 888253 head and valve seating, also valve seals before you re assemble.
Also early head should have 888230/231 3 bolt cams, where 888253 head will have single bolt cams. Use early cams on re build.