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

[TRD184]

hey, i have some no0b 18RGU question if anyone could help me, first off, is the 18RGU an interferance motor? secondly, does anyone know the swept volume of the 18RG cylinders? thirdly, what were toyota's specs for shaving the 18RG head?? the maximum removable, and the minimum head thickness?? sorry to ask so much. i dont where else im going to find this info. thanks

[JustenGT8]

Yes def an interference engine...speaking from experience Swept vol 79mm from memory but easy to search for that to confirm. You can take as much as you want off the head as long as you factor that in elsewhere (cam timing, valve clearance, head bolt length)

[TRD184]

how much valve clearance does an 18RGU (***253) have, is there a way i can calculate this befoe i take my head off? theorhetically, the valve clearance would give me a ceiling with how much to shave off, and then id just need to calculate the compression ratio id end up with to decide how much. has anyone on here shaved their 18RGU head to bring compression up? i dont want anything stupid, the car has to be reliable, i was aiming for somewhere close to early 18RG compression( 9.1 i think it was?) if its acheivable.as this is the first engine i have pulled apart by myself (albeit the bottom end, i dont want to touch it if i dont have to) thanks for the help justen

[Omegaman]

i know the gu has the 8.7.1 pistons, but isn't it a bit dangerous shaving more tha 1mm off the head.
you have to take into account the above, plus timing chain tension and valve to piston clearance also.
I would've thought shave the head and look for 9.7.1 rg pistons, also checking the valve clearances to get the best compression results.

[TRD184]

aahk so the difference in compression was due to different pistons?, i dint realise rg's were that much higher compression then rgu's. i didnt even think of the chain tension being effected. thanks!
i shall take this information and mull over it thanks for the advise. maybe id be better off looking for a whole 18RG, pulling it right down and start from scratch (that way i can still drive my car too!!)
i like the sound of this
cheers.

[Omegaman]

if you sourced the RG pistons 9.7, it will solve most of your performance issues. if your looking at rebuilding yr gu, you can mix and match pistons, cams.
an FYI ( rg's -9.7.1 pistons. gu's 8.7.1 and geu's 8.3.1
Read through this thread, it will tell you the differences and what would be a good build.

[TRD184]

so the 9.7.1 pistons, straight into gu. simple as that (so to speak)
ive made my way thorugh the first 5 pages...my head hurts haha

[river]

Hi,

I wouldn't be shaving too much off the head. Just use the 9.7 pistons,

For 18R-G, 18R-GR and 18R-GU diagrams.....
http://www.toymods.org.au/forums/sho...hlight=mammoth

For 18R-GUE diagrams.....
http://users.on.net/~csharman/docs/18rgeu.pdf

seeyuzz
river

[Omegaman]

so the 9.7.1 pistons, straight into gu. simple as that (so to speak)
ive made my way thorugh the first 5 pages...my head hurts haha

they slot straight in (so to speak)
i've done it on my build, using a *****253 head, also the *****231 rg cams. made a difference. Add a good air intake and you feel the difference.

[jabbatron]

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[Unda Presha]

Jabbatron,

We recently brought a head stud kit for our new stroker 18R. The kit is a Ford Escort which fit perfectly. We just need to turned them around. We brought our kit loose so we dont have a part number from Performance Wholesale in Brisbane. The nuts for the kit are a M12 x 1.5. Give Performance Wholesale a call and maybe they can help. The guy who brought my kit was Mark Ashford if that helps.

If you want a mains stud kit I have one for sale. It is a 22R ARP kit?

[jabbatron]

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[Unda Presha]

We inverted them from their normal fit when they are fitted to the Escort. It appears Ford have a different thread in the block but the thread for the nut end is the same as the Toyota block.

[jabbatron]

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[bholmberg]

can't you just use a grade 8 M12 bolt of the correct length and thread? correct me if i'm wrong, but there is nothing too special about the head bolts in an 18rg. in which case a standard bolt shop like keables or blackwoods (in melbourne) should be able to help.