rn20 engine upgrade

[thdevilshands]

hi all,
I have an rn20, a recently acquired freebie, now I want to do some stuff w/the engine and I was wondering if anyone had some advice.

Either: new engine - not sure what would be the easiest/best value swap?

OR: Have a play with the 12r thats currently in there. I have an 18r and an 18rc that could be used for donor bits, I really don't know much about the possibilities but I'm sure I read somewhere that u can use 12r block and 18r head in some combination, for some reason, like i said I know nothing about the theory behind engines etc so any advice will be much appreciated

[old_school_jap1]

contrary to popular belief, i have found that the 18rg head will not go on an 12r block.....bolt pattern is totally different. whack the 18r with a 5 speed in there and beef it up

[thdevilshands]

mmmmm thanks old skool jap, u always have the info 4 me, what a champ!!!

just out of curiosity wht would one do such a thing anyway, just to rev faster? I guess the 12r has shorter stroke than 18r, as i said engine theory aint anything i'm familiar with.

So..... anyone got ideas for engine bits for a 18R that will do the beefing job.
I'm guessing cam, better head?, valve stuff?? Lambolica's post in R engine hist thread mentions that "16R Conrods are commonly used to stroke the 18R out to 2.4lt
This is in combination with 22R-E pistons and 20r crank.
Using 22R pistons alone brings the 18R out to 2150cc."
http://www.toymods.net/forums/showthread.php?t=205

is this a good way to go or are there other options worth looking at, are those bits commonly avail?

I don't want to spend "heaps" so any info wud b gud
cheers

[old_school_jap1]

the 18r has a very revvy and ideal rod to stroke ratio standard. the 2.4 litre stroker messes with this and is generally not a great thing unless you whack a turbo on at the same time. buy some flat top 22r pistons and put them in, that is about the best thing you can do for an 18r cheaply besides a set of extractors, lightened flywheel or better carb.

[thdevilshands]

yeah I really like the way the 18r happily revs its head off, the rt104 it came out of has been my daily for like six years and following the 'retirement' of the mighty corona I can't seem to let go so 18r it is.

Should be an easy swap, I was gonna put that engine in a RN40 that has 18rc w blown timing cover but the bench seats on the rn20 are heaps more my thing. Luckily there's a free brake upgrade in there too + a five speed box + spare diff etc etc...

Now I wonder, will the column shift in the rn20 be a rediculous hassle to convert to five speed or will the existing lever arrangement allow for an easy transition?

[Glenno52]

contrary to popular belief, i have found that the 12r head will not go on an 18r block.....bolt pattern is totally different. whack the 18r with a 5 speed in there and beef it up

12r...Pushrods, 18r...Overhead cam Why would anyone even think about the heads being interchangable

[old_school_jap1]

mainly because the 3t is ohv and you can put the twin cam head on that without much trouble. some people say that the head bolt pattern is the same between all R motors, i have found this to be untrue. note; i got it around the wrong way in the original post

[Glenno52]

mainly because the 3t is ohv and you can put the twin cam head on that without much trouble. some people say that the head bolt pattern is the same between all R motors, i have found this to be untrue. note; i got it around the wrong way in the original post

t engines...maybe, but I thought the discussion here was about r engines

I think i'll opt out of this one...my head hurts!

[thdevilshands]

bump...
mybe its a silly question, just wonderin tho...
colum shift 4speed in the rn20, can i drop the 5speeed from th3 rn40 in and just drive?

[SeptemberSquall]

hide it away or you will wake up one morning to find your diff missing
whatever u do dont buy an ms65 too or it will be an irresistable one stop shop for a theif