up the power on the 18r

[liteace]

Im going from a 5R to an 18R so from OHV to OHC alone is an upgrade in revs/smoothness
while OHC to DOHC is not much of an upgrade.
The use of larger pistons to increase bore size and longer rod with shorter piston height would
be an nice upgrade for compression along with what MorGo has described.

personally I like the old 18rc motor that I know with a little boost and h20 should be nice for 100hp atw.

[MorGo]

Once again:the 18R-C is a unbeliavle modification of a good engine!
Machining out the chamber to lower compression and other mods just to be compliant to California emission regulations... I bet they made the situation worse than cleaning the air.
The 8R/18R are fine engines of the time.Heavy of course but so were all others then (some exotics not included;ordinary commuters that anyone can afford).
Same effort to tune as Ford OHC and one may start to think wichc one to do..
But one will go to the easier route and choose the engine with more aftermarket (not mentioning factory!) performance parts!

The lovly 21R;not many consider it as a performance engine.. Head is much like the Ford CVH in port configuration. Only made better.Both are medicore in stock but ported brilliant!
Oh yes,21R is crap;everybody KNOWS that!
22R head is crap and very difficult to improve when 21R just needs to be done.But why bother since everyone knows it all (by old wives tales) that it's crap!

If someone is interested the 18R big valve head,intake manifold and sidedraft carbs maybe in sale (the Cressida I sold is to be converted to 2JZ-GTE..)

[trevv]

Are there any problem with putting an 18r head on an 18rc motor, i intend to keep the 18rc motor in my celica. Just want to make it as good as can. The celica is having factory aircon fitted this week. I do not want a high power motor, just want to get the old 18rc as good as can be, my 18 year old son drives it.

[MorGo]

Are there any problem with putting an 18r head on an 18rc motor, i intend to keep the 18rc motor in my celica. Just want to make it as good as can. The celica is having factory aircon fitted this week. I do not want a high power motor, just want to get the old 18rc as good as can be, my 18 year old son drives it.

They are just the same;the 18R head is just the better chamber;not the emissions made 18R-C (C-as for California emissions)
My Cressida with 18R (selfmade intake for 40 mm sidedrafts) and 2" exhaust run 16,7/176km/h at quarter..
Just the carbs and headwork (what I do as a profession)
Feel free not to have head modified..

[trevv]

Thanks thats what i thought but the company that has the head for sale told me there are 2 types of head one that has the chain tensioner on the block the other type has the chain tensioner on the head only. I could not find any info on this i thought all had chain tensioners are on the block, so i was not sure.

[Dazza]

You can bolt an 18R head onto an 18RC block. I did it to my hilux about 20 years ago. The 18RC has the tensioner on the head where you can undo a nut on the outside to release the tension. I cant remember how the 18R tensioner worked but i know it was just a straight bolt on job. The 18R head had better exhaust ports.

[trevv]

Would a efi manifold from a 18rg fit an 18rc head inlet ports.

[Javal]

Would a efi manifold from a 18rg fit an 18rc head inlet ports.

No way bud, ports are on the wrong side of the head, wrong shape and wrong spacing. If you wanted an EFI 18R, you could track down a super rare 18R(E?) Injection setup, but they're so old and uncommon I'd suggest using an 18R to side draught manifold and putting an injection body on it along with a crank trigger wheel and basic ecu