18RC valve clearances (eleventy-trillionth thread)

[thechuckster]

hi folks,

i've just reset my valve clearances to factory limits on my trusty 18RTE - to get rid of a single noisy tappet sound... and now i've got lots of extra tapping sounds.

I know the factory suggests:
WARM
INT 0.2 mm (8 thou)
EX 0.39 mm (15.5 thou)

COLD
INT 0.18 mm (7 thou)
EX 0.33 mm (13 thou)

but i'm curious if anyone runs smaller gaps with their 18R or 18RC (not 18RG).

Some searching of here found a few threads with one suggesting 0.36mm warm Exhaust - but otherwise they were the same values.

I'm going to do some tuning before i go back and fix this irritating noise (i have to remove the intake, TB, injectors, wiring etc to get to the rocker cover so it's a major job) but i was wondering if i could go smaller without causing excessive wear and valves being forced open.

I run a non-stock cam - slightly more lift with less overlap. I set these with the engine cold as i have to lean on the exposed turbo when measuring stuff.

tia,
Charles.

[Rodger]

Charles,

Perhaps there was some oil gunk build up on the rockers that opened the gaps when measuring? Gave that slight tight feel and hence you have opened them a touch.

I run 0.02mm less on intake and 0.04mm less on exhaust than OEM minimums, on my 2Ts without problems. Sneaks just that tiny bit more lift and duration out of the cam.

Regards

Rodger

[Gavatron]

18R's don't need valve clearances. As long as there are valves there and they move somewhat, she'll be right

[thechuckster]

lol .. if only it was that simple ;-)

[brett_celicacoupe]

my haynes manual suggests 8 and 12 thou, hot.


7.5 thou difference seems like a fair bit!

did you have the cam in right position for each time you set the clearance?

[thechuckster]

i used the measurements on the sticker attached to the rocker cover... after all these year's its still readable.

i can't set the valves warm as it takes to long to remove all the stuff on the engine and the turbo has to be cold anyway (some inlet bolts require me to reach around and under turbo.

yes, is possible that cam wan't in right spot.

[RT104GT]

my haynes manual suggests 8 and 12 thou, hot.


7.5 thou difference seems like a fair bit!

did you have the cam in right position for each time you set the clearance?

Original Jap handbook states.... yoha nici san!!

Set timing at 10 degrees btdc at 850 rpm (DWELL ANGLE).

valve clearances are same as 2T engine

0.18mm INLET 0.33mm exhaust for 16R 16RB 18RE

compared with 0.29 Inlet 0.34 inlet 18RG 18RGU

Spark gaps 0.7 to 0.8 mm compared with 1.0 mm for 18RG which is same as L28T engine.

if you dont set them hot they will surely rattle like my L28 which I lazily set cold for the same reasons.

[RT104GT]

18R's don't need valve clearances. As long as there are valves there and they move somewhat, she'll be right

Remind me to pass whenever you sell anything..

[RT104GT]

hi folks,

i've just reset my valve clearances to factory limits on my trusty 18RTE - to get rid of a single noisy tappet sound... and now i've got lots of extra tapping sounds.


Charles.

At least if they are noisy they are open.

I have Turbo L28 set same way COLD and it rattles when hot.

But I know that in the case of a turbo that valve stem temps are hotter when driven hard so I should not have valve problems and they will gradually recess in with time.

I set them at 25 thou nearly 10 thou over but they are fine.

[allencr]

Do all of them sound the same, or maybe only the in. or ex.?
If only a few - less then half of the same ones and you're sure you've done a decent job, then your cam is worn.

Look at the preload that hydraulic's are set at - minus zero clearance. I'd think that it wouldn't let the valves make enough contact to cool down & crush through the carbon & they'd all burn up, but they don't!