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

[ra_28]

To set up for no shim, you would need either valves with the stem protruding further past the colletts, or have a larger base circle diameter, which when combined with your increased lift would indeed move the tip of the cam lobe dangerously close to the valve cover.

Hi

It has been setup with valve stems protruding further past the collects.

Alex

[Zammo]

NO SHIMS ARE U MAD

no srsly educate me on why one would do this. I havnt finnished my coffee this morning my brain cant work out the logic?

[ra_28]

Pretty much comes down to less valve train weight.
In an every day car I wouldn't have gone down this path but for a "toy" I have no problem with trying to free up the engine as much as I can.

Now please explain to me why you think I'm mad Zammo??

[Zammo]

in that case i no longer think you are mad

But smashing the bucket directly against the valve ? wouldnt that either mushroom the valve or hammer the bucket both of which are more expensive to replace than shims ?

[ra_28]

The bucket is reinforced on the inside like a shim, I can see your point about the possible mushroom over the end of the valve but they are stainless valves and I'm confident my head builder knows what he's doing, hopefully? LOL

[Zammo]

it will hold up alright i guess

id strip it down & check the buckets & valves tops early and often just to be sure though

[ra_28]

Once it's done about 5000km's I'll check it which should take about 3yrs at the amount I drive it. LOL

[Zammo]

that not the way RG should be driven


It should be driven in anger frequently

[ra_28]

My back pocket and my license can't afford for me to drive it often in Anger. LOL Plus the clutch is a nightmare such a pain in the ass in traffic.

[MorGo]

Well,example Yaris engines have no shims (different thickness buckets used to adjust clearance) so nothing new there.
In fact last 2JZ head I did converted to 2NZ-buckets;just drop-in (after careful measuring to get correct buckets)

[o_man_ra23]

The bucket won't mushroom the valve any more than a shim would. After having a shim dislodge and munting a valve, I can see the merit in using bucket over valve. Just means if the valve clearances open up for whatever reason (can't really see why they would though) then you are up for new valves.

[Unda Presha]

Guys believe me a shim can become dislodged under a bucket. It has happened to me once when a shim dislodged under a bucket (intake) and causing that valve to touch the piston and cracking that piston. It can occur when you valve bounce the motor from high RPM and lack of valve spring pressure. Considering when I raced my turbo 18RG, I would leave the start line up to 7500RPM with 32psi and then rev it past 8300RPM around 38psi causing it to valve bounce but generally it would just wear dishes into the buckets.

[MorGo]

Sure,the shims can and do get mislocated!
When I run carbs and MSD with limiter I learned that well!
Even with MSD's "soft touch" limiter when you push fresh charge to exhaust manifold under pressure and it ignites there:BANG!
That pressure force exhaust valve away from seat and bucket and shim just hover there and hopefully get back when the valve with retainer came back to cam.
Springs may be well up the rpm run but the spark limiter overrides them.NA engine;no problem but as you add boost..
So if possible use FUEL CUT!
Or convert to shimless system (of course it don't remove the issue of losing the valve control;it just don't lose shims!)

[GT1978]

Speaking of shims. Wasn't there a shim exchange thread somewhere? I've searched here, google and even on 1st Gen but haven't been able to find it.

I've been buying shims but at $9.90ea it starts to add up.

Glen

[MorGo]

The 3d gen 3S-GE and BEAMS have same shims as 18R-G/2T-G so at least they should be available from Toyota