An interesting shot of an RC cylinderhead. Look’s kind of scrap to me.

Worrying is the amount of material loss .
Replacement, factory, det..

9 stud 185 head from RC


185


9 stud 185 head from RC



CS awaiting upgrade level2


It's clearly evident that some degree of cylinder head material over laps the valve seats making me V happy



only small area cleaned for inspection, 1 o'clock . good seat. Including some cosmic impact, previously noted from last service.

Above head ran18 months flawlessly.

How & what , that’s the interesting part, I have my theories, not wanting to taint the water, thought I would ask here for some input before posting…

not having much to do with Toyota, still acquiring understanding, an interesting part , would like to know more about Toyota’s laser process used … on some gen of cylhead.
Why it was used, what benefits, what serviceability change, replacement issues, any know flow, reliability proofing etc..

Could it be a similar letdown as other revisions that were implemented to later gen of fours…lol

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Black UK 96 205 shed with heater full on telemetry.

project six million dollar 185, faster, stronger, lighter than before.

Sorry Jon,

I know nothing of the "lazer cut" seats. It sounds to me like marketing guff to me as I can't really see what a lazer has to do with valve seats

Have those seats been creeping? Looks to me like they have

I think the laser cutting bit takes place on the seats before they are fitted to the head. Laser cutting is just a method of creating a very accurate profile on the seats. I dont think the process has anything to do with how they are mounted. Especially into an alloy head.

Graham

Or alternatively, they laser cut the holes in the head where the valve seats are to be fitted.

Graham

Kind of what I had assumed but I know diddly about the actual facts in this matter. This must be a common-place method used now?

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JP
GT4DC Treasurer

Grey St185 RC
Silver BMW E46 M3
Multicolour yawn Honda VFR400
Silver Honda Civic Type-R

laser's don't like cutting blanked holes

how does one limit the depth of burn from a laser.

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Black UK 96 205 shed with heater full on telemetry.

project six million dollar 185, faster, stronger, lighter than before.

You cant. Lasers have the advantage whereby you have a cutting tool that can be reduced down to the size of a few microns in diameter. No milling machine would provide a viable tool of this size. Also with an argon jet that washes away molten material under high pressure and the fact that there is very little localised heat beyond the area that's been cut will give you a very clean cut that doesn't require additional machining afterwards. A laser needs to cut right through any material that it's being used on. However you can limit the depth of cutting in a situation whereby you have say a disk to cut out of the side of a hollow egg without cutting through the other side of the egg.

Graham

Theirs me thinking that valve seats were ground finished..

Wonder what power of laser would be required.

Over time have had stuff laser cut, its by no means a perfect finish.

water jet on the other hand can offer much better finish..

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Black UK 96 205 shed with heater full on telemetry.

project six million dollar 185, faster, stronger, lighter than before.

focus grasshopper...

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ST205




"And God said, Let the earth bring forth grass, and the earth brought forth grass and the Rastafarians smoked it."

These days they cut gear teeth with lasers to make gearboxes. It cuts down on production costs because it's accurate, quick and theres no overheads on replacing cutting tools. A lot of it's to do with the material specs you work with. An alloy of iron, nickel, cadmium, chromium etc behaves very differently on cutting/machining dependent on the proportions that those alloys are put together. Generally it does'nt affect the overall strength of the steel but it does affect how easily it can be machined/laser cut.

Hmm, good info. I guess the dpeth of the cut depends on laser intensity & focal length?

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JP
GT4DC Treasurer

Grey St185 RC
Silver BMW E46 M3
Multicolour yawn Honda VFR400
Silver Honda Civic Type-R

very true graham..

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Black UK 96 205 shed with heater full on telemetry.

project six million dollar 185, faster, stronger, lighter than before.

i know some industrial laser pulsate freq for penetration control but even so, its not that controllable cutting a blank hole in a chunk of alloy without going though is a challenge, when compared to cutting teeth / shapes etc.

Modern day technology, always something new that amazes me.

bit like the white led's, never in a month of Sunday’ did they think that was possible.. back 15 yrs.

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Black UK 96 205 shed with heater full on telemetry.

project six million dollar 185, faster, stronger, lighter than before.

Intensity with regard to power then yes. Focal length no. Taking the egg scenario earlier, the way to reduce the laser cutting right through the egg is to fill it with very small glass beads. This refracts the light energy and absorbs it along with the heat energy. Probably wouldn't work with an actual egg because the beads get very hot. But would work with more resilient materials even light aluminium alloys such as duralamin etc.

Graham

Its been quite some time since i was involved in machining - those days of my apprenticeship seem a lifetime away...

I was sure i remembered something about focal length (i worked in a electron microscope machine shop for a while)

i found this on the net:

http://www.resonetics.com/PDF/MDDI_Micromachining.pdf


A tool based on a pulsed laser peels the material like an onion—layer by layer.
Each pulse removes an amount set by the pulse energy, the focused power (energy density), and the absorption characteristics of the machined material.

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ST205




"And God said, Let the earth bring forth grass, and the earth brought forth grass and the Rastafarians smoked it."