Grinding shims

[Sam_Q]

Just wanted to know if there is an issue with grabbing shims out of a bucket over shim type setup (think 4age) and grinding them on a surface grinder? I understand that theres no way I would grind off the top side because of the finish but can the bottom be done? I know people would say it goes through the case hardned layer but would it matter?

[fixeruperer]

i use a bench grinder, ive done thousands of shims that way.

[Sam_Q]

sarcasm I think I can safely assume

[fixeruperer]

hey ? maybe not thousands but heaps.
more than i can remember

[oldcorollas]

depending on how thick the shim is, the hardening may go all the way through, so it may not be a problem.

[allencr]

I'd think no problem at all with all that surface contact area on the follower, compared to a Jag, Alfa or Lotus Twincam that only contact the valve stem tip and were ground using the the side of the wheel.
If you're worried about it breaking, grind it 20 to 30%, put it in the vise, hit it with a hammer & compare it to a stock one. Snap with a lot less effort?

[Sam_Q]

just to clarify when I mean surface grinder I meant one of these that has a magnetic bed and a vertical grindering wheel, highly accurate.

[toddw]

I removed the head of my 80 series Landcruiser a few years ago after it had a loose valve insert. I got the head seviced and set up my a very reputable engine shop here in Brisbane. Because it was my head I paid a fair bit of attention to it and noticed that a few of the shims had been ground and were facing upward (camshaft side). I asked the question raised here to the head engine builder and was informed that they are hardened all the way through. Assembled it back up and no worries. It has now done 100k after head was removed and 340K in total. No problems at all.

[legend]

u could use a sharping stone

[oldcorollas]

as long as the wheel has been dressed correctly... i assume the shims will be magnetic enough. then again.. check first...
you might need to go slowly or take off small amounts at a time to prevent it being spat out by the wheel tho.

[styler]

or you can buy shims at any size at about $10 - $15 ea,
maybe discount for bulk?

http://www.precisionshims.com.au/

[Viper]

Sam, there is a guy near St. Kilda who sells shims.
.05mm differences if I remember correctly.
About $3 each.
I can dig up his contact details if you are interested.
Talking to him, using a die grinder to remove .01 to .04mm of material seemed 'normal'

[ONCE-NA]

Yeah I've done them in my shitter daily 3RZ, on gas, the valves recess quicker and I didn't want to be frequently buying new shims. I used an old bucket to hold them while I used the side of the bench grinder wheel. Note, with the shim upside down.

[Sam_Q]

ok thanks guys, i dont think I have ever had so much of a confirmation on a subect before!

[allencr]

ok thanks guys, i dont think I have ever had so much of a confirmation on a subect before!

It was much less of the typical Sam_Q Question' then usual!!

May I ask the price of the grinder? 2 or 3 phase motor, diamond dresser?

[Sam_Q]

I have no idea, its just a random picture I got off the internet. I would get the guy in our tool room here at my work to do mine.

The reason I asked about this subject is that someone I know who is usually always right said that you cant grind shims no matter what and it confused me as I didnt see the problem.

[love ke70]

they are case hardened.
not hardened all the way through.
yes u can do it, but viper, could you please dig up those details? i would like new ones with my build.

and sam q. what motor is this for? the one you are currently building?
because, when you get a head machinedand the valves done etc, they can set your valve clearances using your current shims, by taking the tip off your valve stem...
cheers, andrew

[oldcorollas]

they are case hardened.
not hardened all the way through.
yes u can do it, but viper, could you please dig up those details? i would like new ones with my build.

and sam q. what motor is this for? the one you are currently building?
because, when you get a head machinedand the valves done etc, they can set your valve clearances using your current shims, by taking the tip off your valve stem...
cheers, andrew

are you sure they are not through hardened?
if th eshims are only a mm or so, they might be surface hadened only if they were carburised or nitrided.. but if they were induction of furnace heated followed by quenching, then it is more likely to go through thickness..

if anyone has a spare they wanna send to japan, i have a microhardness tester, and probably a nano indenter i can use

you can only grind the tip by the amount the valve seat is machined.. you don7t want to do that too many times .. but yeah, it can be done..

[love ke70]

are you sure they are not through hardened?
if th eshims are only a mm or so, they might be surface hadened only if they were carburised or nitrided.. but if they were induction of furnace heated followed by quenching, then it is more likely to go through thickness..

2.5mm thick shim. engineering shop i took mine too said only case hardened, but hey, could be wrong....

if anyone has a spare they wanna send to japan, i have a microhardness tester, and probably a nano indenter i can use

how much is postage gonna be? and do you want a ground or unground shimmy bimmy?

you can only grind the tip by the amount the valve seat is machined.. you don7t want to do that too many times .. but yeah, it can be done..

why cant u take a little extra?
and on a standard head job ahem thats all you need....

[oldcorollas]

ahh.. 2.5 is a bit bigger than i thougth they were .. maybe they are case hardened then... i was thinking more like 1mm thick.

nfi on postage.. although there aren't any 4AGs at the wreckers, if there are more common toyota engines (2J? 1UZ? 1G?) that have the same shims, i cna prolly snag one for free... once the 2 or 3m of snow melts

hmm, taking extra puts the valve further in = slightly lower compression, thinner seats etc etc.... is not that bad, but.. meh, shims are easier