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2006 Hyundai Tiburon GS 2.0L
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Discussion Starter · #1 ·
Hello forum
Q. Has anyone done a valve reseating job of the 2.0L cylinder head valves using a valve grinding stone set?
If so whats the seat angle 30, 45 60 degrees?
What stone sizes for intake and exhaust?
Recommended kits to purchase?

The issue:
Im having trouble lapping about 5-valves (exhaust and intake) that wont pass the water test keeps leaking after
re-lapping (course & fine paste) each of them 5-6 times each trying to avoid machine shop $$$ if possible

Thank you for your wisdom!
mike
 

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I'm no engine rebuild expert, but I have lapped some valves back to sealing condition. I know I should really have had these heads worked at a machine shop, but it was an experiment, that has worked out well so far.

So... A couple questions. What grit(s) are you using for your lapping? In my non-expert opinion, I've not seen anything fine enough available off the shelf at the local stores. I've seen the Clover brand double ended can thing, and even their fine grit isn't fine enough to satisfy me.

Next, have you tried painting the valve sealing surfaces (on both the valve tulip and the seat) with a sharpie or something to see what the contact pattern looks like? Might give you some insight into what you're dealing with.

And last, are you sure the valves aren't bent? That would show up with the sharpie test too.

Because everyone likes pics, here's an example of before and after for one of the heads I've lapped into submission:
Automotive tire Automotive lighting Alloy wheel Rim Motor vehicle


And after. Yes, the contact patch is wider than spec and there are still a few tiny divots, but for this car, I''m OK with that.
Circle Automotive tire Rim Auto part Metal
 

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Oh, and forgot... To answer your original question, I've never used the grinding stones.

I worry more about chattering and misalignment with the stones and I don't trust that it would work out right. The lapping process removes material so much slower that I find it easy to control. I worry that I would not be able to control the stones.
 

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Oh, and forgot... To answer your original question, I've never used the grinding stones.

I worry more about chattering and misalignment with the stones and I don't trust that it would work out right. The lapping process removes material so much slower that I find it easy to control. I worry that I would not be able to control the stones.
The stone sets I have seen have a long guide shaft that the stone is on and the shaft goes into the valve guide. Thus it's aligned.
Yes, usually a good lapping job is enough unless you really burned a valve.
 

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Right. The arbor and stones are guided for alignment, but I still think there are a whole bunch of ways I could screw that up. :D

I mean, I'm no machinist, but I think I'm pretty good with that kind of work and I'd still be apprehensive about grinding the seats, And I certainly wouldn't try it on my "good" head the first time right out of the box. I'd want a junker head to experiment on first.
 

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Discussion Starter · #8 ·
Huge thank you Tiberius & Charlie III
The fine compound I don't know the grit?
What do you recommend?

After 3x with drill and hose lapping and then hand lapping I switch to another intake valve and that seemed to
stop the leak with the water test after one hand lapping job

So appreciate the FSM for the valve specs sheet
 

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I did a couple minutes of web searching and came up with a document that says the Versa Chem grinding compound you have there is 120 grit for the coarse and 220 grit for the fine:
Font Screenshot Parallel Number Document


I don't like the circular grooves that remain on your sealing surface and that's why I switched to something much finer. For the work I've done, I used 800 grit grease based compound. Yes, it takes longer because it removes material at a much slower rate, but I like the finish a lot better.

I bought this a bunch of years ago, and I think I got it from ebay. No idea if it's still available, but this is what I've been using:
Automotive tire Motor vehicle Automotive design Bumper Drinkware
 

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Oh, and I see you painted the valve and seat with sharpie, but it looks like from the next pic that you put the grinding compound on it and gave it a spin? If that's the case, then you didn't do it right... Paint it with the sharpie and then put the valve in dry. No grinding compound.

Lightly press the painted valve into the seat and rotate it back and forth a little (maybe ten degrees) and then take the valve back out and see where the sharpie has been removed.

Kinda hard to describe with just words.... Does that make any sense?
 

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Discussion Starter · #11 ·
Thank you Tiberius....Im very grateful for your help and input
Yes i did the sharpie thing so wrong......ill try it the right way :)
I also ordered the 800 grit valve lapping compound on E-bay and will use that instead

Also have you used or would you recommend using the plastic hose/tube on the end of the valve with a drill to spin slowly back and forth to lap the valves method? Or just stick with the hand lapping (see picture)

Once again thank you Tiberius
mike
 

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I usually do by hand. I have a hand crank machine that rotates back and forth as well as the rod with suction cups.
I do a bit of twisting/lapping, lift the valve up, rotate 90*, drop back to the seat, do more lapping, repeat.
Wipe the compound off, check the valve and seat surface. If not correct, add more compound and repeat.
 

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Ok thank you Charlie-III
If I may ask, where did you pick up the hand crank machine?
It was my fathers, likely 55-60 years old. Sorta like an old gear drive drill, but does a twisting action in each direction (maybe 90* each way per crank).
 

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Oh boy... Since we're going to get into it and I'm going to look like the back woods shade tree cretin.....You engine experts may want to look away now.

I made a wooden valve lapping adapter tool that looks like this:
Motor vehicle Automotive tire Engineering Gas Automotive exterior


I put double back sticky tape on the big end and then stick the valve tulip to that and then use my cordless electric drill chucked up on the other end of the wooden dowel to spin the whole thing. Looks like this:
Motor vehicle Wood Automotive tire Passive circuit component Automotive exterior


Motor vehicle Hood Automotive tire Automotive design Automotive exterior


The drill turns the dowel, and the tape (which is stuck to the valve tulip) spins the valve. It's essentially the same process as using the suction cup stick, but I do it with my drill:
Automotive tire Light Hubcap Auto part Gas


So why do I do it that way?

1) I think the tape sticks better to the valve head than the rubber suction cups. Eventually the tape will pull off the valve and you'll have to refresh the tape but I just keep putting a fresh square on top of the piece that just pulled off the valve. Eventually when I've got a whole bunch of layers built up, I'll pull them all off the tool and start fresh, but I think the multiple layers provide a small amount of compliance to the adhesive joint that actually makes the joint more robust and tolerant to slight misalignment.

2) Speaking of misalignment... The wooden dowel will bend and accommodate misalignment while you're spinning the assembly. I wouldn't want to use a metal rod there. The wood's flexibility helps.

3) Since I'm PUSHING the valve into the head instead of pulling it (with the plastic tubing), I can not only generate more force, but I can also get a better feel for how much pressure I'm applying. Easier to modulate and control the pressure.

So yes... The professionals would run me out of town for my ridiculous shop built tool and procedure, but that's what I do. The rest of my procedure is pretty much the same as Charlies.

Using the drill, I spin maybe twenty times in one direction, pulling the valve up every two or three rotations. Then I reverse direction and do the same thing spinning the other way. After doing that a couple times, I pull the valve up, clean off the grinding compound, decide if I need more and then repeat if necessary. Checking with sharpie (dry) every now and then to see how things look. I've got the machinist’s blue dykem too, but sharpie is sitting right there and is easier on these small parts.

A 15 second video would probably explain things a whole lot easier, but that's way above my pay grade. :D
 

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I won't look away.
How fast are you spinning the valve? Hopefully not too fast, like maybe 1/4 speed or less should be fine.
Spinning fast is also likely messier and you need to make sure all the compound is cleaned up before final assembly.
 

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How fast are you spinning the valve? Hopefully not too fast,
I haven't measured it but I'm using the low speed setting on my (ten year?) old cordless drill. Quick search on the web says it's probably around 200-300 RPM?

I can tell you that it's slow enough that I don't get any compound flinging around at all. All the grinding compound stays at the surfaces I'm lapping and I don't have compound spatter anywhere.

I certainly wouldn't use the highest speed that most electric drills can generate. If you're using a cordless and it has as low speed setting, try that. And if you're using a plug in variable speed drill without a speed range setting, then you would have to keep the speed way down at the low end. If your plug in drill is like mine, it would be difficult to control.
 

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Ok thank you Charlie-III
If I may ask, where did you pick up the hand crank machine?
the hand crank tool long gone as is mine. here is a "modern day" replacement. https://www.amazon.com/WINTOOLS-Lap...rds=valve+grinding+tool&qid=1655490128&sr=8-5 get a tube of Prussian Blue. its a blue paste that doesnt dry fast. you put a small dab on the valve seat. then put in the valve and turn it. take the valve out and you can see the details of the sealing surface. when lapping the valve, it is best to do by hand as the grit wears down very quickly and you can hear that as you twist back and forth. when you hear it quiet down, lift the valve out of the seat and turn slightly and lap again. repeat until you get a good seal. Neway sells a decent hand valve seat cutting tool if you serious about doing valve work. hope this helps.
 
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