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Gm Head Gaskets
- Thread starter 6.2 turbo
- Start date
Matt Bachand
Depends on the 6.5
Then theres always a GOOD set of tin snips with the Left cutter, Right Cutter, and Straight Cutter (3 snips).
I know Home Depot sells copper sheets, just not sure how thick they are, or how large they are, they are squares, but question is how long. I will check next time I'm in there. They sell them in the aisle with the Aluminum Lengths, Threaded Rod, and Angle Iron and Diamond Plate Sheets.
I know Home Depot sells copper sheets, just not sure how thick they are, or how large they are, they are squares, but question is how long. I will check next time I'm in there. They sell them in the aisle with the Aluminum Lengths, Threaded Rod, and Angle Iron and Diamond Plate Sheets.
redshift96
Diesel Knucklehead
Copper
Unfortunately, no matter how well you clamp the work, you're still going to get a fair amount of flash/burr on the edges of the copper sheet, especially if you use a jigsaw. The copper is usually just too soft to avoid some deformation in the process of cutting it. Less so if you order a harder grade, but I've *always* had to dress edges no matter the temper or thickness, and no matter the cutting tool. So this will probably hold no matter what technique you use, unless you stamp it out with a precision die, or have it machined, whether by water, laser or on a conventional mill. (And even then, the machinist is just going to deburr the edges for you.)
You might want to check into having it plasma cut on a CNC router table. Can't tell you whether this would give you any better edge finish, but it'd certainly be cheaper than laser or waterjet. I could possibly give you a quote for this from another shop in my building. Want me to ask about it?
Personally, I'd be reluctant to try to do something like this with hand tools, ie x-acto or whatever. BUT.... give me a nice Dremel with a fine router bit, and using the old gasket as a template for the bit to ride against, I'd bet one could make a damn close duplicate of the original, then use a deburring tool for the slight bit of flashing left.
Do you know what grade/temper of copper to use for these? I'm sure it matters, but I don't know what the best choice would be.
Here on the west coast, I use a vendor called "Sequoia Copper & Brass" (in... Hayward, I think?) for most of my stuff, as they have great tech and sales support and decent (neither cheap or expensive) prices. I bet you could get a recommendation for a good east coast vendor if you give them a call.
In an interesting aside, I just heard from a friend that his late model PowerSmoke uses solid *aluminum* factory head gaskets. Innnnnteresting.
Unfortunately, no matter how well you clamp the work, you're still going to get a fair amount of flash/burr on the edges of the copper sheet, especially if you use a jigsaw. The copper is usually just too soft to avoid some deformation in the process of cutting it. Less so if you order a harder grade, but I've *always* had to dress edges no matter the temper or thickness, and no matter the cutting tool. So this will probably hold no matter what technique you use, unless you stamp it out with a precision die, or have it machined, whether by water, laser or on a conventional mill. (And even then, the machinist is just going to deburr the edges for you.)
You might want to check into having it plasma cut on a CNC router table. Can't tell you whether this would give you any better edge finish, but it'd certainly be cheaper than laser or waterjet. I could possibly give you a quote for this from another shop in my building. Want me to ask about it?
Personally, I'd be reluctant to try to do something like this with hand tools, ie x-acto or whatever. BUT.... give me a nice Dremel with a fine router bit, and using the old gasket as a template for the bit to ride against, I'd bet one could make a damn close duplicate of the original, then use a deburring tool for the slight bit of flashing left.
Do you know what grade/temper of copper to use for these? I'm sure it matters, but I don't know what the best choice would be.
Here on the west coast, I use a vendor called "Sequoia Copper & Brass" (in... Hayward, I think?) for most of my stuff, as they have great tech and sales support and decent (neither cheap or expensive) prices. I bet you could get a recommendation for a good east coast vendor if you give them a call.
In an interesting aside, I just heard from a friend that his late model PowerSmoke uses solid *aluminum* factory head gaskets. Innnnnteresting.
redshift96
Diesel Knucklehead
I'd guess it would be best to order whatever hardness material you want to end up with, and just adjust your cutting speed as req'd to accomodate the pliability of the material. You can usually get it "hard", "half-hard", & "dead soft" without any special ordering. Possibly some other hardnesses as well, depending on grade and thickness.
I'm guessing that if some gaskets are annealed, it's because they need to be a certain hard/softness in order to seal properly. If they are die-stamping them, they would work harden in places, thus maybe need some annealing to address this, or to gain a consistent hardness throughout the piece? Not sure, but I wouldn't be shy about picking the brains of some tech support guys on this, if I were you.
I'd figure out what the big name suppliers use for grade and hardness, and go from there. Why reinvent the wheel?
The cutting part should actually be pretty easy. My plasma-cutting guy suggests using the plasma head for rough-cut, and switching to a regular cutter on a mechanical router head for the finish cuts. He thinks the thermal conductivity of the copper would be problematic for precision cuts with the plasma cutter.
Hope this helps a little.
Another thought... you could likely use a photoresist technique to mask the area you want to retain, and use a nitric acid bath to simply etch away the material you don't want. If you prepped it yourself, I bet a plating shop could do this for you pretty cheap. The resist and solvent is cheap.
If it were me, I'd use the Dremel router technique for a prototype, then figure out a more efficient method if you decide you want to pursue making more than a few of them at a time.
I'm guessing that if some gaskets are annealed, it's because they need to be a certain hard/softness in order to seal properly. If they are die-stamping them, they would work harden in places, thus maybe need some annealing to address this, or to gain a consistent hardness throughout the piece? Not sure, but I wouldn't be shy about picking the brains of some tech support guys on this, if I were you.
I'd figure out what the big name suppliers use for grade and hardness, and go from there. Why reinvent the wheel?
The cutting part should actually be pretty easy. My plasma-cutting guy suggests using the plasma head for rough-cut, and switching to a regular cutter on a mechanical router head for the finish cuts. He thinks the thermal conductivity of the copper would be problematic for precision cuts with the plasma cutter.
Hope this helps a little.
Another thought... you could likely use a photoresist technique to mask the area you want to retain, and use a nitric acid bath to simply etch away the material you don't want. If you prepped it yourself, I bet a plating shop could do this for you pretty cheap. The resist and solvent is cheap.
If it were me, I'd use the Dremel router technique for a prototype, then figure out a more efficient method if you decide you want to pursue making more than a few of them at a time.
buddy
Active Member
Whatever you need to bring compression to 21:1 is what I would get. Did you account for the precup volume in the compression ratio?
I just deducted .010 from stock 21.5 compression and got 22.5. Either Bill or me is figuring wrong,because my pistons stick out as much as .018 max, and about .015 with the piston centered ,and Bill said .007 will get 22.5 with stock valve protrusion.
buddy
Active Member
I think stock they will stick out about .005" with the 21.5:1 ratio using OEM gasket
And its a good estimate using .01" as adding 1 more to the ratio. If it was really 21.5 to start with and you decrease it .01 it will be 22.65:1
I would get the .054" gaskets which should leave you right about 21:1 or a bit less.
And its a good estimate using .01" as adding 1 more to the ratio. If it was really 21.5 to start with and you decrease it .01 it will be 22.65:1
I would get the .054" gaskets which should leave you right about 21:1 or a bit less.
redshift96
Diesel Knucklehead
Cu mat'l
Just so happens I have some leftover 0.040" cold rolled 99.9% Cu sheet, ASTM 8370 & B152-97a.
Should have more than enough for two gaskets. If you want it, it's yours for the cost of shipping from California. I could check into whether the guy in my building could cut the HG pattern with his CNC plasma cutter if you want. He owes me a favor, so it could be cheap.
That's the only thickness I have available though, so can't help if you need something thicker.
Just so happens I have some leftover 0.040" cold rolled 99.9% Cu sheet, ASTM 8370 & B152-97a.
Should have more than enough for two gaskets. If you want it, it's yours for the cost of shipping from California. I could check into whether the guy in my building could cut the HG pattern with his CNC plasma cutter if you want. He owes me a favor, so it could be cheap.
That's the only thickness I have available though, so can't help if you need something thicker.
I have had good luck using red and blue lock tight, one on each engine for the 2 6.2's I put the ARP's in. I put the stud in and then double nutted the stud to tighten it into the block. Then install the head. None of the finger tight BS. So far it has worked, no coolant in the oil, with oil analysis to back it up. Head gaskets are difficult to install over the studs! I have had the heads off one of the engines 3 times for other reasons and not had any issues with the studs. Engine was out for the heads though.
I tightened the studs in my 6.2 also, they sealed fine. My 6.5 I used old bolts. But the copper gaskets leak quit a bit ,only when driving. Max boost is 25 psi,and starving for fuel. Compression ratio is 22.5,and cranking psi is 500 .
turbonator
Member
Very interesting read, this was all going down in the beginning of this thread, about the same time that we were putting our "Pugg" motor together.
We machined the heads at the stud\nut surface to accept an "rubber o-ring" to resolve the ARP leakage issue.
We have the Cometics on her. How did your testing of Corteco gaskets work? The gaskets in stock now here, are another set of Cometics (.070"), and a set of Felpro (.055").
Hopefully we can get to building soon, so as to have some current results to add to this mix.
We machined the heads at the stud\nut surface to accept an "rubber o-ring" to resolve the ARP leakage issue.
We have the Cometics on her. How did your testing of Corteco gaskets work? The gaskets in stock now here, are another set of Cometics (.070"), and a set of Felpro (.055").
Hopefully we can get to building soon, so as to have some current results to add to this mix.
I still have the Cortecos,the fire ring is to narrow for an o ring. I pulled both heads this evening. Same old story,leaking at the ends. I checked the pass side head ,it is not warped. I wish I would have let the orings stick out farther ,instead of the recommended .010 thousandths .
turbonator
Member
do you think it is possible to machine the head and block to add another bolt or stud in those problem areas? there must be some way to correct that... did you ever give any thought to what chevydiesel posted about fire ringing the coolant passages there? that might stop the gasket from pushing out...
The copper did't push out,just leaked at that spot. It wonders me if the cylinder wall flexes ,right at that spot,since it has a fairly long open area. Seems like there could be a support in the middle. I would suggest,before you concrete the block,shove a rod down through both rear coolant ports. Maybe leave it stick up a little. I was coming up with some far out ideas,like totally plugging the hole and rerouting the water externally. Another idea was to drill and tap a bolt in the side of the rear of the block,and thread it in with a jam nut,so as to support the cyl wall. Having a extra head bolt there would be best,not sure how easy that would be.
