can't seal the head
- Thread starter froggie9189
- Start date
Re: head gasket won't seal
Are you using accorn nuts? Sometimes the accorn nuts bottom out and won't let the head seat properly....
Re: head gasket won't seal
Also, you might have to remove the head and cylinder and wet sand the mating surfaces smooth. I (like many others here) used sand paper on a piece of glass to ensure there was a smooth surface. My stock head had a good sized gouge when I got it and am sure it would have leaked. My cylinder was not exactly smooth either. I used 1000 grit sandpaper, wet. People use a coarser grit, that is just what I had on me at the time.
Also, you might have to remove the head and cylinder and wet sand the mating surfaces smooth. I (like many others here) used sand paper on a piece of glass to ensure there was a smooth surface. My stock head had a good sized gouge when I got it and am sure it would have leaked. My cylinder was not exactly smooth either. I used 1000 grit sandpaper, wet. People use a coarser grit, that is just what I had on me at the time.
I replied in your post in the general discussion section as well...
You might have to remove the head and cylinder and wet sand the mating surfaces smooth. I (like many others here) used sand paper on a piece of glass to ensure there was a smooth surface. My stock head had a good sized gouge when I got it and am sure it would have leaked. My cylinder was not exactly smooth either. I used 1000 grit sandpaper, wet. People use a coarser grit, that is just what I had on me at the time.
Scotto mentioned that if you are using acorn nuts on the head, that they can bottom out before torquing down the head enough. If so, you should switch them out for regular nuts.
You might have to remove the head and cylinder and wet sand the mating surfaces smooth. I (like many others here) used sand paper on a piece of glass to ensure there was a smooth surface. My stock head had a good sized gouge when I got it and am sure it would have leaked. My cylinder was not exactly smooth either. I used 1000 grit sandpaper, wet. People use a coarser grit, that is just what I had on me at the time.
Scotto mentioned that if you are using acorn nuts on the head, that they can bottom out before torquing down the head enough. If so, you should switch them out for regular nuts.
I removed the original thread. We discourage posting the same question multiple times in different areas of the forum.
Follow Maurtis's advice. The lapping will go quicker with a courser grade of paper; I start with 280 then work down to 400.
Here's a couple of hints:
Use a wide magic marker, or machinist dye to paint the gasket sealing surface before you start sanding. On the first couple of strokes you'll quickly see where the high and low spots are as the ink/dye is removed. Keep going until you have a flat, uniform surface. Same for the cylinder mating surface. If you didn't remove the cylinder from the lower case you'll need to pack it with an oil soaked rag to catch any sanding residue. You don't want that scratching up the cylinder walls and rings.
While working the head over the sandpaper keep rotating it in your hand so you don't sand an angle into it. Same for the cylinder.
By all means replace the chrome acorn nuts with hex nuts, preferably the kind with a wide flat shoulder. Use a torque wrench and tighten the head nuts down to about 130 to 150 inch pounds, alternating from side to side as you tighten. After the engine has reached operating temperature a couple of times check, don't tighten, them. Use that torque wrench, not brute force. Those are only 8mm steel studs into a cast aluminum case. If you don't get a turn with the wrech set at your original value do not try to get them to turn, even a little.
Following this advice you don't need gasket sealers or head gasket goop. The stock gasket, properly torqued and a flat sealing surface will work just find without bandaids.
Tom
Follow Maurtis's advice. The lapping will go quicker with a courser grade of paper; I start with 280 then work down to 400.
Here's a couple of hints:
Use a wide magic marker, or machinist dye to paint the gasket sealing surface before you start sanding. On the first couple of strokes you'll quickly see where the high and low spots are as the ink/dye is removed. Keep going until you have a flat, uniform surface. Same for the cylinder mating surface. If you didn't remove the cylinder from the lower case you'll need to pack it with an oil soaked rag to catch any sanding residue. You don't want that scratching up the cylinder walls and rings.
While working the head over the sandpaper keep rotating it in your hand so you don't sand an angle into it. Same for the cylinder.
By all means replace the chrome acorn nuts with hex nuts, preferably the kind with a wide flat shoulder. Use a torque wrench and tighten the head nuts down to about 130 to 150 inch pounds, alternating from side to side as you tighten. After the engine has reached operating temperature a couple of times check, don't tighten, them. Use that torque wrench, not brute force. Those are only 8mm steel studs into a cast aluminum case. If you don't get a turn with the wrech set at your original value do not try to get them to turn, even a little.
Following this advice you don't need gasket sealers or head gasket goop. The stock gasket, properly torqued and a flat sealing surface will work just find without bandaids.
Tom
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