Head Gasket Leak?

twowheeldreams · December 28, 2005, 02:19:08 PM

I have noticed an oil leaking from my engine and have found that it is coming from the area circled in the pictures. Is this the head gasket and is there any fix besides replacing the head gasket. From reading other posts it seems like this is a common problem. Thanks for your help!

scratch · December 28, 2005, 02:27:26 PM

It doesn't seem to be serious. The only other way to 'fix' it is to wait until your next valve check (every 4000 miles) and check the torque of all your cylinder head nuts (4 inside the cover, 4 outside).

twowheeldreams · December 28, 2005, 02:28:59 PM

well when i ride it i end up with an oil covered right foot and pant leg, not to mention the engine and rear tire!

btw, the pics are with the engine just cleaned and with no oil showing (havent started it since).

scratch · December 28, 2005, 02:32:44 PM

That sounds serious. I think you're going to need to replace that gasket. Expecially, if you are loosing alot of oil.

Edit: you could just go ahead and take the valve cover off and torque the head nuts anyway, but a leak that serious says to me it's time to replace.

that_guy · December 28, 2005, 03:37:29 PM

I would say you need to go ahead and replace it just to be safe. A simple torque issue of the head bolts wouldn't usually cause a leak of that scale.

scratch · December 28, 2005, 04:14:09 PM

I'm stating that they may have come loose. It is one of the things that the mechanics are supposed to check at first service; to make sure that they are at the proper torque/tightness.

dgyver · December 28, 2005, 05:18:07 PM

Actually, per the service manual, the head is supposed to be torqued every 4k miles or 12 months.

There are 4 o-rings that sit on top of the cylinder. They are part of the lubrication system that supplies oil to the cams. These are possibly the location of the leak since they are under pressure. Best to replace those as well as the head gasket.

makenzie71 · December 28, 2005, 05:47:22 PM

new gasket. pronto.

...on a side note...

I've never done much internal modification to a gs motor. I rebuilt one a long time ago, but didn't alter anything...followed the manual I had. Since then I got into building EX500 engines and I've learned how to build them without using a headgasket. Lap the block and head surfaces down and use copper-spray and they'll last about 10,000 miles..actually some of the ones I've built exceeded that a great deal but I saw no reason to not suggest a tear down at 10k. The biggest point to this was to up the compression. There are no interference problems or anything and it was a VERY noticeable gain in power (10~ish).

Could that be done with the GS? Seems like with an oil-cooled motor there's even less to worry about...

dgyver · December 28, 2005, 06:03:12 PM

Gaskets are needed for making up the machining tolerances. Copper coat does basically the same thing. Not using gaskets on an air cooled motor would be a bad idea. Too much temperature change.

makenzie71 · December 28, 2005, 06:07:08 PM

Quote from: dgyverGaskets are needed for making up the machining tolerances. Not using gaskets on an air cooled motor would be a bad idea. Too much temperature change.

I was kinda thinking the material differences in the block and head (fe vs al) might make it a bit more difficult on the GS.

dgyver · December 28, 2005, 06:14:28 PM

Head and cylinder block are both aluminum.

makenzie71 · December 28, 2005, 06:16:49 PM

Quote from: dgyverHead and cylinder block are both aluminum.

My mistake.

Then there really wouldn't be that much to worry about, then...just like with the EX. I'm not saying it'd be a very lasting motor, but if the head and block are made out of the same stuff then there really shouldn't a problem, unless it's mechanical.

dgyver · December 28, 2005, 06:27:21 PM

Custom work can work to the tolerances required. Mass production cannot, at a reasonable cost. Not sure if I would trust it yet.

makenzie71 · December 28, 2005, 06:31:44 PM

true. I lapped the head and block down to near-glass RA before the ex started sealing right all the time. The is probably a little different in structure, too...who knows. I'll have to get one to tinker with eventually.

Blueknyt · December 28, 2005, 07:52:37 PM

you can reuse the old head gasket once completly cleaned and then copper coated, but you still need to replace the rubber coated metal Orings. a WHOLE gasket kit will only run you about 60$ and it has every seal and gasket that goes into that engine.

twowheeldreams · December 28, 2005, 08:23:02 PM

Quote from: dgyverThere are 4 o-rings that sit on top of the cylinder. They are part of the lubrication system that supplies oil to the cams. These are possibly the location of the leak since they are under pressure. Best to replace those as well as the head gasket.

good thing i got those too!

Bob Broussard · December 29, 2005, 10:56:31 PM

Lapping the surfaces just to eliminate the head gasket seems like alot of effort for a little more compression.
I have a head with a section cutout to show the valves. I'm going to see how much I can mill off to get a compression increase. I'm going to mill the cylinders too. Then I'll do it to a good head and see how it works.
When I assemble it I'll use the stock head gasket with coppercoat sprayed on. I'll have to degree the cams and all.
I'm going to do before and after dyno runs and compression checks.

makenzie71 · December 29, 2005, 11:14:07 PM

lapping really isn't that labor intensive. just a couple of hours.

GeeP · December 29, 2005, 11:23:56 PM

Two things are necessary for a gasketless seal:

1) FLATNESS - The surface must be flat enough that there are no gaps between the mating surfaces.

2) SURFACE FINISH - Machining marks are "tall" enough to allow water to flow through.

The best procedure is to clean up both the block and cylinder with a fly cutter in a single pass at finishing feeds and speeds. Use a rigid mill with rigid fixturing. A little bridgeport doesn't have the rigidity to swing a 14" flycutter, you'll need a production mill like a Kearney and Trecker #2. This assures flatness.

Lap by hand. After lapping, print the pieces with blue to ensure you have total contact. If not, tweak with 1500 grit sandpaper.

If done correctly it will never leak, assuming that the head nuts don't lose torque. This type of gasketless seal is commonly used in high pressure pumps.

dgyver · December 30, 2005, 04:54:40 AM

Quote from: Bob BroussardLapping the surfaces just to eliminate the head gasket seems like alot of effort for a little more compression.
I have a head with a section cutout to show the valves. I'm going to see how much I can mill off to get a compression increase. I'm going to mill the cylinders too. Then I'll do it to a good head and see how it works.
When I assemble it I'll use the stock head gasket with coppercoat sprayed on. I'll have to degree the cams and all.
I'm going to do before and after dyno runs and compression checks.

Bob...Be careful on milling the cylinders. I have one that has been milled and with a stock thickness gasket, one of the pistons was hitting the milled head while running, even left an impression. A thicker copper gasket eliminated hitting the head but then I found the piston was hitting the spark plugs, not something I checked since I had them out while checking valve-piston clearances. Both of these issues can be resolved by a little machining to the pistons. This was when I was building the first 555 motor. I did not use the cylinder and still have it. If you want a measurement of the mill, let me know.

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Head Gasket Leak?