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Author Topic: McCoy 35 head gasket is not in the house  (Read 859 times)

Offline Dave Moritz

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McCoy 35 head gasket is not in the house
« on: May 29, 2022, 08:25:44 PM »
Nice motor that actually runs without one. Leaking compression, though so would like to install one. Will try aluminum pop can material unless someone here advises against it. What say ye?

Dave Mo…
It’s a very strange world we live in, Master Jack.” (4 Jacks and a Jill)

Offline Dan McEntee

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Re: McCoy 35 head gasket is not in the house
« Reply #1 on: May 29, 2022, 08:44:59 PM »
   If you have the left overs and can measure the thickness, go to the auto parts store and see what they have in gasket material in a similar thickness in a black, high temp material. Easy enough to make with a sharp Xacto knife and some circle templates. Cut the center hole first and get it to fit properly and then use a sharp o-ring pick or ice pick to mark the hole locations Sharpen up the end of a length of 3/32* tubing to use as a punch to cut clean holes. Then cut the outer diameter. If you can find some of that green gasket material that Perfect that will work if it's big enough. I think an old playing card will work also. That material is pretty tough and has a nice coating on it that helps with the seal. I've used bad original ones in an emergency that had a thin coating of #2 Permatex on both sides and the engine ran well with no leaks. I don't think soda can stock will be soft enough and thick enough for a McCoy .35, but I have never tried that.
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Offline Dave Moritz

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Re: McCoy 35 head gasket is not in the house
« Reply #2 on: May 29, 2022, 10:28:32 PM »
Very good, Dan. I just noticed that there is a shallow, circular channel on the head to accommodate the gasket. Presently it’s filled with hard fibrous material. I’ll ditch the aluminum idea in favor of a stock gasket or players card. Will have to scratch out the fibrous gunk carefully to clear the channel. Thanks.

Dave Mo…
It’s a very strange world we live in, Master Jack.” (4 Jacks and a Jill)

Offline kenneth cook

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Re: McCoy 35 head gasket is not in the house
« Reply #3 on: May 30, 2022, 05:26:57 AM »
               Even though your head gasket is probably shot due to it's age, the base gasket is going to be very short lived when you do fix the head. If interested, here's a link:  http://www.icbimproducts.com/     offers a  base and head gasket  McCoy .35 Cylinder Head SET-121179
McCoy .35 Cylinder Head Gasket 2 Pc SET, Upper & Lower

   

Offline Dan McEntee

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Re: McCoy 35 head gasket is not in the house
« Reply #4 on: May 30, 2022, 06:55:40 AM »
Very good, Dan. I just noticed that there is a shallow, circular channel on the head to accommodate the gasket. Presently it’s filled with hard fibrous material. I’ll ditch the aluminum idea in favor of a stock gasket or players card. Will have to scratch out the fibrous gunk carefully to clear the channel. Thanks.

Dave Mo…

     That fibrous gunk is the old gasket. The company that Ken mentions sells on eBay I think and is a good option that I forgot to mention. I was running a Red Head .35 for a hobby shop customer once to show him some of the basics, and got the engine started easy enough and needled it until it settled into a nice four stroke. We were working in my driveway and as I was trying to talk to him over the engine noise, I heard the exhaust note and RPMs start to change. I looked down at the engine and started to see part of the head gasket start to work it's way out, and when it got to a point where the openi9ng got large enough to really lose compression, it quit! I have never seen an engine spit out a head gasket before that!!! This was when I tried the #2 Permatex trick and it seemed to work fine on the subsequent runs we tried, but you have to have something to work with.
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   Dan McEntee
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Offline john e. holliday

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Re: McCoy 35 head gasket is not in the house
« Reply #5 on: May 30, 2022, 10:39:01 AM »
Jim Lee sells a gasket making tool at @Lees Machine Shop@ in the vendors corner.  I have replaced the McCoy gaskets with soda pop cans.  Make enough to get the thickness of the old gasket material.  So ar no problems.  Check tightness of screws after the first run. D>K
John E. "DOC" Holliday
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Offline Dave Moritz

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Re: McCoy 35 head gasket is not in the house
« Reply #6 on: May 31, 2022, 08:00:46 PM »
Great responses, all. I took the plunge on the link Ken supplied and await the order. Should run well when all is said and done.

Thanks.

Dave Mo…
It’s a very strange world we live in, Master Jack.” (4 Jacks and a Jill)

Offline Dave Moritz

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Re: McCoy 35 head gasket is not in the house
« Reply #7 on: May 31, 2022, 09:42:41 PM »
I tried to remove the cylinder from the crankcase without success. Heat didn’t work. Maybe try a penetrating oil soak. But I’m thinking about skipping this one and only replacing the head gasket.

Dave …
It’s a very strange world we live in, Master Jack.” (4 Jacks and a Jill)

Offline Dave Hull

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Re: McCoy 35 head gasket is not in the house
« Reply #8 on: June 01, 2022, 02:08:34 AM »
Moe,

If it is stuck on there (and didn't move at all when you tried to move it) I'd reassemble the whole enchilada and run it. If it doesn't leak, you're golden.

Dave

Offline kenneth cook

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Re: McCoy 35 head gasket is not in the house
« Reply #9 on: June 01, 2022, 03:22:42 AM »
            I'm well aware of the cylinders ability to not let go. I liberally pour oil all around the cylinder to case connection. I use a gloves and hold the case and begin heating the cylinder with a heat gun that's used for paint stripping.  The oil will really smoke when hot enough. Insure the piston is at the bottom of it's travel and heat inside the cylinder as well to insure thorough heat transfer. Any castor between the liner and the case acts like glue and this is generally what is being stubborn.  I then twist the cylinder rather than try and pull on it to break it free. Having a prop on the shaft can also allow for some better holding power which also gets your hands out of the heat and real hot areas.

Offline Christopher Root

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Re: McCoy 35 head gasket is not in the house
« Reply #10 on: June 01, 2022, 07:37:21 AM »
Aluminum tape from the hardware store works well also

Offline Dave Moritz

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Re: McCoy 35 head gasket is not in the house
« Reply #11 on: June 01, 2022, 09:51:18 AM »
Wow, Ken, that baby must really be on there to warrant that kind of treatment. Mine doesn’t leak so I’ll likely go with the Divot’s culinary approach.

Thanks, John and Chris, for the aluminum suggestions.

Dave Moe…
It’s a very strange world we live in, Master Jack.” (4 Jacks and a Jill)

Online Dave_Trible

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Re: McCoy 35 head gasket is not in the house
« Reply #12 on: June 01, 2022, 05:38:17 PM »
I see someone suggested aluminum tape-this works.  I use the aluminum foil duct tape for engine gaskets and gaskets for pipe headers.  Just clean the top of the cylinder perfectly clean with acetone.  Stick on a piece of the tape then cut away the excess inside and out with a sharp new exacto blade.  After you run the engine once and it's still warm re-tighten the head bolts then it's good to go.  As far as getting things apart I've resorted (successfully) to putting the whole engine in the oven at 350-400 for twenty minutes.  It will all come apart pretty easily after that,  of course using hot oven mitts.

Dave
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