Coolant sealing problem

Beck · December 07, 2020, 11:44:21 AM

I am still working on my Mercruiser 4 banger. I have 1 nearly finished and I don't remember what head gasket I used. It appears there are no longer head gaskets made for the motor. It uses a Ford 460 head, but the Ford head gaskets won't seal. The Ford block and head have coolant holes, and the gasket for it has sealant around those holes. The Mercruiser has an open deck (see photo). The out of stock Mercruiser head gasket had a sealant ring to go around the open deck.
I have been in a discussion about closing the block's deck. It has been done by others, but in the past it was mostly done to bore the factory cylinders out and replace them with new large diameter sleeves. Coolant holes to match the Ford gasket are drilled into the insert. If making an insert to close the deck I have some questions.

How thick of material to use? I was thinking 3/8" others thought ¼". The block will need to be decked after installation.

What alloy?

How do I cut it (I need to make 3)? Band saw would be a pain, Plasma cutter, Water jet, Laser Another guy is trying to get a good file made for the CNC cutter guys. Apparently that takes a special type of file and conversion is an issue.
When guys are making these into big bore motors they often deck the block by quite a bit and weld a plate to the top of the block or make a plate that is retained by the head bolts. The guys like me that are staying with the factory bore normally cut an insert that fits in the coolant passage opening which leads to my nest question.

How to attach it? The method I have seen is TIG welding. Another guy thought the aluminum solder. I am wondering if the aluminum epoxy (Ford truck bed stuff) would hold up. The epoxy wouldn't distort anything like the welding could.

WZ JUNK · December 07, 2020, 01:01:26 PM

I know that Doug's is a different situation, but I would give him a call. Call or contact me for his cell phone number. His. old land line number went with the sale of the shop.

enjenjo · December 07, 2020, 08:33:39 PM

My thought would be an O ring groove around the perimeter of the deck. It could easily be CNC machined once you make a file.

Beck · December 07, 2020, 10:40:35 PM

Quote from: "enjenjo"My thought would be an O ring groove around the perimeter of the deck. It could easily be CNC machined once you make a file.

That "make a file" is way beyond me.

kb426 · December 08, 2020, 08:45:25 AM

I made a blower intake manifold for a wedge chrysler years ago. I put it in a vertical mill and squared it with one side of the table. I used an 1/8" end mill and cut the groove around 6 thousands less than the oring measured. I think it would be possible to do the same with your block. Maybe a .090" oring might be a better fit. The next option is to modify a head gasket to do something similar.

enjenjo · December 08, 2020, 05:40:45 PM

Quote from: "Beck"
Quote from: "enjenjo"My thought would be an O ring groove around the perimeter of the deck. It could easily be CNC machined once you make a file.
That "make a file" is way beyond me.

To make a file lay down a piece of paper, ect. and set the deck on it. Trace around the outside of the deck surface. The make a new line on the paper 1/8" inside the outside of the deck. The second line becomes your pattern. The shop can use that pattern to create the milling file for the CNC mill.

Beck · December 09, 2020, 12:16:51 PM

Quote from: "enjenjo"
To make a file lay down a piece of paper, ect. and set the deck on it. Trace around the outside of the deck surface. The make a new line on the paper 1/8" inside the outside of the deck. The second line becomes your pattern. The shop can use that pattern to create the milling file for the CNC mill.

I had been following another guy trying to do this. He traced the pattern of the insert (we are looking at filling the opening of the deck). He created a PDF file. He had some problems with skips and double lines, which the CNC won't tolerate. He took it to a plasma cutter or laser cutter and was told the file needed to be in DXF. He has tried to use online conversion sites with no luck. He finally sent it to an online company for conversion. I haven't heard back from him if he received the file.

I don't know how the piece will be held for cutting since it has to be cut around the outside and inside. That leaves no place to clamp unless it is done in stages.

Fat Cat · December 11, 2020, 12:00:46 AM

Quote from: "Beck"
Quote from: "enjenjo"
To make a file lay down a piece of paper, ect. and set the deck on it. Trace around the outside of the deck surface. The make a new line on the paper 1/8" inside the outside of the deck. The second line becomes your pattern. The shop can use that pattern to create the milling file for the CNC mill.

I had been following another guy trying to do this. He traced the pattern of the insert (we are looking at filling the opening of the deck). He created a PDF file. He had some problems with skips and double lines, which the CNC won't tolerate. He took it to a plasma cutter or laser cutter and was told the file needed to be in DXF. He has tried to use online conversion sites with no luck. He finally sent it to an online company for conversion. I haven't heard back from him if he received the file.

I don't know how the piece will be held for cutting since it has to be cut around the outside and inside. That leaves no place to clamp unless it is done in stages.

If you get the PDF file I might be able to convert it o a DXF file for him. I do this stuff at work all the time.