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Farmer Ted
03-10-2005, 10:03 PM
what are the holes on the side of the exhaust manifold for?

Are they freeze plugs?

They have what looks like a quarter sized disc in them?

What happens if one of these discs falls out? How do you reinstall it? Can it be reinstalled?

Professor
03-10-2005, 10:17 PM
Farmer,
Was this a trick question? It reminds me of the movie Risky Business where Rebecca tells Tom, “Yes, No…Maybe. But, if it had been you asking her this question I am sure she would have said, “Yes, yes…yes.”

Farmer Ted
03-10-2005, 10:20 PM
Farmer,
Was this a trick question? It reminds me of the movie Risky Business where Rebecca tells Tom, “Yes, No…Maybe. But, if it had been you asking her this question I am sure she would have said, “Yes, yes…yes.”

Just curious, the 98 is securly parked on the beach FMC (fully mission capable) just waiting on the WX to cooperate

Lance
03-10-2005, 10:24 PM
Just for the record I don't believe they are 'freeze plugs' but instead are 'casting plugs'. The holes in the casting are put there as a necessary part of the engine casting process and is the location where the sand from the sand casting is flushed out. They do often in fact save people from and expensive engine replacement because they will blow out in some cases when water freezes but that is not their intended purpose I don't think.

If you do a google on "freeze plug sand casting" you will find several references to this. There are probably some engineers on the board that have spent some time in a foundry (at least in school) that can describe the process.

So I think the answers are:

1: The holes are to let the sand out after the manifolds are cast in the foundry,

2: No they are not freeze plugs,

3: Probably just get new plugs and bang them in with a hammer.

Farmer Ted
03-10-2005, 10:28 PM
Just for the record I don't believe they are 'freeze plugs' but instead are 'casting plugs'. The holes in the casting are put there as a necessary part of the engine casting process and is the location where the sand from the sand casting is flushed out. They do often in fact save people from and expensive engine replacement because they will blow out in some cases when water freezes but that is not their intended purpose I don't think.

If you do a google on "freeze plug sand casting" you will find several references to this. There are probably some engineers on the board that have spent some time in a foundry (at least in school) that can describe the process.

So I think the answers are:

1: The holes are to let the sand out after the manifolds are cast in the foundry,

2: No they are not freeze plugs,

3: Probably just get new plugs and bang them in with a hammer.


Thank you sir!

Professor
03-10-2005, 10:34 PM
Yeah, don’t know why I couldn’t remember :uglyhamme
Lance’s answer is much better, but Farmer…can’t you just hear Rebecca telling you that right now???

dchatagnon
10-19-2005, 05:42 PM
I have removed my exhaust manifold and I want to clean the inside before to repaint them and put it back.
What do you suggest?

thanks.
Damien

PointTaken
10-19-2005, 05:48 PM
Just for the record I don't believe they are 'freeze plugs' but instead are 'casting plugs'. The holes in the casting are put there as a necessary part of the engine casting process and is the location where the sand from the sand casting is flushed out. They do often in fact save people from and expensive engine replacement because they will blow out in some cases when water freezes but that is not their intended purpose I don't think.

If you do a google on "freeze plug sand casting" you will find several references to this. There are probably some engineers on the board that have spent some time in a foundry (at least in school) that can describe the process.

So I think the answers are:

1: The holes are to let the sand out after the manifolds are cast in the foundry,

2: No they are not freeze plugs,

3: Probably just get new plugs and bang them in with a hammer.
Lance, that was a very informative answer. I was always told they were freeze plugs also.

Andyg
10-19-2005, 06:01 PM
Just for the record I don't believe they are 'freeze plugs' but instead are 'casting plugs'. The holes in the casting are put there as a necessary part of the engine casting process and is the location where the sand from the sand casting is flushed out. They do often in fact save people from and expensive engine replacement because they will blow out in some cases when water freezes but that is not their intended purpose I don't think.

If you do a google on "freeze plug sand casting" you will find several references to this. There are probably some engineers on the board that have spent some time in a foundry (at least in school) that can describe the process.

So I think the answers are:

1: The holes are to let the sand out after the manifolds are cast in the foundry,

2: No they are not freeze plugs,

3: Probably just get new plugs and bang them in with a hammer.

You got half of it. The plugs are where the supports are for supporting the sand cores during the casting process. It is hard to suspend a core in the middle of the die, gravity is funny that way. The secondary benefit is it helps with removal of the sand after casting.

Andyg
10-19-2005, 06:40 PM
I have removed my exhaust manifold and I want to clean the inside before to repaint them and put it back.
What do you suggest?

thanks.
Damien


I just had my aluminum ETX manifolds plastic bead blasted to remove all the paint. If you are talking about removing the paint/rust from cast iron manifolds so you can repaint them I would use a glass bead blast or aluminum oxide blast. Make sure you protect the threads and gasket surfaces though. If you are talking about trying to remove carbon and rust from the inside I wouldn't waist my time.

Andyg

Ric
10-19-2005, 06:44 PM
I just had my aluminum ETX manifolds plastic bead blasted to remove all the paint. If you are talking about removing the paint/rust from cast iron manifolds so you can repaint them I would use a glass bead blast or aluminum oxide blast. Make sure you protect the threads and gasket surfaces though. If you are talking about trying to remove carbon and rust from the inside I wouldn't waist my time.

Andyg
blasted the etx's!??? are you going for a polished finish or what's the story?

Andyg
10-19-2005, 06:48 PM
blasted the etx's!??? are you going for a polished finish or what's the story?

They are getting polished as we speak. Another good reason to work for Harley, I have access to a ton of metal finishers. Don't worry I will post pictures when they are done and installed. I hope they look as good as the LQ9 manifolds that MC by design sells, see the picture.

Ric
10-19-2005, 06:52 PM
They are getting polished as we speak. Another good reason to work for Harley, I have access to a ton of metal finishers. Don't worry I will post pictures when they are done and installed. I hope they look as good as the LQ9 manifolds that MC by design sells, see the picture.
whoah! I didnt know that was done or could be done! :cool: Yes I'd love to see pics and details as to how much polish work is needed after blasting and if there are any heat implications from the work?

Andyg
10-19-2005, 07:03 PM
whoah! I didnt know that was done or could be done! :cool: Yes I'd love to see pics and details as to how much polish work is needed after blasting and if there are any heat implications from the work?


I was thinkg about getting them chrome plate until I recieved them and could see them in person. Since these things are sand cast they are full of porosity (tiny air bubbles). When you polish the aluminum you take the solid layer off the casting and expose this porosity. If you plate it and then expose it to any kind of heat the air trapped in these bubbles under the chrome will cause blistering. So I decided to just get them polished instead.

Unfortunately I can't tell you how much it is going to cost because the place down the street from work blasted them for me for free and the polisher is polishing them as "prototypes" for me free as well.

I can tell you they will take a decent amount of work to polish. The paint really masks the surface finish of the casting. Luckily this place is set up with some really nice equipment and can probably have one done in less than an hour.

Ric
10-19-2005, 07:15 PM
I was thinkg about getting them chrome plate until I recieved them and could see them in person. Since these things are sand cast they are full of porosity (tiny air bubbles). When you polish the aluminum you take the solid layer off the casting and expose this porosity. If you plate it and then expose it to any kind of heat the air trapped in these bubbles under the chrome will cause blistering. So I decided to just get them polished instead.

Unfortunately I can't tell you how much it is going to cost because the place down the street from work blasted them for me for free and the polisher is polishing them as "prototypes" for me free as well.

I can tell you they will take a decent amount of work to polish. The paint really masks the surface finish of the casting. Luckily this place is set up with some really nice equipment and can probably have one done in less than an hour.
will there be any concern with the amount of heat dissipating off the uncoated aluminum? not that the ambient in the motor box might get alot higher (if any.) But more a question of, does the black keep an amount of heat in the manifold by design?
I certainly don't know but my modifications always bite me in the uh .. ankle, so I overthink this stuff.

88 PS190
10-19-2005, 07:22 PM
As far as cleaning the insides what's wrong w/ using a good radiator type acid flush, then using water to neutralize it? Should allow a pretty good clean

bigmac
10-19-2005, 07:44 PM
They are getting polished as we speak. Another good reason to work for Harley, I have access to a ton of metal finishers. Don't worry I will post pictures when they are done and installed. I hope they look as good as the LQ9 manifolds that MC by design sells, see the picture.


If they're not shiney enough after polishing, I suppose you could have them chromed...

edit: ah...never mind...

Andyg
10-19-2005, 11:45 PM
will there be any concern with the amount of heat dissipating off the uncoated aluminum? not that the ambient in the motor box might get alot higher (if any.) But more a question of, does the black keep an amount of heat in the manifold by design?
I certainly don't know but my modifications always bite me in the uh .. ankle, so I overthink this stuff.


I don't think there will be any problems with the heat. On our air cooled Harley engines we have several parts that are polished aluminum and they don't have any problems with heat. In fact one of the hottest parts on the bike (rocker covers) are polished in some cases. With the water jacket manifolds it should control the heat that is generated also.

Engine Nut
10-24-2005, 02:07 PM
I don't think there will be any problems with the heat. On our air cooled Harley engines we have several parts that are polished aluminum and they don't have any problems with heat. In fact one of the hottest parts on the bike (rocker covers) are polished in some cases. With the water jacket manifolds it should control the heat that is generated also.

Indmar actually has the ETX manifolds polished and installs them on an engine that we build for that other boat company that starts with the letter "M". They are used on a 383 Hammerhead engine. They are a little pricey though with a suggested retail price of $1000.00 each.

Engine Nut

Workin' 4 Toys
10-24-2005, 05:01 PM
Why not have them ceramic coated?