Slant Six Forum :: Hrrrrooo? (Aluminum SL6 Head)

I went and looked at the auction again. One thing that bothers me about this is that the seller has zero feedback as a seller. All his feedback is as a buyer. Sure would hate for it to be a scam.

Something else I noticed. He said; "This is one of just a handful of aluminum Slant Six heads...Don't miss out !" Does that mean he has more than one?.....Hmmmmm.

Roger

Something else I noticed. He said; "This is one of just a handful of aluminum Slant Six heads...Don't miss out !" Does that mean he has more than one?.....Hmmmmm.

Roger

as for absolute positioning (as opposed to incremental), you could use the holes for the head bolts. I think that would be the most accurate starting point on a cylinder head.

Quote:

as for absolute positioning (as opposed to incremental), you could use the holes for the head bolts. I think that would be the most accurate starting point on a cylinder head.

I would think even those are not accurate enough. The dowl pin holes are the only logical points on the head to use since they are what locate the head not head bolts.

I don't understand why anyone would want to measure this prototype aluminum head unless he intends to make an exact copy of it. If we were to make an improved aluminum (or cast iron) head, the key measurements are on any slant six block and valve cover. A foundry (especially one with CAD 3D modelling capability) that can design and build cylinder heads should be able to make a complete design based on specifications and sketches.

Author:	DynoDave [ Thu Nov 30, 2006 2:45 am ]
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Quote: I went and looked at the auction again. One thing that bothers me about this is that the seller has zero feedback as a seller. All his feedback is as a buyer. Sure would hate for it to be a scam. Something else I noticed. He said; "This is one of just a handful of aluminum Slant Six heads...Don't miss out !" Does that mean he has more than one?.....Hmmmmm. Roger Well, 99% of my ebay feedback (in the hundreds) is all purchases. I wouldn't worry too much about that, as long as he's been there a while, and has positive feedback. I wondered if there was more than one myself. As I mentioned, if having a set of eyes/hands on the part, or delivering the cash in person and picking up the part in person would help, I'll be happy to do that.

Author:	sick6 [ Thu Nov 30, 2006 5:02 am ]
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CMM-ing: true, a cmm can only read where it can touch (basic feeler is 2 inches long, I used a 5 incher, I can't think you'd need a longer one than that). that is why you touch more than the minimum amount of points to have enough data to do the math to find out where its going. true, you need 3 points to a plane, that is minimum basic math. for any kind of slope you would use many more. to figure the shape of an ellipse about an inch long I used 14 points, so you can see more detail. it is a simple matter then to have the program fill in the blanks. I have done this with multiple lockheed and boeing parts (I worked in a particular machine shop that made things for them). we also had flow benches right next door....... anyway, I just can't think of anything better to use. the quality of the information is going to vary greatly by the quality of what you are using for a CMM (especially if you are comparing a 3 axis to a 5 axis).

Author:	slantzilla [ Thu Nov 30, 2006 6:19 am ]
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Quote: Something else I noticed. He said; "This is one of just a handful of aluminum Slant Six heads...Don't miss out !" Does that mean he has more than one?.....Hmmmmm. Roger Yes. Steve Magnate of Hot Rod magazine has 2. Doug has been very involved with them I believe.

Author:	slantvaliant [ Thu Nov 30, 2006 6:52 am ]
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I think you'll need to use several tools to accurately record what is there. Don't get me wrong. CMM'ing would be great! A good accurate model of this head would be a great thing to have. When I mentioned the three point, two point, one point, I wasn't talking about the shape of any feature, I was talking about the datum points - reference surfaces already on the piece, used for fixturing. Fixtures are built to position the piece with regard to those points. Defining the surfaces and features takes lots of points, as you said. The more, the better. But you have to have a reference point to measure from to get the relative positions. I'm not sure that a CMM would be the best way to get into the water passages to look at the internal walls. I'll take a look at my spare heads. Even if it can reach, programming it to get in there without crashing would be a bear. I guess you could go manual - not fun. I worked in a foundry doing investment casting of vanes and blades for assorted turbine engines. Military and commercial jet engines, and industrial turbines. Anything spinning that fast and having that kind of flow has to have everything just right. The CMM rooms were busy places checking everything from the ceramic cores, to the wax patterns, and of course the finished pieces.

Author:	sick6 [ Thu Nov 30, 2006 10:39 am ]
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as for absolute positioning (as opposed to incremental), you could use the holes for the head bolts. I think that would be the most accurate starting point on a cylinder head. I wouldn't use the edge of most anything if it was a cast piece. might run into some flash. so what is the plan now among the bidders? someone from here still going to try to buy it for reference or are you thinking of following doc's lead and starting from scratch? please don't let this fade into oblivion again!

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Author:	Tom Drake [ Thu Nov 30, 2006 11:41 am ]
Post subject:
Quote: as for absolute positioning (as opposed to incremental), you could use the holes for the head bolts. I think that would be the most accurate starting point on a cylinder head. I would think even those are not accurate enough. The dowl pin holes are the only logical points on the head to use since they are what locate the head not head bolts.

Author:	FrankRaso [ Thu Nov 30, 2006 11:43 am ]
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I don't understand why anyone would want to measure this prototype aluminum head unless he intends to make an exact copy of it. If we were to make an improved aluminum (or cast iron) head, the key measurements are on any slant six block and valve cover. A foundry (especially one with CAD 3D modelling capability) that can design and build cylinder heads should be able to make a complete design based on specifications and sketches. If there is interest in manufacturing a new cylinder head, I think Doug should form a corporation and seek investors from the slant six community. With some preliminary cost estimates from a suitable foundry, the new corporation could take orders for an initial production run. Reproducing engine components for a limited market might be a frustrating exercise. Since Doug already undertook something like this with his reproduction hyper-pak intake manifold and Dutra-Duals exhaust manifold, maybe he could share his experiences with us.

Author:	DionR [ Thu Nov 30, 2006 12:18 pm ]
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So what happened? Ebay link says bidding has ended, but that is early, isn't it? Did someone buy it?

Author:	DionR [ Thu Nov 30, 2006 12:21 pm ]
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"The seller ended this listing early because of an error in the minimum bid or reserve amount." Is the seller playing games? Wonder what the minimum bid is now (it is re-listed).

Author:	Tom Drake [ Thu Nov 30, 2006 12:46 pm ]
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MUCH MUCH HIGHER! Too many emails and he probably saw this thread.

Author:	Pierre [ Thu Nov 30, 2006 1:03 pm ]
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The $1500 bid was retracted as well last night before the first auciton was ended.

Author:	sick6 [ Thu Nov 30, 2006 1:31 pm ]
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Quote: Quote: as for absolute positioning (as opposed to incremental), you could use the holes for the head bolts. I think that would be the most accurate starting point on a cylinder head. I would think even those are not accurate enough. The dowl pin holes are the only logical points on the head to use since they are what locate the head not head bolts. I agree, thats what I meant, but I did not word it correctly. Quote: I don't understand why anyone would want to measure this prototype aluminum head unless he intends to make an exact copy of it. If we were to make an improved aluminum (or cast iron) head, the key measurements are on any slant six block and valve cover. A foundry (especially one with CAD 3D modelling capability) that can design and build cylinder heads should be able to make a complete design based on specifications and sketches. a sketch is not going to cut it. far too much trig involved in a port to make that happen. machinist hate sketches. no one can make a decent one anymore anyway. the reason for doing it would be (for me anyway) would be just to have a piece of history. others might want it for an exact copy. since I already have a performance head it doesn't effect me anyway.

Author:	oldgoat83 [ Thu Nov 30, 2006 1:40 pm ]
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That leaves us with one choice, unless it's re-listed. The DD Design would be an obvious choice as it is probably the most complete design available. This would also prevent the design by committee that would leave everyone wanting. Doc, how much work would be left in completing your design? What type of licensing would you want in supplying this design for production? What volume of production would be needed? (How many could be sold?) Cost associated with production? Lots of questions to be asked.

Author:	Joshie225 [ Thu Nov 30, 2006 2:14 pm ]
Post subject:	Very interesting...
I was the one that put in the $1500 bid and retracted it this morning. I had bid $1000 previously and reentered that bid. $1500 was a little too rich for me at the moment. The head has been relisted with an unknown reserve. I put in a $1000 bid and it did not meet reserve. Who knows, the reserve could still be $1500, but it's more than $1000.

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Author:	SlantSixDan [ Thu Nov 30, 2006 2:20 pm ]
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Josh, can I ask a question again? I don't mean to be snarky, but...why are you doing this? Seems to me that placing and retracting bids to try and find the reserve can only do one thing, and that is to piss off the seller. I don't agree with undisclosed reserves, but the seller has a right to an undisclosed reserve if that is what he wants, and I am betting his reserve is higher now than it was before expressly out of displeasure at having been "jerked around" by bids placed in an effort to do an end run around his undisclosed reserve. What's the point, man? :shrug: