![]() |
If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below. |
|
|
Thread Tools | Display Modes |
#51
|
|||
|
|||
![]()
On Jan 12, 9:53*pm, "Maxwell" #$$9#@%%%.^^^ wrote:
wrote in message Casting your own VW head can be done, but it's not nearly as easy as you would like to suggest. If you have examples to the contrary, as I said before, I'm not the only one on this news group that would love to see them. As I said it it depends on your definition of easy. Sounds to me like your one of those builders that is best sticking to a quick build RV with a FWF package since everything has been already worked out. Independent and creative thought apparently is a challenge for you. If an RV is in fact the path you have chosen my condolences go out to Mr. VanGrusvens customer service staff. ======================= Leon McAtee |
#52
|
|||
|
|||
![]()
On Jan 8, 12:34*pm, " wrote:
What IS needed are aluminum head-castings having twice as much fin- area as what's presently available. *This won't fit on a bug or bus so there is no start-up money. *Coming up with the cores should have been done by the EAA -- about fifty years ago. *The fact it wasn't *is good evidence that it won't. As I lay there taking my afternoon nap my mind wandered over this subject and the thought came to me that we, at least I, have strayed from the essence of this discussion and lost site of what we really need to accomplish. Our goal. A real, hold in your hands, VW head with adequate cooling capacity for aircraft power settings.. It has become quite clear that other than maybe 3 of us reading this thread that the casting of things of this nature, "on the cheep" to steal a phrase, is about as likely as being able to buy a Moller at the local auto mart in the next decade. Even those that can grasp the concepts needed to cast and machine some VW heads still need to build or buy a whole set of new toy ..., er a ... tools. This doesn't get any one closer to flying behind a VW conversion which is kind of the point of this whole thought exercise isn't it? The path being pursued might result in good cooling heads but only for those of us that can make them as I doubt even once proven that anybody would take on the production. There just wouldn't be enough market. Could be wrong but I think we need to presume that these things will never be kitted, only plans made items. Which means the average home builder needs realistic ways to make them with out adding another few hundred hours and dollars to the project just for heads. 'course there might be those that would enjoy learning casting as much as building airplanes................. My slumbering mind wandered to the solution of another of my flying problems - the making of some props - and a comment my brother made about using the same methods used to duplicate props to cut the fins on our cast heads. Not a bad idea as I also remembered seeing a tracing lathe operating at a science museum many years ago in Toronto where I was attending an ultralight convention, way back in the late 70's. It was just finishing up duplicating a coke bottle and I remember that it did a good enough job that the painted lettering was duplicated in the steel replica as well. So what would be so hard about adapting a propeller duplicating pantograph to the task of finish machining a rough casting? http://culverprops.com/culverintro.php Video here. Substitute a Dremel/die grinder for the saw blade and add an adjustable tracing wheel or point. I'm thinking really basic casting here. Something with just the ports and combustion chamber close to finished, with lumps else where as needed. These castings would be simple enough that any back yard caster that can make a core for the ports could ram them up using a plaster cast pattern passed along from another builder. Those with the desire could cast up several castings and sell for other experimenters to finish at a very reasonable cost. Since we are talking about using a pantograph the pattern need not be 1:1 scale. In fact something on the order of 3:1 lets the builder work from full size drawings in plywood for fins and Bondo for glue and filler when constructing the pattern. Maybe with luck some homebuilders get together, use the divide and conquer method, one making the castings and the second making the milling machine? But we now need a third homebuilder. One that can machine and install the guides and valve seats and tap the various holes for studs. This too is within the reach of a true home builder. The tools needed are not that hard to make and the whole operation can be done by hand if needed. I know some will scoff, but at one time just such tools were sold by Assenmacher and others for the VW shops. The tough part was getting the old seats out. They sold tools for that as well. A simple drill press make things quicker. The required tools are quite simple and anyone with access to a lathe and GOOD measuring tools can make and use them. At this point any machine shop or VW mechanic can hone/ream the guides, cut the seats with a Neway cutter (please use no stones here), bore the head for the cylinder face and send you back to bolt them on your short block. Now with any luck I'll be over this crud in a few days and no longer need my afternoon nap. Will be nice to get some real work done again ========================== Leon McAtee |
#53
|
|||
|
|||
![]()
On Jan 13, 3:38*pm, "
wrote: So what would be so hard about adapting a propeller duplicating pantograph to the task of finish machining a rough casting? ----------------------------------------------------------------------------------------------------- Neat play on words :-) The basic problem is one of rigidity. The initial cut must also be your finished cut, with regard to width. Unfortunately, air heats as it expands. If the walls of the fin are perpendicular then it's ability to couple heat to the air becomes a function of the width of the channel between the perpendicular 'walls' of your fins, as well as the pressure of the air flowing in that perpendicularly walled canyon. As it is, with the amount of draft found in the typical casting, you need one hell of a lot of air-pressure for the thing to work properly. In other words, if all you can do is make a vertically sided cut, then the EFFECTIVE depth of the thing becomes a function of its width. Since your width is also a function of the rigidity of your tooling, with a width of an eighth of an inch or there abouts, your effective depth is reduced to about half an inch. To go any deeper, the walls would have to taper, or be stepped, or whatever. This is based on the thermal transfer equations found in Taylor, Liston and others. ---------------------------------------------------------------------------------------- ... The tough part was getting the old seats out. --------------------------------------------------------------------------------------- Joke, right? To remove swaged-in seats from aluminum heads you fire up your buzz- box, fill your coffee cup with ice water, scratch an arc on one side of the seat then weave a bead about 5/8" long x 3 passes 'deep,' transfer your arc to the OPPOSITE side of the seat and do the same... then dash your cup of iced water on the thing. Amidst the frying and the hissing and the steam getting under your helmet you'll hear a musical little PING! and your valve seat will be cocked up at an angle, easily grasped with a pair of vise-grips welded to a barrel- nut, which you've screwed to the business-end of your slide-hammer. Give it a couple of slaps and there's your valve seat. -R.S.Hoover |
#54
|
|||
|
|||
![]()
wrote in message
... On Jan 8, 12:34 pm, " wrote: What IS needed are aluminum head-castings having twice as much fin- area as what's presently available. This won't fit on a bug or bus so there is no start-up money. Coming up with the cores should have been done by the EAA -- about fifty years ago. The fact it wasn't is good evidence that it won't. As I lay there taking my afternoon nap my mind wandered over this subject and the thought came to me that we, at least I, have strayed from the essence of this discussion and lost site of what we really need to accomplish. Our goal. A real, hold in your hands, VW head with adequate cooling capacity for aircraft power settings.. It has become quite clear that other than maybe 3 of us reading this thread that the casting of things of this nature, "on the cheep" to steal a phrase, is about as likely as being able to buy a Moller at the local auto mart in the next decade. Even those that can grasp the concepts needed to cast and machine some VW heads still need to build or buy a whole set of new toy ..., er a ... tools. This doesn't get any one closer to flying behind a VW conversion which is kind of the point of this whole thought exercise isn't it? -----------much more snipped, new post begins----------- At the obvious cost of proving myself a heretic regarding VWs.... We could go back into the old debate about whether a nearly stock VW engine could be a reliable 50 to 60hp powerplant with the right sort of pressure cooling system. With all due respect to Bob, a/k/a Veeduber, I am still convinced that it can; but he has also convinced me that it makes little or no sense and will result in marginal performance. The reality is that, as the displacement approaches 2.2 litres, the result looks more and more like an over weight and under strength Jabiru. Worse yet, the price difference narrows dramatically. And, if you place much value on your time, the VW conversion becomes the more costly. I admit that I still like the VW. But I also have to admit that, with the Rotax and Jabiru as competition, it really belongs on a sngle seater. Peter |
#55
|
|||
|
|||
![]()
..
On Jan 8, 12:34*pm, " wrote: What IS needed are aluminum head-castings having twice as much fin- area as what's presently available. ------------------------------------------------------------------ We need a CASTING because we need the DRAFT that goes with it. Come up with a set of fins that leaves a clean impression in our casting media and we'll automatically get a set of fins that does a dandy job of coupling heat to air being forced down through, over, passed an' whatever THROUGH those fins. Now all we gotta do is come up with ENOUGH of those fins... as determined by their area... to deal with the anticipated amount of HEAT and we're on the road to Rio. Or where-ever. -R.S.Hoover |
#56
|
|||
|
|||
![]()
....an' finally...
I gotta memory chip in my hand here that sez 'T2,' meaning it's got mostly Teenie Two drawings on it. It is a two gigabyte chip, which means it can't be ALL T2 stuff. Sure enough, one of the folders sez 'Engine.' Pull that up and there's about a dozen sub-files, one of which is 'HEADS.' Pull THAT up and you got fifty drawings of VW cylinder heads, a lot of which is bumpf... three nearly identical drawings of the same thing representing sequential SAVE's so as not to lose anything as I work on the drawing(s) (...which is a pretty boring way to pass the day.... but a royal ****er to spend a whole day doing a drawing only to LOSE the sonofabitch because I hit the wrong button or whatever, hence lotsa copies of... whatever). So why mention it? Because others may find some of the drawings of interest. So provide me with a VALID address and I'll sendm' to you, gratis. -R.S.Hoover |
#57
|
|||
|
|||
![]()
On Jan 13, 10:02*pm, " wrote:
The basic problem is one of rigidity. Agreed, thought about that too. Vibration is a significant concearn *The initial cut must also be your finished cut, with regard to width. * Never actually done this, of course, but from my limited machining experience I'm not too sure that it's not a task that can't be done. I was thinking something like a 4" grinder mounted to the tool post with a carbide saw blade. once the fins got thin/deep enough wrap some rubber tube or o-ring material in the fins adjacent to the cut. Joke, right? To remove swaged-in seats from aluminum heads you fire up your buzz- box, Nope, no joke. Real life is a joke at times :-( The shop I started at had no form of electric welder! The pull'n was done/attempted with one of those slide hammer tools like a large oil piston remover. When I moved on to my own shop I couldn't justify the cost of the tooling needed for valve seat replacement since new heads were so cheep .... Brazil owed us lots of money back then :-) |
#58
|
|||
|
|||
![]()
On Jan 14, 6:39*am, "
wrote: On Jan 13, 10:02*pm, " wrote: The basic problem is one of rigidity. Agreed, thought about that too. *Vibration is a significant concearn *The initial cut must also be your finished cut, with regard to width. * Never actually done this, of course, but from my limited machining experience I'm not too sure that it's not a task that can't be done. I was thinking something like a 4" grinder mounted to the tool post with a carbide saw blade. *once the fins got thin/deep enough wrap some rubber tube or o-ring material in the fins adjacent to the cut. Joke, right? To remove swaged-in seats from aluminum heads you fire up your buzz- box, Nope, no joke. *Real life is a joke at times :-( * The shop I started at had no form of electric welder! *The pull'n was done/attempted with one of those slide hammer tools like a large oil piston remover. *When I moved on to my own shop I couldn't justify the cost of the tooling needed for valve seat replacement since new heads were so cheep .... Brazil owed us lots of money back then :-) How about welding some extra fin material to an existing head? Ed |
#59
|
|||
|
|||
![]()
On Jan 13, 10:06*pm, "Peter Dohm" wrote:
At the obvious cost of proving myself a heretic regarding VWs.... We could go back into the old debate about whether a nearly stock VW engine could be a reliable 50 to 60hp powerplant with the right sort of pressure cooling system. *With all due respect to Bob, a/k/a Veeduber, I am still convinced that it can I have to side with VeeDuber here. I've got the benefit of experience he probably doesn't. All my ground bound VW's operated at a density altitude of 7000 ft - on average. When it comes too cooling by air it takes air to do the cooling. We have less of it here than folks in his area do. A VW bus with a stock 1600cc was marginal and if modified to give it's rated hp at our density altitude cooling became enemy number one. My motors lasted longer than the guys across town in large part because I was PICKY about the cooling, going to such extremes as siliconeing the gap between the fan housing and the cylinder covers to keep the cooling air inside. I bought spark plug hole seals by the hundreds............. The later model bus with the 1700/2000 would even show signs of heat stress in stock form if the seal between the engine and body was missing (flat rate shop across town never put them back). Point is, cooling these things IS a problem. As much as I like the old air-cooled VW's they have real problems and limitations. The most reliable VW bus motor was one I ripped out of a Rabbit and stuffed into the hole. 100K miles later with no heating problems, more hill climbing power and fuel efficiency made the cost of the swaps worth every penny. Rabbit radiator fits under the deck sideways and the customers had heat too..... no more scraping the ice off the inside of the windows as you drove. BTW did you know that a stripped 8 valve VW water cooled motor weighs LESS than an air cooled TP IV? Rather than keep flogging the air- cooled why not try a belt PSRU on one of these canted over at about 45 degrees? Simple as an air-cooled 1600 based VW? No. More reliable? Probably. ============================== Leon McAtee |
#60
|
|||
|
|||
![]() wrote in message ... On Jan 13, 10:06 pm, "Peter Dohm" wrote: At the obvious cost of proving myself a heretic regarding VWs.... We could go back into the old debate about whether a nearly stock VW engine could be a reliable 50 to 60hp powerplant with the right sort of pressure cooling system. With all due respect to Bob, a/k/a Veeduber, I am still convinced that it can I have to side with VeeDuber here. I've got the benefit of experience he probably doesn't. All my ground bound VW's operated at a density altitude of 7000 ft - on average. When it comes too cooling by air it takes air to do the cooling. We have less of it here than folks in his area do. A VW bus with a stock 1600cc was marginal and if modified to give it's rated hp at our density altitude cooling became enemy number one. My motors lasted longer than the guys across town in large part because I was PICKY about the cooling, going to such extremes as siliconeing the gap between the fan housing and the cylinder covers to keep the cooling air inside. I bought spark plug hole seals by the hundreds............. The later model bus with the 1700/2000 would even show signs of heat stress in stock form if the seal between the engine and body was missing (flat rate shop across town never put them back). Point is, cooling these things IS a problem. As much as I like the old air-cooled VW's they have real problems and limitations. The most reliable VW bus motor was one I ripped out of a Rabbit and stuffed into the hole. 100K miles later with no heating problems, more hill climbing power and fuel efficiency made the cost of the swaps worth every penny. Rabbit radiator fits under the deck sideways and the customers had heat too..... no more scraping the ice off the inside of the windows as you drove. BTW did you know that a stripped 8 valve VW water cooled motor weighs LESS than an air cooled TP IV? Rather than keep flogging the air- cooled why not try a belt PSRU on one of these canted over at about 45 degrees? Simple as an air-cooled 1600 based VW? No. More reliable? Probably. ============================== Leon McAtee Interesting. I did not know that the 8 valve VW was lighter than the Type IV, especially since I believed that it probably had an iron block. I have never been a fan of reduction drives; but there were a lot of conversions based upon inline fours with belt reduction drives during that time period. AFAIK, several were quite successfull. And a lot of the newer engines are lighter for their power and might be easier to cool. Peter |
Thread Tools | |
Display Modes | |
|
|
![]() |
||||
Thread | Thread Starter | Forum | Replies | Last Post |
Yeah! I'm back online..No thanks to Charley. | CFLav8r | Piloting | 10 | August 24th 04 04:14 AM |
Yeah, I got that one... | Wade Meyers | Military Aviation | 0 | July 1st 03 04:45 AM |