PeeWee V4 slow build

[Cogsy]

With still no word on the new castings, but a desire to keep machining something, I decided to have a go at casting my own heads.

I cut up an old alloy intake manifold from a Ford 6 cylinder engine and threw in some bits and pieces I had around the place as well. Once it was melted I also added around 4% copper to the melt, based on some experiments bmac2 did recently, to improve the machinability.

I measured the castings I have and there was plenty of meat in them to use them as patterns directly so that's what I did. Here's the result straight out of the sand.



Here's a shot of them with an original casting for comparison. You can see my surface finish is nowhere near as good.



I figured I could fix the finish problem later, so I attempted to machine them. They cut very nicely, not gummy at all, but they were full of tiny little gas holes and were unusable. I was annoyed so I didn't get any photos of the porosity.

So I have decided to abandon my casting attempts as everything I cast lately has been porous (I think I might be making the melt too hot), plus my surface finish isn't up to scratch. Instead, I grabbed a couple of scrap Ali bars from my stockpile and I will attempt to machine the heads from solid. I don't have a bar big enough to make the two heads together so I'll have to make them one at a time and hope they come out the same.

Here's the first piece of scrap straight out of the pile.



And here it is all squared up and ready to go.



Next update we should know if this plan is going to work.

 

[michael-au]

Nice try bad luck it didn't work out for you, bummer

The silver bullet head I made from bar stock its not that hard to do, hope it goes well for you

Michael

 

[gus]

Hi Cogsy,

Molten Aluminum absorbs hydrogen and when poured, the absorbed hydrogen is released and porosity or very small pockets appear. Before pouring, the melt must be degassed and if better surface finish is desired,use refining chemical. Have done my fair share casting auto condensate traps for compressed air. Some where in the YouTube a gentleman used household chemicals such baking soda and sodium chloride. Please surf YouTube.Good Luck. After 20 years,I cannot recall the trade names of degassing cakes and refining additive.

 

[Cogsy]

Thanks Gus. I have seen people using table salt and others using lite salt (Sodium Chloride and potassium Chloride I think) as degassing agents. I tried the lite salt for this pour - I think the theory is to change the gaseous hydrogen into Hydrochloric Acid - but it failed. I really think my crucible is the wrong design and the metal can't melt fast enough, so the metal that melt first gets way too hot and absorbs far too much hydrogen. This casting stuff sure is tricky - I got better results melting aluminium in a stainless steel bowl over a fire made from BBQ briquettes! I think I'll improve as I get more experience.

 

[gus]

Degassing Molten Aluminum.

Here's how I did it years back with 50 kg aluminum charge.
The degassing tablet must pushed all the way down to bottom of crucuble so that gas release with garbage floats up.Degassing Chemical thrown on the surface and stirred,will not do a good degassing job.I did this and got poor results. Called the Foundry Supplier for expert advice. A DIY thermocouple Pyrometer would be needed to check melt temperature. With scrap pistons, pouring temperature ideally is 715 C as advised but I got best results at 680/690C.
The DIY 50kg capacity gas fired furnace too 3 hours to melt. This is a slow melt.
Refining chemical can be sprinkle on top and stirred . Resulting dross skimmed off.

Will DIY Pyrometer with thermocouple wire and ''millimeter ammeter. Will find a way to calibrate. Thermocouple wire comes in different grades and class. I lost touch could be type J K L ?? Will experiment with multimeter .

All in, it took me 2 months to get the first piece of perfect casting. Bought and read a big pile of reference books and even went to Shanghai Compressor Plant to learn from the masters. ( Went there for a meeting)Over a sumptous dinner and lots of millet wine, lots of technical advice came forth. Phone numbers if I need to check with them. All in made 300 pcs of Auto Condensate Traps to assemble 300---------7.5hp Air Compressors.

 

[Cogsy]

I've made some progress with the heads. First up I measured the rocker post as best as I could, then scribbled half a page of math to work out the angle of the post and the height of the block I needed for the sine bar. I had to rest the sine bar on parallels as it's 5 inches long and the vise is only 4 inches wide.



Then I machined a groove with one of my new, cheap end mills.



And rounded the top of the rocker post with a carbide tipped wood router bit.



It was then a simple matter of machining the rest of the top to the same level and machining the side and bottom to required thickness.



Then a couple of cosmetic grooves with a 3mm ball nose end mill finished it off. I then repeated the whole process a second time and now I have 2 head blanks all ready for many holes to be drilled.



Next time - many holes will be drilled!

 

[michael-au]

Nice work on the blanks Cogsy 😀

 

[Cogsy]

I got some more done to the heads, although I currently have some meds keeping me out of the shop most of the time.

First I used a centre cutting 1/2" endmill to start the combustion chamber, then enlarged it to 0.628" with the boring head. This was interesting as it showed me just how 'domed' a plunge cut with an endmill actually is. You can tell by the small pip left in the centre after flattening the rest with the boring head.



I then spotted and drilled the valve cage holes and drilled a blind hole for the first part of the water passages.



Then the rocker post was milled away where the rockers will go. I toyed with the idea of removing all the remaining post except for what is actually need to support the rocker shaft (3 x 0.152" posts) but decided it would look nicer as designed. I may try out the other look on one of my scrap head castings just to see. I can always change it later.



With the head bolt holes drilled and counterbored the heads are starting to take shape. I won't be drilling any of the ports until I have the valve cages made and installed, which will be my next step.

 

[michael-au]

Nice job Cogsy, the heads look really good 👍

 

[gus]

The heads look good.

 

[Davewild]

They look great Cogsy, another part that I'm fearful of, they are just so small, I been home a week and am nearly caught up with other work, shop time very soon.

Dave

 

[e.picler]

Hi Cogsy!
Your work is progressing very well.
Very good machining work. I'm following with close interest as the PeeWee will be my next project.

Congratulations.

Edi

 

[Cogsy]

Thanks for the kind words guys.

Got a little more done and made the valve cages. Made 2 extra for spares (plus one not in the photo that I forgot to ream). This is the first time I've ever had to 'mass produce' a part and I thought it would get a little boring, but it was fun to get into a routine and see a small pile of almost identical parts build up. It was also surprisingly satisfying to see how close each part turned out in relation to the plan and each other. Every one of these parts are between + 0.01mm / - 0.00mm of the plan in diameter, which is good for me.

The packaging in the background is for my 3/32" machine reamer - rather an unfortunate brand name they chose



Next up will be the retainers and the valves themselves, then I'll fit the guides and drill the ports.

 

[spurgear]

http://www.floridaame.org/GalleryPages/g1m0210.htm

AS per dirk
The castings for the Peewee engine were proven by Bob Shores himself. This was the last engine he built in the year and a half prior to his passing. His engine ran, and is now placed away for safe keeping by his family.


That engine was never ran, & donated to;


https://www.flickr.com/photos/157942...57649482852173



craftsmanshipmuseum.com/KnappCol.htm

 

[Cogsy]

I can't believe it's been over 3 years since I posted in this thread - time flies when you're too busy to have fun it seems. I have made some progress with the engine in all this time, though not as much as I would like (it's not running yet), so I thought it was time to post some updates.

As part of my 'getting back into machining' strategy, I built Brian Rupnow's vertical single engine as documented in this thread [LINK], and I made a change to the way I do things while I was building it. Previously, I tended to put parts aside 'for later' when I got to a tricky procedure or where I could destroy the part with a mistake. This leads to a large pile of half finished parts. So as part of my new philosophy - "build it til it's done" - I started back on the Peewee with the idea of drilling the intake and exhaust ports to complete the heads.

All set up with a sine bar to get the correct angle, and using my new cheapy DRO it was a very simple procedure - I should never have put it off in the first place.



And a shot of the heads with the rocker arms temporarily installed just to see what they look like after all this time.



Next instalment will be the much-dreaded machining of the new block casting. I spent years worrying about this point...

 

[Cogsy]

After reading everything I could to prepare myself, I finally sucked up the courage to make an attempt on machining the block casting. This was my first real machining on a purchased casting and I knew a major mistake here would probably mean the end of this engine for me.

To start with, I found the centre of each cylinder bank and drew a line down, perpendicular to each bank. I then drew a line through the centre of the block, down through the intersection point. Finally, I marked a line 90 degrees to the centre line, again through the intersection point. This intersection point is the centre of the crankshaft, and the horizontal line will be the bottom of the cylinder block.



Now that the marking out was finished for this point, I completely disregarded it, flipped the block over and took a quick cut over the bottom just to have an even surface to work with.



Flipping the block back over, I shimmed one side until the centreline I marked earlier was as close to vertical as I could make it and then took a very slight skim cut over the very top edges of the cylinder banks. So slight in fact, that it doesn't really show in this picture, but trust me, it is there.



The skim cut over the top of the block became a level datum point so I could again flip it over and cut the bottom until it was level and parallel to the top. From there I indicated the block to as square as I could in the Y plane. The picture is a bit of a mock-up and shows the indicator running along the front of the block but in reality (because that surface is later machined square and is irrelevant as-cast) I actually indicated both sides of the block and attempted to get them as even as possible. The casting was quite close to being parallel on each side and I had no real trouble setting it reasonably square along the plane. I also want to mention that my camera seems to amplify the amount of surface rust on my clamping set - it looks like I store them in a bucket of salt water but in the flesh they don't look anywhere near as rusty. This picture was taken during the damp ofwinter and I have cleaned and oiled them up since it was taken.



Now I had the block square in the Y direction I took a shallow pass across the end so I had a square surface in the X direction to indicate from in the next steps. You can see from the angle of the cut how out of square the end of the casting is. This is no problem at all as both ends of the casting are completely machined flat and square to the sides.

 

[Herbiev]

Looking good so far Al

 

[Cogsy]

Indicating from the previous cut I made to the rear, I could square the back of the block with a nice finish, but stayed clear of the final dimension for now. I probably didn't need to do this step and could have just used the earlier cut but it only wasted a little time and allowed me to sweep the entire rear face and check for square.





From there, I was able to set the block entirely square with the mill by angling the vice as I indicated the back, which allowed me to mill the bottom to final dimension and set up for the drilling and tapping of the oil pan (sump we Aussies call it) for 2-56 bolts and the centre main bearing housing for 4-40.



At the same time I also pocketed the bottom of the block and trimmed the installed centre bearing housing and centre web to width.



Finishing up with this setup, I machined a 1/2" deep portion of both ends of the block to 0.005" over final dimension to use as reference points for the final operations on the ends.

 

[Cogsy]

I just noticed the water bottle in the last picture and thought I'd better explain. Despite what it looks like, I'm not (yet) bottling my urine in case of emergency but instead it's WD40 in an old water bottle with a couple of holes punched in the lid. I got sick of buying horrendously expensive aerosol cans and bought 4 litres for about the price of 5 cans. At the rate I'm using it (which is much easier to control than a spray can) I estimate it will last me about 8 years. I tried using pump spray bottles to dispense it but not only does it spray it far too heavily than I need, the WD40 seems to 'eat' the seals in the things (at least the cheap ones) and they fail quickly. I still have a spray can around somewhere for those times I need the pressure (like a stuck padlock or something) but I never need it for engine building.

 

[pickleford75]

Great to see you back at it.... I'm doing the same thing on my Hodgson radial project I started about 10 years ago :hDe: great work on your peewee v4 looking forward to seeing it completed.