PeeWee V4 slow build

[Blogwitch]

Al,

If you are using WD40 for aluminium most of the time, then paraffin (kerosene) is a lot cheaper and works just as well, in fact better sometimes than WD..

John

 

[Cogsy]

Thanks John. I'll grab a bottle next time I'm at the hardware (it's no longer available at petrol stations round here as far as I know) and give it a whirl. My wife doesn't appreciate the smell of WD40 on my clothes when I come in from the shed - in fact she claims I "stink" - so the kerosene might solve that issue as well.

 

[Cogsy]

At this point I could bolt the sump on and use the previously machined strip to indicate the front of the block nice and square. The overhang of the front of the sump was a convenient way to pick up the exact bottom surface of the block as well.



Once I machined the front face down to final dimension, the centre of the block along the bottom (if that makes sense) was then picked up so the crank tunnel could be drilled, bored and reamed to 1/2" and the cam tunnel was similarly drilled and reamed in reference to the crank.







Next step was the boring of the gear recesses. This engine uses an idler gear in the geartrain so the camshaft rotates in the same direction as the crank does. I assume it was designed this way to give a nice vertical separation between the crank and cam while also keeping the individual gear sizes relatively small.



The timing cover mounting and associated accessory holes were drilled and tapped at the same time while I still had the crankshaft centre point as a reference.



Finally, the block was flipped over to the back face and again indicated off the previously machined strip. The whole face was then taken down to final dimension and (although they're not in the picture) the 2 rear coolant holes were drilled and tapped. Apart from 2 bell housing adapter holes which have their placement determined later in the build, the front and rear block faces are now complete. So far, so good.

 

[deeferdog]

Looking good AL, I like your work. Cheers, Peter

 

[Cogsy]

Moving on to the cylinder 'bores' (though they will have liners installed so they're probably officially called something else), which was another job I was afraid of messing up.

I started by aligning the scribe marks on the front of the block square to the mill and marked each side of the 1/2" drill rod, which is standing in for the crankshaft at the moment. I can't remember why I marked each side of the crank but I'm sure I thought it was important at the time.



After drilling and tapping the head mounting holes, the bores were started with several drill steps up to 1/2" (which is the biggest drill I have that's still smaller than my needed finished dimension).



The bores were brought to size with a boring bar and a counterbore cut into the top for the liners to locate in. In this picture you can see the coolant passage in the back of the rear cylinder. This passage connects with the front when the coolant chambers are cut.



Before I changed setup and lost square with the bore, I drilled and reamed the lifter bush holes and spotted with an endmill to flatten the top of each hole.



Back to the cylinder bores, I used a 5/8" diameter woodruff cutter to machine the coolant chambers. The cutter is small enough to insert into the bore then I fed in the required depth. From there I simply moved the table in a square pattern and the chamber was done. You can see how the cut has now connected with the coolant hole from the rear cylinder and although you can't tell from this picture, it connects with the vertical coolant outflow passage towards the front of the block as well (the hole between the front 2 head mount holes).



Once all the operations were repeated for the second bank, I machined the boss for the distributor but neglected to take any photos it seems. As the block is almost completely machined at this point, I figured it was a good idea to weigh the block for a comparison against it's original state. You'll have to convert to your preferred units if you desire, but you can see I machined away close to half of it. These castings machined reasonably well and although they have a tiny bit of porosity they will work just fine. The few surface pinholes that show up on camera are mostly invisible in the flesh and aren't big enough to cause any difficulty.



And finally I just had to bolt the heads on for a quick mock up to give me an idea of size. As it turned out, the block was tricky to machine at times and I'm glad to have it behind me, but I'm reasonably happy with how it turned out and I did enjoy the work.

 

[michael-au]

Looking good, you will be finished in no time, great work

 

[bouch]

At this point I could bolt the sump on and use the previously machined strip to indicate the front of the block nice and square. The overhang of the front of the sump was a convenient way to pick up the exact bottom surface of the block as well.

View attachment 92852

8>< snip ><8

Finally, the block was flipped over to the back face and again indicated off the previously machined strip. The whole face was then taken down to final dimension and (although they're not in the picture) the 2 rear coolant holes were drilled and tapped. Apart from 2 bell housing adapter holes which have their placement determined later in the build, the front and rear block faces are now complete. So far, so good.

View attachment 92858

Quite a bit of extra metal to remove off that casting...

I like the fixture you use on the sides of the block to help clamp it in the vise. I'll have to remember that for future use...

 

[Cogsy]

With the block now complete I thought I'd give the liners a go next. So I dug up a piece of 1" 12L14 bar and lopped a suitable bit off with my trusty hacksaw (I really need to get a motor mounted on my power hacksaw one day).



A simple bit of turning later and I had these 4 liners within spec of each other - actually that's not true, I spec'd each one to the hole it was intended for which is why I marked them. At this point they've been reamed but will be honed after they're installed in the block and finish machined.



I applied some Loctite to the OD of the liners and pressed them all in. No pictures of this operation as I needed more hands than I have just to get the job done and had no way to take photos as well. You can see in this shot they all sit proud of the deck surface.



Now it was back into the vice and I swept the deck surface to align it perfectly square. From here I face milled the liners and deck down to finished height which removed the last smidge of deck height and ensured the liners were flush with the surface of the block. Except for final honing the liners are finished and now I truly have holes I can call 'bores'.





With that somewhat nail biting portion of the build finished, I thought a nice quick part was in order, so I decided to build the PCV. The body of it was a simple turning and threading operation but I ran into a problem with the top. The body has a male thread and the top of the valve screws on to it. The problem is I don't have a bottoming or plug tap for this size, just a tapered one. With the very short length of the part I couldn't even start the thread. After a little head scratching, I ended up making basically a threaded bush, then soldering a piece of brass on one end.



I then mounted the body back in the lathe and screwed the top on so I could machine it to shape. Again, I did not take any photos of this operation as I honestly didn't think it was going to work. I expected the thin body wouldn't be able to hold up to the cutting forces, especially with an interrupted cut. However, with lots of very light passes it ended up ok.



I've never been this deep into a build without making pistons so they are next on the agenda. I always enjoy making pistons as even people with zero engine knowledge recognise them and are impressed by how small and shiny they turn out.

 

[Brian Rupnow]

Al--I'm watching your build closely from over here on the far side of the world, and you are doing a marvelous job. Your engine looks great.---Brian

 

[Sleddog]

Good work Al. I enjoy the step by step build log. Keep it up.

Jack

 

[michael-au]

Good work Al, block looks really good

 

[Cogsy]

Instead of the pistons I figured I'd attempt the centre main bearing first so I could finally mount the crank properly. I started with a chunk of 1-1/2" LG2 bearing bronze but I couldn't face another marathon hacksawing session, so I used a slitting saw to cut it in half instead. Once I had 2 pieces I took a quick skim cut to smooth the cut sides.



From there I soft soldered the two halves back together. I tried to get both halves lined up but it's a tricky job that needs more than two hands and it's not critical at all, so rough enough was good enough.



Then it was into the 4 jaw and adjusted til the join was centred. I used the point of a live centre as a reference and it took no time at all.



I would like to say it was then a simple boring and turning operation but in reality the thin thrust edges of the bearing deformed during machining and took a lot of fettling to reshape and adjust to fit. Then a quick flash of the torch (after marking both halves to keep them matched) separated them ready for fitting. After having seen how Michael-au machined his big-end bearings using a dummy conrod end for support while turning, I'm going to copy his method for my big-ends and I expect they'll go a lot easier than this one did.



Finally, I slopped a bit of light weight oil on everything, temporarily fitted the crank and spun it by hand (with a spanner) to free it up a little. Once I was happy everything was properly aligned and fully lubricated, I spun it over at a few hundred rpm using the lathe to drive it and it now turns nice and smoothly, though it's still got a little ways to go before I'd call it free-spinning.

 

[Cogsy]

And with the crank now in place, I could finally start on the pistons. The first operation is the most fun, with a nice and simple turning job to make some cute little piston blanks. I used a reground parting blade to cut the ring grooves (they're about 0.035" wide from memory) and took a partial depth parting cut at the correct piston length (plus a smidge for final facing) leaving a decent stub, machined concentric to the piston, to hold onto for further operations.



Onto the mill, I held the stub in a 5C collet in a square holding block and centred with the ever-useful coaxial indicator. From here cutting the conrod clearance slot was a simple piece of milling.



Laying the collet block down and rotating it 90 degrees ensured the gudgeon pin hole was perfectly orthogonal (that's a fancy word for perpendicular I've been wanting to use ) to the slot I'd just milled. Then it was just a matter of repeating for the rest of the bunch (7 in total for some extras for safety and maybe a key-chain or something).



Then they were returned to the lathe and parted off from the stubs. I elected to hold them by the stub for the parting to make sure the fragile pistons weren't damaged, then I lightly chucked each piston in turn, wrapped in some protective masking tape, and faced off the final couple of thou to finish. These 4 are the ones destined to go up and down really fast and make lots of noise.



Really happy to be getting the main rotating elements done now. Hopefully soon I'll be able to spin the crank and have things going up and down which will amuse me for hours at a time.

 

[michael-au]

Coming along nicely

 

[Brian Rupnow]

Great work, as usual Cogsy. I'm watching.--Brian

 

[Herbiev]

Looking great so far Cogsy. Keep the pics coming.

 

[Cogsy]

With the pistons all finished I thought the next logical step was the conrods. This is a part I've had issues with getting right in the past and now I had to make 4 exactly the same so I was more than little worried about how to go about it. In the end though, I came up with a procedure that produced 7 almost exact copies with relative ease - again I wanted spares and tiny pistons on tiny conrods are just so darned cute!

I started by machining a rectangular lump of ali for the end caps, then drilled the bolt holes and oil passage for a bunch of caps at a time. Exact sizing of the blank wasn't really important here, though the height of the caps was machined to final dimension and the bottom face of the blank had a nice finish on it.



As this engine relies on oil splash lubrication, each big-end cap has a 'dipper' on it to splash the oil from the sump. To achieve this feature I used an endmill to remove all but a thin strip own the centre of the blank, then cut away all except the required dippers. They'll receive a final shaping later on.





The cap strip was then bolted to a drilled and tapped plate and the whole thing was skimmed down to required thickness. From this point on the caps are matched to their rods and can't be mixed up.



The big-ends were drilled and reamed along the joint of the two pieces of stock and the little-ends drilled and reamed at the same time. I didn't have an appropriately sized reamer for the little-ends so I made one up from drill rod. I tested it as it was created so it would achieve the fit I was after and it turned out well (although it doesn't look the best). The blanks were then sawn apart in to individual pieces with extra material all round.



With an appropriate bush for the big-end, the blanks were screwed to a sacrificial plate and a dummy gudgeon pin pressed into the little-end/sacrificial plate to accurately locate the blank. Shaping was then a simple process with an endmill. For the little-ends I trimmed to size at this point, then used filing buttons to radius the end. As they're so small this only took a couple of minutes total.





Now the rods were shaped, each rod/cap set was marked to keep them paired and correctly oriented, then I could finally separate them and do a final shape of the oil dipper. A little bit of cosmetic finishing (though not a huge amount as most will never be seen) and they're complete.





So in the end they weren't as tough to make as I feared but there sure was a lot of work in them. As I anticipate the big-end bearings are going to be quite a challenge as well, I think I'll move on to something a little easier for now.

 

[Brian Rupnow]

Are you going to drill passages through the dippers and up to the inside surface of the rod cap?---Brian

 

[Cogsy]

Are you going to drill passages through the dippers and up to the inside surface of the rod cap?---Brian

Looking back, it doesn't show up well in the pictures but yes, they are all drilled through the dippers and the cap. The pic where it looks like I'm making the top of a castle wall shows the through holes, but when the angles are cut the holes are on the cut edge and don't show up well.

 

[Cogsy]

Just a brief update today while my lunch is cooking (beef, cheese and bacon pie in the oven as we speak). I decided to tackle the backing plate, or, as we used to call it, the sandwich plate between the block and the bell housing.

I started by chucking a bit of rough sawn (hand sawn ) ali plate in the 4 jaw, with enough offset to have extra material all round, and drilled the crankshaft through hole. I marked the approximate edges and hole location with a sharpie just for ease of setup in the chuck.



After facing the whole plate flat I kept taking what were basically facing cuts but leaving the raised centre section to locate the ID of the bell housing. Once that was done it was off to the mill to cut the basic outside shape of the backing plate.





Once I'd drilled the mounting holes, I removed the part from the vice remounted it in a vertical orientation. In fact, I had to reorient it quite a few times to cut the various angles, cutaways and chamfers.



Once the outside had the correct shape, I remounted it horizontally in the vice but upside down to what it had been. Then it was a simple matter of face milling it down to required thickness, which removed all the extra material as well. A quick hand file of the upper 'tang' chamfer and it was complete.





As the backing plate was a relatively quick and easy part to make, I followed it up with another simple part - the flywheel. The hardest step was the first one, where I had to hand saw a lump off a piece of 40mm tool steel. It's decent stuff to machine but incredibly tiresome to hacksaw.



I turned it to major diameter, drilled the centre and recessed for the retaining nut. From there, although I didn't take a picture of it, I cut a series of steps by eye as the rear face of the flywheel is a domed shape and I still haven't made a radius turner yet.



I blended the steps using a file under power, then cleaned it up with sandpaper to a very nice finish (if I do say so myself). This part is entirely contained within the bell housing and is not visible on the completed engine, so it really wasn't necessary, but the tool steel cleaned up so nicely I just couldn't help but polish it.



Again I didn't take a picture, but after parting it off I turned it around, faced it flat and cut the 10 degree taper to mate to the crankshaft to finish it off. I can't take a picture of the finished flywheel now as it's currently hidden inside the bell housing which I've installed just to see how the whole engine is looking so far. My pie is now ready so I'm off to scoff it down!

Edit: I thought I'd better include a picture of the mock up since I mentioned it and someone might be interested.