Gallery, Projects and General > Project Logs
Webster IC Engine build log.
madjackghengis:
Hi Chris, I watch your build with enthusiasm and a bit of amusement, as what you are doing is what I've done most of my life on a larger scale, and yet the exact same issues are important and confront the engine builder. From that perspective, remember that paper gaskets not only seal things up, they also act as heat dams, reducing transferred heat to things like carbonators, which sometimes makes the difference between barely running, and a great running engine. I have used a piece of shirt cardboard, spray painted on both sides with aluminum paint, several coats letting each dry in between, as head gaskets for motorcycles and car engines, when I couldn't afford or couldn't get real gaskets. Those guides and seats turned out great, and should be just the thing to make it run well, I'm looking forward to the video of it running. :hammer: :poke: :beer: Cheers, Jack
dbvandy:
I hate that we lost a few days worth of posts.... :zap:
raynerd:
HAHA - I can`t bloody believe it!!!
If any of you read my reply before it was deleted, I wrote that there must have been another problem with the site because when I clicked to "post" my long reply, it told me the website was down and I lost my post. However, 20 mins later I managed to make another post. Now it has been deleted again, lol, :lol: :bang: This post really isn`t meant to be!
I just wanted to say thanks for the words of encouragement from those that posted and had posted but have been deleted due to the server crash.
Madjack - I`m glad your enjoying reading this thread and it is nice to hear that others have the same issues I have!
Doug - I haven`t thought too much about the springs yet. I guess they are quite important in terms of how much pressure they are applying - did you wind your own springs or where did you get them from?
dbvandy:
--- Quote from: craynerd on April 13, 2011, 02:27:37 AM ---Doug - I haven`t thought too much about the springs yet. I guess they are quite important in terms of how much pressure they are applying - did you wind your own springs or where did you get them from?
--- End quote ---
I wound my own for the webster, but not the Otto. it is pretty straight forward and you can get the music wire from about any hobby shop. Any hardware store should have a selection of springs, you just have to make sure the intake is lighter than the exhaust.
You can do it....
Doug
raynerd:
Doug - I may very well wind my own then. I have another question if you will; How did you connect the intake and exhaust to the valve block? I know the plans call for drilling 0.188" through the valve blocks into the guide (that is correct isn`t it? - you insert the valve guide into the valve block, loctitie it in and then once set, drill through the block and through the guide so that gases are entering below the valve?) Anyway, my question was how to attach the actual carb or exhaust itself. 0.188" is about 4.7mm, considering I`ve made the block a bit thicker as you advised, would it be worth drilling through the valve block and guide 4.2mm (just under 0.188") and then tap M5 so that any exhaust or intake can be screwed into positions? Or would the seal not be good enough? I just prefer the idea that inlet and exhaust can be changed than permenantly loctited in position. Any thoughts?
Anyway, after playing around with my fire piston, I moved onto the valve block.I really struggled to come to a decision on how to machine this. As far as I could see, the important factors were that the 3 blocks had to have a perfectly flat surfaces to mate well (I expect gaskets will be used still) and that one of the long sides will be perfectly flat so that it will seal well with the cylinder head. I needed to convert the bolt holes to metric because I didn`t want to go searching for the imperial bolts. I changed them all to M3, but it was hard work as they were quite close to holes colliding with one another going through in all directions.
I wanted to use brass so I took one of my stock 1.5" square bars and cut off 3 slithers. I then faced up the surfaces to thickness. I moved from the plans as another builder, Doug, advised, making the top and bottom block a little thicker to allow a better connection with the exhaust and intake.
So now do I work on each individually and hope they all square up at the end? No chance, I know my limitations and the only way I would get everything to locate would be to make it as one block. So I marked out the top block but allowed 1mm the close sides to machine back as well so in reality I didn`t have a datum face yet.
I then clamped, drilled through the top two blocks and tapped the bottom block, holding them all together.
I then spent a long time aligning the bolts with the new face that was to be cut, i.e getting the bolts parallel with the bed. I then squared up the rest of the block to size:
I then centre drilled (and will located off this hole when I took it apart to increase the hole dia of the two out blocks. I then horizontally drilled the two holes to bolt the block the head. This was near to colliding with the centre hole and the 4 holes holding the block together. I had concerns the drill would wander and intercept another hole ruining the block but I peck drilled slowly and all was fine! I then countersunk the holes for countersunk allen screws.
From the other side, the 0.188" hole is drilled into the centre bore of the valve block which connects to the head.
I then took to block apart so that I could drill and counter drill the outside blocks to insert the valve guides.
And this is where I am currently at... an exploded photo showing the top valve guide fully inserted and the bottom valve guide about to be pushed into position.
One of the valve guides is a fantastic pressure fit, the other is just a "good" fit so I hope that the loctite I use will provide a good enough seal. I expect it will. So the next job is to loctite them in place once I`m happy everything is ok, let that set and then drill into the side of the blocks, through the guides for the exhaust and inlet holes. Before all that, I need to cut the valves and use some grinding paste to lap them to the valve guide seats.
Navigation
[0] Message Index
[#] Next page
[*] Previous page
Go to full version