Another Westbury Seal 15cc

[doubletop]

A washer would do it. You may need to relieve the tops of the bushes to clear the adjacent tappets.

Charles

Yes I considered that but remaking the bushes to take up the difference is my preference. I was just wondering if the designed 1/32” gap had a purpose.

That crankshaft come out well 

Does it appear straight?

To finish off the bearing sections I would suggest hold one end in a collet chuck (if you have one) and supporting the other end with a live centre while you skim the journal.

Roger

Thank you

That is more or less what I did. However, I needed to remove the end webs so I could test the bearings against the journals. That meant the centres were removed. I just made a bush to support the crank in a chuck in the tailstock.  It was 5/16 for the timing end and  I then used the taper on the flywheel end as I needed full access to 3/8” sections for the bearings.

And yes it is straight it rotates nicely in the bearings when installed in the crankcase

I must admit I am enjoying this build, I'm with the rest the crank looks great!
Art

Art

Thank you. Encouragement is always appreciated

Pete

[doubletop]

With the camshaft and crankshaft done and the camshaft bushes remade to remove any unnecessary end float to was time to get the timing idler gear located. I hadn't drawn the idler stud in CAD so hadn't taken into account the space it needed when I had drawn the timing cover. I then started an exercise investigating alternatives that would fit the space available. All would have required some adjustment of the internal walls of the timing cover. I had considered Vixens approach of a stud with a single bolt through the middle but rejected it because of the location close to the bearing. However, after a few days of procrastination I decided to investigate further

Plans of various options



Theoretically a 3mm bolt would land on the flange of the timing housing holding the bearing







So on to the mill and check where it would actually land

<a href="https://www.youtube.com/watch?v=MiPV_7yH1O8" target="_blank">http://www.youtube.com/watch?v=MiPV_7yH1O8</a>



Job done




<a href="https://www.youtube.com/watch?v=fKSXS_PwlAw" target="_blank">http://www.youtube.com/watch?v=fKSXS_PwlAw</a>

You will notice that I have gone for the ZZ shielded bearings. Doing hat just needed an additional 1/32" depth on the nose bearing holder as the timing bearing holder had the space for the extra size of the ZZ bearings

Pete

[doubletop]

Next job was the valves. Something I hadn’t been looking forward to. I don’t like repetitive jobs, particularly when the is potential for things to go wrong. Eight valves with stems 1.047” long and only 3/32” diameter definitely falls into that category.

I had decided to make them from 5/16” silver steel. I had found, by accident, that it cuts nicely with CCGT060204 inserts rather than the usual CCMT060204. I had understood the CCGT inserts were for brass, bronze and aluminium. That appears not to be so as the sharp tip cuts steel nicely. Especially for small jobs

I had started by cutting the 1.047” stem in one go and had been successful for the first valve but on the second the inevitable disaster struck



The obvious thing to do was to support the end in a centre but that just impedes the ability to access the job. Westbury provided the solution and maybe I should have read his notes first.

If only ordinary tools are available, however, it is advisable to turn down the extreme end of the shank to finished size, chamfer the end and support with a hollow centre

I proceeded with turning and finishing the extreme end and threading it. Then finishing the head end. Ignoring the use of a centre. I found it unnecessary.

First Half



Second Half



I wasn’t going to do the chamfer at this stage. I will grind those with the diamond wheel on my tool and cutter grinder.

Once done I just cut the valve off the stock ready to finish the top face later.

With eight valves done I was concerned that facing off the heads to size they may shear off when the stems are only 3/32”. In addition at my ER32 collets only go down to 3mm. but I have a 90 year old Lorch lathe that has a 3/32’ collet. Rather that use the Lorch I opted for the collet in collet approach which worked fine.

Rather that risk one of the valves I did a test piece first



Eight valves installed awaiting the seats to be finished



The next job will be bevelling the valve heads and cutting the valve seats. As I said I will be doing that in my tool and cutter grinder.

To cut the valve seats I will make a seat cutting tool to fit the guides



Pete

[samc88]

Really nice, its definitely looking engine like now!

[internal_fire]

I had decided to make them from 5/16” silver steel. I had found, by accident, that it cuts nicely with CCGT060204 inserts rather than the usual CCGT060204. I had understood the CCGT inserts were for brass, bronze and aluminium. That appears not to be so as the sharp tip cuts steel nicely. Especially for small jobs

Sharp inserts are more fragile, and they will not last as long, but for typical amateur requirements they are very useful. The carbide mix may be a bit different, but the inserts are still very hard compared to HSS.

Gene

[crueby]

I had decided to make them from 5/16” silver steel. I had found, by accident, that it cuts nicely with CCGT060204 inserts rather than the usual CCGT060204. I had understood the CCGT inserts were for brass, bronze and aluminium. That appears not to be so as the sharp tip cuts steel nicely. Especially for small jobs

Sharp inserts are more fragile, and they will not last as long, but for typical amateur requirements they are very useful. The carbide mix may be a bit different, but the inserts are still very hard compared to HSS.

Gene

Um, unless my eyes are skipping, you gave the exact same insert number both times? 

[doubletop]

Really nice, its definitely looking engine like now!

Sam

Thank you, very much appreciated

Sharp inserts are more fragile, and they will not last as long, but for typical amateur requirements they are very useful. The carbide mix may be a bit different, but the inserts are still very hard compared to HSS.

Gene

Yes I had a couple of the tell tale “dink” sounds as a chip was taken out of the tip and performance dropped off. Worth it though to get the job done.

Um, unless my eyes are skipping, you gave the exact same insert number both times? 

Yes a case of more haste and less speed. Copy and paste and not editing the result. I have amended the original

Pete

[Jasonb]

I use the **GT for most work these days and started using them on all metals years ago.

On a job like this you can also go with the more pointed DCGT which will clear a tailstock ctr, this is a 2.5mm valve with ctr drilled hole. I make them overlength and then turn of the end while held in a collet, you can poke them in from the back of the collet.

[doubletop]

I use the **GT for most work these days and started using them on all metals years ago.

On a job like this you can also go with the more pointed DCGT which will clear a tailstock ctr, this is a 2.5mm valve with ctr drilled hole. I make them overlength and then turn of the end while held in a collet, you can poke them in from the back of the collet.

Jason

Funny you should say that because after this experience my plan is to purchase some DCGT to augment my DCMT stock. I have a pack of DCMT on my desk to remind me to order them

Pete

[doubletop]

Now on to the valve seat cutter and grinding the chamfer on the valves

First cut the 4 facets. Note the extra-long stem to enable it to be held in the cutter grinder collet.



Then into the cutter grinder for the chamfer. This setting will be retained for doing the valves later.



Now the valves. Again like the ER32 collets the U2 collets in the cutter grinder they only go down to 3mm. So a collet in collet solution. As the U2 collets are hollow the Lorch draw bar can be used to pull in the 3/32” Lorch collet.



The valve blank in place



And ground. The cutter grinder has a micrometer adjustment of the grinding wheel. Bring it up to touch the corner of the bland and move slowly towards the blank while rotating it. Only a 0.8mm cut required



Eight valves done



And in the block



I just need to lap them in but that can wait until I get the engine further assembled as the valves can then be pressure tested as we go

Pete

[Admiral_dk]

All the parts done so far are looking Great 

Per             

[doubletop]

All the parts done so far are looking Great 

Per             

Thank you. I am getting there

Pete

[doubletop]

I had naively thought that the combustion cavities cast into the head would be Ok but they are not the overall with of the cavities is short and the valve foul the head. In hindsight I should have realised this was going to be the case because the spacing of the plug holes wasn't near the drawing dimensions and I had to centralise the plug holes on the cast in webs. The spacing of the stud holes didn't line up with the casting either.



So, I have now had to draw up the cavities in CAD so that I can re-machine them. That made also realise that the part of the cavity where the piston protrudes is also wrong. Which then leads me to a decision do I make the head accept the piston protrusion or shorten the conrods?



After a bit juggling in the CAD I think I will reduce the length of the conrods so the piston stays in the bore at the top of the stroke. I believe that will result in a better compression ratio as the combustion cavity volume will be reduced, be less machining of the head as it just needs the valve space to be adjusted and it should also alleviate some of the problem with the conrods hitting the lower edge of the cylinder liners. (As I am writing this am I having a déjà vu moment here with Vixens thread?)

Pete

[Vixen]

(As I am writing this am I having a déjà vu moment here with Vixens thread?)
Pete

Déjà vu??   Non, je vous l'ai dit   



These and other problems are caused by Westbury never having built a Seal engine himself, so he never detected or corrected any of his many drawing errors.

Mike

[doubletop]

(As I am writing this am I having a déjà vu moment here with Vixens thread?)
Pete

Déjà vu??   Non, je vous l'ai dit   



These and other problems are caused by Westbury never having built a Seal engine himself, so he never detected or corrected any of his many drawing errors.

Mike

Mike

After I posted I went your thread and checked what you had done.  You said you had left it as cast but did you relieve the area for the valves? It looks like you may have done.

Then I realised I could use a neat feature of Fusion to do a comparison. It enables you to bring in"canvases" and scale them. Notwithstanding that the photos of the heads are a bit scewed here are ours


Mine vs EW drawing                                               Vixen vs EW drawing                                                Mine vs Vixen

     



The size of the cylinder space is less on my casting and the spacing of each cylinder slightly out

Pete