Westbury Seal by Vixen

[Jasonb]

biggest problem I can see is that having already upped the diameter you will be getting very close together and the wall of any sleeve will have to be very thin, as these holes are machined through the valve seats they will also need to be made larger and the 3/8" lip will almost touch the next once enlarged.

Of the three engines that I have made with tappets, one (Nemett) has bushes by design, Hoglet has none but that's more  adisplay design and the Midget I opted to add them as they were not on the very basic 1934 design.

[Vixen]

Jason, Here are the promised photos of drilling and tapping of the cylinder head stud holes. You may have noticed that I did the water jacket machining and stud drilling on my larger, newer machine vice. This proved to be a problem when it came to tapping the stud holes; it used up too much headroom. I was forced to move the cylinder block to the smaller vice to provide enough clearance for the tapping operation.







You are right about the diameter of any tappet bush being a problem, as they can only be machined by reaching through the small valve guide holes. One possibility would be to use thin wall hard brass for the tappet bush. I found some K+N thin wall tube (14 thou") that is a nice interference fit in the casting. If I used that, I would be back to Westbury's 0.25" dimension for the tappet. At least I have one viable option.



Mike

[Jasonb]

looking even better with a few more holes in it. Would it be possible to fit "top hat" shaped tappets from below to keep your larger contact diameter but allow for the 1/4" ID tube?

I'm in no rush to get out of lockdown, if this is what retirement is meant to be like I could quite get used to it

[Jo]

I'm in no rush to get out of lockdown, if this is what retirement is meant to be like I could quite get used to it

Retirement is not like this     It is much better   

Jo

[Vixen]

Jason,

Nothing is impossible. 

It would require a facing tool to be pulled up (through the valve guide hole) to square off the inside of the crankcase at the bottom of the new brass cam follower bush to make room for the 'top hat' on a revised item 17




Like Jo says. Retirement is when you are free to roam and do whatever you like. It's so much better


Mike

[Admiral_dk]

I really see why you asked about gaskets now, with all that material removed and a "cut through drawing" to remind me that there is hardly any flat surfaces left of any with that mate up, to "support it" .... the suggested liquid gasket is probably the only way .... 

Nice work as usually Mike 

[gadabout]

Mike,
 I had to line bore the camshaft tunnel as I couldn't insert the cam. made two bushes for the ends and a long 1/4" shaft with a cutter inserted in the middle to clean up the cam bore. I had some concerns with the amount of material left to guide the tappets but thought I would go to plan and see what happens and mod later if needed
Mark

[Vixen]

Thanks for your feedback, It's always welcome and could avoid me repeating an avoidable mistake.

I have been able to make a little more progress with the Seal's crankcase. The bottom face of the casting was machined to size and the inside of the base flange profiled. The sump (oil pan) fixing holes were then drilled and tapped. I prefer to tap the holes in the machine at the same time as drilling the holes. I always use green Trafelux tapping paste, it reduces the cutting force and helps clear/ control the chips in the tap's flutes.






While everything was set up and square, I machined the outside profile of the four mounting lugs and faced off both ends of the crankcase. I decided to leave the lower crankcase 20 thou oversize at either end. I will adjust the position of the bearings, within the bearing housings, to compensate. Note to self, mark up the drawings immediately, least you forget.






The final jobs will be to bore the crankshaft and camshaft registers in both end faces and then to open out the valve chest space.


Mike

[Dave Otto]

Nice work and nice progress Mike!

Dave

[Jasonb]

Does look so much neater with those clean up cuts inside and around the feet. Talking of which those vertical webs are not very well positioned unless you tap the holes and fit screws from below

[gadabout]

This is going to be the finest bestest Seal ever!!!
Mark

[ChuckKey]

If you decide not to bush the tappet holes, you could improve their wearing qualities (and consistent fit)  by ballizing them. I did this initially on the Seagull (before deciding on the bigger tappets and bushes).
I had not tried it before, and was pretty impressed with my work. I found room for bronze bushes 11/32" OD x 9/32" ID, and the valve centrelines are at 7/16" centres, same as the Seal.

[Vixen]

Thank you all for calling and and for your generous comments.

The water jacket area has been machined with four square edges, they provide excellent reference faces for the remaining machining operations. The crankshaft and camshaft bearing registers were machined in both ends of the crankcase, their positions being referenced from the top corners of the water jacket.






The cast space in the valve chest was machined to size and depth again using the corner of the water jacket as the reference point






The oil filler/ dipstick feature was machined with the crankcase tilted over at 20*to match the angle of the casting. The hole was bored 11/32" all the way through the side wall of the crankcase casting.




I then changed the tilt angle to 16* before facing off and threading the top face of the oil filler/ dipstick feature. I discovered it was necessary to make this change to Westbury's drawing to prevent the dipstick clashing with the rotating crankshaft. I was alerted to this potential clash when I examined his cross section drawing.




All that's left to machine on the crankcase is the inlet and outlet ports. They will have to wait until the valve guides are made and fitted, so the ports can be bored though the sides of the valve guides. Oh!! and then there is the clash between the two cylinder head studs and the inlet manifold studs to deal with.


ChuckKey, thanks for the advice regarding the tappet guides. I have never tried and so I have no experience of 'how to' or the beneficial effects of ballizing an aluminium bore, I think I would prefer to use a bronze bush, which I am more familiar with. The profiling of the lower part of the crankcase as provided adequate access from below to open up the tappet bores to the larger size needed for the bronze bushes. I would need a removable cutter of the correct diameter attached to a long 1/4" pilot shaft, with a pilot bush in the valve guide hole. That's good, as I now have two options to consider.

[Craig DeShong]

Hi Mike
Your Seal is coming together quickly, and your work is extraordinary as always.  Loving watching this engine come together. 

And yes, staying in and staying safe.

  

[gadabout]

Mike,
The cavity for the valve springs etc really needs to have the corners squared up as much as possible , I left a 3/16 radius there and it is very hard to adjust the valve clearance as it is hard to get a spanner in there to lock and unlock the nuts from my experience
Cheers
Mark