Brian Lawrence
Member
I plan on just either using a 30° or a 45° angle I think using just a one line seat will just work fine. it works on my vintage Harleys. Try and also get a good strong spring as well.
Brian
Brian
Ageless 9 and 18 Radial
- Thread starter rlo1
- Start date
Help Support Home Model Engine Machinist Forum:
A feeling of satisfaction knowing that these cam rings turned out as well as they did. I chewed up an endmill on each one of those 4140 rings. I bought the plans 15years ago and had no clue how I was going to make these cams. I just knew that cutting them manually would be tough. I enjoy the CNC as it takes the hard part of machining and enables average machinists like me the ability to produce nice parts.
No shame in using the best machine you can access. The best jobs come from the best decisions. You made a good one there!
K2
K2
Thommo
Well-Known Member
Hi RLO1. Just wondering what is with the colour scheme on your machine base?? Is that how it came or do you just like colourful machines
Hi RLO1. Just wondering what is with the colour scheme on your machine base?? Is that how it came or do you just like colourful machines
I am poking fun at my ocd every time when I look at it. I did have plans for patterns but after 20 fixture changes I gave up!
This is how to spend a relaxing afternoon.
Hi Rio.
I got the "play bar" - but no link to a file to play...
I know that "watching paint dry" can be a relaxing way to do nothing, but watching a "play-bar" play nothing is less exciting. Please can you re-load the file link?
Cheers!
K2
I got the "play bar" - but no link to a file to play...
I know that "watching paint dry" can be a relaxing way to do nothing, but watching a "play-bar" play nothing is less exciting. Please can you re-load the file link?
Cheers!
K2
Sorry about that the file was too large to upload. I am attempting to correct it.
Making lots of valves
Well, I’ve been doing nothing but lapping valves and pressure testing cylinder heads. I have finished over 30 of them and they are all in good shape and ready to be installed. It was a lot of work and required many repeat testing and re-lapping to get the seal correct so that I will have good compression.
I used permatex lapping compound which has four layers of grit and it seem to work pretty good with the stainless valves and the brass seats. Sometimes I had to do it to maybe even three times to get a good seal. I would also at the very end use Brasso to polish the seats and give it a kind of a finished and it really did help on the pressure test.
Soaking in WD-40
I used permatex lapping compound which has four layers of grit and it seem to work pretty good with the stainless valves and the brass seats. Sometimes I had to do it to maybe even three times to get a good seal. I would also at the very end use Brasso to polish the seats and give it a kind of a finished and it really did help on the pressure test.
Soaking in WD-40
BTW I tested them at #140psi.
cwelkie
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I too have had good success with Brasso as a polish on valve seats. It made a significant difference on both aluminium and steel seats with stainless valves for me ... more than I'd expected. So much so that if I can turn the valve guide and seat in the same setup, a polish with Brasso has provided a seal right away - no other lapping required. (There, I've now jinxed it!).
Great progress on your build. I like seeing a CNC machine being used for these "one-off" projects rather than repetitive production.
Charlie
Rlo,
How was your pressure test run? Did you pressurize and then with a shut-off valve watch the cylinder leakdown time on a pressure meter? If so, what kind of leakdown times did you see? Also, did this test include the washers selected to correct the head orientations with respect to the block? - Terry
How was your pressure test run? Did you pressurize and then with a shut-off valve watch the cylinder leakdown time on a pressure meter? If so, what kind of leakdown times did you see? Also, did this test include the washers selected to correct the head orientations with respect to the block? - Terry
Seat width varied from a nice polished narrow ring to about 0.030 wide. It all depended on how square I installed the seat. Any variation was removed with the lapping.
This test was just for valve seats. I am going to clock and locktite the cylinder heads to the cylinders during final assembly.
The test was done using 140# compressed air. I had to use an O-ring inside the cylinder on the test block to get it to seal. I used the cordless drill with an adapter two spin every valve with the lapping compound in order to set the seat. I would then inject brasso into the seat using a syringe and lap more and in both directions. There were times when I had to re-lap the valve about two or three times to get it to seat properly. It would be obvious that the valve was leaking when you put that much air pressure on it because it just blew by like crazy. After lapping and cleaning (and installing a plug) I pressurized the head to 140#. You can tell by the leak rate reducing to a point where it would stop or just be were barely whispering. As you can see by the video that was one of the last ones I did and it sealed up pretty good. I am glad I took the two weeks for this process. I only did 2-3 at a time because of the tedious steps involved. I have 33 completed cylinder heads. I need only 27. They’ve all been tested. After I mate them to the cylinders they will become unique sets that I can interchange as necessary depending on their performance. -RonO
I had an interesting experience during this lapping process. I used an ultrasonic cleaner with simple green to make sure that I broke down and removed all the lapping compound and Brasso from the valve area before pressure testing and final assembly.
If you leave aluminum in simple green that’s hot it will oxidize the aluminum and slowly turn it black. It takes about an hour but if you forget about your parts and you just leave them soaking not thinking that there’s any damage that can be done to come back and you find out that your cylinder heads are all black.
On a positive note it removed the surface tooling marks from the part
Now that I have cylinder heads that are all different colors of grey I needed to get them back to normal aluminum. So I used some paint prep liquid from Eastwood to soak the cylinder heads and it quickly brightened them up and made them all the same color.
Lessons learned. -RonO
If you leave aluminum in simple green that’s hot it will oxidize the aluminum and slowly turn it black. It takes about an hour but if you forget about your parts and you just leave them soaking not thinking that there’s any damage that can be done to come back and you find out that your cylinder heads are all black.
On a positive note it removed the surface tooling marks from the part
Now that I have cylinder heads that are all different colors of grey I needed to get them back to normal aluminum. So I used some paint prep liquid from Eastwood to soak the cylinder heads and it quickly brightened them up and made them all the same color.
Lessons learned. -RonO
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I discovered something similar using a few different 'green' degreasing product formulas, some even diluted with water. They started doing a matt etch on aluminum before I fished them out. Now I'm using a blue Loctite product that does not do this to aluminum, either straight or diluted in water.
Anyone have suggestions on how to "Brad" the pins holding the crankshaft together?? Should I drive them in with Loctite? Do I need to peen them?
Richard Hed
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Can you show your parts?
