9 1/2 Engine rebuild II

Discuss the new 9 1/2 and 1200 Sport models

9 1/2 Engine rebuild II

Postby VesaII » 14 Apr 2018 15:42

Heads are done and ready for coating. Peter at company Virtauskansi did really a first class job. He thinks we might get some 10-15% more flow by this. He also found some nasty brittles on intake seats. Luckily they are horisontally thus not altering tightness.

And three pictures...
Notice how smooth radius cut valve seats are and notice 30deg cut back on intake valve. Valve guides look like they should now.

http://www.hotrod.com/articles/valve-angle/
http://www.williamsperformanceengines.com/valves.html
http://www.rlengines.com/Web_Pages/Serid_101_Seat_and_Guide_Machine.html
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Last edited by VesaII on 07 May 2018 15:35, edited 1 time in total.
VesaII
 
Posts: 17
Joined: 25 Jul 2017 06:51

Re: 9 1/2 Engine rebuild II

Postby VesaII » 01 May 2018 12:31

Exhaust valves...

As you may recall i was forced to replace one exhaust valve. When i saw how much nicer new exhaust valves was, i could not resist to change them all. Here you have some pictures and arguments why this was a must. Initial plan was to use old exhaust so they are rebuilt as well, but they has only one 45 cut on them.

1) New exhaust valves weight 47g when finished. Old ones some 51g and intake as comparison 52g as average.
2) New valves have thinner shaft
3) Second 30deg cut is done immediately after seating surface
4) There is more material on new valve head to make it more reliable when seating surface is moved out. It also allows a nice radius on side of combustion chamber: http://www.s262612653.websitehome.co.uk ... heads9.gif

After this mod there is not much improvement left to do on cylinder heads but coating...
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ValvesInplace.png
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VesaII
 
Posts: 17
Joined: 25 Jul 2017 06:51

Re: 9 1/2 Engine rebuild II

Postby VesaII » 06 Jun 2018 19:16

Will be continued in here http://www.ital-web.de/forum/viewforum.php?f=25 with more pictures...
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VesaII
 
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