OST-013: Massaging a virgin ;)

[oldeskewltoy]

What have we here.... :cool:





Let me introduce to you a virgin :eek:




It is a brand new bare head - no valves, no seals, no wear! Work will begin on Monday


This head is one of those being sold here: http://forums.club4ag.com/zerothread?id=93590

[Bean]

lucky number 13 for me - looking forward to the progress

general information - two weeks ago pismir had still one left, in case anyone is interested.

[banpei]

Holy crap!

[Bean]

banpei Wrote:Holy crap!

you can say that again as I have another one of these being fitted with OS valves and worked by Loynings

[oldeskewltoy]

[oldeskewltoy]

Well.... here are some before photos......

intake ports... note @ the top of each photo the mismatched seat. Also note the casting flash

intake #1


intake #2


intake #3


intake #4



The exhaust ports are always rough, note how the port walls are "crowding" the flow.

exhaust #1


exhaust #2


exhaust #3


exhaust #4 - note the mismatch size(one side is taller then the other) of the bowl from the right to the left in this port.... compare it to exhaust #3 and it is more evident



Finally, chamber views. Note in these photos: 1) rough chamber edges(gasket mounting area) where the surface was machined. 2) the mismatched seats. 3) casting flash/flaws

chamber #1 - both views



chamber #2 - both views



chamber #3 - both views



chamber #4 - both views

[oldeskewltoy]

the proverbial other forum Wrote:Are you going to cc the virgin chambers?

GREAT question....... and YES - that way I'll know definatively how large a truly stock combustion chamber is

[oldeskewltoy]

Work begins by checking the combustion chamber volumes. To do this I use a burette



Chamber #4 measures out to 36.5cc.



The other chambers measure out to; #3 = 36cc, #2 = 36.25cc, and #1 = 36.25cc




As I deshroud the chamber, I'll also be equalizing their volume. Here is a photo show chamber #4 deshrouded, #3 chamber in the photo is not yet deshrouded. The chamber walls have been highly polished



Bowl work begins, bowl #8 on the intake side is roughed to size. The factory production process is not perfect, so work is done to blend the bowls, valve seats and the chamber walls to allow maximum flow




Working a bowl the key area is always the roof, here the bowl roof has been cleaned up, the guide narrowed some, and the guide boss has been narrowed substantially




Finally for this post, a before and after on bowl #8

[Project D]

So now everyone can know that the stock chamber is between 36cc and 36.5cc, pretty cool to get proper CR
Will you measure chambers after deshrouding ?

Also, can you show us the tool you use for the guide boss ?!

[oldeskewltoy]

Project D Wrote:So now everyone can know that the stock chamber is between 36cc and 36.5cc, pretty cool to get proper CR
Will you measure chambers after deshrouding ?

Also, can you show us the tool you use for the guide boss ?!

I told my client that I would make sure all the chambers were balanced, so yes... I will have #s after deshrouding

I use a Dremel for all of the porting I do. The guide bosses were reduced using a round cutting bit



I then cleaned up after the round cutter with a few different round tipped abrasive bits