squeak93
15 Year Member
Well the good news is you can find the limits of the head now port wise since you're scrapping it.
Good luck on the part hunt!
Good luck on the part hunt!
Thats the plan. I want to keep working the port over and then cut the head down the center of the ports to see where it was getting thin.Well the good news is you can find the limits of the head now port wise since you're scrapping it.
Good luck on the part hunt!
Thats the plan. I want to keep working the port over and then cut the head down the center of the ports to see where it was getting thin.
Castings are definitely known to vary. I don't necessarily want to use it as an exact model, but just see if the good I thought I was doing really removed enough material compared to a port that I didnt do as much work on.Well,.....it's a safe bet it was getting thin where you ground into the water jacket.
Personally, I don't know how much faith I'd put into a cut apart casting when using it as a reference standard for how far you can go into the future...(unless you're gonna get real conservative based on what you determine to be a "thin area". Different castings all probably yield more or less tolerance for aggressive porting.
Whats the area that looks like a port behind the actual exhaust port?Never seen that before.Castings are definitely known to vary. I don't necessarily want to use it as an exact model, but just see if the good I thought I was doing really removed enough material compared to a port that I didnt do as much work on.
For example - how much did I really grind out in the short turn?
And for the record, the port wasn't where I thought it was. Shoulda had the picture in front of me...
Well, a good point was made elsewhere. More than likely, if I have to make changes, it will not be in the valve/seat area so it shouldn't matter that I have the valve job or not. I need to polish the chambers on the other head and I will have the valves and seats done.
The main concern would be if you pay the $275 for the machine work and then you get flow results that don't meet your expectations and you start digging back into the heads and mess something up you are out a whole bunch of money now.
Edit: In order for them to do the valve job/cut valve seats won't they need to install the valves & springs in order to ensure a tight seal?
The valve is cut at a different angle than the seat. IIRC the seat is 45* the valve is cut @44*. A typical 3 angle valve job has the top of the seat cut @30*, the seat @45* and the throat of the seat @70*. with the valve having an angle of 44*. the valve may also be back cut to help improve flow. It can get even more complex than that if you want to get into the high zoot stuff.Im not sure how it works. The seats are cut with a certain angle to match the angle of the valve as far as I know.
But yes, if I pay all of that money and something gets messed up afterwards, I will not be happy, to say the least. I'm trying to stay right at $500 and should a be little over. My calcs are at $555 right now, and should have heads that flow a little less than a TW 170.