Is my 505 turbo head CNC machined?

[Alfanatiker]

My intake in the head are approx 41mm (so rather large) and appears to be machined from both sides. And the intake manifold is only 36mm so it is not even a close match.

Could I be a owner of some head that is worked on?

[Bean]

They look stock, if you stick your finger into the intake you should feel a fairly abrupt inside radius - if it’s been worked on that would be gone.

Spark plug type and location would be a bigger indicator if the head was a Danielson head - 10mm plugs at a different angle than the casting plug hole would confirm it.

Rabin

[Alfanatiker]

I didn't necessarily think it was a Danielson head. I was mostly very surprised about the fact that the intake obviously is machined especially from the side of the seat, and the fact that the intake manifold has as much as 5mm smaller radius than the head. The manifold is pretty stupid compared to the head port and makes for an incredible bottleneck in this case.

Plugs are normal 14mm btw.

 

Regarding the abrupt edge, I recon you are talking about the "radius" before the bowl, and not something that should be similar to the edge in the exhaust ports that has the lose short pipes to seal between the head and the manifold?

The port is at least smooth all the way in, and is either machined or probably has the nicest casting surface I've seen in a head before.

[Bean]

The inner radius before the valve is what I meant - red arrow pointing to it here:

 

You can usually feel a fairly abrupt transition there which would benefit from some smoothing.

Rabin

[Alfanatiker]

It is for sure a sharp edge there I will fix when I first have the engine out of the car.

But do you have any comment about the intake manifold? Why is it only 36mm when the head is 41mm? Why did Peugeot make it like this? Its like the head was made for much more power than the manifold.
And since the manifold has such a large radius on the pipe, it is pretty much impossible to increase the runner size all the way to match the head. We have a very long bottle neck on our engines.

[Bean]

I’ve never noticed the disparity in intake port to the head port size difference!

I admit I’m not a big fan of the intake design at all with the TB entry on one end with a very small plenum shape, I felt the distribution to the runners has to be terrible.

I’ve toyed with redoing the intake plenum and throttle body location so distribution is better, but neglected the runners themselves.  One could look at doing a gradual expanding taper in the runner to intake port to make the transition better, but a custom intake with new runners and plenum might be best.

Rabin