Datsun Roadster Forum-311s.org

Might be, but they are Total Seal rings and use a second rail to create an almost no leak down seal. Seems wide, but its better wide than too tight! Broke a ring in #4 once from being too tight we think... still had 210lbs of compression. Not sure what rendition of the motor this is, but judging on the rich condition noted I'm thinking pre- EFI.

Have an iron head with some plasticene in the exhaust port.
Looks like someone was checking out making the port smaller....
Doesn't seem they addressed the short side turn very well, likely because they also didn't raise the roof of the port (no actual porting done)....

Greg,
I thought the reliefs were only on the intake side, but, looking at your pictures again, it looks like there are reliefs for both the intake and exhaust?
Am I seeing that right? Is that stock?

Anyone here have experience with Aaron Kelly or AVP Heads?

Daryl Smith wrote: ↑Wed Apr 03, 2024 12:59 pm Greg,
I thought the reliefs were only on the intake side, but, looking at your pictures again, it looks like there are reliefs for both the intake and exhaust?
Am I seeing that right? Is that stock?

Yes, exist as stock, opened up a bit on mine.

Actually it only the exhaust valve that hits the block with stock valves in a U20. When I built my engine, and checked it with setup springs, only the exhaust valve was hitting the top of the cylinder bore. So I took the block down to machine stop at the time, (they closed about a year later) and they relieved the top of the bore.
Dave

Here is a rough drawing of what I would like to do with the exhaust port. Red shows, roughly, the current shape of the port. Green shows how I would like to modify it. The dark lines are the combustion chamber and valve seat.
The port is a tad small and long to be able to get in there with a welding rod, and these heads are, apparently a bitch to weld anyway, so I am not going that route. A port 'tongue' is a good possibility, possibly welded to the header. Still thinking on it.
For my 2065cc engine I'm looking at raising the floor .250". For a stock 1600, possibly over .500".
Currently there is almost no 'short side radius', the area where the exhaust at the bottom of the port turns to exit the head, and the port is oversized for the displacement, so raising the floor of the port would 'fix' both problems, while making the port more consistently shaped. Tongue...or.....

Got out a protractor and it looks like the valve angle in relation to the head surface is in the area of 9.5 to 10 degrees.
Anyone confirm this or seen this in print somewhere?

Thanks,