Big Bore Do-over

[culberro]

Do the simple stuff (porting/smoothing) yourself, and then get a shop to deck the head.
Honestly, decking the head for higher CR is going to be 80% (pulled out of my bum) of what you're after.

[Jack]

Originally Posted by culberro

Do the simple stuff (porting/smoothing) yourself, and then get a shop to deck the head.
Honestly, decking the head for higher CR is going to be 80% (pulled out of my bum) of what you're after.

Yup

[R32RennSport]

Thanks guys, I appreciate everyone for their input. Just want to move in the right direction without overthinking it.

[spock345]

Originally Posted by R32RennSport

Thanks guys, I appreciate everyone for their input. Just want to move in the right direction without overthinking it.

I am looking for some numbers on combustion chamber volume given how much is shaved off the head. Can you share the combustion chamber volume measurements when you take them?

[R32RennSport]

Originally Posted by spock345

I am looking for some numbers on combustion chamber volume given how much is shaved off the head. Can you share the combustion chamber volume measurements when you take them?

Sure thing. I'll definitely be taking a bunch more measurements the second time around and documenting as I go along.

[bongo]

You might try Mike Yoes at Yoes porting in Fairfield. He has done plenty of Volvo heads and can do a basic job for a reasonable price
https://www.yoesheadporting.com/

[Jack]

forgot to add
the intake ports on these heads are pretty crappy. Adding tapered spacers helps. I wish heads were aluminum because then you can add and subtract as you wish

need more fiddling but you get the idea

[cwdodson88]

Originally Posted by R32RennSport

Holy crap! That head is way shaved down, what are the CC's and projected static compression ratio??? Also, are the intake and exhaust valves sharing recesses? That's nuts. What kind of performance are you looking at? What will be the primary use of this car?

I just had a set of Gary's gstellsr valves installed, 46/38's and they're sitting about 0.008-0.010" apart. Had to have then intake seats installed, then the exhaust seat cut to overlap the intake Looks like it'll be money. I've still got to re-cc the chambers, clean up the seat>port blend, then decide how much I want to futz with the exhaust SSR. So far, its just bowl blended, and very lightly radiused, then smoothed to 180 grit roloc drums. There is some thought about doing what Jacks got there, but I had seen a couple that used a tongue off the header to take up some space in the floor... Not set on anything yet, gotta get the fun monies back up so I can tackle the butchered bottom end.

The hope at the moment is to have the exhaust flowing decent, and the intake at 42.5mm from the manifold to the valve. Surprising how much I was able to open up at the bowls.

[vintagewrench]

Originally Posted by cwdodson88

I just had a set of Gary's gstellsr valves installed, 46/38's and they're sitting about 0.008-0.010" apart. Had to have then intake seats installed, then the exhaust seat cut to overlap the intake Looks like it'll be money.

Good luck with it and hope you get the extra flow you are looking for. However be aware that with simeased valve seats like this in B20 heads the head itself tends to crack between the seats in race engines.

[cwdodson88]

Originally Posted by vintagewrench

Good luck with it and hope you get the extra flow you are looking for. However be aware that with simeased valve seats like this in B20 heads the head itself tends to crack between the seats in race engines.

Totally aware... Although I dont plan to beat on it too hard since I've been overpowering my trans since the last turbo/IC setup. I have started designing a billet head just in case. I've got 3 pieces of scrap to try. Couple cases of beer for the programmer, and a weekend in front of the 5 axis should do it.

[vintagewrench]

Originally Posted by cwdodson88

Totally aware... Although I dont plan to beat on it too hard since I've been overpowering my trans since the last turbo/IC setup. I have started designing a billet head just in case. I've got 3 pieces of scrap to try. Couple cases of beer for the programmer, and a weekend in front of the 5 axis should do it.

Good luck with it!