Volvo B20 ported head,now pics.

Varje frän turbomotor grundas på en frän sugmotor!
Miksa89
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Volvo B20 ported head,now pics.

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Just bought nicely ported B20 head with 46/37 valves.

Do someone have a hint is it someone known person done in the past? Over 30 years ago.

Head has "270873-1352" stamped above 1. cylinder intake flatspot where injector holes are in injection heads.
Senast redigerad av Miksa89 den fre feb 24, 2023 6:55 pm, redigerad totalt 1 gånger.
Miksa89
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Re: Volvo B20 ported head identification.

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https://miksa89.imgbb.com/

Uploaded few pictures.

What do you guys think about it?
Inlet smallest are is ~37mm between seat and guide,and exhaust smallest area ~33.5mm under seat.

What should i do with exhaust valves because they sit about 1.75mm deeper than inlet valves. Or the worst sits 1.8mm deeper and "best" about 1mm deeper and other 2 near 1.7mm deeper.

Should i just take it to machineshop and tell them to do seat job to new 38mm valves and make them all sit even nomatter it means they are like 2mm deeper than inlets?
quattro
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Re: Volvo B20 ported head,now pics.

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I'm not an expert when it comes to porting, but I will offer a few thoughts.

- The inlet valves seems too big. They sit very close the chamber walls and I think that might have a negative effect on both flow and swirl.
- The exhaust valves seems too small. Exhaust valves do not lose flow when sitting close to the walls the same way inlet valves do.
- I don't think that the fact that the exhaust valves are a bit recessed into the chamber ceiling will hurt flow. I think it might just as well act like a funnel, help channeling the exhaust gasses into the exhaust tract.

To sum it up: Inlet valves too close to the walls. Exhaust valves too small. That they sit low in the head should not be a problem.
Miksa89
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Re: Volvo B20 ported head,now pics.

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quattro skrev: mån feb 27, 2023 8:05 pm I'm not an expert when it comes to porting, but I will offer a few thoughts.

- The inlet valves seems too big. They sit very close the chamber walls and I think that might have a negative effect on both flow and swirl.
- The exhaust valves seems too small. Exhaust valves do not lose flow when sitting close to the walls the same way inlet valves do.
- I don't think that the fact that the exhaust valves are a bit recessed into the chamber ceiling will hurt flow. I think it might just as well act like a funnel, help channeling the exhaust gasses into the exhaust tract.

To sum it up: Inlet valves too close to the walls. Exhaust valves too small. That they sit low in the head should not be a problem.
Thaks for your answer.

Plan is to put in new 38mm exhaust valves and tell machine shop to cut seats so that they all sit at same level,so all deep as the deepest now.

Not mutch to do with inlets because combustion chamber is 92mm wide and bore is 92mm. :?
quattro
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Re: Volvo B20 ported head,now pics.

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I would widen out the combustion chamber around the inlet valves - make the chamber more look like a wide funnel. At the bottom of the chamber it doesn't have to be wider than it is because at low valve lift there's not much air streaming in. But to gradually widen the chamber as valve lift increases would be a step in the right direction, I think.
That would also stop the incoming gas from hitting the chamber wall and instead guiding it out into the cylinder in a swirling motion. Depending on how you do it. The drawback is that you would lose some of your current compression ratio so you need to measure that and figure out if you need to do anything about it.

Here's a picture of a Volvo Evo top that shows what I'm talking about. I'm not suggesting you could do it exactly like this - but this shows the direction you would want to go in. http://www.topplocksverkstan.se/bilder/ ... 02,810.jpg
As you can see the chamber is widened out in the same way around the exhaust valve as well. I would do that too. I think that would do more for power than changing to bigger exhaust valves. That the valves are a bit "sunken in" I would not change - apart from making them all sit at the deepest level - but incorporate it into the overall "funnel-shape" you would want to create around the exhaust valve.

But, as I said I'm not an expert in these things but I think this is more or less what the experts would say.
Miksa89
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Re: Volvo B20 ported head,now pics.

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quattro skrev: tor mar 02, 2023 10:09 am I would widen out the combustion chamber around the inlet valves - make the chamber more look like a wide funnel. At the bottom of the chamber it doesn't have to be wider than it is because at low valve lift there's not much air streaming in. But to gradually widen the chamber as valve lift increases would be a step in the right direction, I think.
That would also stop the incoming gas from hitting the chamber wall and instead guiding it out into the cylinder in a swirling motion. Depending on how you do it. The drawback is that you would lose some of your current compression ratio so you need to measure that and figure out if you need to do anything about it.

Here's a picture of a Volvo Evo top that shows what I'm talking about. I'm not suggesting you could do it exactly like this - but this shows the direction you would want to go in. http://www.topplocksverkstan.se/bilder/ ... 02,810.jpg
As you can see the chamber is widened out in the same way around the exhaust valve as well. I would do that too. I think that would do more for power than changing to bigger exhaust valves. That the valves are a bit "sunken in" I would not change - apart from making them all sit at the deepest level - but incorporate it into the overall "funnel-shape" you would want to create around the exhaust valve.

But, as I said I'm not an expert in these things but I think this is more or less what the experts would say.
Thanks again for your reply. 8)

What do you think about that way the exhaustport has been made? I mean that way the guide and that hump just slightly lowered but shaped so that theres nice smooth path on the outer side of the port? Meaning the side of port wich is closer to cylinderwall side. Hard to tell without flow bench but looks and feels reasonable? But not the "normal" way wich was to remove the hymp and shorten guide?
quattro
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Re: Volvo B20 ported head,now pics.

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Personally I think the exhaust ports looks pretty good. At least so good that I think that if you try to make them better the risk that you make them worse is bigger than the chance that you make them better.

Then there's the question of the balance between inlet and outlet flow, plus what air speed you would want in the ports. Bigger ports will need a bigger cam in order to work well. That combo is not the best for an engine that you want to use to drive around town - or on the highway for that matter. It will be noisy on the highway and "jumpy" to drive in town.

So I would say do not make the ports larger than they are. And I would get an adjustable cam gear. It will let you find the cam position that gives you the best balance between low end traction and top end power. And the balance between the inlet/outlet ports will automatically be taken into consideration as well.
Miksa89
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Re: Volvo B20 ported head,now pics.

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quattro skrev: ons mar 08, 2023 11:25 am Personally I think the exhaust ports looks pretty good. At least so good that I think that if you try to make them better the risk that you make them worse is bigger than the chance that you make them better.

Then there's the question of the balance between inlet and outlet flow, plus what air speed you would want in the ports. Bigger ports will need a bigger cam in order to work well. That combo is not the best for an engine that you want to use to drive around town - or on the highway for that matter. It will be noisy on the highway and "jumpy" to drive in town.

So I would say do not make the ports larger than they are. And I would get an adjustable cam gear. It will let you find the cam position that gives you the best balance between low end traction and top end power. And the balance between the inlet/outlet ports will automatically be taken into consideration as well.

Okey!

I have aluminium camgear set that im planning to do adjustable and modify camgear-cover so theres cover plate wich i can remove and adjust cam there. So no need to take whole camgear-cover off when adjusting cam.

I have Agap 272-13.3 cam.

No need to worry about highway comfortability,its guarenteed with M45+4.10 back axle and without any noise isolators/carpets. :hihi:
quattro
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Re: Volvo B20 ported head,now pics.

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Sounds OK.
So the next step should be to build it and test it in order to find out if it behaves the way you want it to.
Miksa89
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Re: Volvo B20 ported head,now pics.

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quattro skrev: fre mar 10, 2023 6:10 pm Sounds OK.
So the next step should be to build it and test it in order to find out if it behaves the way you want it to.

Yes. Waiting to get my new billet flywheel and clutch so i can take crank and flywheel/clutch to be balanced.
And need to bore block 92mm and test aseembly it so i can determine how much i need to skim the block.

And H-rods needs smaller small end bushnings to fit 92mm 35 comp height pistons.

Many thimgs to do still but hoping getting it running this year. 8)
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