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advantage of heron head? (2008 bump)

die trying

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Joined
Oct 19, 2007
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nebraski
Is there any advantage to the heron head and its dished pistons over a 531 and stock pistons? It reminds me of an upside down hemi and I know the hemispherical shape allows for better combustion vs wedge but does that alone condone tearing my engine apart and swapping in new pistons and a 631 vs swapping on a 531? Would to motor be more free revving due to less mass in the pistons? Might this also free up some hp and/or result in less stress on the rods and crank? Am I also correct in understanding they were not available in north america?

I already searched around, that's how I found out about these massive lumps of aluminum. What a fascinating application of age old technology.
 
the 631 head AFAIK was only used in n/a applications and never saw the likes of a turbocharger
because of this the only pistons available for it are higher compression ones that are not suitable to having lots of fun with 25lb of boost on pump gas

because of the strange design its basically impossible to have custom pistons made for using the head ....
 
I'd imagine the piston would be heavier. Because the dish is so ****ing huge, you need a really thick compression height, which would mess with r/s ratio anyway, but i'd think the dish itself would be heavier then just a flat thin piston top
 
it was designed for hot climate markets that have shiitty gas, it was carbureted and served its purpose well. no need to explore further.
 
i still have one of these heads at home, i think it is designed to work as a high swirl motor, the CC's are in the pistons (much like on a lot of Diesels) . These engine's had a highish CR, i believe 10,5:1, and a very tame cam (mine came with a T in it, i believe it is OEM)
I have been thinking of using this head on my engine converting it into a B230HK +T. The Heron design was meant to use high CR but still be detonation-resistant so you could use low grade fuel.
i figured it might make an interesting LPT-engine , specially with decent EFI on high grade fuel or LPG.

But then i decided against it because it would become to expensive. (i don't have the shortblock/pistons to go with the head)
 
i still have one of these heads at home, i think it is designed to work as a high swirl motor, the CC's are in the pistons (much like on a lot of Diesels) . These engine's had a highish CR, i believe 10,5:1, and a very tame cam (mine came with a T in it, i believe it is OEM)
I have been thinking of using this head on my engine converting it into a B230HK +T. The Heron design was meant to use high CR but still be detonation-resistant so you could use low grade fuel.
i figured it might make an interesting LPT-engine.

But then i decided against it because it would become to expensive. (i don't have the shortblock/pistons to go with the head)

You should build it for methanol.
 
That would be fun and doable as well but methanol is not easily available here.
even E85 or E10 is not available at the gasstations.
 
These engine's had a highish CR, i believe 10,5:1, The Heron design was meant to use high CR but still be detonation-resistant so you could use low grade fuel.

well, that sold me on it. guess i better start saving up for shipping from the wrong side of the atlantic
 
well, that sold me on it. guess i better start saving up for shipping from the wrong side of the atlantic


How did just a high CR sell you on it? There are other high CR engines that are readily available without wasting money on rare parts. You see people running that head in a high performance application? I see 405's, 530's and 531's. Save the headache, buy a 531, have it ported, install larger valves and better valve springs and be done with it.
 
Good squish on a 405/530/531 head will make it detonation resistant too.

I'm running roughly 10.75:1 CR in my PV's motor with no pinging (premium, 93 octane) because it's built with good squish. An aluminum headed car would be even better (more even temps in the CC).
 
Good squish on a 405/530/531 head will make it detonation resistant too.

I'm running roughly 10.75:1 CR in my PV's motor with no pinging (premium, 93 octane) because it's built with good squish. An aluminum headed car would be even better (more even temps in the CC).


That is true.

I hope our OP here isn't turning into the next Barry.
 
it wasn't high compression that sold me, its the combustion chamber design which allows higher (higher being the operative word) compression with crappy gas than a traditional in head combustion chamber. i spend alot of time in rural iowa where the only fuel offerings are diesel and 89 octane varnish thats been sitting in their tanks for six months, so something that can run a tight squish on lamp oil would be ideal compared to a shaved 531 which requires 92 and a bottle of octane boost just to idle correctly. if that is not YOUR ideal setup then thats fine, but it is my ideal setup and it is apparently exactly what it was designed for.

thanks for thinking im an idiot though.

I'm not shy and i'm not gonna lurk for a year until i know all you little buzzwords before asking a question either. i may not have a degree in fluid dynamics or mechanical engineering (and neither do YOU!) but i understand how an internal combustion engine works and the differences between the various cycles etc. Of course if i described the operation of something just a little different, like a miller cycle engine, some of you would probably start flinging crap around like you're in an apehouse. way to think outsideside the econobox guys. you naysayers all must be right, this is a dead end technology and thats exactly why they are using similar systems in new cars. i know for a fact that mitsubishi uses a similar piston and head design for its FTO mivec motor, but hey what do they know its not like they have engineers working on their designs or anything. I would expect this on a honda civic forum, but i assumed volvophiles were a little more mature.

to you who realize that volvo spent thousands if not millions of dollars in researching and implementing this design for a specific purpose thank you for your input in helping me discover exactly what that purpose was.
 
Of course if i described the operation of something just a little different, like a miller cycle engine, some of you would probably start flinging crap around like you're in an apehouse. way to think outsideside the econobox guys.
This is why you should lurk.

you naysayers all must be right, this is a dead end technology and thats exactly why they are using similar systems in new cars.
No they aren't

i know for a fact that mitsubishi uses a similar piston and head design for its FTO mivec motor, but hey what do they know its not like they have engineers working on their designs or anything.
That's not a Heron head.
I would expect this on a honda civic forum, but i assumed volvophiles were a little more mature.
It's not a question of maturity. It's a matter of you being a militant moron.

to you who realize that volvo spent thousands if not millions of dollars in researching and implementing this design for a specific purpose thank you for your input in helping me discover exactly what that purpose was.
Your question was answered. It was also pointed out why it's not a reasonable choice 30 years after it ended production.
 
it wasn't high compression that sold me, its the combustion chamber design which allows higher (higher being the operative word) compression with crappy gas than a traditional in head combustion chamber. i spend alot of time in rural iowa where the only fuel offerings are diesel and 89 octane varnish thats been sitting in their tanks for six months, so something that can run a tight squish on lamp oil would be ideal compared to a shaved 531 which requires 92 and a bottle of octane boost just to idle correctly. if that is not YOUR ideal setup then thats fine, but it is my ideal setup and it is apparently exactly what it was designed for.

thanks for thinking im an idiot though.

I'm not shy and i'm not gonna lurk for a year until i know all you little buzzwords before asking a question either. i may not have a degree in fluid dynamics or mechanical engineering (and neither do YOU!) but i understand how an internal combustion engine works and the differences between the various cycles etc. Of course if i described the operation of something just a little different, like a miller cycle engine, some of you would probably start flinging crap around like you're in an apehouse. way to think outsideside the econobox guys. you naysayers all must be right, this is a dead end technology and thats exactly why they are using similar systems in new cars. i know for a fact that mitsubishi uses a similar piston and head design for its FTO mivec motor, but hey what do they know its not like they have engineers working on their designs or anything. I would expect this on a honda civic forum, but i assumed volvophiles were a little more mature.

to you who realize that volvo spent thousands if not millions of dollars in researching and implementing this design for a specific purpose thank you for your input in helping me discover exactly what that purpose was.

Lets start off with this- I DON'T have a degree in engineering or fluid dynamics but I have worked on a flowbench to work heads, have you ever even seen one in person? I spent YEARS building performance engine for a living. I primarily built engines to run on PUMP GAS in street cars with as much HP as I could squeeze out of it.
What is the reason for a high compression engine to run on **** gas? Why do it with rare parts? If you are going ot run **** gas why waste your money?
So Mitsu uses a similar design in their MIVEC engines? MIVEC is like VTEC, an acronym. THey apply that name to their variable valve timing design, not the engine as a whole. And their compression ratios aren't that high either. What makes you think they would run on **** gas like you want?
What does that make the Volvo design good? I'm sure they dropped the design because it was not good otherwise they would have continued to produce it for years. If Volvo spent alot of money on the design would that cause them to keep building a failure? Nope.
You are only looking at one aspect of the design, not any changes in the stroke or rod length or anything else that can change how the engine operates with substandard fuel.
Did I say anything about a shaved head? Idle isn't dictated by only the head.
If you really want an engine to run good on **** gas you don't have to control the burn in the piston, you can control it in the head. Building the engine with the pistons out of the bore rather than stting way down helps control the burn. Shaping the combustion chamber properly will do more for you as well. Then you have to consider cam profile and ignition timing to control the event timing.
If the Heron was so good it would still be around. Heavier pistons and an akward combustion chamber design aren't what I would go for.

Poi was slightly more elegant in his response that I, but right as well.

Lucky- mabye we should lok up his SN as see when the last activity was?
 
Way to go chaps, another problem solved:-P


I had a b230k in my old 740, it was tough as old boots. I'm sure it pulled better than the B230e in the 240.
 
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