Discussion
First problem is the bore spacing the same?
Then are the oil and water ports in the same place.
Then you have to bodge a bottom pulley system up to take the belt.
Plus the hassle of aligning the heads perfectly for the weld so the camshaft/s can run true (and you'll still have to line bore it) And where will you get the camshaft from?
But the most glaring problem of all..........................
You've just spent weeks of your life building this supermotor, and your going to use K-jet???????
You would be better advised to use throttle bodies and an engine management solution, but then again you would see a benefit from banging them on with the OHV head still and save a lot of stress.
But I know what you mean, I do the same, it seems technical car problems are the ideal way to get off to sleep, I'm still debating what to do with my 924s!
Then are the oil and water ports in the same place.
Then you have to bodge a bottom pulley system up to take the belt.
Plus the hassle of aligning the heads perfectly for the weld so the camshaft/s can run true (and you'll still have to line bore it) And where will you get the camshaft from?
But the most glaring problem of all..........................
You've just spent weeks of your life building this supermotor, and your going to use K-jet???????
You would be better advised to use throttle bodies and an engine management solution, but then again you would see a benefit from banging them on with the OHV head still and save a lot of stress.
But I know what you mean, I do the same, it seems technical car problems are the ideal way to get off to sleep, I'm still debating what to do with my 924s!
Well the OHC redblocks are essentially the same block as the OHV ones, just with a different head. They even still have the OHV camshaft in the block to drive the distributor and oil pump. Bore spacing is not one of the problems you run into when trying to use an OHC crank in an OHV block, and the B30 has the same bore spacing as the fours, so I think we're OK there.
Oil and water passages I'm not totally certain about... it's the sort of thing that does tend to undergo minor modifications when a manufacturer converts an engine to OHC. I don't have a good idea about it from looking at stuff other people have done, because said "stuff" would mostly be people doing their own OHC conversions on fours, and they don't bother, they just use the whole engine. Something is telling me that the water passages don't quite match up but it's not so bad that you can't modify things so that they do. Not quite sure where I've got that from. Oil passages... well if they don't they don't, but I don't see any difficulty in blocking them off altogether and plumbing in an oil feed using external pipework.
Bottom pulley is unlikely to be a major difficulty, OHC bottom pulley setup tweaked in my lathe if necessary (I think it is necessary, but as I already have the lathe, not a problem.)
Alignment of the heads is the big one. I can make up a jig to bolt onto the manifold faces and the block face to align it initially, the problem as I see it is making sure it retains the alignment after being cooked welding. It does make me wonder if it would be worth looking at epoxy instead. A correctly prepared epoxy bond with aluminium is stronger than the metal, it's just the question of finding a grade of epoxy that will take the temperature. Araldite won't do it
but I think there exist high-temperature grades that might.
Camshaft... plenty of people have cut and joined motorcycle camshafts, at least... so it ought to be possible!
K-Jet, ah well, this is where it really runs into the pigeon stuff
The reasons I want to do it, my principles of getting parts off other things rather than buying new, all sorts 
Part of the idea is "I wish Volvo had done this themselves", and if they had K-Jet is what it would have ended up with.
It's easy and cheap to get the complete set of parts required off scrap cars... buying the whole car if necessary, it's on plenty of cars that are worth no more than scrap value.
If I go for the engine management idea then it'll never get anywhere as I'll be sidetracked for ages into designing and building the thing. Yes, I know you can buy them, but I also know what the electronic parts cost to build them from scratch, and embedded control systems are something I particularly enjoy making. It would be fun, but it would take ages, and it would probably cost more getting hold of the electromechanical components to go with it than it would to get hold of a complete K-Jet off a scrap car.
K-Jet installations on things like 80s Volvos and Golf GTIs don't give me any cause to think negatively of the system. It may not be the ultimate for peak power, but with an automatic box the engine hardly ever gets a chance to rev out anyway. It's reliable and reasonably economical. People do seem to be fond of replacing it with Webers, but I'm not sure that's down to anything much more than either making full race engines or simply not understanding it.
Oil and water passages I'm not totally certain about... it's the sort of thing that does tend to undergo minor modifications when a manufacturer converts an engine to OHC. I don't have a good idea about it from looking at stuff other people have done, because said "stuff" would mostly be people doing their own OHC conversions on fours, and they don't bother, they just use the whole engine. Something is telling me that the water passages don't quite match up but it's not so bad that you can't modify things so that they do. Not quite sure where I've got that from. Oil passages... well if they don't they don't, but I don't see any difficulty in blocking them off altogether and plumbing in an oil feed using external pipework.
Bottom pulley is unlikely to be a major difficulty, OHC bottom pulley setup tweaked in my lathe if necessary (I think it is necessary, but as I already have the lathe, not a problem.)
Alignment of the heads is the big one. I can make up a jig to bolt onto the manifold faces and the block face to align it initially, the problem as I see it is making sure it retains the alignment after being cooked welding. It does make me wonder if it would be worth looking at epoxy instead. A correctly prepared epoxy bond with aluminium is stronger than the metal, it's just the question of finding a grade of epoxy that will take the temperature. Araldite won't do it
but I think there exist high-temperature grades that might.Camshaft... plenty of people have cut and joined motorcycle camshafts, at least... so it ought to be possible!
K-Jet, ah well, this is where it really runs into the pigeon stuff
The reasons I want to do it, my principles of getting parts off other things rather than buying new, all sorts Part of the idea is "I wish Volvo had done this themselves", and if they had K-Jet is what it would have ended up with.
It's easy and cheap to get the complete set of parts required off scrap cars... buying the whole car if necessary, it's on plenty of cars that are worth no more than scrap value.
If I go for the engine management idea then it'll never get anywhere as I'll be sidetracked for ages into designing and building the thing. Yes, I know you can buy them, but I also know what the electronic parts cost to build them from scratch, and embedded control systems are something I particularly enjoy making. It would be fun, but it would take ages, and it would probably cost more getting hold of the electromechanical components to go with it than it would to get hold of a complete K-Jet off a scrap car.
K-Jet installations on things like 80s Volvos and Golf GTIs don't give me any cause to think negatively of the system. It may not be the ultimate for peak power, but with an automatic box the engine hardly ever gets a chance to rev out anyway. It's reliable and reasonably economical. People do seem to be fond of replacing it with Webers, but I'm not sure that's down to anything much more than either making full race engines or simply not understanding it.
Lol you've thought about this far too seriously, it's a good job we don't drink together, I've come up with some insane drunken plans over the years, the 924 quattro was one of the more amusing.
I think in this case you would be mad to consider it, and you would be best off going down the route of an engine swap, still interesting though!
K-jet...............I love it, it's totally reliable (provided it is left alone) very robust, simple, and economical. But crap for power, it has a whacking great diaphragm in the air stream for starters. I've had K-jet on lots of cars and never been tempted to change it as it works very very well, but I wouldn't install it as fresh build.
I think in this case you would be mad to consider it, and you would be best off going down the route of an engine swap, still interesting though!
K-jet...............I love it, it's totally reliable (provided it is left alone) very robust, simple, and economical. But crap for power, it has a whacking great diaphragm in the air stream for starters. I've had K-jet on lots of cars and never been tempted to change it as it works very very well, but I wouldn't install it as fresh build.
I see what you mean, a 924 quattro does sound like the sort of idea I'd go for if I was more oriented towards German cars
I also know what you mean about the flap thing on the fuel distributor, I feel a bit the same about it myself... which leads me to think of things like removing it altogether and operating the metering plunger from an actuator servoed to an ultrasonic doppler flowmeter...
I also know what you mean about the flap thing on the fuel distributor, I feel a bit the same about it myself... which leads me to think of things like removing it altogether and operating the metering plunger from an actuator servoed to an ultrasonic doppler flowmeter...
Well I've always steered clear of electronic trickery, my theory being if a carb or k-jet equipped car breaks by the side of the road then provided you have fuel to the device and it is in working order then you don't need to worry about fuel being the issue and just have to chase ignition. But having started this daft supercharger project and looking at megasquirt systems I must say I'm seriously impressed. The next 964 project was going to be fueled off PMO carbs, but I seriously think throttle bodies and megasquirt will be the way forwards.
BTW I'm quite a swedish fan myself, and was considering dropping a saab turbut in to my MGB.
What's the deal with the pigeons though.........They are sinister little beasties.
BTW I'm quite a swedish fan myself, and was considering dropping a saab turbut in to my MGB.
What's the deal with the pigeons though.........They are sinister little beasties.
Different engine but with a cut'n'shut head:
http://forums.hybridz.org/showthread.php?t=100001
Creating a DOHC head to fit Nissans venerable L series engine as used in the original Datsun Zeds.
Helps that the bloke runs a machine shop of course. He has got the engine working, 3.1l twin turbo. Lots more reading on the built engine here:
http://forums.hybridz.org/showthread.php?t=120659
I think the relevance here is that he didn't weld the head sections together due to it being impossible to seal the water and oil passages.
Cheers,
Rob
http://forums.hybridz.org/showthread.php?t=100001
Creating a DOHC head to fit Nissans venerable L series engine as used in the original Datsun Zeds.
Helps that the bloke runs a machine shop of course. He has got the engine working, 3.1l twin turbo. Lots more reading on the built engine here:
http://forums.hybridz.org/showthread.php?t=120659
I think the relevance here is that he didn't weld the head sections together due to it being impossible to seal the water and oil passages.
Cheers,
Rob
The point of insanity with that nissan project is that Nissan already make a lovely 6 pot with dohc, that being the rb series fitted to skylines among others.
Depending how much (bet there isn't enough) it might be possible to make individual heads to go on (in the style of beetle or 911 but with water and oil passages fed off an external feed.) with a top mounted cam box.
In fact to be honest I'd sooner try and adapt a head off a totally different (but 6cylinder) engine to fit.
Depending how much (bet there isn't enough) it might be possible to make individual heads to go on (in the style of beetle or 911 but with water and oil passages fed off an external feed.) with a top mounted cam box.
In fact to be honest I'd sooner try and adapt a head off a totally different (but 6cylinder) engine to fit.
I think you're wasting your time- mainly because you can't weld the coolant passages in the head back together.
Besides, the B30 is capable of making bonkers power as a pushrod motor. I can put you in touch with a guy who'll supply you with Carillo style rods and forged pistons [u]very[/u] cheaply.;)
Just in case you really do decide you have too much spare time, here's a link to a thread on Turbobricks where a B20 is getting some serious work including changing the approach of the ports by around 30 degrees!!!
Bonkers B20
Besides, the B30 is capable of making bonkers power as a pushrod motor. I can put you in touch with a guy who'll supply you with Carillo style rods and forged pistons [u]very[/u] cheaply.;)
Just in case you really do decide you have too much spare time, here's a link to a thread on Turbobricks where a B20 is getting some serious work including changing the approach of the ports by around 30 degrees!!!
Bonkers B20
Welding up the coolant passages doesn't seem to be stopping that chap
Part of my thinking is the "this is what Volvo should have done" bit they did an OHC conversion on the fours, so they should have done it on the six... I'm thinking it should give around 200bhp, and I am given to understand that beyond that you begin to run into problems due to the length of the crank, though I have not been able to find anything that goes into detail or any source of stronger cranks.
They're excellent, I like having them around
Part of my thinking is the "this is what Volvo should have done" bit
they did an OHC conversion on the fours, so they should have done it on the six... I'm thinking it should give around 200bhp, and I am given to understand that beyond that you begin to run into problems due to the length of the crank, though I have not been able to find anything that goes into detail or any source of stronger cranks.wildoliver said:
What's the deal with the pigeons though.........They are sinister little beasties.
Sinister? They're excellent, I like having them around Pigeon said:
Welding up the coolant passages doesn't seem to be stopping that chap
Part of my thinking is the "this is what Volvo should have done" bit they did an OHC conversion on the fours, so they should have done it on the six... I'm thinking it should give around 200bhp, and I am given to understand that beyond that you begin to run into problems due to the length of the crank, though I have not been able to find anything that goes into detail or any source of stronger cranks.
They're excellent, I like having them around
Just slap a turbo on it, there's your 200hp and it's easy!Part of my thinking is the "this is what Volvo should have done" bit
they did an OHC conversion on the fours, so they should have done it on the six... I'm thinking it should give around 200bhp, and I am given to understand that beyond that you begin to run into problems due to the length of the crank, though I have not been able to find anything that goes into detail or any source of stronger cranks.wildoliver said:
What's the deal with the pigeons though.........They are sinister little beasties.
Sinister? They're excellent, I like having them around I tell you though Pigeons are sinister, they are plotting to take over the world. I suspect an unholy alliance with cats myself.
I think you're mental for even trying it - go for it!
http://uk.rs-online.com/web/search/searchBrowseAct...
this stuff is the business.
http://uk.rs-online.com/web/search/searchBrowseAct...
this stuff is the business.
Pigeon said:
Camshaft... plenty of people have cut and joined motorcycle camshafts, at least... so it ought to be possible!
K-Jet, ah well, this is where it really runs into the pigeon stuff The reasons I want to do it, my principles of getting parts off other things rather than buying new, all sorts
You'd have to probably get camshafts recast from blanks for each of the 3 cylinder banks- to take into account the new firing order.K-Jet, ah well, this is where it really runs into the pigeon stuff
The reasons I want to do it, my principles of getting parts off other things rather than buying new, all sorts Also- is this lot chain driven?
I'm not an engine chain drive designer, but after many a lengthy conversation with Wheeljack- he showed me just how difficult it is- and what has to be considered. I dont think the issues are neccessarily insurmountable. Do the water ways and oil ways match up- or would they after the head chop?
An OHC engine needs more oil in the top end (as I've learned painfully with my Challenger- but thats another story)- does the OHC head have an oil spray bar?
Are the combustion chambers of a similar design or would you have to get pistons especially made to suit your desired compression ratio (no big deal).
I like K Jet and it take care of itself.
Its no Hotwire system but people often talk about its losses but I wonder just how bad they are compared to L Jet with that terrible air measuring 'barn door' which is of a small area and quite hard to push or carbs with their velocity stack-venturis.
One of the bigger issues with K Jet is its intolerance to agressive overlap/wild cams.
Edited by Marquis_Rex on Friday 19th September 13:58
Marquis_Rex said:
Pigeon said:
Camshaft... plenty of people have cut and joined motorcycle camshafts, at least... so it ought to be possible!
K-Jet, ah well, this is where it really runs into the pigeon stuff The reasons I want to do it, my principles of getting parts off other things rather than buying new, all sorts
You'd have to probably get camshafts recast from blanks for each of the 3 cylinder banks- to take into account the new firing order.K-Jet, ah well, this is where it really runs into the pigeon stuff
The reasons I want to do it, my principles of getting parts off other things rather than buying new, all sorts I was thinking of joining two suitably cut-down four-cylinder blanks and then having the result ground with six-cylinder timings.
Marquis_Rex said:
Also- is this lot chain driven?
I'm not an engine chain drive designer, but after many a lengthy conversation with Wheeljack- he showed me just how difficult it is- and what has to be considered. I dont think the issues are neccessarily insurmountable.
No, it's a belt. I was reckoning on taking the whole lot, pulleys and tensioner assembly off the front of the OHC engine and looking for a heavy-duty belt...I'm not an engine chain drive designer, but after many a lengthy conversation with Wheeljack- he showed me just how difficult it is- and what has to be considered. I dont think the issues are neccessarily insurmountable.
Marquis_Rex said:
Do the water ways and oil ways match up- or would they after the head chop?
An OHC engine needs more oil in the top end (as I've learned painfully with my Challenger- but thats another story)- does the OHC head have an oil spray bar?
No, it doesn't. It has an oil feed which comes up around one of the head bolts and goes through galleries to the camshaft bearings. The camshaft actuates the valves directly, it is vertically above the valves and bears on bucket tappets. The cam carrier part of the head casting is more or less shaped like a bath, with transverse partitions for the camshaft bearings and the tappets sticking up through the bottom to as little height as necessary, so all the oil that escapes from the sides of the camshaft bearings then drains onto the upper faces of the buckets.An OHC engine needs more oil in the top end (as I've learned painfully with my Challenger- but thats another story)- does the OHC head have an oil spray bar?
The OHV head arranges for the oil feed to the rocker shaft in the same way but I'm not sure which bolt it uses. I figure it's not a major worry anyway because it's easy to plumb in an external oil feed.
There's no reason why it shouldn't be possible to fit an oil spray bar but camshaft wear is not a noted problem with these engines and since the cams would still be operating under the same conditions I am thinking all I need to do is make sure the oil pump is capable of supplying the requirements of 1.5 four-pot heads.
The water passages... I said above I wasn't sure, I've now checked it out and they don't match up. On the OHV engine they are smallish circular holes in the triangular spaces between the head bolts and the points at which the bores come closest together. On the OHC engine they are pairs of more or less triangular apertures in the spaces between the cylinders, the head bolts and the edges of the block.
I'm not sure why they've done this - whether it's to allow for a greater potential to increase the bore size or whether it's to increase flow...
If it's just for bore size potential then I think there's no problem in simply drilling holes in the appropriate place in the OHC head and blanking off the originals. This would also be bringing the water into the head closer to the exhaust valves, which should be beneficial... but I have my doubts as to whether the flow would be adequate.
I am thinking the thing to do here is to increase the pumping capacity of the cooling system and provide an additional external water feed to the head.
Marquis_Rex said:
Are the combustion chambers of a similar design or would you have to get pistons especially made to suit your desired compression ratio (no big deal).
Very similar... both heads have valves arranged centrally along the centre line of the engine and simple bathtub chambers. The OHV combustion chamber is a very simple "Hornby train set oval" shape with parallel sides, the OHC one is more of a "chain drive with unequal pulleys" shape, still with straight sides but with a larger radius curve at the inlet valve end. It is possible to overbore the OHV block to accept OHC pistons which would keep all the in-cylinder geometry factory standard.Marquis_Rex said:
I like K Jet and it take care of itself.
Its no Hotwire system but people often talk about its losses but I wonder just how bad they are compared to L Jet with that terrible air measuring 'barn door' which is of a small area and quite hard to push or carbs with their velocity stack-venturis.
One of the bigger issues with K Jet is its intolerance to agressive overlap/wild cams.
I am thinking that the curtain area of a K-Jet "flapper" is pretty huge...Its no Hotwire system but people often talk about its losses but I wonder just how bad they are compared to L Jet with that terrible air measuring 'barn door' which is of a small area and quite hard to push or carbs with their velocity stack-venturis.
One of the bigger issues with K Jet is its intolerance to agressive overlap/wild cams.
I wasn't planning on using an aggressive cam, I'm thinking either the same profile as Volvo used on the K-Jet engines or the Volvo "K cam" profile, which is nothing to do with K-Jet, it is the one which offers the lowest increase in tune over the standard production cams, still gives decent bottom-end performance and I believe does not upset K-Jet.
The problem I see is that there's nothing wrong with the B30 in the first place.
I'm all for one off conversions and clever engineering but I really think you're on to a loser with one.
Give someone like Catcams a call and ask them how much to have a one off cam made. When you get up off the floor I think you'll reconsider the idea.
Get some decent rods & pistons (they are available if you know where to look and not too spendy either), a Holset HX or HY35 from a Cummins B series diesel and add Megasquirt to the mix.
How much power do you want to make? 30psi of boost would see with around 6-700hp.
I'm all for one off conversions and clever engineering but I really think you're on to a loser with one.
Give someone like Catcams a call and ask them how much to have a one off cam made. When you get up off the floor I think you'll reconsider the idea.
Get some decent rods & pistons (they are available if you know where to look and not too spendy either), a Holset HX or HY35 from a Cummins B series diesel and add Megasquirt to the mix.
How much power do you want to make? 30psi of boost would see with around 6-700hp.
Which reminds me, I must follow your suggestion of joining turbobricks and get that question asked about the B30 crank...
The thing about this idea is that it isn't just about increasing the power output. My estimate is that the power output will be something under 200bhp, going on what the standard OHC fours do. I could probably get the same or better result in pure power terms by fitting triple SUs on a Penta manifold in place of the standard twin Strombergs on the restrictive preheater-thingy manifold, a free flowing exhaust, larger valves and a K cam to the standard OHV configuration, with a lot less buggering about.
I am thinking more in terms of rewriting history "what would it be like if Volvo had done this"...
When the 240 series replaced the 140 series, the major mechanical change was that the four-cylinder engine was converted to OHC. It worked very well and they carried on using that engine for nearly 20 years.
In the six-cylinder variants, though, the 260 did not feature an OHC conversion of the preceding model's engine. It had that horrible 90 degree V6 which apart from eating camshafts was as rough as a badger's arse, and was a definite backward step in terms of refinement, a 260 is like a tractor compared to a 160. The 160 purrs, the 260 goes dugga-dugga-dugga. Also, unlike the fours, it actually had less power than the engine it replaced.
In my opinion the 260 should have featured an OHC version of the B30, and I want to make "the engine that Volvo should have made" so we can see what it would have been like.
The thing about this idea is that it isn't just about increasing the power output. My estimate is that the power output will be something under 200bhp, going on what the standard OHC fours do. I could probably get the same or better result in pure power terms by fitting triple SUs on a Penta manifold in place of the standard twin Strombergs on the restrictive preheater-thingy manifold, a free flowing exhaust, larger valves and a K cam to the standard OHV configuration, with a lot less buggering about.
I am thinking more in terms of rewriting history
"what would it be like if Volvo had done this"...When the 240 series replaced the 140 series, the major mechanical change was that the four-cylinder engine was converted to OHC. It worked very well and they carried on using that engine for nearly 20 years.
In the six-cylinder variants, though, the 260 did not feature an OHC conversion of the preceding model's engine. It had that horrible 90 degree V6 which apart from eating camshafts was as rough as a badger's arse, and was a definite backward step in terms of refinement, a 260 is like a tractor compared to a 160. The 160 purrs, the 260 goes dugga-dugga-dugga. Also, unlike the fours, it actually had less power than the engine it replaced.
In my opinion the 260 should have featured an OHC version of the B30, and I want to make "the engine that Volvo should have made" so we can see what it would have been like.
Pigeon said:
Marquis_Rex said:
Pigeon said:
Camshaft... plenty of people have cut and joined motorcycle camshafts, at least... so it ought to be possible!
K-Jet, ah well, this is where it really runs into the pigeon stuff The reasons I want to do it, my principles of getting parts off other things rather than buying new, all sorts
You'd have to probably get camshafts recast from blanks for each of the 3 cylinder banks- to take into account the new firing order.K-Jet, ah well, this is where it really runs into the pigeon stuff
The reasons I want to do it, my principles of getting parts off other things rather than buying new, all sorts I was thinking of joining two suitably cut-down four-cylinder blanks and then having the result ground with six-cylinder timings.
Marquis_Rex said:
Also- is this lot chain driven?
I'm not an engine chain drive designer, but after many a lengthy conversation with Wheeljack- he showed me just how difficult it is- and what has to be considered. I dont think the issues are neccessarily insurmountable.
No, it's a belt. I was reckoning on taking the whole lot, pulleys and tensioner assembly off the front of the OHC engine and looking for a heavy-duty belt...I'm not an engine chain drive designer, but after many a lengthy conversation with Wheeljack- he showed me just how difficult it is- and what has to be considered. I dont think the issues are neccessarily insurmountable.
Marquis_Rex said:
Do the water ways and oil ways match up- or would they after the head chop?
An OHC engine needs more oil in the top end (as I've learned painfully with my Challenger- but thats another story)- does the OHC head have an oil spray bar?
No, it doesn't. It has an oil feed which comes up around one of the head bolts and goes through galleries to the camshaft bearings. The camshaft actuates the valves directly, it is vertically above the valves and bears on bucket tappets. The cam carrier part of the head casting is more or less shaped like a bath, with transverse partitions for the camshaft bearings and the tappets sticking up through the bottom to as little height as necessary, so all the oil that escapes from the sides of the camshaft bearings then drains onto the upper faces of the buckets.An OHC engine needs more oil in the top end (as I've learned painfully with my Challenger- but thats another story)- does the OHC head have an oil spray bar?
The OHV head arranges for the oil feed to the rocker shaft in the same way but I'm not sure which bolt it uses. I figure it's not a major worry anyway because it's easy to plumb in an external oil feed.
There's no reason why it shouldn't be possible to fit an oil spray bar but camshaft wear is not a noted problem with these engines and since the cams would still be operating under the same conditions I am thinking all I need to do is make sure the oil pump is capable of supplying the requirements of 1.5 four-pot heads.
The water passages... I said above I wasn't sure, I've now checked it out and they don't match up. On the OHV engine they are smallish circular holes in the triangular spaces between the head bolts and the points at which the bores come closest together. On the OHC engine they are pairs of more or less triangular apertures in the spaces between the cylinders, the head bolts and the edges of the block.
I'm not sure why they've done this - whether it's to allow for a greater potential to increase the bore size or whether it's to increase flow...
If it's just for bore size potential then I think there's no problem in simply drilling holes in the appropriate place in the OHC head and blanking off the originals. This would also be bringing the water into the head closer to the exhaust valves, which should be beneficial... but I have my doubts as to whether the flow would be adequate.
I am thinking the thing to do here is to increase the pumping capacity of the cooling system and provide an additional external water feed to the head.
Marquis_Rex said:
Are the combustion chambers of a similar design or would you have to get pistons especially made to suit your desired compression ratio (no big deal).
Very similar... both heads have valves arranged centrally along the centre line of the engine and simple bathtub chambers. The OHV combustion chamber is a very simple "Hornby train set oval" shape with parallel sides, the OHC one is more of a "chain drive with unequal pulleys" shape, still with straight sides but with a larger radius curve at the inlet valve end. It is possible to overbore the OHV block to accept OHC pistons which would keep all the in-cylinder geometry factory standard.Marquis_Rex said:
I like K Jet and it take care of itself.
Its no Hotwire system but people often talk about its losses but I wonder just how bad they are compared to L Jet with that terrible air measuring 'barn door' which is of a small area and quite hard to push or carbs with their velocity stack-venturis.
One of the bigger issues with K Jet is its intolerance to agressive overlap/wild cams.
I am thinking that the curtain area of a K-Jet "flapper" is pretty huge...Its no Hotwire system but people often talk about its losses but I wonder just how bad they are compared to L Jet with that terrible air measuring 'barn door' which is of a small area and quite hard to push or carbs with their velocity stack-venturis.
One of the bigger issues with K Jet is its intolerance to agressive overlap/wild cams.
I wasn't planning on using an aggressive cam, I'm thinking either the same profile as Volvo used on the K-Jet engines or the Volvo "K cam" profile, which is nothing to do with K-Jet, it is the one which offers the lowest increase in tune over the standard production cams, still gives decent bottom-end performance and I believe does not upset K-Jet.
My appologies, for some reason I thoght the B30 was a V6.
In which case I'm sure it should be alot easier in terms of the cam drive- just carrying over pretty uch, especially if the blcok deck height and position of the idler pulleys can be duplicated etc etc. How is it tensioned?
Belt drives are also easier to mess with than chains.
From what you say the design is direct acting with all the valves inline- so not a cross flow head?
Do you hope to weld up the two cylinders from the OHC 4 cylinder head to the other 4? now you've inspired ME to do something to my BMW project but thats another story!
I think external water pipes outside the block is a plausible solution- BMW used this solution on some of their M engines in the past.
Forget about my comments on the oilspay bar, I was confused, if the 4 cylinder OHC engine doesnt need it this I 6 OHC probably doesnt either. *crosses fingers*
VWs have similar arangements and dont need them.
I think what BBq and wildoliver say, makes rational sense in a kind of function approach, but this project doesnt sound like its a rational thing- more to do with passion and the 'journey' being more important than the end result.
I've done similar things also- I wanted to do a 4 valve straight six for my BMW E21 3 series, but NOT by simply dropping in the modern fully mnapped 328i engine- as I wanted it with dizzy drive and how BMW would have made it if they produced it and I used to get alot of flack for that. I also wanted to use a purely mechanical plunger pump fueling system rather than K jet or some mapped affair and I got alot of flack for that also- just stick to your guns and do what makes you happy/fulfilled
I think 200 Bhp is ambitious from a 3 litre non cross flow Volvo engine: Its not impossible, as you can go for a more agressive cam and shift the power torque compromise toward top end power- but it doesnt sound like this is what you want to do. 200 BHp from a 3 litre is the kind of numbers BMW would get from their excellent flowing-fast burning shallow 2 valve hemis with good torque around the late seventies. if you reduced intake and exhaust losses- you could possibly approach this figure without an agressive cam- if you were willing to compromise on exhuast boom and intake noise (which would probably sound great anyway).
There are examples of high BHP/litre engines with this combution chamber/port arrangement: The original 1.6 litre 1588 cc VW golf GTi, but that used an agressive cam and was peaky with peak torque at 5100 rpm and peak power abouve 6000 rpm.
The difference in projects such as these and my BMW stuff I've done for years is that you really have to be innovative and a pioneer in your own right. There's very little availiable. I used to hate the Ford guys- they had everything- special pistons were availiable for the Essex and Cologn engines, cam profiles, especial cam profiles etc etc. I had to get stuff custom made for my BMW all the time, and I had to populate my own knowledge as people didnt really know stuff about them. It wasnt too bad, as I work in engine R and D, with access to flow benches etc etc.
You'll have to be equally innovative. Now I'm playing with American stuff- its all easy-almost too easy. Everything is availiable off the shelf. roller lifters, rockers with needle bearings, disc brakes, rack and pinion steering set ups etc etc.
good luck
Pigeon said:
I am thinking more in terms of rewriting history "what would it be like if Volvo had done this"...
When the 240 series replaced the 140 series, the major mechanical change was that the four-cylinder engine was converted to OHC. It worked very well and they carried on using that engine for nearly 20 years.
In the six-cylinder variants, though, the 260 did not feature an OHC conversion of the preceding model's engine. It had that horrible 90 degree V6 which apart from eating camshafts was as rough as a badger's arse, and was a definite backward step in terms of refinement, a 260 is like a tractor compared to a 160. The 160 purrs, the 260 goes dugga-dugga-dugga. Also, unlike the fours, it actually had less power than the engine it replaced.
In my opinion the 260 should have featured an OHC version of the B30, and I want to make "the engine that Volvo should have made" so we can see what it would have been like.
I think you'r justification for the project is very interesting, but probably lost on most people here. You dont have to justify what you want to do to others anyway. "what would it be like if Volvo had done this"...When the 240 series replaced the 140 series, the major mechanical change was that the four-cylinder engine was converted to OHC. It worked very well and they carried on using that engine for nearly 20 years.
In the six-cylinder variants, though, the 260 did not feature an OHC conversion of the preceding model's engine. It had that horrible 90 degree V6 which apart from eating camshafts was as rough as a badger's arse, and was a definite backward step in terms of refinement, a 260 is like a tractor compared to a 160. The 160 purrs, the 260 goes dugga-dugga-dugga. Also, unlike the fours, it actually had less power than the engine it replaced.
In my opinion the 260 should have featured an OHC version of the B30, and I want to make "the engine that Volvo should have made" so we can see what it would have been like.
The 90 degree V6 sounds like its uneven firing to get the crank/piston balance. So it probably fires 150-90-150-90. The other way to get a 90 degree V6 balanced is do what Mercedes and Audi do now and offset the crank pins. Its unlikely a modern engine would ever do the uneven firing thing. In the 19070s it was common however, with Masserati and this Volvo, I think Buick chopped a V8 and did the same thing.
I would be interested to hear what that uneven firing sounds like. I know the uneven firing of a conventional V8 leads to its beautiful burble- and introduced some interesting harmonics. I can also believe, no, I know this kind of uneven firing will lead to powerloss- due to charge robbing/interference issues-could even lead to a rough idle. I always thought it would be characterful. So bored of anodyne corporate refined motors
Interesting that you say it eats camshafts, I heard the 90 degree Buick V6 has chain drive issues, due to un equal loading on the chain drive.
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