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"Blueprinting" VW heads
Hi Volks,
I'm aware of the importance of keeping head chamber volume equal across all the 4 cylinders as well as the benefits of a port and polish job. But I am wondering about the techniques of cleaning up the exterior fin area of the stock cast VW cylinder head. Specifically, I would like to clean up the casting imperfections (casting flash?) between each of the fins. I look "down" into the head fins (from the perspective of the air coming from the fan shroud) and I see places where it would seem that the VW engineers intended for air to blow through. But deep in those places are blockages by random "flash" (like the plastic flashing have to trim away when you build a model airplane or such). My first impulse was to get a small flat-headed screwdriver and rubber mallet...but that didn't seem wise. What tool should I use to get deep in there and clear out those places between the fins. I know it seems anal but I am trying to blueprint the cooling design of my 1776cc Type 1 engine (with Webcam 163 camshaft) so that I may safely run a higher CR (9.2:1) while running pump (Premium) gas in California. I am running the late Doghouse fanshroud with all cooling flaps and all the other various cooling tin that everyone forgets about. I am also exploring getting heat barrier coatings applied to the head combustion chamber by these guys: http://www.replikamaschinen.com/ If the cost of getting those coatings done is less than $300, I am certainly going for it. Anyways, thanks for any advice on head fin cleanup as well as highest CR for my engine. Regards, Geoffe Elias '74 Super Beetle |
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#2
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"Blueprinting" VW heads
Geoffe Elias wrote:
> Hi Volks, > I'm aware of the importance of keeping head chamber volume equal > across all the 4 cylinders as well as the benefits of a port and > polish job. if this is a street car, do not polish the intake ports. The exhaust and intake port flow should be in a certain relation to each other, for the head to work well. (Exhaust flows less, 1target is a certain percentage of intake flow, like 85% for example). If you just go to town and hog the ports out as big as you can, you will likely ruin the heads. More flow can be found safely from a professional competition valve job. (Including but not limited to what is called "3-angle valve grind" ) The valves and seats are ground to certain progressive angles (or a controlled smooth radius), and the valve faces can be radiused too (but only on one side.The exh is ground on the piston side, while intake valves are radiused on the port side. If memory serves... ) There's more that can be done to the valves depending on their design. > But I am wondering about the techniques of cleaning up > the exterior fin area of the stock cast VW cylinder head. > Specifically, I would like to clean up the casting imperfections > (casting flash?) between each of the fins. Yes, do it. Some cheap aftermarket "stock heads" have an obscene amount of flash clogging up all passages. > I look "down" into the head fins (from the perspective of the air > coming from the fan shroud) and I see places where it would seem that > the VW engineers intended for air to blow through. But deep in those > places are blockages by random "flash" (like the plastic flashing have > to trim away when you build a model airplane or such). My first > impulse was to get a small flat-headed screwdriver and rubber > mallet...but that didn't seem wise. What tool should I use to get > deep in there and clear out those places between the fins. I drill them. No shock of hammer blows. > I know it seems anal but I am trying to blueprint the cooling design > of my 1776cc Type 1 engine (with Webcam 163 camshaft) so that I may > safely run a higher CR (9.2:1) while running pump (Premium) gas in > California. I am running the late Doghouse fanshroud with all cooling > flaps and all the other various cooling tin that everyone forgets > about. What is the octane of your premium gas? 9.2:1 is too much for that cam, unless it's pretty darn high octane gas. Don't go over 9:1, and if you have the kind of fuel I think you do, you need to stay in the 8.7:1 neighborhood. You will need to slightly radius all sharp edges in the combustion chamber. Also unshroud the valves in the chambers. Make chambers deep and narrow, if you need more volume. Do not widen them. You want the mixture to be concentrated in a tight, small area. It can be deep, but not any wider than it has to. You also want to run a very tight deck height. Between 1.1 and 1.3mm, NO MORE. I'd rather try to get it closer to 1.1mm. Set that first, then figure out how big your chambers need to be, to produce the CR you want. Then work on the chambers to get there. > I am also exploring getting heat barrier coatings applied to the > head combustion chamber by these guys: > http://www.replikamaschinen.com/ If the cost of getting those > coatings done is less than $300, I am certainly going for it. No personal experience. Some people say it works. Jan |
#3
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"Blueprinting" VW heads
Jan Andersson wrote:
> Geoffe Elias wrote: >> Hi Volks, >> I'm aware of the importance of keeping head chamber volume equal >> across all the 4 cylinders as well as the benefits of a port and >> polish job. > > if this is a street car, do not polish the intake ports. > The exhaust and intake port flow should be in a certain relation to each > other, for the head to work well. (Exhaust flows less, 1target is a > certain percentage of intake flow, like 85% for example). > If you just go to town and hog the ports out as big as you can, you will > likely ruin the heads. > > More flow can be found safely from a professional competition valve job. > (Including but not limited to what is called "3-angle valve grind" ) > The valves and seats are ground to certain progressive angles (or a > controlled smooth radius), and the valve faces can be radiused too (but > only on one side.The exh is ground on the piston side, while intake > valves are radiused on the port side. If memory serves... ) > There's more that can be done to the valves depending on their design. > > >> But I am wondering about the techniques of cleaning up >> the exterior fin area of the stock cast VW cylinder head. >> Specifically, I would like to clean up the casting imperfections >> (casting flash?) between each of the fins. > > > Yes, do it. Some cheap aftermarket "stock heads" have an obscene amount > of flash clogging up all passages. > > >> I look "down" into the head fins (from the perspective of the air >> coming from the fan shroud) and I see places where it would seem that >> the VW engineers intended for air to blow through. But deep in those >> places are blockages by random "flash" (like the plastic flashing have >> to trim away when you build a model airplane or such). My first >> impulse was to get a small flat-headed screwdriver and rubber >> mallet...but that didn't seem wise. What tool should I use to get >> deep in there and clear out those places between the fins. > > I drill them. No shock of hammer blows. > > > >> I know it seems anal but I am trying to blueprint the cooling design >> of my 1776cc Type 1 engine (with Webcam 163 camshaft) so that I may >> safely run a higher CR (9.2:1) while running pump (Premium) gas in >> California. I am running the late Doghouse fanshroud with all cooling >> flaps and all the other various cooling tin that everyone forgets >> about. > > What is the octane of your premium gas? > 9.2:1 is too much for that cam, unless it's pretty darn high octane gas. > Don't go over 9:1, and if you have the kind of fuel I think you do, you > need to stay in the 8.7:1 neighborhood. > > You will need to slightly radius all sharp edges in the combustion > chamber. Also unshroud the valves in the chambers. Make chambers deep > and narrow, if you need more volume. Do not widen them. You want the > mixture to be concentrated in a tight, small area. It can be deep, but > not any wider than it has to. > > You also want to run a very tight deck height. Between 1.1 and 1.3mm, NO > MORE. I'd rather try to get it closer to 1.1mm. Set that first, then > figure out how big your chambers need to be, to produce the CR you want. > Then work on the chambers to get there. > > > > >> I am also exploring getting heat barrier coatings applied to the >> head combustion chamber by these guys: >> http://www.replikamaschinen.com/ If the cost of getting those >> coatings done is less than $300, I am certainly going for it. > > No personal experience. Some people say it works. > > > Jan Oh yea, you can most likely run 1.25:1 rockers with that cam, for a little more lift. |
#4
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"Blueprinting" VW heads
Hi Jan,
Thanks for the drill idea! Will look at long enough drill bits to make this happen. As for the main question about CR: Over where I am at, it is 91 octane. My current CR is 8.2:1. I agree that a jump to 9.2:1 is steep, but I was wondering if the use of heat barrier coatings could justify that jump. Problem is that the engine is running a bit too cool, even cooler than the stock 1600 (with the same cooling setup). I can't give any real temp numbers but only a comparative observation is based upon the use of a Berg oil dipstick temp sensor device. -Geoffe Elias '74 Super Beetle On Apr 8, 4:36*pm, Jan Andersson > wrote: > Geoffe Elias wrote: > > Hi Volks, > > * I'm aware of the importance of keeping head chamber volume equal > > across all the 4 cylinders as well as the benefits of a port and > > polish job. > > if this is a street car, do not polish the intake ports. > The exhaust and intake port flow should be in a certain relation to each > other, for the head to work well. (Exhaust flows less, 1target is a > certain percentage of intake flow, like 85% for example). > If you just go to town and hog the ports out as big as you can, you will > * likely ruin the heads. > > More flow can be found safely from a professional competition valve job. > (Including but not limited to what is called "3-angle valve grind" ) > The valves and seats are ground to certain progressive angles (or a > controlled smooth radius), and the valve faces can be radiused too (but > only on one side.The exh is ground on the piston side, while intake > valves are radiused on the port side. If memory serves... *) > There's more that can be done to the valves depending on their design. > > > But I am wondering about the techniques of cleaning up > > the exterior fin area of the stock cast VW cylinder head. > > Specifically, I would like to clean up the casting imperfections > > (casting flash?) between each of the fins. > > Yes, do it. Some cheap aftermarket "stock heads" have an obscene amount > of flash clogging up all passages. > > > * I look "down" into the head fins (from the perspective of the air > > coming from the fan shroud) and I see places where it would seem that > > the VW engineers intended for air to blow through. *But deep in those > > places are blockages by random "flash" (like the plastic flashing have > > to trim away when you build a model airplane or such). My first > > impulse was to get a small flat-headed screwdriver and rubber > > mallet...but that didn't seem wise. *What tool should I use to get > > deep in there and clear out those places between the fins. > > I drill them. No shock of hammer blows. > > > * I know it seems anal but I am trying to blueprint the cooling design > > of my 1776cc Type 1 engine (with Webcam 163 camshaft) so that I may > > safely run a higher CR (9.2:1) while running pump (Premium) gas in > > California. *I am running the late Doghouse fanshroud with all cooling > > flaps and all the other various cooling tin that everyone forgets > > about. > > What is the octane of your premium gas? > 9.2:1 is too much for that cam, unless it's pretty darn high octane gas. > Don't go over 9:1, and if you have the kind of fuel I think you do, you > need to stay in the 8.7:1 neighborhood. > > You will need to slightly radius all sharp edges in the combustion > chamber. Also unshroud the valves in the chambers. Make chambers deep > and narrow, if you need more volume. Do not widen them. You want the > mixture to be concentrated in a tight, small area. It can be deep, but > not any wider than it has to. > > You also want to run a very tight deck height. Between 1.1 and 1.3mm, NO > MORE. I'd rather try to get it closer to 1.1mm. Set that first, then > figure out how big your chambers need to be, to produce the CR you want. > Then work on the chambers to get there. > > > * I am also exploring getting heat barrier coatings applied to the > > head combustion chamber by these guys: > >http://www.replikamaschinen.com/*If the cost of getting those > > coatings done is less than $300, I am certainly going for it. > > No personal experience. Some people say it works. > > Jan |
#5
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"Blueprinting" VW heads
On Apr 8, 2:50*pm, Geoffe Elias > wrote:
> *What tool should I use to get > deep in there and clear out those places between the fins. > ------------------------------------------------------------------------------------------------ The proper tool is a pneumatically powered 'riffler' with a set of coarse files... but since you don't have any of that stuff (...or you wouldn't have asked the question :-) try a saber saw with a LONG, COARSE-TOOTHED blade, such as for cutting wood. That should fairly well on the fins. But the holes around the exhaust valve guides are more important (seriously). Try using long drills ('air-craft drills'). You can't use most rotary tools... as soon as they pick up a bit of aluminum they become imbalanced and are liable to walk the die-grinder right out of your hand, Worse-case? A set of Swiss machinist's files and LOTS of patience. (Give the files a spritz of WD-40 every now & then to keep them from loading up.) --------------------------------------------------------------------------------------------------- > * I know it seems anal but I am trying to blueprint the cooling design > of my 1776cc Type 1 engine (with Webcam 163 camshaft) so that I may > safely run a higher CR (9.2:1) while running pump (Premium) gas in > California. *I am running the late Doghouse fanshroud with all cooling > flaps and all the other various cooling tin that everyone forgets > about. > ------------------------------------------------------------------------------------------------ I think you'd be wise to stick with 8.5:1 or LOWER. It's not you nor the machine work, it's that rotten ****ing FUEL they're selling us nowadays. It may say... whatever on the pump but that doesn't mean that's what you're getting in your tank. My bike runs 10:1 (old CX-500) The only fuel it will run on nowadays is 100LL from the airport. Liv & lurn. -Bob Hoover |
#6
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"Blueprinting" VW heads
Ah, well it looks like in order to do the proper job, get the proper
tools. Am going to look into the cheapo diamond rifflers as suggested by jtbartlett as well. Meanwhile, while searching around, discovered the following place which think is a brilliant idea: http://www.techshop.ws Too bad about the crap fuel issue though. I guess besides the fact that watercooled engines can handle autodetonation better due to their ability to shed waste heat better, they also can rely on a whole bunch of other tricks like computerized engine management with knock sensors and such. -Geoffe Elias '74 Super Beetle On Apr 10, 2:56*am, Bob Hoover > wrote: > On Apr 8, 2:50*pm, Geoffe Elias > wrote: > > > *What tool should I use to get > > deep in there and clear out those places between the fins. > > ------------------------------------------------------------------------------------------------ > > The proper tool is a pneumatically powered 'riffler' with a set of > coarse files... but since you don't have any of that stuff (...or you > wouldn't have asked the question :-) *try a saber saw with a LONG, > COARSE-TOOTHED blade, such as for cutting wood. *That should fairly > well on the fins. *But the holes around the exhaust valve guides are > more important (seriously). *Try using long drills ('air-craft > drills'). *You can't use most rotary tools... as soon as they pick up > a bit of aluminum they become imbalanced and are liable to walk the > die-grinder right out of your hand, *Worse-case? *A set of Swiss > machinist's files and LOTS of patience. *(Give the files a spritz of > WD-40 every now & then to keep them from loading up.) > > --------------------------------------------------------------------------------------------------- > > > * I know it seems anal but I am trying to blueprint the cooling design > > of my 1776cc Type 1 engine (with Webcam 163 camshaft) so that I may > > safely run a higher CR (9.2:1) while running pump (Premium) gas in > > California. *I am running the late Doghouse fanshroud with all cooling > > flaps and all the other various cooling tin that everyone forgets > > about. > > ------------------------------------------------------------------------------------------------ > > I think you'd be wise to stick with 8.5:1 or LOWER. *It's not you nor > the machine work, it's that rotten ****ing FUEL they're selling us > nowadays. *It may say... whatever on the pump but that doesn't mean > that's what you're getting in your tank. *My bike runs 10:1 (old > CX-500) *The only fuel it will run on nowadays is 100LL from the > airport. *Liv & lurn. > > -Bob Hoover |
#7
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"Blueprinting" VW heads
Geoffe Elias wrote:
> Too bad about the crap fuel issue though. I guess besides the fact > that watercooled engines can handle autodetonation better due to their > ability to shed waste heat better, they also can rely on a whole bunch > of other tricks like computerized engine management with knock sensors > and such. engine management and knock sensors are also available in many aftermarket kits, that could also be used on an aircooled VW engine. Many people have "modernized" their VW engines this way, especially when building turbo engines that by nature come with higher risks of detonation damage etc.. and really need good mixture control. |
#8
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"Blueprinting" VW heads
On Apr 10, 7:45*pm, Geoffe Elias > wrote:
> *I guess besides the fact > that watercooled engines can handle autodetonation better due to their > ability to shed waste heat better, they also can rely on a whole bunch > of other tricks like computerized engine management with knock sensors > and such. > ----------------------------------------------------------------------------------------------------------- It's not just the fact they are liquid-cooled. The foundation issue is the use of a computer to control the process of combustion. Most folks start acting silly when you say things like that but it's the truth. Light the fire in ANY gasoline-fuel, spark-ignited engine and the following 'combustion event' will take something like two thousandths of a second REGARDLESS of your rpm. (There is a clue buried in there. QED and all that.) The basic combustion controller is a chip from Zilog. Pretty crude but it's cheap and has a good track record with regard to failures. AND it runs in the megahertz range, meaning you've got tons of time to do whatever needs doing before the NEXT 'combustion event' comes around. But that's just the start of it. In a modern-day vehicle you're liable to have as many as SEVEN 'computers,' if your definition is limited to microprcessors capable of reading instructions, doing things and recording the results. The literal definition of a 'computer' is an MPU, an I/O controller, and some memory. The fact you can get all that on one chip doesn't change anything. The distinction is between 'controlling' something and controlling something on the results of a computation. What makes it tricky is when the computer in charge of combustion starts using INPUT from one or more of those other computers to determine when the engine gets another shot of fuel, how much fuel it gets and so forth. Actually, it's rather interesting. Study of the code gives you a keen insight as to the politics behind how all that crap -- most of which is carcinogenic -- got into our motor vehicle fuel... then getting you to pay a PREMIUM for such crap. Clearly, we have the best government money can buy :-) -Bob Hoover |
#9
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"Blueprinting" VW heads
On Sun, 12 Apr 2009 21:13:29 +0200, Bob Hoover > wrote:
> On Apr 10, 7:45 pm, Geoffe Elias > wrote: > >> I guess besides the fact >> that watercooled engines can handle autodetonation better due to their >> ability to shed waste heat better, they also can rely on a whole bunch >> of other tricks like computerized engine management with knock sensors >> and such. >> ----------------------------------------------------------------------------------------------------------- > > It's not just the fact they are liquid-cooled. The foundation issue > is the use of a computer to control the process of combustion. Most > folks start acting silly when you say things like that but it's the > truth. Light the fire in ANY gasoline-fuel, spark-ignited engine and > the following 'combustion event' will take something like two > thousandths of a second REGARDLESS of your rpm. (There is a clue > buried in there. QED and all that.) The basic combustion controller > is a chip from Zilog. Pretty crude but it's cheap and has a good > track record with regard to failures. AND it runs in the megahertz > range, meaning you've got tons of time to do whatever needs doing > before the NEXT 'combustion event' comes around. > > But that's just the start of it. In a modern-day vehicle you're > liable to have as many as SEVEN 'computers,' if your definition is > limited to microprcessors capable of reading instructions, doing > things and recording the results. The literal definition of a > 'computer' is an MPU, an I/O controller, and some memory. The fact > you can get all that on one chip doesn't change anything. The > distinction is between 'controlling' something and controlling > something on the results of a computation. What makes it tricky is > when the computer in charge of combustion starts using INPUT from one > or more of those other computers to determine when the engine gets > another shot of fuel, how much fuel it gets and so forth. > > Actually, it's rather interesting. Study of the code gives you a > keen insight as to the politics behind how all that crap -- most of > which is carcinogenic -- got into our motor vehicle fuel... then > getting you to pay a PREMIUM for such crap. Clearly, we have the best > government money can buy :-) > > -Bob Hoover Well, we have the best Gazoline money can buy... Our politicians on the other hand you can have at a very reasonable rate. :-] J. -- Using Opera's revolutionary e-mail client: http://www.opera.com/mail/ |
#10
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"Blueprinting" VW heads
>>Light the fire in ANY gasoline-fuel, spark-ignited engine and
the following 'combustion event' will take something like two thousandths of a second REGARDLESS of your rpm<<< Well, sorta. It will depend greatly upon the combustion pressure. At peak torque the fuel is burning much more rapidly than at cruise. >> The basic combustion controller is a chip from Zilog.<< I think that most current automotive applications use the Freescale line HCS12 processors. They replaced the Mot6800 Risc and Zilog series in most cases. |
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