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This is just starting I already have a few images on the other Jim k thread, but I am starting a new one showing all my misinformed and misguided interpretation of the book, along with a few ideas I picked up on the Japanese site as well.
The plan, 46mm BMW goodies, 45mm dcoe152(spain) and a broom handle and some drywall nails for the 'hot' cams!
Photo 1 shows the head after cleaning and it looks like I might be starting this thread prematurely as it has some severe water damage to the 3 and 4 intake bowl. I have another head that may be used if this damage turns out to be too deep to grind out, OR if a majority of the pits come out, what say you regarding a little JB weld to smooth it out?
This being as it were, I started with the manifold which I think is the easy way to go if you have never done this before as the mounts tell you exactly where to start. I was kind of unsure of the starting points noted in the book for the head itself.- do you start on the floor, or the top of the port or center.. any way, I think this is the way to be %100 sure of your locations.
I mounted the mounts and the carbs and there you go.. actually kind of off center to the left is where everything landed, so that is where I started.
Photo 3 shows how much you really got to remove and man, its alot!
The manifold actually gets kind of thin around the back recess for the carb mount bolts and its 'feels' like it isnt going to be any thicker the 3/16" toward the front , couple that with the fact that the carbs tend to be a little offset from the ports and you can see this **** is not joke. I going to carry on and see what happens.
 

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OK this is some of the valve stuff I picked up from some shop in some part of socal. I got passed along and pointed toward one shop to the next till I ended up in a strip mall wedged between two taco trucks with a valve shop in the basement. Anyway super nice guy and set me up with valves seats and guides NOT fron a 325 or what ever the book said but from a M10 motor ! the 325 did not have 46mm valves, some of the old 2002 ti's did- not sure which ones and it really dosent matter, but FYI it is from the M10.
Must be an Aussie thing.
The valve seats we of course 45* and I have them check out for that and it was golden so I did a little polish on the fronts and tranisitions being careful not to touch the seats and stems. I use a foredom tool which is very nice to work with for long hours , quite, smooth and powerful. I spun the valve on a drill press and worked the valve into quite a lather,to 2000 wet actually.
Last shot is a before and after.
The BMW valves are about 3/16 shorter and will require some noodleing for the springs and such
 

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OK this is some of the valve stuff I picked up from some shop in some part of socal. I got passed along and pointed toward one shop to the next till I ended up in a strip mall wedged between two taco trucks with a valve shop in the basement. Anyway super nice guy and set me up with valves seats and guides NOT fron a 325 or what ever the book said but from a M10 motor ! the 325 did not have 46mm valves, some of the old 2002 ti's did- not sure which ones and it really dosent matter, but FYI it is from the M10.
Must be an Aussie thing.
The valve seats we of course 45* and I have them check out for that and it was golden so I did a little polish on the fronts and tranisitions being careful not to touch the seats and stems. I use a foredom tool which is very nice to work with for long hours , quite, smooth and powerful. I spun the valve on a drill press and worked the valve into quite a lather,to 2000 wet actually.
Last shot is a before and after.
The BMW valves are about 3/16 shorter and will require some noodleing for the springs and such

Did you stop and try the tacos?
 

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Discussion Starter #4
no, they made them with cheeze wizz and wonder bread, the carna asada was actually old tootsie rolls I think. So I passed.
shouldnt you be out slapping around girls about now ? I got a kid whats your excuse?
 

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Well, I'll be damned!! All the proofreading and one more mistake found...you are right, the valves are NOT from the 325 but the 525/528/728/730 series, BMW P/N 11341257592. The ones you got from the old 2002ti and used in the 316/318/320/520 are also 46mm but they're too short (103.8mm, BMW P/N 11341254625)and the wrong shape for best flow. If you really want the best, go for the 47mm valves from the new 525i/735iL engines, BMW P/N 11341705560. Both these are 106.5mm long and if the machine shop doesn't butcher the seats and sink them in, you end up with best flow + good CR and no problems with valve clearance shims.
Jim K.
 

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Ill be watching this thread closely as I'm also at the same spot with my engine rebuild. I'm also rebuilding my head to Jim K specs from his book of course!!!


Thanks Jim for the BMW part numbers. Do you have a favorite source to get them from?
 

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Jim, will you be on the alfagtv6.com/bb forum anytime soon? I have a question for you about intake manifold choices on a V6 transaxle car.
 

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Discussion Starter #10
Thanks Jim! that is great news, and great info. sounds huge, sounds radical- I like
THis works out great considering I am going to scrap the head at the shop now and use a new one so the seats have not been installed.
Now the $56,000 question- what kind of seats?
I will be posting shots of the intake porting shortly.
 

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I read both Alfa sites daily but for various reasons I have minimized my partcipation, let's not get into it.
I can readily find all kinds of BMW valves here in Athens, 46mm ones cost ~25Euros and if I remember right, 47mm ones ~30Euros (as of 6-8 months ago). As for seats, I don't use BMW ones but the machine shop looks around and picks ones with the right dimensions; for instance, in the 3liter head with the 46mm valves, he used some seats from some Fiat truck (!) which were very hard and modified them to suit. Its very important not to sink the seats in the head as you'll have problems requiring ultra-thin shims (they start at 1.300mm). If all work is properly done, you end up with shims around 1.8-2mm which is very convenient.
I suggest you send the heads to an experienced porter for the final seat work, its a very crucial area for flow. 3-angle seats still are very good for great results.
Jim K.
 

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OK this is some of the valve stuff I picked up from some shop in some part of socal. I got passed along and pointed toward one shop to the next till I ended up in a strip mall wedged between two taco trucks with a valve shop in the basement. Anyway super nice guy and set me up with valves seats and guides NOT fron a 325 or what ever the book said but from a M10 motor ! the 325 did not have 46mm valves, some of the old 2002 ti's did- not sure which ones and it really dosent matter, but FYI it is from the M10.
Must be an Aussie thing.
The valve seats we of course 45* and I have them check out for that and it was golden so I did a little polish on the fronts and tranisitions being careful not to touch the seats and stems. I use a foredom tool which is very nice to work with for long hours , quite, smooth and powerful. I spun the valve on a drill press and worked the valve into quite a lather,to 2000 wet actually.
Last shot is a before and after.
The BMW valves are about 3/16 shorter and will require some noodleing for the springs and such

Wow, the back of that valve looks beautiful. One question. Don't you want a little turbulence to help mix the air/fuel mixture? I can't see having a polished valve gaining much in the way of flow. I'd really like to see the flow bench #s when you are done.

Will
 

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Discussion Starter #14
I think the valve itself would cause plenty of mixin' although I'm no expert.
also let's not forget that the valves and just about everything else in the head stays polished and clean for about 3 seconds before carbon starts to collect and things stop being shiney. But i will flow bench it .
 

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Well I have half of the intake half way done. This was a good way to get to know and love the porting process with out too much risk as I had the mounts to show me the way.
All in all, pretty easy so far, as you can get to both sides of the manifold and its a simple profile to match. I do however think the taper from 46 to 41.5mm which takes place at the front half of the manifold is drastic enough to have more clearification as to where the center line lives and where exactly does that dia. relate to the old dimentions. In the book we have a drawing that is not exactly to scale and is a little light around the bosses and centerlines. I was going to have my guy make a solid works model using the book but it turns out there were too many missing measurments to make it right. What we really need is a larger photo of a cross section, that way I can take the knowns and build a complete 3d model of the port so I can find any point and its relationship to static landmarks! Jim...?
Photo 2 is the first transition from 46 to 41.5 shy about .5 for finish.
I start with a carbide bit and then go to a rat tail file for the final shaping.
I could go on and on about how the file is the greatest tool mankind has access to now and forever but I will pass on that, all I can say is that the file, if used properly is the most accurate controlable read-able device you have in that old coffee can on the window sill. You can see that the markings made by the file tell me exactly where the taper stops and starts and how the rounds are kept round. learning how to read a file is straight forward IF the user has the right stroke, which is kind of like rowing a boat its wrist, waist, shoulder and hands, all working together to keep things round or flat..enough about that, just remember if you use a file to shape- it is not a saw- its more of a paint brush.
after the rat tail, a flap wheel at low speed is worked in a controlled circle counter rotation to the tool and not back and forth like, again, a saw. You can feel the tool jump if you are out of round and again, dont simply dig out the low spots, all the more reason to use the file, you cannot get a low spot mid way through a plane using a file, cant happen, therefore you cant screw up! I am trying to make a perfect tapered cylinder and you have to 'think' like a cone, BE the cone
 

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All in all, pretty easy so far, as you can get to both sides of the manifold and its a simple profile to match. I do however think the taper from 46 to 41.5mm which takes place at the front half of the manifold is drastic enough to have more clearification as to where the center line lives and where exactly does that dia. relate to the old dimentions.
Peter,

I think JimK has written the tao of Alfa cylinder porting. :) Hiis diagram intentionally provides a relative increment of taper because head porting is about half science and half art. IMHO it's more important to focus on the smoothness of the taper rather than trying to locate an exact point for its start. My take on laminar flow is that it is a generalized phenomena and so the fact that a taper happens is probably more important to flow than the exact point of its start. Thus (again in my opinion) in his diagram, Jim gives us a general idea of where to make the port changes. Implicitly, a few mm's either way shouldn't make that much difference. It goes without saying, however, that once you've decided where your particular taper begins that it pays to be consistent when you work on the other ports.

Thanks for posting your progress. It looks like you are doing some good work! :)
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Discussion Starter #17
I totally agree with the things you say, regarding smoothness,consistent tapers and such and I HOPE what you say about a few mm's +- and there impact on flow is equally as true. being that this is such a new process /program, to me, I just want to make sure I can blame someone else if I get 114 HP on the dyno;) .
I think I will be able to get the hang of this 'feeling' for flow, at least in a meta sort of way, once I get to the actual head until then or in spite of my perception of the information, I only have the numbers..
I am looking for just this sort of input however, its going right into the soup!
Thanks.
ps. eddy is the real name, shelf the pete thing.;)
 

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I totally agree with the things you say, regarding smoothness,consistent tapers and such and I HOPE what you say about a few mm's +- and there impact on flow is equally as true. being that this is such a new process /program, to me, I just want to make sure I can blame someone else if I get 114 HP on the dyno;) .

Eddy,

Your head is definitely going to flow more air than one with a typical 3 angle valve job and stock ports. It will also (probably) flow less than a head modified using a flow bench. JimK developed his particular head design using a flowbench and, if you get close to what he did, you'll have a satisfactory result. That's one of the best things about his books. But there are also as many different approaches to porting Alfa heads as there are people doing the work.

I'll admit to being a little biased in favor of Jim's approach because when I got his first book I was surprised to find that my most recent (and successful) head porting attempt was, in fact, pretty close to what he'd published. That head worked really well. Before I started that head I read about everything I could find; various hot rod magazines, David Vizard's head porting book. Some conversatiions with with Alfa legend, John Shankle, helped as did the guys in the hot rod machine shop I used who had a lot of experience porting Chrysler Hemis. That's the fun thing about doing this: there is informaton out there that you can use and, also, there are people who know things who are usually willing to help if you ask the right questions.

Come to think of it, I have a friend with a blown up Sperry Stage 5 head. I'll see if I can get him to get me those measurments.
It'd be interesting to compare the two designs.
 

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No I had a little detour with the spica that was in the 74. I had to spent the extra scratch on putting in the 40's I had and that pretty much put the other head on hold. The up side- crazy fast ! so much fun over 2500 rpms I can hardly stop smiling, in fact I picked it up today and the only thing crazier then the fun was the bill! (well worth it)
I have 11mm cams and we lightened the flywheel 4 or 5 lbs. super mid to high range, but I couldnt get the vilocity stacks in and the K&N filter was too shallow, so I might be missing some low end, but fun enough!
As for the new head, I have one (again) ready to go, but its from a later model spider and the manifold hits a part of the casting so that needs to be ground off also it has the intake ports stepped for the bosch injection so I have to see if the port dimentions will work.
I will go at it in a few months.
 

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