Now that I look, it's there clear as day That's right, we'll never all be happy....as long as the parts do what you want them to do, I guess that's enough.
Your latest rendering, post #73, I like the best. Clean, simple, even has the Advance/Retard markings. Great work! If you wanted the 'gee whiz' design of a pin, to help keep the cam gear from slipping while setting the timing, don't make it threaded. The pin would simply hold the gear while tightening, then pull out when done. Personally, I don't think it's necessary. As to recovering R&D for non-business work (posts 15 & 16)...this is a sour spot for me, a personal pet peeve, so of course people will disagree. As an enthusiast, I do stuff for the joy of the hobby. If I do something that helps then I share. I can understand a business wanting to recoup costs, no arguement there. But if you're an individual doing something on your own time in your area of expertise and come up with something that is beneficial to the hobby and have the means to make it available for others within and do so, great, charge enough to cover materials/fab/shipping/etc. but NOT R&D. That payback for that is the knowledge & pride that your contribution is helping the community. There are times when capitalism just goes too far. I have a college degree (I, not mommy & daddy, put myself through college). I have spent days researching -- sometimes outside my area of expertise just to make sure I've got my ducks in a row. Yes, I consider my time valuable and charge my employers when they require it. But I don't charge my fellow hobbiests that time when I've done it on my own i.e. they haven't HIRED me! I know many people won't agree and will give good, logical explainations. That's fine, I support differences of opinion. But to me, they're more interested in making a buck; it's just that doing so may help the community they're presently involved in. That mentality, to me, is more business-like than neighbor-like. Take it as you will, it's my opinion.
i have no intention of recovering R&D, i need to do this for myself so in a sense i hired myself and will eat the time, no biggie. i'm sharing with others who maybe interested in getting a set for themselves, the more people i have the lower the manufacturing cost will drop. for now the price of these isn't set becouse i have no idea how maney people are interested let alone would be willing to buy a set. my set will allways cost more than the procceding sets, so even if i get 10 people saying yes we want a set, i will still have to pay the initial charge for mine due to set up and machine time which is always high for the first or only one. i have no econimic advantage for getting more people interested. it would be for them, if it's one here and one there then they would all cost roughly 1k. but by doing a run of them then the cost to you goes down. if i had the money to burn i might make a few sets and hold on to them but if they dont move then i have some very expensive jewlery sitting around.
You probably know this, but just in case: Each bank has 2 cam gears, with the flanges in different locations on the gear. One gear has a flange on it's rear as in your rendering, the other has a flange around the front. Thus there's a flange on each side of the belt. As to lining up the timing holes. The stock gears come with a row of 4 holes grouped along 1 side, & a 5th hole 180 degrees out from the 4-hole pattern. When doing a major service where the cam alignment was off when I removed the cam covers, I've often found that NONE of the holes will line up in the approximate position the gear was in when it was removed from the cam. Usually the holes originally pinned put the cam mark closest to the cam cap mark with the gear in that general position. Presumably this was why that hole pair was used in the first place. It was the closest available w/o pulling the belt off & rotating the cam gear. When this happens, you have to remove the cam belt, rotate the cam gear ~ 45 degrees & check to see if you have matching holes, sometimes you have to repeat this 3 times to get a perfect match(sigh). The Al cam gear available from Nick's Forza Ferrari has a full set of holes. It avoids this little problem. As to your cam gear clamp, Its similar to a one of several designs I came up with a couple of years ago & discarded as not being sufficiently flexable, or else have mechanical interference problems. There are indeed times when you want to just hold the cams in place while changing the belt, which it shold do, as long as the cross-bar is sufficiently rigid to ensure the timing is spot on. I'm not sure there's sufficient clearance to slip the cross-bar behind the cam gears, especially on the 4V front bank. Things are very tight in there. As most members know, I've been selling a simple clamp for the 2V engine that does the job for over a year. I haven't got my 4V clamp design into production tho.
yes i do know the flange swaps sides, thank you though. i had noticed the 1 hole sitting out there but couldn't figure out why. adding additional holes thus completting the circle of 25* spacing is simple enough the space is there. 91tr posted a great excell file that show permutations of degrees available from the 28* cam holes the 25* pulley holes and the 12* tooth spacing. so yes i agree a real pain to get it set right consedering how many options there are. being that i have the tooth spacing laid out in CAD it allows me to see the spacing and layout needed to design a tool to hold both cams together without interference. my idea was to hold the pullies just behind the belt, the pully is is wider than the belt by at least 1/4" giving you enough material thickness to hold the cams, slide the belt forward enough to clamp the pulley and it should be good to go. now in the real world i'll see. not trying to nose you out of a product in the least, i figured i'd give it a shot since i have the CAD/CAM softeware and the parts designed. another thought is to engineer a tool into the new pulley design, but that would only be good for those who have my new pullies. trying not to leave anyone out.
I have been wondering something on occasion, and these last few threads have brought it to attention again. Without digging down through all my boxes of engine parts, I am absolutely positive my cam pulleys have pin holes that go completely around the pulley for pinning the pulley to the cam. Yet there are references to pulleys only haveing six holes, if I am reading this right. Do I simply have early pulleys that Ferrari changed up from, am I reading something wrong, or do I have oddball pulleys and need to go dig them out to verify?? I guess that was how I was thinking of this, that with all the pulley holes, I thought I recalled you could get within 3 degrees, which would be close enough with that first design pulley to register it at, or close to zero.
Uhhmmm, in the words of Rosanne Rosannadanna, nevermind. I had to go dig them out and look. What I had thought were holes, were simply grease marks from the camshaft holes. All my pulleys have 3 holes.
This got me to wondering if I was having another Alzheimer's attack. Pulled out my spare set of plastic cam gears & guess I was. The cam gears have 5 holes, all on the same side. From the impressions on their back, the cams have 3 holes on one side, with a 4th hole about 180* opposite the 3 hole pattern. Last fall I helped with a 328 major & we compared it's metal cam gears with my plastic ones. The hole patterns were the same. Now krowbar has a set with a different pattern!
I have never seen a pulley with less than 5 holes, but I guess it could be. I have gained a bit of adjustability by chucking the pulley in a rotary indexing fixture, and drilling another set of 5 holes opposite the original, but timed off by 1/2 degree. Gets things a bit closer, and I have found that a pin can be used in the new section, without pulling the pulley and turning it. (the old dance). I still prefer the first design, as I do not tend to think it would work loose if tightened properly. I would tend to think that the belt would break, probably @ the lower pulley before the pulley would slip. I note that other "imports" use that design succesfully, FWIW
I too vote in favor of the design in #73. 5 6mm screws into helicoils and properly torqued should provde sufficient normal force between the two halves so that slippage isn't an issue. Just measured one of my plastic gears, the teeth are 1.180" long, not 1.250". The belt is 1" wide so there's 0.180" left over for the clamp. This is still reasonable space if the tool's sole purpose is to just hold the gears in place for a belt change. The tool could be made out 0.150" or even 0.1" stock & should work fine. I went back & took a 2nd look at the drawing & realized I was miss-interpreting how the tool fit on the cam gears. The cross-bar goes down between the two gears. So the clearance concern I raised in my earlier post isn't valid. This is indeed a varient of the scheme I looked at awhile back. Also finally remembered why I discarded it. OUR REQUIREMENTS ARE DIFFERENT: In addition to the design goal of holding the cam gears in place for a belt change, I wanted a tool design that could be used to keep the cam gears from turning while breaking loose/torqueing the cam gear bolt. This was a major requirement because with 1 exception , all the majors I've performed had at least 1 cam misaligned. So I had to break the gear loose & pull it off in order to match up the holes. I decided that the tool's narrow teeth would concentrate excessive force on a small area of the cam gear's teeth. Didn't believe this would be a problem with the new metal cam gears, but my concern was that it would break the plastic cam gear teeth. . That's why I've been working on a design that fits in the somewhat triangular gaps between the 2 gears & grabs the full width of several teeth. My 2V tool avoids the fragile teeth problem by grabbing onto the cams just behind the cam gears. A bit of trivia: The only difference between the front flange & rear flange plastic cam gears is which edge of the gear the plastic flange is glued onto! That's right, the body of the gear is the same for both parts, even stamped with the same mold #. It also explains why the flange pops off so easily. A 2nd bit of trivia: If you break the cam gear bolt loose, don't forget to fully remove the bolt & replace the o-ring around it. Otherwise you'll have an oil leak
Yup, I understand all of that and I see where you're coming from. Sounds like you're doing it the right way
I thought I'd take a quick pic and post it, and I actually needed to dig all four out and look at them to make sure anyway. Here ya go... Image Unavailable, Please Login
the tool would only be to hold the cams in place not to break the bolt loose i agree, not enough surface area to withstand the force. it would also most likley be made from brass or soft aluminum so as not to marr the teeth..ditto on the o-ring, hollow cams make for some fun oil leaks personaly i'd rather see a tool that holds the cam stock in place to release the pulley since the force of the bolt is in there not in the pulley. but that may not be possible, i'd have to give the cams a closer look. in order to get the spare pullies of my new old cams, i put them in my vice with allen wrenches in a tooth on either side to prevent rotation. walla they unbolted with ease and no marring of the the teeth. i wasn't concerned with damaging the pullies as two were already beatup.
if my wife caught me doing that on our white carpet i'd be typing with two bloddy stumps right now. but wow mine are all 5 hole, the 82' set and the 75' carb set. interesting...
I had a less cool, but also less money thought...OEM pulleys fitted with a new 6061 hub. The metals a bit thin so it would need to be thru bolts in from the back side witht the head keyed to the current mounting hub to prvent them from rotating. Nylocs on the from side...and of course a pin to lock the timing
the biggest cost factor is the milling of the teeth, the rest is simple mill and lathe work. i'm trying to follow your idea, if your replacing the outer toothed hub then you'd need 7075 aluminum with a nutural hard anodize. that belt really eats away the material. i like your idea but i really can't follow it, are you saying to replace the toothed hub or the inner keyed area? one of the other design constraints is the back to front face dimensions. the belt accutually rides past the back face where pulley pins to the cam. keeping it centered to pulley and lower pullies keeps me from getting to radicle with the design. i'd be more than happy to do a layout for you if you can explain it a little better to my mushy brain i have the original layout in CAD.
I'm saying keep the part with the teeth and cut out the center. Make a new center to bolt to the cam and bolt the tooth part to it. I think it will require thru bolts, but I also think something with a reduced head thickness will fit. I'm thinking very similar to what you're already thinking, just usting the teeth part from the OEM pulley.Does that make sense?
i see, the only problem is the cross section of the OEM pulley. in cross section, it has a small rib in the center that runs down to the face of the plate you attach to the cam. by removing the centerplate you won't have enough material to attach the new plate to. also the cost of setting up and milling out the steel iner would negate any cost savings. from what i can see the OEM pulley is a steel hub with a molded on fiberglass tooth ring. in order insure accurate degree setting the iner hub would have to ride on a .001" gap, i dont think thats possible with molding slag in the way. please don't think i'm raining on your parade, i like the idea. if those issues can be worked around then it could be doable. first though i'd want to cut a OEM pulley in half to geta real good idea as to what is going on. the reason i went to complete replacement of the pulley is the cost of replacement used steel ones. i was quoted a $250 per pulley, i can make the aluminum adjustable for less.
Ahhh, you have the plastic pulleys. My pulleys are steel (could be iron I guess). The toothed section and hub are one piece so it can be machined any old way without concern....appearently not a workable option for all. On mine, there is about 1 hour or lathe time to cut all 4 pulleys, maybe 1 more hour on the mill to drill and slot them. 2-3 more hours to make the new center hubs....seemed easy and cheap.
don't discount it, it could be very possible. couple points. if it is machined from steel stock than it's doable with attention spent on centering the new larger hole and reeming the surface to achive a close tollerence for the center hub. the center hub would have to be made from steel not aluminum due to the expansive difference in the properties, otherwise adjusting on a warm engine will be a no go. if it is made from cast grey iron, well then it's not possible as further machine could induce cracks, but i doubt that they cast the parts for the pullies.
While my steel pulleys can be cut and made to work, it sounds like the other versions maybe can't...so here's another though. I bet you could simply turn the pulley around inside out. Now there is plenty of room for a second piece behine it. You pin the the new spacer to the cam. You drill the OEM pulley with new pin holes on a larger OD, say on 10* spacing. You drill the spacer on 10.5* pattern. Use a pin to loch the OEM pulley to the spacer at any timing you please and a single bolt (longer the OEM) thru the center hole to hold the whole thing on. Or use the OEM hole on 25* and finish the pattern so you have 14 or them and do 24* in the sparcer, now you can go +/- 14* in 2 degree steps. Now we're talking 2 or 3 hours of machining and a bolt - it should be a $200-$300 dollar conversion.
here's the problems i ran into when designing the new pulley. tool space, i.e. wrench socket clearence bolt-head spacing washer clearance material wall thickness for drilling & tapping and the need to retain if not add additional pin holes to set up factory timing. all these issues can be easly delt with if we had at least a 4.5" dia pulley. we don't it's less than 3" inside of the teeth. from there we have a 24mm head bolt & a .236" pin. so all our new hardware and layout need to fit into a width of 0.65" or just over 1/2". not alot of room. i took your idea to cad and the problem i have is getting additional room for putting in hardware that would hold the two together with out just relying on a pin. an interference fit would be need to keep both peices together effectivly and those pins are hard to install/remove. the other issue is i did a layout with the set screw earlier, that required 21 evenly spaced holes on one peice and 20 on the other spaced out in intervals growing from 1*~10* if those holes are not placed in the right radial distance from the center then there is to little material left before the pulley will shear. it's always the simingly simple and small parts that will have you pulling your hair out. don't fret i've spent two weeks on layouts, it'll drive you crazy. no different from the issues you've been dealing with on the FI front.
would only need to hold cam belt drive gears stationary during belt changes...I know this tool is not the main topic of the thread .. but thought I would advocate for its development
You don't need to hold the 2 together, you can just use the thru bolt into the cam. And if we are willing to live with 2* steps, you can also use the pin hole pattern already in the pulley and just extend it all the way around...I think that gets you 14 holes, so 7 on each side of zero, or +/- 14* each way. It might be possible to put a second row of holes on a slightly larger radius, but it's not really required.
i see where your going, tell me if i'm off anywhere. in order to use the main bolt into the cam, you'd need to keep the existing pulley as is but add additional hole's for degree's. then machine another center peice that would use those holes and fit into the original pulley. OK so far, but to make any adjustments you still need to loosen the cam bolt and jump teeth. however the real problem lays in the setting up the original timing, those pin holes on the OEM pulley get in the way of additional work. you'll still need to pin the pulley to the cam, one of those two pieces need to be fixed to the cams intial timing. if its the center piece then the bolt going into the cam cannot hold the outer hub, if its the out hub then the reverse is true. but if you pin them all together then there is no need for the center piece. i wish i could post dwg. files to show you what i'm talking about. i'll try some DXF formats to jpeg... the design dosn't stray far enough from the OEM setup to be worth the time to me. if i can get more people willing to buy the design i have for the adjustable one, then when run, the batch cost comes down do approx, $190. per pulley. i would think that those mods plus the additional center piece would cost the same if not more.
