VWDiesel.net The IDI, TDI, and mTDI source.
General Information => General => Topic started by: burn_your_money on April 09, 2010, 11:42:49 pm
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Well here it is. Pretty interesting stuff if you ask me. Hopefully we can have some more cams added soon.
(http://img.photobucket.com/albums/v603/burnyourmoney/Camshafts2.jpg)
BTW that G60 cam would rock the valves off the pistons on an AAZ. Dr. Diesel has a graph showing that one...
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hey man, if I sent you an ABA cam could you plot it as well?
-Owen
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Sure I suppose. Would you want it back?
I'll try and get pictures up of the setup we were using. It would be somewhat easy to build yourself with just scraps.
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depends what the map looks like...
but certainly not before the fall, so you could take your time.
a pic of the apparatus would be great!
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I'm curious, you comment that the g60 cam would be valves off pistons, but I'm looking at it in the overlap area, and it's almost exactly the same as the solid lifter cam, so really the issue would only be the amount of the valve lash wouldn't it? In fact, the intake is entirely along or within the AAZ's white line, so it is just the exhaust side that is a little slower to close at overlap, and ten or twelve thou. should be fixable with a little flycut if need be. Could somebody explain where I am missing something?
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if this could be mapped in degrees of crankshaft rotation, I could model it in autocad to check for piston/valve interference as the piston comes to the top of its stroke.
could make designing(or finding) the best cam a little easier.
-Owen
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(http://img.photobucket.com/albums/v603/burnyourmoney/Overlap.jpg)
Here you can see just the overlap. The G60 has just a bit too much.
We have mapped them vs the AAZ piston. I don't have that info, Dr. Diesel does. I'm sure he'll chime in at some time.
The AAZ piston hangs out at TDC a lot longer then the 1.6 piston. The G60 cam *might* clear it.
This is still a work in progress. There are a lot more cams to measure and plot.
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If in the need of science, you need a brand spanking new AAZ cam to graph, I have one. Never been run. I would of course perfer to have it back ;). I am not using it right now so there is no major rush. Anyone want to kick in a few bucks to help cover shipping/ ins. back and forth?
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Hey Burn, I have a topline cam that is perfect except the pulley taper broke off (lets not talk about it though :-[ :P), needless to say it's useless and is waaaay too embarassing to hang on my trophy wall ::).
It's off a mech lifter 1.6 head and I think they list the TD and NA heads and cams as the same PN.
If you want it let me know......
EDIT: I don't know what shipping will cost but if it won't be worth it I won't be too hurt.
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if this could be mapped in degrees of crankshaft rotation, I could model it in autocad to check for piston/valve interference as the piston comes to the top of its stroke.
could make designing(or finding) the best cam a little easier.
-Owen
Mapping in crank degrees is just double the cam degrees. After 180* cam, crank starts the second revolution.
Perhaps we could convince the creators of the data to post the raw data (comma delinked or something else simple to keep file size down) and then we could play with it ourselves. ;) Anyways, thanks for the data and charts, it's nice to see what these cams are actually like.
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I would be happy to pay the postage for the cam I would like mapped, and the raw data would be great too.
I could easily build a "test engine" in autocad(either AAZ or 1.6, or whatever stroke/rod length) to check for interference.
all I would really need is piston to head distance(at TDC) and valve recess into the head distance.
that with extrapolating valve lift at degrees crankshaft rotation the interference would be easy to spot.
-Owen
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Just IM me if you want the excel file. If you want it converted to crank degrees first just let me know.
I would like to measure the Topline one but I don't think we would be able to without the taper. That's what we hook the degree wheel up to.
It would be interesting to see how much wear the AAZ cams take over time, but I don't really think it would be beneficial. If anyone thinks it is LMK. Probably looking at $40-$60 there and back for shipping.
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I have a MatLab license if we want a graphical representation of piston and valve...
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I've mapped everything out at a much finer resolution re: piston movement vs valve movement. The G60 cam ruins both the 1.6L and 1.9L engines. Ruins. Especially the 1.9L
In theory, if you had a 1-notch 1.6L with the piston at the absolute minimum projection as allowed by Bentley for a 1-notch engine, and installed a 3 notch gasket, and survived reading this run-on sentence without going blind, then, again in theory, you'd finally achieve piston to valve clearance of about 0.003". (roughly the thickness of a hair) That's on average far less than 1/10th of normal clearances. A normal buildup of carbon on the surfaces would likely spell game over, let alone things like heat expansion, belt tension and timing irregularities. Bottom line is, unless you're doing something to space the head significantly further from the block than normal, (read as, no start in the cold due to low static AND dynamic compression) the G60 cam is a write-off. *edit* Most other older gas engine cams would be even worse, as they ALL have even more overlap than the G60 cam. Newer engine cams might come close, but still don't quite fit. That's without even getting into how you'd turn a gas cam with a diesel engine.
Observe:
(http://img.photobucket.com/albums/v225/vwpics/StockG60AAZ.jpg)
This graph represents an AAZ 1.9L engine. The blue line is the piston movement, truncated to avoid an unnecessarily huge graph. The red line is the exhaust valve and the green line is the intake valve. The flat lines of the valve curves represent the valve faces in the closed postion and is accurately calculated in distance away from the pistons at TDC in a best-case scenario engine. Meaning, of all the piston projection vs gasket thickness combinations allowed by Bentley, the largest clearance combo was used. Any other combination would only serve to drive the valves deeper into the pistons.
Conclusion: Crossbreeding ain't gonna work.
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from the cam specs for gasser engines that I have read, the G60 is not the most conservative cam by a long shot.
in order to meet emissions, the second gen(OBD2) ABA has lots of negative overlap(time that both valves are closed)
also the euro K-grind(mechanical) has lots(and I mean lots) of negative overlap.
the ABA cam I have(OBD2) supposedly has 7 degrees of negative overlap measured at .5mm of valve lift.
how many degrees are both valves closed(less than .5mm lift) on an AAZ/1.6 cam?
as for connecting the cam sprocket, iw would not be hard to have an adapter machined to fit on the gasser cam nose with a keyway, allowing the taper fit of the diesel sprocket.
-Owen
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You mean... like this? ;D
(http://img.photobucket.com/albums/v225/vwpics/DSC09308.jpg)
The OBDII ABA cam we mapped out is almost identical to the stock G60 cam. I've yet to delve deeper into specifics, but the common specs are:
G60 Intake 260 total duration 212 @.050" .400" total lift
ABAOBDII 262 total duration 210 @.050" .416" total lift
G60 exhaust 264 total duration 232 @.050" .400" total lift
ABAOBDII 262 total duration 210 @.050" .417" total lift.
It's a little bit closer to success, but still a major buzzkill, as can be seen below.
(http://img.photobucket.com/albums/v225/vwpics/AAZvsABAobd2.jpg)
I'm actually working with a cam company now to see what can be done. Results very soon.
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could you post a graph of a stock cam-vs-piston please?
how much clearance would be needed between valve/piston?
how much would you have to cut valve pockets into the piston tops to clear an ABA cam?
(and thanks for doing all this research for all of us)
do you have any specs from the K-grind gasser cam?
its a mech cam that is supposedly the most conservative cam on the planet.
-Owen
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I intend to... when I get to it. :) Much more pressing matters at the moment.
I don't know what a safe minimum clearance is, or how to come up with an answer beyond dispute.
In the very least, we'd need to know how much growth from heat expansion the internals could possibly undergo, as well as growth from stretch due to dynamic forces. Not to mention how much cank-to-cam phase distortion (i just made that term up to sound smart :P) occurs due to valve spring compression and extension, air charge compression and power stroke (valve train momentum preventing perfectly matched timing to the crank-- same reason for the ratcheting alternator pulley on newer TDI's), and how much timing phase distortion could possibly be experienced from the range of operable timing belt tensions. Then calculate those numbers into a worst-case scenario dimension to reflect the change in piston:valve clearance. I'm sure there's more factors in this equation, but I'm not an engineer.
To be absolutely safe, one would want to maintain minimum clearances as outlined by the OE piston projection/valve face depth/gasket thickness combinations.
As far as cutting valve reliefs in the pistons, I think that'd be somewhat detrimental. The blast ramps already cast into the pistons are very important to proper combustion, and mucking those up with valve relief pockets could more than offset any gain from ramming a gasser cam in there.
There's a great deal of theory-- and effect, behind those blast ramps. I think there was a topic on here 5-ish years ago discussing it.
I've considered all this for some time now, and have personally come to the conclusion that a custom-made diesel specific performance camshaft is the way to go. I'm well on the way to achieving that at this point. Having said that, if anyone else wanted to try installing a gas cam directly, I'm interested in hearing about it and seeing pics of the results.
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There is a knowledgeable, competent and well respected cam grinder in the lower mainland. (At least, the last time I talked to them, it was ~3 years ago.) I was wondering myself what it would take to just bring the little bit near overlap down to provide adequate clearance myself. I'd have thought (perhaps wrongly) that flycutting the valve recesses 10-20 thou wouldn't be a big deal, but perhaps more thought is needed on my part. I also haven't got the actual numbers to make the determination of what clearancing would actually be neccesary. Dr. D., BYM has offered the file with the cam data, is there any chance you'd share your file with the piston data? Any chance you have the same data for a 1.6? Is this series calculated, or actually measured? If measured, do you know the piston protrusion from the cylinder it was measured on? I could easily do a little manip within the sheet to show what sort of clearance would actually be present/required with each cam. I agree that any change that puts you closer than stock during overlap is probably unwise, although depending on what the factory clearance actually is, I might be tempted to run a TINY bit closer if I thought there would be a significant benefit. Anyways, with your data, I could easily figure out and show how much tighter each cam would be, and then repost that here.
Before I forget, Thank You to both Dr.D. and BYM for getting and sharing this information in the first place.
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I'd have thought (perhaps wrongly) that flycutting the valve recesses 10-20 thou wouldn't be a big deal,
If you mean deepening the indentations already on the pistons, they aren't valve recesses, they're blast ramps (our term anyway, maybe not a diesel engineers' term), and fiddling with them will alter, perhaps radically, the way the engine runs.
Otherwise, if you mean to simply cut recesses into the piston, the same thing applies, as it would meddle with the blast ramps.
Someone could try it... Maybe on an old engine, that wouldn't break anyone's heart if it didn't work and was relegated to scrap.
I'd suggest holding off for a bit before pouring time and money into something unnecessary. Performance cams are on the horizon. I too, have hooked up with a good cam grinder. ;)
When I get a chance, i'll put out the data for those interested.
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I have a spare car with a motor in it(mech lifters) that I would not feel bad about experimenting with.
I would be happy to try out some things in the fall, including radical cams and cutting valve pockets in the pistons.
-Owen
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That's good! Just stick with the scientfic method and do several identical dyno tests before and after and average the results. Change one variable at a time, and document each thoroughly. Without that kind of accuracy, it's speculation. That blastramp profile has a big say in how the engine's power curve looks like. Who knows? Maybe it'll work even better. :)
One small issue is hydraulic cams have a much smaller base circle than solid cams. There isn't an OE solid lifter shim thick enough to achieve correct valve lash. Lash caps on the valves might work.
With the correct valve lash achieved, the gasser hydraulic cam's profile will be significantly less in a solid lifter engine than when measured as a hydraulic cam, remember.
The other unknown at this point is, will hydraulic lifters pump up enough to run a gasser cam in a diesel head. Diesel base circle is bigger than gas too. According to a local valvetrain overhaul shop, there are about 5 different styles of VW hydraulic lifter. Maybe one of the thicker gasser lifters would drop into the diesel head, oil hole hopefully lining up with the bore supply gallery, to take up the extra clearance no problem. Or, maybe not. In any case, the shop said you don't want to run a hydro lifter at either full max extension or full compression. Seems a lot simpler just to make a proper diesel performance cam.
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unfortunately there is no dyno that will let a diesel in locally, but accurate 0-60 times could be gathered(I have a lead on a speedo built for a motorcycle that has a built in stopwatch to accurately measure)
as for the lifter thing, I was under the impression that there was only one part number for mk2-3 hydro lifters(gas and diesel)
I have run hydro cams in a mech head before with shims under the buckets(lash caps) with success, so I dont see any reason that would not work. but as you say there is no chance of a mech cam working in a hydro head(as the lifters don't like to be depressed that far) so even if the K-grind was a good fit, it would only work in mech heads.
a performance cam built just for a diesel would be great, but unless the cost can be brought down to what gasser performance cams cost($150-200) I would not be very interested. part of the reason I have been playing around with the idea of a gasser cam, is that they can be had for cheap(especially the stock ones that would be conservative enough to work) and the little bit of fabrication it may take, is what I own a VW for in the first place.
-Owen
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One thing that wouldnt be bad on an aftermarket came was if we could get the taper like a 16v so we could run adjustable cam sprockets. So just anyone can adjust their timing so far out of specs they can bend valves. :D
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Hm. They don't like the diesel smoke? Why not let a diesel in?
I wonder if it's even remotely practical to measure an engine's deflection on it's mounts as a way to indicate torque. Probably not, nvm.
A Gtech or similar would be helpful, for peak HP, at least, as well as 0-60 and Q-mile times.
I haven't investigated the differences in lifters since hearing that from the shop. I do know that G60 lifters are different than diesel, visually, anyway. That isn't to say that they wouldn't happily interchange. Apparently MkIV lifters are different again. Perhaps they meant of all years and engines of VW hydro lifters, there are several different models.
I'll just come out and say it.
I'm on the verge of releasing a drop-in hydraulic performance cam, the price of which I think everyone will find quite agreeable.
More soon.
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Hm. They don't like the diesel smoke? Why not let a diesel in?
I wonder if it's even remotely practical to measure an engine's deflection on it's mounts as a way to indicate torque. Probably not, nvm.
A Gtech or similar would be helpful, for peak HP, at least, as well as 0-60 and Q-mile times.
I haven't investigated the differences in lifters since hearing that from the shop. I do know that G60 lifters are different than diesel, visually, anyway. That isn't to say that they wouldn't happily interchange. Apparently MkIV lifters are different again. Perhaps they meant of all years and engines of VW hydro lifters, there are several different models.
I'll just come out an say it.
I'm on the verge of releasing a drop-in hydraulic performance cam, the price of which I think everyone will find quite agreeable.
You meant mechanical right? ;D
More soon.
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no, i meant hydraulic. Which I suppose means some people (solid lifter people) won't necessarily find the price agreeable or otherwise. ;D
I hope to have a chance to work on a solid cam grind, but not in the immediate future plans at this time.
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Could we solid lifter guys take up the slack with shims or are we just out?
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hm.
you know what... When I get a chance, I'll set this cam up in a solid lifter engine with the correct clearances and see what kind of a plot it makes. My gut feeling is that the performance improvement won't be worth the cost, but we'll see.
Keep in mind that you'll have to put some sort of a spacer between the valve stem tip and the underside of the mechanical lifter. Either that, or have custom thickness lifter shims made. I'd suggest the former, as proper valve lash caps likely already exist from a valve company like Manley or the like, and having a good job done with the proper materials for lifter shims would likely prove frustrating.
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I made lash caps by cutting circles out of appropriate thickness shim stock and putting it under the lifter bucket, worked fine.
this performance cam, are you willing to discuss what it is?
more lift? more duration? etc...?
if the stock cams are really close to the pistons already, what have you changed to make the performance cam, and how much has it been changed?
theoretically how much more air(in %) would it flow? (area under the curve)?
sorry to batter you with questions, but this is a big deal!
-Owen
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I made lash caps by cutting circles out of appropriate thickness shim stock and putting it under the lifter bucket, worked fine.
-Owen
For measurement purposes, I put lifter shims under the lifters as well as on top where they belonged. It seemed to work well enough, but a tight-fitting 'top hat' that fits over the valve stem tip alone would present far less mass to propel around.
You do like to tinker, huh? ;D I like that stuff.
sorry to batter you with questions, but this is a big deal!
I know. I'm really excited about it! All will be revealed in detail very soon. End of the week, I hope.
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good to hear that!
I just hope that you are willing to share info about what is different about the cam that makes it better(even if that is not actual duration degrees etc...)
I am always disappointed by people who sell "performance" parts without any actual info about the specifics.
-Owen
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I wonder if it's even remotely practical to measure an engine's deflection on it's mounts as a way to indicate torque. Probably not, nvm.
I'll just come out and say it.
I'm on the verge of releasing a drop-in hydraulic performance cam, the price of which I think everyone will find quite agreeable.
More soon.
Possible, yes. Easy even, if you know how. But not cheap.
All sorts of industrial equipment is equipped with built in scales, these scales are constructed by mounting the equipment on a load cell beam with a strain gauge in it. The strain gauge measures the tiny deflection of the beam, and outputs a voltage propotional to the load. Replace the front engine mount with a load cell, and you'd have a variable voltage signal that is directly proportional to the torque that the engine is putting down, in realtime. Calibration to easily repeatable (on different cars) would be difficult, but with a little time on a dyno, I could easily figure out the conversion factor for any given car, to have the output displayed as ft-lbs or N-m. Unfortunately the load cells are not cheap, so unless someone wanted to put several hundred dollars into such a project...
BTW, there are also load cells available in a washer style. I have considered putting one under a head bolt to see what sort of forces the head bolts actually withstand. They are to pricey to put under all the bolts, but could anyone suggest which head bolt would see the highest loads? To look at it another way, when you lift a head, where does the gasket usually fail, nearest to which bolt?
Eagerly awaiting info on the cam... I'll likely not be buying for a few months, but I'm almost for sure in for one, at a reasonable price, IF you are willing to release (at least privately) the full specs. I know you risk someone stealing it, but I think you'll convince a lot more of the people here to buy one if you actually share the profile in the same way as you have with these stock cams. I am not willing to buy anything on a try it you'll like it basis. I want to see real specs before I spend my money, so I can be sure I'm buying what I think I want. Then if I'm wrong I have no-one to blame but me. Just a thought, but if you are needing to make up a minimum number to make a go of it, I'd guess that there are enough of us willing to do a group buy type order to get you started, depending on pricing, of course.
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I'm not worried about anyone stealing the cam profile. It can't really be done just from the numbers, anyway. I will disclose everything. :) Wait and see.
The load cell is an iteresting idea. I think it'd take a huge amount of work to set up a database from which you could accurately tell HP form load on the front mount. For example, the weight of an a/c compressor might skew results, as would slope of the road, condition of the rear engine mounts, etc.
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I'm not worried about anyone stealing the cam profile. It can't really be done just from the numbers, anyway. I will disclose everything. :) Wait and see.
I'm gonna grind one out of 2 inch rebar......... ;D jk
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hehe
actually, if anyone wants to give me a quote on making steel cam blanks, i'm interested.
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We used to dyno John Deere tractors off the PTO shaft. It had a drive shaft. I SUPPOSE that could be attached to a set of rollers (or a drive flange bolted to a flywheel on an engine on a stand)
Maybe a local dealership could be convinced to allow you to make something compatible.
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Well, I looked it up, and the load cells are 3-600 bucks. I think there may be cheaper ones out there, but that is what I could find so far. As I said, I am considering running one under a head bolt, but... it's pricey, and would mean running some sort of constant datalog, or at least peak signal memory. To do a "dyno" would be easy, and absolutely repeatable on the same car, that is the signal level would always be X at a certain torque level from the engine. If the engine is changed to make 50% more torque, then the signal would be 50% higher. The problem is that the signal level would need to be checked on a dyno for calibration, and then it would still vary somewhat even between two similar cars, due to small differences in geometry. mk1,mk2,mk3 etc would all vary greatly. Unless I can find a source of the load cells for $50 or less, I won't be doing the dyno thing.
I'm still looking for info on where the head gaskets let go, so I know where to place a load cell on a head bolt.
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Could anyone figure out the duration of the stock cam of our diesel. I looked breifly through this and saw degrees but no mention of the actual duration of the cam. I need to know it to get an idea for my runner length. If it is in the bentley, tell me or let me know as I didn't think to look until right now.
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That technical kind of info isn't gonna be in the bentley. That would make things so simple tho.
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I would do the numbers if I knew how. Anyone have a formula for converting the charts we have into duration?
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I am finding it slowly. This isn't total duration, but a start.
Quote, originally posted by "VW diesel cam specs" »
ALH camshaft measured @ 1mm
Duration @ 1mm: 189*/189*
Valve Lift: .337”/.337”
Centerlines: 110.5*/113.5*
Lobe Center: 112*
Valve Timing: @ 1mm -16/25 – 28/-19
Valve Overlap: @ 1mm -35*
SDI camshaft measured @ 1mm
Duration @ 1mm: 194*/210*
Valve Lift: N/A
Centerlines: 108*/115*
Lobe Center: 111.5*
Valve Timing: @ 1mm -11/25 – 40/-10
Valve Overlap: @ 1mm -21*
AAZ camshaft measured @ 1mm
Duration @ 1mm: 194*/199*
Valve Lift: .337”/.332”
Centerlines: 103*/106*
Lobe Center: 104.5*
Valve Timing: @ 1mm -6/20 – 25.5/-6.5
Valve Overlap: @ 1mm -12.5*
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some guys are looking at cams. This maybe helpful