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Engine Specific Info and Questions => IDI Engine => Topic started by: scopefrfd on January 16, 2007, 08:45:58 pm
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I was going over some posts on the inherent weakness of the AAZ crankshaft keyway. Some repairs, the crankshaft keyway is welded up and the crank snout is reground to accept a tdi "D" crank gear. Others the crank snout is machined 180 degrees opposite of the factory key way.
My question is why can't the crank snout be ground where the keyway is, without welding. Doesn't the new machined outer edges of the new "D" crank gear basically take all the load? I believe the keyway is cut a little deeper on the crank but that "gap" would be in the center of the D-crank gear. I can't imagine the center of the crankgear being subjected to that much force.
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hi,
the load is not transfered by the snout!
it is just for centering the crank-gear, the load ist only transfered by the surfacepressure done by the bolt.
due to vibrations, reused bolts, non plain contact surface and other factors the bolt gets loose or breaks.
after some time VW changed the bolt from 10.8 (6 edges) to 12.9 (12 edges)
especially the heavy wheel /w rubberdamper for driving the generator/powersteering etc. belt seems to have a negative effect when the rubber gets worn out and the wheel isnt longer balanced.
greets, michael
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my understanding is the welding builds up the snout back up to stock dimensions or more so the gear fits properly.
i don't see why it couldn't be machined in the same spot?
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I always weld them up because the face and the outside diameter is usually worn and no longer true. While I'm at it I fill in the old keyway. Welding also allows me to make the crank snout slightly oversize for a light press fit in the pulley and on the "flat". An undamaged crank could probably just be machined across the old keyway, but I've never worked on an undamaged crank...
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I do them the same way as QuickTD.
I have done many undamaged cranks,but still weld them up and remachine to slightly over size,so the gear is a light press fit.
The TDI gear is a D shape inside,but it does not go all the way trough the gear.The actual area where the flat sits on the crank is only about 1/8" deep.If the gear does not fit tight,it will rock and wobble,and then it comes loose and spins.
I've seen some guys attempt this repair and never have success,as they are not precise,or don't weld up the crank first.When you entire engine (big $$$$) is at stake,don't cheap out on the proper repair.It costs a little more to weld and remachine,but it's worth it.
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I realize this is an old post, but I have some questions about repairing / modifying the crank nose on my aaz.
For welding, what part of the crank are you building up with weld? The face and the circumference, along with the keyway?.........and then machining it all to allow for a tight press fit to the AHU "D" gear?
My crank is in good shape and the keyway is not buggered..........so just weld the keyway or? I want to do the mod before it gets buggered.
Also, does it matter how the "D" is oriented on the crank in regard to timing marks and timing the engine?
Lastly, buy an oem Febi gear or a $15 Chinese copy.........is there an appreciable difference?
Thanks
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I don't see any reason you couldn't machine it where the key is now.
I welded mine up but it was just cause I could, so I did.
The 22 tooth sprocket really doesn't need to be timed exactly from what I've heard. I maintained the timing pretty close when I milled the flat for the new sprocket. Again, why not if it's possible. The fit was good and as mentioned, it's the new, properly torqued bolt that does all the "holding".
(https://lh3.googleusercontent.com/-Cfj-B0V9NMo/UcL75lvhf0I/AAAAAAAAB4k/n1-pVDvmRbs/w975-h731-no/DSC00430.JPG)
I think the off-shore sprocket will be fine. It is an important bit though so if you have doubts and a more familiar brand will make you feel safer, I'd go for it.
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What are you guys welding with, I'd be worried about making things worse with the flux core in my MIG...
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What are you guys welding with, I'd be worried about making things worse with the flux core in my MIG...
I preheated it a bit so it wouldn't get hard and if I recall, ground out the key way some to remove the sharp corners in the bottom (to avoid pinholes). I used .035 wire and 75% argon. It was scary but it turned out good.
Flux-core would do it, just not as easy to control (too hot for me anyway). I don't really think it needs to be done though if the fit is still good. My original keyway was fine and so was the sprocket. I am also running a V-belt so probably didn't need to do anything but use a new bolt.
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that seems reasonable enough, I was thinking more of the folk adding materiel to the OD of the thing.
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I think QuickTD and wyldman weld up the face, the outer circumference, the keyway, and then machine the whole crank end to mate with a light press fit, to the specific sprocket that they have selected for the repair. One of them dishes the face so that the sprocket won't roll around on the bolt. I'd like to hear more about the dishing of the crank face, as in how many thousandths deep?
I am going to have a machine shop do this repair, however, I do not want to leave the process to someone who really doesn't have an idea of the problems [ and required fix ] that the AAZ has regarding the sprocket keyway, and the torsional loads placed upon the crank from a non-decoupler pulley alternator. I want to be able to provide the appropriate answers and direction to the machinist [ who has likely never seen this problem before ] so that the repair is done right.
The TDI AHU sprocket is $62.00 from my local VW dealership.
Does anyone know if the crank bolt for the AAZ and the AHU are the same part number? Or are they different bolts altogether? Same for the rear crank gasket? Same gasket for both the AAZ and the AHU?
Would be nice to get all of this online at one place, but id parts does not have any AAZ parts listed, only AHU.
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I think QuickTD and wyldman weld up the face, the outer circumference, the keyway, and then machine the whole crank end to mate with a light press fit, to the specific sprocket that they have selected for the repair. One of them dishes the face so that the sprocket won't roll around on the bolt. I'd like to hear more about the dishing of the crank face, as in how many thousandths deep?
I am going to have a machine shop do this repair, however, I do not want to leave the process to someone who really doesn't have an idea of the problems [ and required fix ] that the AAZ has regarding the sprocket keyway, and the torsional loads placed upon the crank from a non-decoupler pulley alternator. I want to be able to provide the appropriate answers and direction to the machinist [ who has likely never seen this problem before ] so that the repair is done right.
The TDI AHU sprocket is $62.00 from my local VW dealership.
Does anyone know if the crank bolt for the AAZ and the AHU are the same part number? Or are they different bolts altogether? Same for the rear crank gasket? Same gasket for both the AAZ and the AHU?
Would be nice to get all of this online at one place, but id parts does not have any AAZ parts listed, only AHU.
I don't think it's that big of a deal but do whatever you feel is needed. I believe the specified torque of a new bolt (TTY) is the ticket. The bolt (when torqued properly) is a very serious "spring". I believe the working mate is made between the inside flat face of the sprocket and the end of the flat crank. An interference fit is still radial and while it may insure concentricity, it is a radial fit and won't help resist (radial) torque as well as the properly mated faces.
If you can't rely on the bolt, everything else you do (short of a heat-shrink fit) is moot. Once it moves, it's all downhill from there.
If you need to machine the crank because the crank is buggered (welding it up before hand), a light press fit is certainly no harm. Maybe just take the sprocket with you and tell the guy what you want - he really doesn't need to know why.
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I made a nice jig for making the front face of the crank true in-car. I have welded up the crank before, but don't typically. I just cut the new keyway opposite the old one.
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Scarry stuff but I'm glad people are capable of it. I have yet to remove the crank bolt on the AAZ in the 82. Plan to avoid it as long as possible.
And to stay with V belts.
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Scarry stuff but I'm glad people are capable of it. I have yet to remove the crank bolt on the AAZ in the 82. Plan to avoid it as long as possible.
And to stay with V belts.
I agree with the v-belt concept - simple but effective. I'm sure others who have the serpentine set-up could chime in here but I am a machine designer and have used sprag (one-way) clutches before - they fail eventually and if you consider how many times your right foot lets off the throttle, it can happen sooner than you think. Shortly after that the sprocket starts to get hammered by inertia with no forgiveness.
I only did the "D" fix because it was easy at the time. Under different circumstances, I'd have left it alone (with the exception of a new bolt and proper torque).
For anyone reading this that may not know, a serpentine belt is extremely good at transmitting 100% of the torque produced at the crank - meaning zero slip. The alternator is a heavy mass of spinning copper and steel. Every lift of your right foot from the accelerator pedal immediately changes the speed of the crank and the alternator mass doesn't quite keep up with that change. The difference between the two components gets transferred to the connection between the sprocket and crank. Hence, the need for the best connection possible.
A V-belt allows a bit of slip and will soak up most of the variation of the two.
I think I need an intervention ;D
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The GOOD thing about the serp belt though is it makes for way easier belt changes plus it opens you up to the world of high output alternators. No re-tensioning either.
FWIW it isn't so much the letting off the pedal that is the issue as it is the pulses of power as pistons speed up on the combustion stroke and slow down on the compression stroke. Hammers the hell out of the keyway on the crank sprocket. The "D" style is a million times better.
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Porsche uses the same one way clutch on the M96 motors that have been out awhile. When they aren't failing in some other comical fashion, those little clutches fail on them as well.
Not the best little piece.
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The GOOD thing about the serp belt though is it makes for way easier belt changes plus it opens you up to the world of high output alternators. No re-tensioning either.
FWIW it isn't so much the letting off the pedal that is the issue as it is the pulses of power as pistons speed up on the combustion stroke and slow down on the compression stroke. Hammers the hell out of the keyway on the crank sprocket. The "D" style is a million times better.
OK, makes sense - that would explain why the clutches fail so "quickly". They are typically rated for millions of cycles. I have used them for industrial shears cutting carbon fiber cloth and they perform for several years. The pulses from a diesel would chew through the cycles pretty fast.
I also get where the serp belt can drive a bigger alternator. Any idea how many amps the v-belt can safely drive? Mine is a stock 60. Could a v-belt drive a 90?
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Yes, most of the a/c cars got 90 amps in the mk2 anyway. And all that I have seen were v belt.
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Yup, AC cars got a 90A, though they also have all sorts of belt-related issues. That has a lot to do with the particular conflaburation of belts that VW used to be sure.
FWIW the clutched alt pulleys do last a pretty long time. Seems they are good for 100,000km+ for most people. They seem to outlast the typical timing belt replacement interval for instance.
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MK2 ac vbelt system is among one of VW's worst designs.
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Scarry stuff but I'm glad people are capable of it. I have yet to remove the crank bolt on the AAZ in the 82. Plan to avoid it as long as possible.
And to stay with V belts.
wolf-walker,
Wondering if you would provide more info on using the V belt and V belt pulleys on your aaz?
I too would like to use the V belt set up in my aaz that came from a 1993 Golf. My aaz is going in my Samurai, and I have the ACME 1.9TD installation kit with the alternator up grade......a bracket for a GM CS130 105 Amp Alternator.
For the belts, I'm thinking....... one V belt for the crankshaft pulley / Alt pulley, and a second V belt for the crankshaft pulley / water pump pulley. Is this how you have yours configured?
I realize that the 1.9 came with a power steering pump that was included in the crankshaft / water pump belt-group, and that the belt tension was adjusted through the power steering bracket adjustment.
I have no use for the power steering pump and bracketry and want to leave it out of the build, so I'm wondering how one tensions this belt when it is only on the crank pulley and waterpump pulley?
Place the belt on the two pulleys and THEN bolt the water pump pulley to the pump with the belt under tension?
I have seen a pic by "wazzuk" [ pretty sure he is one of the ACME adapter guys ] on the yahoo groups samurai diesel group showing V belts configured on a 1.9 TD like I just described.
Anybody else run belts this way?
I have done lots of reading on this and yes, that counter-rotational force from the alternator inertia via the serp belt is a keyway killer. I want to stay clear of the serp belt set up for sure.
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Not sure if the link to the pic with the two V belts will work.....
http://groups.yahoo.com/neo/groups/SamuraiDiesel/photos/albums/570646524
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Far as I remember, it was remove from 1.6 and place on 1.9 for the pulleys and brackets, had to hack on some of the covers, it all fits well enough though.
The belt sizes are not stock, every time I replace the things I have to figure them out again since I'm not usually bright enough to save what size fit before.
They are new enough I might be able to now though if you need. Or pics. Mine is the later plastic cover bit, mostly anyway. Think it was actually off a 1.6TD from an
85 Jetta. Stock AC and alt, etc, etc. I wish I had put the adjusting bolt on the bracket that I cobbled off something on my other truck a few years ago.
Stuff all runs together after awhile.
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Thanks ww, I'd like to see some pics of the belt set-up if / when you can.
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Have another question about welding up the crank nose....
This guy had a machinist "spray" weld the crank nose to fit the AHU sprocket. Is spray welding commonly used for this?
I never thought of spray welding, and just thought that it was tig / mig laying a bead-type welding to fill in the keyway and make the crank diameter larger before machining back to dimension.
http://www.vwdiesel.net/forum/index.php?topic=30980.60
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Spray welding is mig welding with a 95/5 or 98/2 gas with the heat and feed turned up. IIRC it is 40% more heat and 20% more feed, you have to play with it a bit, but it was mainly used at first for pressure tested stuff. Now I have Amish guys that do it for the steel work with wheels since it makes a nice self leveling bead.
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There is also a technique where the shaft area is heated to cherry/white hot and metal powder is introduced through the flame. The concept is controlled disposition with little or no stress from a typical welding process.
Typically it is done while the part is rotated slowly.
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wolf-walker,
Wondering if you would provide more info on using the V belt and V belt pulleys on your aaz?
I have done lots of reading on this and yes, that counter-rotational force from the alternator inertia via the serp belt is a keyway killer. I want to stay clear of the serp belt set up for sure.
On the Quantum, the fixed distance for the crank to water pump is overcome by a split pulley on the crank, that has say 10 [9 actually] shims available that are stored behind the pulley as they are removed from in between the pulley, to progressively squeeze the v belt, making the belt try and climb out of the pulley, effectively increasing the diameter of the pulley, and so the tension increases...
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On the Quantum, the fixed distance for the crank to water pump is overcome by a split pulley on the crank, that has say 10 [9 actually] shims available that are stored behind the pulley as they are removed from in between the pulley, to progressively squeeze the v belt, making the belt try and climb out of the pulley, effectively increasing the diameter of the pulley, and so the tension increases...
Very cool. I think the Quantum in Canada was labeled as a Passat. Do you know what year Quantum had the split pulley? I can check that year Passat at the wreckers.
I was just going to roll a belt or two, or three, over and into the water pump / crank pulleys, and choose the belt that had the optimum tension.
Checked with 2 machine shops so far regarding the crank repair...... one declined the job as they have no C&C machine, the other shop wants to just cut the same keyway notch 180 deg from the original, and install a new sprocket ::)......even after I explained that the crank was not buggered [ yet ] and how I wanted the repair done as per TDI sprocket. Spray welding was a no-go for this shop.
I have another machine shop to pester yet.
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On all the Quantums I've worked on, the water pump belt adjustment was accomplished by a split pulley on the water pump, not crank. There was also a split pulley on the crank, but it adjusted the tension of the A/C belt, not the water pump. 1982-1985 1.6TD would be what you are looking for. All the Audi vehicles with the 1.6TD that I've seen had the same belt drive system as the Quantum.
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On all the Quantums I've worked on, the water pump belt adjustment was accomplished by a split pulley on the water pump, not crank. There was also a split pulley on the crank, but it adjusted the tension of the A/C belt, not the water pump. 1982-1985 1.6TD would be what you are looking for. All the Audi vehicles with the 1.6TD that I've seen had the same belt drive system as the Quantum.
Well, lookey there, Andrew is absolutely right. I initially wrote down shims on the pump, but glancing at the ETKA; I mistook the shims on the a/c pulley for the ones on the pump.
There are only six shims on the water pump, but the principle remains the same.
As I don't have a/c it was an easy mistake. Sorry.
It is a bit fiddly to assemble, but the belts last as long as the pump, which is a long time, hence the self misdirection
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Early rabbit of some form used that split pulley shim BS, might have been gassers, or PS pumps, it was something I avoid whatever the app was but I've seen them.
Pcars same bit on that excuse for a cooling system/alternator belt before the moved into the 90s.
Not a fan.
Spokerider, I'll clear off the dust and get some pics sometime soon. If you need em sooner rather than later bug me about it.
The more I think about it, and finding a pic of the AAZ as a bare long block when I got it, everything on there is 1.6 stuff and it works fine.
Crank pulley is different, it came with the AAZ, they made it an actual balancer I think.
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I have the AAZ crank in the machine shop now, hopefully the nose repair goes well and it's not a bubba job. This guy has been in business 37 years, but had not done a vw crank before....I am trusting that it all comes down to the skill and judgement of the machinist doing the work, and not just having the fancy C&C machine, etc, which he does not have.........
I had taken the crank to an auto machine shop first to get their opinion on the repair and he declined doing it, said he didn't have the set-up to grind the flat on the crank. He did say I should have the crank checked for trueness after the repair has been made.......grrrr, more $$. I prolly should however. I would think the vw shop that rebuilt the engine [ in 2008 ] would have done that, but it may get distorted with this current machining.
About the new crank bolt......red Loctite or oil before torqueing? Bently says oil, but I see guys are using red Loctite.
About the new bearing cap bolts I just bought.....they are the "new" style, [ as opposed to the partly threaded shank ] with a fully threaded shank. Torque to 48 ft/lbs and turn a further 90 deg?
Also, looking for any tips on locating piston #1 TDC for installing the timing belt. This engine is going into a Samurai, so I don't have the vw flywheel for the timing mark reference. Suppose I could get a vw flywheel just for this, but I have no vw trans either. I do have a dial gauge and magnetic base.
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Only use red loctite if you hate the person you are selling the car to...
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You can use a clear hose (from the #4 GP hole) with some fluid in it.
Check this out: http://www.vwdiesel.net/forum/index.php?topic=34145.0 (http://www.vwdiesel.net/forum/index.php?topic=34145.0)
Works perfect.
If your lucky you can find a tube with an OD that fits into the GP hole. I re-threaded a brass hose barb.
IMHO, loctite is a band-aid for a properly torqued "new" bolt on a properly machined crank.
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About the new bearing cap bolts I just bought.....they are the "new" style, [ as opposed to the partly threaded shank ] with a fully threaded shank. Torque to 48 ft/lbs and turn a further 90 deg?
Also, looking for any tips on locating piston #1 TDC for installing the timing belt. This engine is going into a Samurai, so I don't have the vw flywheel for the timing mark reference. Suppose I could get a vw flywheel just for this, but I have no vw trans either. I do have a dial gauge and magnetic base.
You can't use the newer style bolts in place of the older style bolts. The new full-thread bolts will be too long and bottom out in the block... As I said, you should have gotten studs...
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About the new bearing cap bolts I just bought.....they are the "new" style, [ as opposed to the partly threaded shank ] with a fully threaded shank. Torque to 48 ft/lbs and turn a further 90 deg?
Also, looking for any tips on locating piston #1 TDC for installing the timing belt. This engine is going into a Samurai, so I don't have the vw flywheel for the timing mark reference. Suppose I could get a vw flywheel just for this, but I have no vw trans either. I do have a dial gauge and magnetic base.
You can't use the newer style bolts in place of the older style bolts. The new full-thread bolts will be too long and bottom out in the block... As I said, you should have gotten studs...
Well I don't know which main cap bolts the engine originally came with, old or new style, as I didn't strip it down and rebuild it, and even then I don't know if the guy rebuilding used new bolts or the original ones when he reassembled the bottom end. The bolts that I just removed are fully threaded and have an 85mm long shank. The vw dealer parts guy sold me 80mm fully threaded bolts......said they were correct for my 1993 aaz.
Studs, better, ok, but I really don't know which to get, and if there are clearance issues with the windage tray, they cost 2 to 3 x the vw bolts, mail order for me, etc. If 2 guys have had bottom end failures out of how many that have done rebuilds using new bolts or even reused the old bolts? The vw parts guy says he almost never sells main bolts, but sells many rod stretch bolts, and claims that the main bolts are re-useable. At least I'm going with new bolts. I ain't done spending $$ on the motor yet ::).......the K03 turbo is original, as is the injection pump, both with 219000 kms on them. Hopefully I can bolt'em on and use them.
At least the oil pump is good.....took it apart yesterday to clean and measure backlash. The oil spray nozzles were not installed with any sealer, so I removed and reinstalled with Lepage 1194 Liquid Gasket and blue Loctite on the retaining bolts.
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You can use a clear hose (from the #4 GP hole) with some fluid in it.
Check this out: http://www.vwdiesel.net/forum/index.php?topic=34145.0 (http://www.vwdiesel.net/forum/index.php?topic=34145.0)
Works perfect.
If your lucky you can find a tube with an OD that fits into the GP hole. I re-threaded a brass hose barb.
IMHO, loctite is a band-aid for a properly torqued "new" bolt on a properly machined crank.
Thanks for the link, the TDC tube method looks easy to do.
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I wouldn't bother checking the crank after machining. For tdc in my sidekick I used a dial indicator with the head off then made an arrow that bolts to the block and made a mark on my pulley.
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I wouldn't bother checking the crank after machining. For tdc in my sidekick I used a dial indicator with the head off then made an arrow that bolts to the block and made a mark on my pulley.
That's kinda what I was thinking, except the head is already on. Maybe use the dial indicator on the bottom of #1 con rod cap?