VWDiesel.net The IDI, TDI, and mTDI source.
Engine Specific Info and Questions => mTDI Mechanical TDI Conversions => Topic started by: rbremiller on January 03, 2014, 03:05:59 pm
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I have a 1991 Audi quattro with an AHU, a 12mm LT AGK pump, K14 turbo, now with new nozzles. It's been on the road as my DD for a year and a half.
http://www.motorgeek.com/viewtopic.php?f=6&t=45645 (http://www.motorgeek.com/viewtopic.php?f=6&t=45645)
(http://i245.photobucket.com/albums/gg45/rbremiller62/DSC04785_zpse240eab1.jpg)
I've been driving the car for over a year with a set of new T4 injectors out of the box. It turns out, they were not .216's as promised but a smaller nozzle with a higher breaking pressure. It caused the engine to run in a very narrow power band and very noisy at all rpms. I changed the pump timing many times looking for the sweet spot.
(http://i245.photobucket.com/albums/gg45/rbremiller62/file_zps528bdd2b.jpg)
New Years Day I installed a set of new Titan nozzles I've waited 8 months for and it runs beautifully now.
(http://i245.photobucket.com/albums/gg45/rbremiller62/DSC02346.jpg)
Pump as it arrived from Berlin via Czech Republic.
I sent the pump initially to Giles to calibrate for my application. The pump was already factory rebuilt so all he had to do was adjust it (whatever it is he does). After I installed the pump but before I started it; I noticed that the yellow sealing paint on every screw was undisturbed. I examined and re-examined close-up pictures I took when I first bought it and they were all exactly the same. So I inferred that he never opened the pump and so it must have been OK(?) He changed the mount bracket after I asked him not to, as I have several. As it turns out then, I had no real reason to send it to him. The pump starts and runs well; but still has clatter under part load. I am looking to adjust the axis governor and would like some input on this. Not so much how to adjust it but whether or not this might help. This pump was originally set up for a lower rpm engine and I think the axis shaft should be turned out a half turn (CCW)? I've had no luck finding any pictures of the inside of an LT pump if anyone can point me in that direction as I want to understand how the low smoke governor works as well. I have rebuilt and repaired several IDI VE pumps, and I'm very familiar with them.
(http://i245.photobucket.com/albums/gg45/rbremiller62/file_zpse327ce6c.jpg)
I've had my project/thread posted on 2 other sites for a few years now. A lot of fluff, K&N filter debates, and dyno queens. I find most who post on this site are more nuts and bolts, grease under the fingernails and most importantly share with me a fierce love for the mTDI. The last reason is what really sets vwdiesel.net apart from any other site. Kudos guys. Thanks in advance.
Rich B.
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I think the partial pedal clatter is just the nature of the beast with a 12mm plunger. The 12mm plunger can inject a lot more fuel in less time and so at partial pedal, the injection event is much shorter and results in more clatter.
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Yes my 12mm 4bt built by libby has quite a bit of clatter. Infact it sounds like a cummins. ;D It also has 230bar opening pressure as well as .216 nozzles.
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My previous setup had a very sharp throttle response which made a difficult transition from on/off throttle. The current nozzles have eliminated that. It's now much smoother; more eTDI, if I may. I now have to reset the pump timing as it smokes too much at .80mm; where it had to be for the previous nozzles. There is such a wide range of adjustment that people are using that it's confusing. I'm going to set it @ 1.15 for now going by one of Andrew's posts about using his piezo timing light to get baseline timing readings from a # of diesels. This is the best explanation I've come across so far. (Thanks Andrew)
I do not know how Westyman (Karl Mullendore) arrived at that recommendation for a timing setting. I can tell you how I've arrived at mine, tho. I have a diesel pulse adapter and strobe timing light with rpm and advance functions. The pulse adapter has a piezo pickup that clamps to the #1 injector line. When the pressure builds in the line, the steel line gets slightly bigger in diameter. That enlargement of the line compresses the piezo crystal and stores a charge in it. When the start of injection occurs, the line relaxes slightly. That relaxation of the pressure on the crystal causes a discharge and sends a signal to the pulse adapter box. That box transforms that signal into a typical spark signal that can be read by a typical gasser timing light. That timing light flashes a strobe light with each pulse. The advance function of the timing light lets me very quickly and accurately see exactly the #1 injector's start of injection. I have tested many VE pumps both TDI and IDI with stock nozzles set to stock timing specs. With calibrated stock injectors and the pump in good condition and set to spec, using my diesel pulse adapter and strobe, the start of injection always falls between 12° BTDC and 14° BTDC. Personally I find that 14° BTDC is to clacky on the TDIs. When building a pump I install it, use my pulse adapter and timing light to initially set it to 12° BTDC. I then adjust the fueling and set the idle. With the idle set I re-check the pulse adapter timing. When I have removed the injection lines I use my dial indicator to check the plunger lift @ TDC for each pump. The delivery valves affect the timing fairly significantly so the plunger lift of each pump will be different, even with a specific set of injectors. I can say that each mTDI pump that I have tested has had to have a plunger lift between 1.15mm and 1.45mm with the idle set and the pulse timing @ 12° BTDC. I attribute the differences entirely to differences in the delivery valves and the amount of residual pressure they hold in the metal lines. Similarly, changing injector opening pressure will change the timing of the start of injection as a higher pop pressure takes more plunger lift to pop.
BTW I just had my first gelling experience ever in 30 years of dieseling and I'm not talking about shoe inserts. The good thing is I knew exactly what it was and just kept moving until I got more fuel and 2 cups of PS. It was -15º last night and 0º this AM. Definitely the coldest weather this car has seen. I don't have the thermostatic filter "T" on my filter flange so that probably contributed to it. I am interested in anyone who's changed the axis governor with good results.
Rich
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I went and paid Andrew a visit back in October and we ended up setting my timing to 12* btdc with his nifty pulse adapter. Prior to that (last march on) I was running my timing anywhere between 1.2 and 1.4 and it just never seemed to be at its full potential per what he said to expect. I have never rechecked with the a dial what it is set to now but we had to bump it past 1.4 where it was set when I showed up to his place in order to get it set to the 12* mark.
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I've been advancing the injection timing in .05mm increments for a few weeks and I'm up to 1.20mm. The useable power is increasing and so is the noise. I'm really understanding now that the "Cummins" rattle is unavoidable with my pump configuration. Got it. The exhaust scent indicates a more complete combustion as well. I'm looking for a piezo pick-up adapter for my timing light ultimately. It's amazing all the different timing specs being used for these 12mm mTDI pumps. Using a light seems to be the only way to put you in the 12º BTDC ballpark. Tuning by ear can be very subjective IMHO.
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AHU, stock turbo, stock intake, no I/C, LR 300TDI with an AAZ camplate (high lift, steep ramps), about 50psi of idle pump pressure, .216" Veg-Injection nozzles on stock injector bodies with tons'o'miles on them.
I have been as high as 1.40mm and a measured low of 1.14mm. I am at 1.14mm right now, but I was also thinking of creeping up on the timing to see how it felt. 1.40mm was FAR too much, mileage was poor over a long highway trip and it was SOO clacky/rattle. 1.14mm seems a little low but it still doing alright.
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Thanks, I appreciate the input. I've followed your thread as well. Going up to 1.25mm and will stay there for a tankful to evaluate power and mileage.
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FWIW, Giles told me to start with 1.25mm for the 12mm bosch pump. From what I have read Libby has posted that would seem accurate. I think he has been everywhere from where 8v is at to 1.5mm depending on the delivery valve lengths. I am not 100% on that so you would have to ask him or read tons of his posts.
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I quote one of Andrew's posts earlier in the thread as a basis for what I'm doing. Giles told me to set the pump between .90mm -.95mm. As I mentioned earlier I've been mislead by Giles about a few things. Thanks for the post; I seem to be on the right track.
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Giles told me to set the pump between .90mm -.95mm. As I mentioned earlier I've been mislead by Giles about a few things. Thanks for the post; I seem to be on the right track.
For a bone stock 12mm Land Rover pump that he didn't touch the insides of?? Interesting..
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It's an AGK VW LT pump. He told me it was the first one he'd seen. My new pump & new injectors sat in his "core return" pile for 3 1/2 weeks because he forgot that's how he told me to send it. His last advice was time it by ear. I just reread the email. This all just an education. Some have had a great experience with Giles' pumps.
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Oh so basically.. this was a completely ***ty experience :0 lol.
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The reason I sent him the pump was to address the low-smoke governor spring issue. When he sent me back the pump; said I might have slight inflexibility at low speed; ie: jerkiness when rolling on the throttle in second gear. I didn't ask him what he did to adjust the pump because it's "impolite." In our arcane little world of VE pump tuning secrets are "golden eggs." I trusted him to do what he said he would do. I've learned a lot more about mTDIs since then. I don't want to impugn anyone's character, just relating my experience.
I moved the timing to 1.26mm this afternoon; will drive it tomorrow to evaluate.
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I've been driving the car and it runs excellent. After a full tank to check mileage I'll probably move it to 1.30mm. I've got some sub-zero temps coming in for a few days so we'll see how it starts.
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Mine is starting well at 1.15mm, I have not tried the 1.3mm region yet.. Only the upper and lower extremes of advance and retarding.
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I backed the timing off again and set it to smoothest & most responsive 'by ear'. I installed an AHU outlet bolt which is a pressure valve and not just an overflow orifice. The engine seems quieter and smoother with that change. I mean it runs beautifully. The 'by ear' pump setting was .80mm when I checked it. Go figure. I bumped it up to .85mm and I'm going to leave it there for a tankful to check mileage. The lower pump lift setting seems to correlate to a better low end torque I can feel pulling up certain hills. The AHU outlet pressure bolt has a lot to do with how well it runs now. I think a version of this bolt is used in the Rover pumps as well. The break-in oil consumption has diminished to 1qt in 5k. I tried using an ALH pressure regulator but it had a sharp knock from a higher pressure I guess. I could see the adjusting pin was tapped in further than mine.
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I have set my idle case pressure to about 30psi as of this past week. I was at near 50psi before at idle.. and it was way too much diesel clatter (advance) when cruising no load. I have never tried as low as .80mm. Maybe I will give that a try this weekend.
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stock 45psi , if it claters up the rpm , add a washer at the addv right at the cap, this should help
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I've driven this car with the pump @ .80mm most of the time since I put it on the road. I got the best mileage 47.5 mpg at this setting. I switched back and forth trying to find the sweet spot. I always returned to .80mm as the smoothest running pump position. With this engine/pump set-up; the timing determines where the torque is going to be. Higher pump lift setting puts the torque band at a higher rpm and low end torque suffers. The same thing with timing an older gas car. Lower pump settings result in a smokier start-up when it's very cold and higher settings are almost smoke free. I'm considering an after-glow switch to help minimize it. When I prioritize my needs for this car; fuel mileage, driveability, then comes performance. I'm in this car for the long term.
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Giles contacted me understandably upset and very insulted by a few of my posts that describe my experience with him. He insists that he disassembled the pump completely and did the gov mod., boost pin mod, and the advance mod. He says he disassembled the entire top. He just sent me(for the first time) calibration specs for my pump he said were made during testing. I have no reason to disbelieve him from the veracity of his statements; nor to let my incorrect information stand. It's very possible I am wrong about him opening up my pump. i apologize to him publicly if my analysis was wrong. He said "I am a Factory Bosch dealer and we have that Yellow paint and use it with all our pumps. I did put the new Yellow paint on the same marks that were there before as I remember." He asked me to respond publicly to his concerns and queries. That said, I am left with no explanation why my pump doesn't fuel smoothly (jerky. flat spots) under full boost acceleration or why I can't drive it slowly in second gear. I wasn't wrong to expect perfection for the price I paid for the service. Yes the pump runs reliably; starts and idles consistently. If I attempt to accelerate quickly through the gears it has a "flat spot and bucks slightly as it attempts to rev higher. It's been that way since I've driven it no matter the timing or injectors or running it out of a small fuel tank under the hood. It accelerates like a turd to be honest and I've never been completely satisfied with that. Giles has an excellent reputation for building good pumps over the years and has every right to want to defend his good name and work. His anger and feelings of insult for my posts mean nothing next to my disappointment though.
Rich
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What a guy..
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Giles contacted me understandably upset and very insulted by a few of my posts that describe my experience with him. <snip> His anger and feelings of insult for my posts mean nothing next to my disappointment though.
Rich
Why not send the pump back for him to take a look at? It seems clear that he is concerned about his rep, so I would expect that he wants to make you a happy customer. Give him a chance to do that.
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Giles contacted me understandably upset and very insulted by a few of my posts that describe my experience with him. <snip> His anger and feelings of insult for my posts mean nothing next to my disappointment though.
Rich
Why not send the pump back for him to take a look at? It seems clear that he is concerned about his rep, so I would expect that he wants to make you a happy customer. Give him a chance to do that.
BTDT. I don't have the time nor the inclination right now. It was foolish for me to publicly mention my difficulty with him.
On a lighter note the car started beautifully at 2ºf this morning; the pump timing is now at .83mm. I moved it up to .90mm for a day; but it wants to run smoothest with best overall power at .83mm. I keep coming back to it.
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I'm really curious here as to what amount of degrees below TDC your pump is compared to mine. I have mine set at 12 degree btdc and it must be well over 1.45mm at least. It starts cold ok with glowplugs need below 25degrees or so and have white smoke for a minute or so depending on how cold it is.
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I cannot explain the huge gap in timing settings people are using. One of my co-workers has a piezo timing light adapter for me. It's a Mac version; uses a 9v battery. I intend to find out where my actual timing is. Once I do that I would like to offer the adapter for others to use to do the same. When it's colder than º20F I have a bit of smoke for 10 seconds or so; it clears quickly holding the throttle at 1500 rpm. The engine runs evenly throughout.
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I can explain the huge gap in timing settings in three ways; differences in injector break pressure, differences in camplate profiles and differences in the plunger or dynamic advance that change the crank/pump degree of the fill port closing and the delivery port opening.
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Sounds right.
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I can explain the huge gap in timing settings in three ways; differences in injector break pressure, differences in camplate profiles and differences in the plunger or dynamic advance that change the crank/pump degree of the fill port closing and the delivery port opening.
Would you care to add more insight as to which level of each would cause what? I mean it is your call and all :).
ie. Higher or lower break pressure, steeper ramps and higher lift vs. lesser ramps and lower lift
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I believe that higher breaking pressure injectors, less abrupt camplate ramp and later closing of of fill/opening of delivery port would each require a higher lift in order to achieve the same actual timing of injection.
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So stock TDI breaking is 195bar? The LT pump must have a steep ramp and high lift cam plate then to require so little advance?
what was the cam like in the pump you built bbbob?
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His pump has the stock Cummins 4BT camplate which has higher overall lift but is less abrupt than the stock TDI camplate. I cannot comment on the LT camplate as I haven't had one but I disagree that it 'must' have a steeper camplate. I mentioned three variables and even if using stock opening pressure injectors it is illogical to assume you can know what 'must' be WRT either of the remaining variables without knowing the other one.
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When someone says "well it must be this then?" instead of "it is this way for sure, I can prove it", it is because they do not know %100 and are implying that by saying that.
So unless you know all of it, most people are just shooting in the dark.. lol.
This pretty much (minimum %78) confirms why timing by ear (or pulse adapter if you have the means), is substantially better then any one timing number for any one engine.
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One other variable that I believe affects the static timing is the residual line pressure determined by the delivery valves.
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When someone says "well it must be this then?" instead of "it is this way for sure, I can prove it", it is because they do not know %100 and are implying that by saying that.
This pretty much (minimum %78) confirms why timing by ear (or pulse adapter if you have the means), is substantially better then any one timing number for any one engine.
Well, timing by ear is for idiots. I suspect you are using some form of performance testing. The G-Tech, Norwegian Dyno, ets are not part of "timing by ear".
I have known guys that did their timing "by ear". The thing was they were CONSTANTLY timing their cars by ear. With the Norwegian Dyno and an hour or two you will know where the sweet spot is. Lock it down and forget it. I always put the indicator to it so I know where to put is back to.
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I got hold of a pulse adapter and checked my timing. http://www.vwdiesel.net/forum/index.php?topic=34340.75 (http://www.vwdiesel.net/forum/index.php?topic=34340.75) It was exactly 12º. I am completely satisfied with all the research and testing I've done that's repeatedly brought me back to this same setting. So: the timing which I set by ear many times and from the recommendations of others with the same pump; it came out at the 12º mark at .83mm lift. I have no reason to continue exploring the pump timing issue with this car.
Rich B
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Here's an update from my last post. I purchased a TDI spec transmission for the car from Frans in The Netherlands this spring. I finished the install last week and returned the car to DD status. The proper gearing is essential for these engines and am looking forward to better mileage and new found driveability. It still starts and runs well at the .83mm pump setting. I re-installed the eTDI return flow restrictor valve and added a non-return valve just after it inline. I had problems with the eTDI restrictor valve draining back and causing hard starts. I prefer the eTDI valve as it seems to have a smoother idle and starts more quickly (with the non-return valve in place). It has a small piston and spring inside that must compress to open the return port like a pressure valve. The stock Audi diesels of this vintage had the non-return valves originally. The one I'm using came off my old '85 Jetta diesel with 400,000 miles on it. I'm going to drive it for a tankful and then consider if I might adjust the timing a bit. There seems to be a 400 rpm difference(lower) in each gear and is way less clattery at steady driving speeds. I have 20k miles on the motor now; the oil consumption is undetectable and the compression seems a little higher as the break-in continues.
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I re-evaluated the IP timing with the new trans. It still runs best at the .83mm setting without a doubt. The first tank with the TDI trans. was 820 miles, used 16.7 gals. for 49.1 mpg.
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it's very to hight static timing >:(
yes .83 it's better ;)
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it's very to hight static timing >:(
yes .83 it's better ;)
Thanks for the confirmation. i appreciate your interest. I will put the timing at .80 when I have an after-glow circuit for the very cold weather. The car starts good at that setting but it's smoky without further glow plug action.
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I have no glow on my vehicle.
I have already started in -15 ° c rolling with 15W50 ca jerk a little time this heater
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Please post a video of this so we can all hear it!! Great build!
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Please post a video of this so we can all hear it!! Great build!
http://vid245.photobucket.com/albums/gg45/rbremiller62/file_zps840184cf.mp4 (http://vid245.photobucket.com/albums/gg45/rbremiller62/file_zps840184cf.mp4)
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Here's an update that's overdue. I finally installed a circuit to extend the glow period after starting. It uses a 50 amp relay and a re-purposed 5 minute wall switch timer. The big news is the last two tanks of fuel netted 50.3mpg and 50.0 respectively. 2nd tank included a 580 mile trip to PA with cruise control at 75mph. Boost held steady at 12psi up the steepest hills. The static timing is now at .945mm to take advantage of the proper gearing. The latest fill was at 835 miles for the most miles ever from 1 tank. The car still runs very well and is the best starting diesel or car of any kind for that matter I've ever owned, period.
(http://i245.photobucket.com/albums/gg45/rbremiller62/file_zpslyk0bija.jpg)
(http://i245.photobucket.com/albums/gg45/rbremiller62/file_zps7optmjsh.jpg)
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Nice. I like the timer. I do notice that without 'afterglow' mine will miss a bit in really cold temps. I imagine that helps.