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Engine Specific Info and Questions => IDI Engine => Topic started by: regcheeseman on August 11, 2011, 02:52:22 pm
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I am running a 10mm headed AAZ pump on my franken.
It was set at 1.2 mm but seemed to stumble when asked to rev from idle, and be reluctant to idle clean when cold. It had quite a heavy clatter that may be knock
I retarded it a bit - the stumble got worse as did the idle and the clatter remained.
so now I timed it up so the flywheel has about 10 degrees more advance than the original 1.2mm setting (I can't measure the lift in situ because I need to make a tool up to get the injection sensor out without having to remove the lines.
However the stumble is improved, the idle is good (engine is warmer by now though) but clatter seems bad.
When I drive the car if I let off the accelerator the clatter is gone, as soon as I start to press the accelerator pedal the clatter is back.
The clatter is heavy at idle but as soon as the throttle is touched it gets a lot louder until the motor is revving hard when it subsides again.
I also let the car sit and tick over and noted that from cold there is some clatter, it disappears nearly totally as the engine warms but as the engine gets hot it's back worse than ever.
Any ideas?
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Maybe the check valves on the rotor? Are the injectors newly balanced and what tips?
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I don't know much of your engine build but I have a 1.6/1.9 Franken motor with a 10mm head on a custom pump from Giles.
I too had a simular noise and condition with the pump timing set the same as yours. Loud clancking, studdering when cold and seemed worse when warmer even throttlred up.
I just backed off timimg when it was running at opperating temp. until the noise subsided. Even during throttling it up. The noise seemed to go away. I thing you had already posted something about your timing before but it worked for me. What injectors are you using? Whats the breaking pressure? Are you using the AAZ injector distributors?
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What injectors are you using? Whats the breaking pressure? Are you using the AAZ injector distributors?
I have AAZ 155 bar injectors, no problems there as it ran quiet with a stock pump on.
Glad you mention the distributors as they will be the original TDI ones - should that matter? I assumed they were a fairly low pressure one way valve?
Maybe the check valves on the rotor?
Do you mean the same things? ???
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Well, Giles told me that when using the dual spring injectors, I should also be using the delivery ports as well. They are different than the single stage injector.
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I'll swap them over an post back the results, that fails, I'll refit the 9mm head.
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Do you mean the same things? ???
Yeah same things.
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The one thing you might want to take into concideration when changing the delivery valve from the single stage to the dual stage is that there is specific sized shims for the dual type compaired to the single type. Also one thing about the dual type delivery valve spacers is that they need to be all the same size and the pump really should be calibrated to get the best output.
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my cummins pump(11mm?) has always clattered really bad when advanced enough to perform properly.
modding the dynamic advance alot helps, but it has always been really loud.
-Owen
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Which camplate are you running? Are you running the camplate that was with the 10mm head or the aaz one? The tdi camplate has a very aggressive ramp compared to the aaz one but very little difference in overall lift. I would run the aaz one. I bet you're on the right track with the delivery valves. The tdi ones are very different in design.
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I've retarded the pump so it's a little over 1.2mm, and swapped the delivery valves.
It's a little quieter, still the noisiest diesel car engine I've ever heard though.
It has the AAZ camplate already.
The fact that the noise stops completely when lifting off the throttle when driving normally, would that signify it is pump noise? I'm concerned it may be motor related but I think I'm being paranoid.
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I share your motor noise concern. Does the torque of the pistons change on the crank from one side to the other on a shift from power on to coast on? Any slack in the bottom on the crank? Miss a few bolts on torque down? The only time I had that kind of clack was with a worn out crank shim on a piston arm. My 2 cents less a penny.
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I remember Libbybapa fighting the exact same issue with a hybrid 10mm pump. Too much clatter when timing was set for good running and poor running, stumbling when timing was set for less clatter. I don't recall him coming up with a solution. I wonder if increasing or decreasing your cracking pressure on the injectors would make a difference. I'm kind of grasping at straws here.
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I remember Libbybapa fighting the exact same issue with a hybrid 10mm pump. Too much clatter when timing was set for good running and poor running, stumbling when timing was set for less clatter. I don't recall him coming up with a solution. I wonder if increasing or decreasing your cracking pressure on the injectors would make a difference. I'm kind of grasping at straws here.
How about changing the rate of advance, probably increasing it.
So is that a weaker advance spring, or would a stronger vane pump pressure regulator do it.
Backing off the max fuel might help, but I guess that's not the direction of the GTD forum.
The official setting for the intercooled SB/RA engines was only 0.9, so why are you 1.2 and higher? :o
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I remember Libbybapa fighting the exact same issue with a hybrid 10mm pump. Too much clatter when timing was set for good running and poor running, stumbling when timing was set for less clatter. I don't recall him coming up with a solution. I wonder if increasing or decreasing your cracking pressure on the injectors would make a difference. I'm kind of grasping at straws here.
How about changing the rate of advance, probably increasing it.
So is that a weaker advance spring, or would a stronger vane pump pressure regulator do it.
Backing off the max fuel might help, but I guess that's not the direction of the GTD forum.
The official setting for the intercooled SB/RA engines was only 0.9, so why are you 1.2 and higher? :o
aaz heads drop compression on a 1.6 so u need more advanced timing since the air won't get hot as soon, but apparently running a bigger pump head has an effect on timing some how, i would think it shortens the duration of the injection procress, which would actually advance timing in a way. but i really don't know dick about injection pumps other than that they have a fly weight governor, a vane pump, and that they advance timing with more internal pressure.
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I align with the pressure regulator idea. Try dropping the IP internal pressure by tapping the pin back the other way. Requires removal from pump to do so.
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I align with the pressure regulator idea. Try dropping the IP internal pressure by tapping the pin back the other way. Requires removal from pump to do so.
Doing that does not affect the rate of advance, merely the settings for advance, as demonstrated with that internal pressure diagram with 'my pump' etc on it.
I've lost grip on what engine you have Reg? So it's a AAZ pump with something bigger head with AAZ engine head with an SB 1.6 block, with a soon to be vnt controlled by thought processes, foot, or simlar.
I read somewhere that AAZ had one power output from factory whether duel spring or single, so I think that is much overrated. Getting timing right for any nozzle is the leading performance factor perhaps.
Thinking about it, perhaps being able to change the preinjection independantly, might help. What if you raised preinjection pressure to bring it closer to the main injection, or even raised main injection pressure to delay it slightly, that would have an effect on the combustion graph
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but apparently running a bigger pump head has an effect on timing some how, i would think it shortens the duration of the injection procress, which would actually advance timing in a way.
A 10mm pump will push more fuel then a 9mm pump in the same stroke due to the larger area and then having an AAZ camplate (steeper ramp than a 1.6 iirc) on it will push that extra fuel in there even faster.
The 10mm pump/AAZ camplate combination probably causes really sudden injection/combustion and the flame front smashing into the piston/cylinder walls is what is causing the noise.
I think I'd try finding a 1.6 camplate to fit and see what happens.
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I am probably wrong, so please feel free to ignore/mock this post, but...
AAZ block (and Pistons) with a TDI head? Surely the piston tops are not shaped right to get the best possible combustion? The AAZ tops are designed to work with Precups, wheras eh piston on the TDI is shaped to facilitate DI?
Could well cause the noises?
??? ???
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I am probably wrong, so please feel free to ignore/mock this post, but...
AAZ block (and Pistons) with a TDI head? Surely the piston tops are not shaped right to get the best possible combustion? The AAZ tops are designed to work with Precups, wheras eh piston on the TDI is shaped to facilitate DI?
Could well cause the noises?
??? ???
no it is an aaz head on a 1.6 block. the tdi head refers to the pump head on the injection pump
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With the threat of a 100 mile drive (this Saturday) as it's first outing, I decided I couldn't take a chance on the pump as it was.
The clack sounded like it was doing some damage, so about 12:30 last night I decided to pull the pump and swap the 10mm head for a 9mm one.
By 2:30am it was stripped on the bench. :)
My boss sent me home an hour early today so I cracked on with the pump and got it built, then the kids came home and I got sidelined with making dinner, running a bath, making the beds, reading stories and other manly things.
It was nearly nine when I was ready to bleed the pump, but it wont ::) 1 and 3 spit a bit, 2 and 4 are dry.
With 1 and 3 unions tightened it nearly starts but not quite, if it would start the pump would clear in a few minutes - I hope it's grease used for the assembly that is blocking things up.
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What kind of "grease" are we talking here? Vaseline is what I use and it dissolves real quick in the diesel. Sounds like you are close. Hope you don't drain the battery cranking on it. That is where I generally get fouled up.
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i wonder if maybe larger injectors would help with the bigger pump heads, possibly gm or mercedes. dave lost power when he swapped to dual stage aaz injectors, and i think they had the mercedes nozzles, but he also had a 9mm pump.
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Hope you don't drain the battery cranking on it. That is where I generally get fouled up.
Kills the battery in about a minute, however owner a big jap diesel with a huge battery and a pair of truck jump leads means I can crank it until the starter motor melts.