VWDiesel.net The IDI, TDI, and mTDI source.
General Information => FAQ/Tech Tips/Please Read First => Topic started by: jimfoo on December 13, 2007, 01:52:29 pm
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The AAZ head and ALL components, valves, camshaft, lifters are the same as the 1Z AHU head. The AAZ and 1Z/AHU TDI pistons are interchangeable. This means an AAZ block CAN be turned into a TDI! :twisted: :twisted: :twisted:
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Cool. Why didn't VW ever make a mechanical TDI? Or did they? What is the advantage of using the pre-chambers? Lower injector pressures needed or what? Just some semi-noob questions for anyone out there.
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Probably better emission and engine management.
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Have not looked at any other posts, but does this mean a DI NA engine is possable?
8) :lol: :roll: :twisted:
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I don't see why not.
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1.6 / 1.9 Franken TDI ???
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Careful fellas, although the AAZ stuff physically fits, the parts are not the same. The AHU has longer valve stems because the valves sit a bit above the deck surface of the head, the AAZ valves are recessed. If you have old style 8mm AAZ valves in an old style AHU head the stem diameter is the same, however, the AAZ valves are a full 2mm shorter in the stem. I would be a little concerned that the lifter would overextend due to the short stem and come apart.
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While I can't seem to compress or extend the lifter by hand, (maybe it needs all the oil pressure to do that) the measured difference between the lowest part of the cam lobe and lifter is less than .01mm. The head's inside, feeler gauges outside, so I'm just using some thin copper flashing. But as I rotate the cam, I can feel the copper being pulled under and ever so slightly compressing the lifter. I am guessing that the relative position of the cam to the valves is the same, so that even though the valves do sit out further, the cam must be closer by the same amount. This is why I like doing projects like this, they dispel the myths and rumors and just provide hard facts that can help people. Just like when I e-mailed Peter at emiata to see if the TDI pistons were similar to the AAZ. He told me they were taller, which they aren't. I guess I should say one thing about the valves. They are 8mm. From looking at sites, it seems some heads may have had 7mm valves, but I'm not sure which ones.
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AAZ engines have 7mm stems from mid-late '95 and up, I have both types so I know this to be fact. 1Z engines have 8mm stems and I thought that all AHU's had 7mm, but maybe it's only ther later ones? I guess if you feel the lifter is not overextended then by all means run the AAZ valves. I was just concerned because the AAZ valves have a different part number and are in actual fact ~2mm shorter overall than TDI valves. As far as the cams, all 4cyl 8 valve VW cams have the same journal size and placement, even the gas engines, but there are many different grinds, power and mileage may vary. I know that a 1.6TD hydraulic cam will bolt in and run in the AHU/1Z as well.
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Well I do appreciate the heads up as if there was a big difference, I might have been screwed. Maybe the TDI lifters are 2mm shorter to make up the difference?
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The lifters are the same TDI to IDI but use a different part number depending on the valve stem size (7mm or 8mm). I'm not sure about the physical difference, they may have a smaller hydraulic piston so they don't pump up with the lighter single springs used in 7mm heads. Some hot rodders claim the newer 7mm stem/single spring lifters weigh less, not much of a concern with a low revving diesel.
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Have not looked at any other posts, but does this mean a DI NA engine is possable?
8) :lol: :roll: :twisted:
Why not, it is already made by factory.
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making it NA just means reducing the fueling, which is probably WAY easier than increasing...
and there were DI engines over in Europe. not sure if it was using Bosch pumps, but i think Renault had a DI mech pump. apparently there are some that could possibly bolt on to 1.9TDI engines. i think the power/smoke was comparable to 1.9 IDI engines though, so they soon switched over to electronic to appease everyone (and squeeze every last mpg out of the engine)
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I fully installed everything for one valve and the camshaft and everything seemed to be ok. I'm having the machine shop put it together so they can double check everything, plus one bearing journal is slightly too small, so I will have them hone it out.
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The machine shop confirmed today that all my AAZ valvetrain components will work with the 1Z head I have. Mine was a '95ish engine I believe.
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So, let me get this right, you have a 1Z head, that is fitting on you 1.9l AAZ, and a AAZ head can fit on a 1.6l, so, this means I may have to buy a new head?
If so, what do I do with my pistons? DI pistons are far from the same as my lowly 1.6l pistions.
Please let me know as my motor is sitting in pieces right now, and have pump just about ready to head to Giles, and a 1.9l idi head to send to Dave...
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So far, there aren't any 1.6 TDI pistons available, though Mr Prothe says he's working on it. Doing a little looking, the 1.2 TDI PD engine has the same bore and stroke, but I don't know if the pins are the same size and in the same place as on a 1.6.
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So far, there aren't any 1.6 TDI pistons available, though Mr Prothe says he's working on it. Doing a little looking, the 1.2 TDI PD engine has the same bore and stroke, but I don't know if the pins are the same size and in the same place as on a 1.6.
i bet they are... or pretty damn close to it. they really seem to beef up PD engines to withstand much more abuse than they actually receive... which make them great for tuning :wink:
i wonder... 1.6PD? :twisted:
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So far, there aren't any 1.6 TDI pistons available, though Mr Prothe says he's working on it. Doing a little looking, the 1.2 TDI PD engine has the same bore and stroke, but I don't know if the pins are the same size and in the same place as on a 1.6.
i bet they are... or pretty damn close to it. they really seem to beef up PD engines to withstand much more abuse than they actually receive... which make them great for tuning :wink:
i wonder... 1.6PD? :twisted:
But does a PD head fit on a 1.6 block? Looks like some one elses turn to create a new franken motor.
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I am not sure how 1.2l can have the same bore and stroke, as this would make it a 1.6l, unless head volume is way, way less.
If indeed the head volume is .4l smaller then I can't see why it wouldn't be the same engine, VW is very smart, why build a different block (R&D, manufacturing) when you already have one that will work, $$ and all.
If the head volume isn't .4l smaller then either the bore or the stroke has to be different, one hopes it is the stroke!
Though this does give me some hope as to a top secret project I am working on!
And on that note, does Mr Prothe have any expected finish date, and a cost?
I will have to PM him to see…
So very promising!!
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Because a 1.2 is a 3 cylinder.
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interesting this thread is
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interesting this thread is
http://www.youtube.com/watch?v=IRd9PGmAQUE&feature=related
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Ignorant, my question is- ;)
what is a PD?
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A tdi engine that uses a small cam driven injection pump with one pump per cylinder. They mount in the head under the valve cover, but are electronically controlled.
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PD = Pump Duse - German for Pump Injector / Unit Injector.
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there were many diesel models produced.
there was a 1.9L SDi non turbo direct injection engine. also a 1.9 IDI N/A. then theres the mechanical injection 1.9LTDi using the Bosche VE injector pump. there are few differences between the first TDi's and the AAZ - injectors, camplate, pistons.... no precups... not much more.
lots of stuff is interchangeable.... great aint it?
so the 1.6 is 76.5mm bore right? surely theres a TDI piston with that diameter.
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The 1.2 mentioned above. Elsewhere, someone found they cost $250 each.
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The 1.2 mentioned above. Elsewhere, someone found they cost $250 each.
just wait for the chinese to start ripping them off :wink:
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You going to be first in line? :wink: