Author Topic: IDI TDI compatability  (Read 18989 times)

December 13, 2007, 01:52:29 pm

jimfoo

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IDI TDI compatability
« on: December 13, 2007, 01:52:29 pm »
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:


Jim
1966 Land-Rover 88" with 1.9 AAZ which has been transformed to an M-TDI
GT1749V, IC , and 2.5" exhaust.
Driven daily

Reply #1December 13, 2007, 01:55:02 pm

rallydiesel

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IDI TDI compatability
« Reply #1 on: December 13, 2007, 01:55:02 pm »
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.
2006 Jetta TDI - gtb1749v, Malone 2, Frank's Titan 2 cam, VR6 clutch....
1991 Jetta TD - sold :(
2001 Golf TDI - Son's
1981 Rabbit - BEW tdi swap project

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Reply #2December 13, 2007, 01:57:04 pm

jimfoo

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IDI TDI compatability
« Reply #2 on: December 13, 2007, 01:57:04 pm »
Probably better emission and engine management.
Jim
1966 Land-Rover 88" with 1.9 AAZ which has been transformed to an M-TDI
GT1749V, IC , and 2.5" exhaust.
Driven daily

Reply #3December 13, 2007, 03:47:48 pm

somolovitch3

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IDI TDI compatability
« Reply #3 on: December 13, 2007, 03:47:48 pm »
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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Reply #4December 13, 2007, 04:08:18 pm

jimfoo

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IDI TDI compatability
« Reply #4 on: December 13, 2007, 04:08:18 pm »
I don't see why not.
Jim
1966 Land-Rover 88" with 1.9 AAZ which has been transformed to an M-TDI
GT1749V, IC , and 2.5" exhaust.
Driven daily

Reply #5December 13, 2007, 11:37:26 pm

subsonic

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IDI TDI compatability
« Reply #5 on: December 13, 2007, 11:37:26 pm »
1.6 / 1.9 Franken TDI ???
2009 Jetta TDI Loyal edition, 6-spd. 16V 2.0CR


1985 VW Golf 5-spd, 4-door, 1.6NA  Bought from orig. owner in Savannah with 42,000 miles.
"Making the jump NA to TD" slow but sure.

1980 VW Rabbit LS 5-spd, 4-door 1.6NA almost 450,000miles  RIP

Reply #6December 14, 2007, 01:19:39 am

QuickTD

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IDI TDI compatability
« Reply #6 on: December 14, 2007, 01:19:39 am »
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.

Reply #7December 14, 2007, 10:51:18 am

jimfoo

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IDI TDI compatability
« Reply #7 on: December 14, 2007, 10:51:18 am »
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.
Jim
1966 Land-Rover 88" with 1.9 AAZ which has been transformed to an M-TDI
GT1749V, IC , and 2.5" exhaust.
Driven daily

Reply #8December 14, 2007, 07:31:47 pm

QuickTD

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IDI TDI compatability
« Reply #8 on: December 14, 2007, 07:31:47 pm »
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.

Reply #9December 14, 2007, 10:07:42 pm

jimfoo

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IDI TDI compatability
« Reply #9 on: December 14, 2007, 10:07:42 pm »
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?
Jim
1966 Land-Rover 88" with 1.9 AAZ which has been transformed to an M-TDI
GT1749V, IC , and 2.5" exhaust.
Driven daily

Reply #10December 15, 2007, 11:21:23 am

QuickTD

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IDI TDI compatability
« Reply #10 on: December 15, 2007, 11:21:23 am »
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.

Reply #11December 16, 2007, 04:04:07 pm

MJF

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IDI TDI compatability
« Reply #11 on: December 16, 2007, 04:04:07 pm »
Quote from: "somolovitch3"
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.
'74 VW Scirocco TD
'86 Audi 80q 1,9TDic
'01 Audi A6q 2,5TDI

Reply #12December 16, 2007, 04:16:22 pm

jtanguay

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IDI TDI compatability
« Reply #12 on: December 16, 2007, 04:16:22 pm »
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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Reply #13December 18, 2007, 11:04:58 pm

jimfoo

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IDI TDI compatability
« Reply #13 on: December 18, 2007, 11:04:58 pm »
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.
Jim
1966 Land-Rover 88" with 1.9 AAZ which has been transformed to an M-TDI
GT1749V, IC , and 2.5" exhaust.
Driven daily

Reply #14December 21, 2007, 02:30:56 pm

jimfoo

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IDI TDI compatability
« Reply #14 on: December 21, 2007, 02:30:56 pm »
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.
Jim
1966 Land-Rover 88" with 1.9 AAZ which has been transformed to an M-TDI
GT1749V, IC , and 2.5" exhaust.
Driven daily