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Engine Specific Info and Questions => IDI Engine => Topic started by: TD_vento on October 19, 2005, 02:45:04 pm
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Hi there, due to melting my engine due to blown head gasket I have got myself a new block.
The crank is damaged on the lip from the famous poor design of the pulley and key fit.
I would like to swap for a tdi style pulley. What do i have to do to make it fit??
The crank will be out so any work can be carried out.
thanks
(http://img235.imageshack.us/img235/1905/kurbellenzahnradaazjx3yu.jpg)
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My procedure is to weld up the old keyway, weld up the outside diameter and the face of the crank nose. The welding is done with a TIG welder and 4340 filler rod. I weld it up in stages so as not to overheat the first journal. The crank is then placed in a lathe with a steady rest on the first main bearing journal. I machine the face and recut the 60º chamfer in the threaded hole in the end. I remove the steady rest and using a live centre in the newly machined centre hole to support the crank, I machine the outside diameter back to a proper press fit in the pulley. I then place the crank on a milling machine, gripping it in a vise by the 2 machined surfaces on the front bobweight. I then cut the "flat" on the nose of the crank. I measure the pulley that will be used (they can vary a bit in size) and make the flat a slight interference fit as well to insure that it goes on tight.
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That does sound like specialist work and i haven't got the tools or experience, i think taking that to a specialist would cost quite a bit. I have a good crank so ill just throw that in instead. Does anybody have the part number for the uprated crank bolt?
thanks for the reply quickTd 8)
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The "new" crank bolt is part number N 905 771 01.
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Nice one QuickGT
I need some tourqe data for the conrods if anyone has a manual.
thanks
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The conrod bolts are torque to yield, they must be replaced if removed. The torque spec is 22ft/lbs plus 1/4 turn. The mains are also TTY, always replace. Tighten to 48ft/lbs plus 1/4 turn.
I would recommend purchasing a manual at your earliest opportunity, there are a fair number of "oddities" to VW diesel engines, making the manual is your most important tool...
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Hmm I have tried it once and i droped a shell. Although i think it was more of a incorrect tourqe values than reusing the bolts.
The rod bolts are like 2.70 pounds which is like 5$ each.
The main ends bolts are 80 pence about 1.4$ each.
Stealership rapes you :x
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Forgot to mention, I was looking at the block with the crank out now and I noticed the oil squirters, can these be installed to 2l 16v engines? I dont think the 9a 16v has them and im using forced induction on it.
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Late model rod bolts are cheaper than older (pre-'95). The old style rods have dowel pins in the caps and take a rather normal looking bolt, oddly enough, these cost $12cdn each. The new style rods have no dowels and have a precision ground portion on the shank of the bolt that aligns the rod cap, for some reason these "special" bolts are only $3 each, go figure...
The main bolts could be replaced with standard class 12.9 socket head cap screws, early AAZ engines used non TTY bolts so I don't see it being a problem, I've done it myself. The torque for the "normal" type cap screws is 48ft/lbs (same as TTY but without the 90º step).
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I bought an '97 1.9TD two weeks ago but have not gotten around to getting it towed home.
Having not seen it up close yet does the '97 model really have a mod. to prevent this loosening pully?
I pick-up on this revision once on vwquebec.ca
( that this problem was solved at factory on the later 1.9TD's )
Thanks,
Hugh
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My 97 is the same as any other 1.9TD. The first "fixed" engines were the 1Z TDI's. Factory rebuilt 1.9TD's sometimes come with the new style crank and pulley, but not always.
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OK, thanks.
Tear apart time 8)
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Ok I got the scored engine and the replacment engine apart. Im using the crank from my burned engine as it is not damaged unlike the replacment engine I picked from junk yard.
Due to the excess heat my old crank seems to have been discoloured where the bearings go both on the rod and main journals. They are smooth tho but have that light yellowish colour.
I will take some pics tomorrow, I was thinking if it is worth having the new replacment block honed since i have everything out? Would i need new piston rings if I just hone it? The bores look in good condition.
Im not brave enough to put the crank back together so Im taking it to the
engine shop for them to do it, I think the crank might need some polishing maybe.
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I was thinking if it is worth having the new replacment block honed since i have everything out? Would i need new piston rings if I just hone it?
Any time you remove the pistons from the bores you need to deglaze the cylinders and replace the rings. Old rings are worn to fit the bores, if their orientation is changed the engine will consume oil and have poor compression. Your machine shop can likely hone the bores and clean the block to remove the honing grit before assembly. New rings are pretty reasonable, less than $100CDN for a complete set last time I purchased them.
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I got the bolts finally, decided to leave the pistons in. To inspection the head needs a skim, it has wraped due to teh heat. the new gasket i got has 2 notches on it, I presume with the decking of teh head the 2 hole gasket will be the right one or does it depend on how much material is shaved off the head? the old gasket is the 1 hole one leaving me to believe its the original gasket and that the head has never shaved off before?
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I think you are wrong, when shaving the head you need to make up for this space somehow, the thicker head gasket is the solution.
the machinist told me that he removed 0.75mm off the head as it had wraped badly. The new gasket i got was a 2 hole one, i think I might need something thicker. Does the manual cover this?
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lilypapa is right, the gasket thickness is determined by piston protrusion, it has nothing to do with the head. Since the head does not have a conventional combustion chamber you won't change the compression very much by machining it. The valve seats were likely machined at the same time, this will usually sink the valves into the head far enough that clearance will not be an issue. Technically, you are not supposed to machine the head because it upsets the relationship between the valves and the deck surface of the head, but for practical purposes it usually works out just fine. There really is no way you can make up the 0.75mm that was taken off the head anyway, the variation from the thickest to the thinnest head gasket is less than 0.4mm.
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I like that you agree, but my user name is a libbybapa rather than lilypapa. Iv'e been called worse, though.
My apologies, I will be more careful in the future... :oops:
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Got the crank in the new engine, installed new big end shells. Come to put thre rod bolts in i notice the dealer have supplied me with the wrong bolts.
There seem to be 2 types, 1 have 2 bumps on them and are longer 45mm thread and the others have 1 bump and are shorter. Im waiting for the others now :(
A quick question, the thrust bearings have 2 channels on them each. Im pretty sure that the channel should be facing opposite side from the bearing on the main end.
thanks
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When a head warps, it's not just the head gasket surface that moves... :shock: You should give some serious thought to having your cam bearings align-bored.
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Hmm it makes sense. Any way to test the alignment before the head goes together?
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Any way to test the alignment before the head goes together?
Remove the lifters, make note of the installed position so they can be returned to thier original holes, an egg carton works good for keeping them sorted. Then install the camshaft and see if it turns freely.
The grooved, silver side of the shell faces the crank, the marked side faces the main bearing.
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Yes the guys are right, head gasket thickness is determined by the piston protrusion above the block. You should clean the piston tops and use either a DTI or depth micrometer to measure the depth.
If you had a factory car with 3 hole gasket this would simply mean that the surface of the block required slightly more machining to clean its surface, or maybe it didnt require it but thats what it got. When your dealing with cast iron and a face mill 12" in diameter... 0.1mm here / there is a reasonable target, compared to machining the likes of alu. in a CNC mill in which case you could quite easily hold a tolerance of 0.05, not +/- 0.1
Skimming an IDI head will increase the compression very slightly, as your removing material from the prechamber but also the recesses around the valves, but you dont really need to take this into consideration. On a DI the compression would change even less. Some engine builders would simply supply the thickest gasket to lessen the chances of a mistake, but if your car left the factory with a 1 notch, you had the head skimmed and you fitted a 3 notch, you would notice the cold starting ability change.
On the mk2 GTD I rebuilt (1.9TD), I only needed a 1 notch gasket, but because I wanted to run higher boost pressure, I installed the 3 notch and increased the boost to 1.5 bar. The car was no problem to start from cold with the glow plugs, but when warm it would turn over a bit longer than the others. No big deal, but it was noticable. You could always make adjustments to have the glow plugs operate above 70C.
When where on the subject, how does everyone feel about lowering compression when raising boost ? Most diesel manufacturers do lower compression slightly on turbocharged engines, for example Perkins engines used in agri. machinery, but how about the Finns who build the 350 - 400 HP Mercedes W123's and W124's (190 / 300). They run OM606, 3 litre straight 6 IDI's with compression of 22:1. Able to bring a turbo as big as a Holset HX40 to over 2 bar !
DM
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I have a manual for TDI audi A3 and it gives the values for the gasket types.
Piston projection 0.91-1mm (1 hole gasket)
- - - 0.01-1.10 (2 hole gasket)
- - - 1.11-1.20 (3 hole gasket)
Now i dont have a dial test indicator to measure the height, ill use some feeler gauges for this.
Are those values above the same for the TD AZZ?
Also need to know the camshaft cap torque settings.
Thanks
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HI guys, finally got the engine together installed everything.
I tried to crank it up but it wont fire, engine turns though. I checked the timming 3 times and its spot on.
Havent done a compression test as I dont have the tool but by turning the engine by hand I could hear the air compressing the same in all 4 cylinders.
I see the air bubbles in the inlet line to the pump so Im assuming diesel is flowing.
I will get some diesel starting spray tomorrow and give it a go.
What could it be? Im not too experienced in this diesel engine or pump.
thanks
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No Im sure the pump is in the correct position, there is only 1 hole on the pump pulley to align with the pump bracket, i used a bolt with similar diameter to keep the pulley in position.
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Wanted to let you know that the car is now running sweet. I found the problem to be a wrong conection on the pump, the 2 black wires which clip on the pump, I had them the wrong way around.
Thaks for the help guys!