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Engine Specific Info and Questions => IDI Engine => Topic started by: paolomarks on February 07, 2013, 02:59:17 pm
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i'M rebuilding my AAZ . Looking for a crankshaft bolt(holds the timing gear on) and a set of main bolts(tightens the crank caps down) Who has them? Thanks, Paolo
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The mains are tricky. They had 2 different mains. m10.-1.5x 65mm OR x 80mm. Since we have had 2 people in the last year blow up #2 main I would NOT run the 65mm mains. I would drill and tap them to 80mm and use an 80mm bolt. IIRC both had the 65mm mains that threw the rod cap. Any 12.9 grade socket head cap screw that size would work OR a normal Hex head cap screw 10.9 grade as that is what came from the factory.
The crank bolt is one time use Torque to Yield and can be had at the dealer or online. Same bolt as the AHU. NOT the same as ALH.
http://www.idparts.com/catalog/product_info.php?cPath=29_74&products_id=1212
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theman53, are the designs for the main caps different between the two main bolts?
Also a good reference about crank bolts I found out. Some older ones were not torque-to-yield, but you can tell which ones are by looking at the bolt head. if there is a cylindrical nub on the end like this:
(https://encrypted-tbn1.gstatic.com/images?q=tbn:ANd9GcROKHcQ7dOzVBzUewXejUpJSiJ9RYvQg_tZPReTcf_JB4E0s-_j)
. . .then they are TTY.
I'm only saying this so that if you get a bolt that doesn't have a nub, you know they gave you the wrong one, like one for an older 1.6.
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Yes I was assuming since he asked that he has the TTY. Either way, the TTY can be used. If there is any place I think a TTY bolt is cool is right here on the crank sprocket.
As far as I know, no. The main caps are identical in everyway. The block was tapped deeper. There is plenty of meat to go the extra 15mm I guess.
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Yes I was assuming since he asked that he has the TTY. Either way, the TTY can be used. If there is any place I think a TTY bolt is cool is right here on the crank sprocket.
Amen brother! And I guess I should check my main bolt holes. Thanks for bringing that up.
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I just put the sprocket on my 1.9. I first tried the old crank sprocket bolt out of an early 11mm block 1.6 and it was too small. But I found the one out of my MkII 12mm hydraulic motor fit perfect. And its a 6 point head so I guess i can reuse it as much as I want.
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Who had the #2 main bearing fail? Were the using the shorter conventional re-useable bolts or the longer TTY ones?
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Smoking eddy and Jimfoo both had the #2 main cap let go and both IIRC had the 65mm main bolts.
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Interesting. The 1.6TD bolts are the same as the shorter AAZ bolts and I'm not aware of any issues. I'm currently assembling an AAZ that has the shorter bolts and will consider the ARP mains.
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Hypothesis:
I think the 1.9 with the longer stroke has more inertia and pulls against the mains harder than the 1.6. Especially at the same rpm of the 1.6. The 1.9 also has more weight in the crank. Add several hundred thousand miles, a rebuild with good compression, maybe things get a bit tough? It would seem VW saw the issue and added 15mm to the bolts to correct it.
It doesn't happen often it seems but we had 2 in short order and when I make my AAZ into the TDI I am either going studs or tapping the hole deeper and longer bolts. I still need to find out if I have the shorter bolts or not before I do this.
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Interesting information indeed. I have the longer 80mm bolts in my AAZ which I'm assuming are TTY. (The Bentley says to give them an extra 1/4 turn) Where can I find replacement
TTY bolts? If I decide to go studs, anyone know the ARP part no.? Thanks, Paolo
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Just an FYI, but I have not been at all impressed with the quality of the TTY main bolts, straight from VW they appear to be poorly made. I just got a set and few of them are straight and in a set of 10, two were so bent that they bound noticeably on install.
(http://i13.photobucket.com/albums/a269/libbybapa/100_2268_zpseca41da8.jpg)
They'd probably straighten when torqued, but it still seems disconcerting considering what can happen if they fail.
I seriously doubt VW went to the TTY bolts to address an issue, but rather to quicken initial assembly. The TTY bolts rarely solve issues and sometimes create them (e.g. 2.1 WBX rod bolts...), but they do assemble quickly at the factory and increase parts sales...
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Hate to say the Subject screams a Michael Scott , that's what she said?
sorry must be the Canadian beer... ;)
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Hate to say the Subject screams a Michael Scott , that's what she said?
sorry must be the Canadian beer... ;)
Bazinga.
So I have some main studs from Raceware for my AAZ already. Based on this thread info, should I go ahead and get the main holes bored and tapped deeper? What's the year/production cutoff for the 65mm mains application if anyone knows?
And I just realized that I never recommended a main bolt application in my FP' that said, I recommend studs if going for power. ARP and as stated above Raceware sell 'em. ARP also does hardened bolts, too. Just thought I'd say that as I never did originally.
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thanks for the responses. Any one have the ARP # for 80mm AAZ Mains? Paolo
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Looking around abit I've found an ARP #204-5402 but that seems to be for the shorter 65mm length. Saw somewhere that a ARP #201-5001 for BMW 2.3 liter might work? Any confirmation on this. Paolo
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So I gave ARP the specs on the longer AAZ mains and they replied that they have none for that application. I went ahead and bought some socket head cap screws. 2 questions for those of you who have used SHCS for the mains: Do you install washers between screw head and main caps? and what do you torque them to? Thanks, Paolo.
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Last time I didn't use any, this time I used a grade 8 washer under mine. I used a torque value about 20% more than stock, since the 12.9 SHCS is about 25% higher tensile strength.
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Thanks , Paolo
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Bumping an old thread....
I just pulled the main bolts to check out the bearings in JUST the caps. I did not pull the crank. The shells looked fine and rotating the crank, the same proved correct for the journals.
Anyhow, I have 65mm bolts with no shoulder under the hex head. I'm guessing these may have been replaced...?
Is the ARP 204-5204 a cure or a bandaid for the potential to crack the caps?
Would retapping the block be a better long term solution?
Are 65mm 12.9 bolts a comparable fix? i do understand that studs have better clamping ability.
I don't plan on building a crazy engine.
-Todd
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No shoulder = stretch bolt, they are single use.
A set of factory AHU bolts will fit fine, are affordable and will do the job safely.
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Aren't the AHU bolts 80mm? Not looking to retap the block if I can avoid it.
-Todd
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I guess I didn't need to bump this thread.
I went out, reinstalled 2 main caps and grabbed a sliding caliper. Shot it down the bolt hole and measured slightly over 78mm. Did this a couple times. Apparently, my block had the shorter bolts installed for no reason.
Question... Is the 80mm that's mentioned an approximate bolt length? I definitely don't want the bolt bottoming out.
-Todd