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Engine Specific Info and Questions => IDI Engine => Topic started by: ToddA1 on December 12, 2015, 11:29:23 am
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So I made a boo boo and neglected to oil the 12mm head bolts, prior to installation. Bolts were cracking and popping, but I marched forward with the installation.
After a test drive around the block, sure enough, the head gasket was leaking. I have a new set of bolts on the way, and I was planning on swapping and going through the torque process, one at a time.
My thought was the bolts may not have stretched, if the initial torque specs were never met.
Has anyone ever measured the length of used head bolts vs. the 115mm that new bolts measure?
-Todd
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When they say stretch bolts they mean more the bolts are stretched in a way that they have spring tension holding them at maximum clamping force. When loosened They should return to practically the same size They were originally. Think of a spring. They shouldnt actually deform and elongate unless overtorqued and stretched too far. Over torqueing them causing them to physical stretch beyond their integrity and creates less clamping force. Basically you're tightening the bolts to the point that they are at their peak holding strength. The reason they arnt reuseable is the integrity of the metal has been compromised once they have been "stretched". Its like bending metal back and forth a bunch of times until it snaps.
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Hmmmm.... I understand the metal has memory, but I was under the impression they actually elongated and stayed elongated.
Thanks for the reply.
-Todd
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anti-seize will do, i like the copper stuff, although if you torqued correctly not oiling shouldnt cause hg to leak. bolts 'cracking&popping' is normal during 180dg & 90dg turns. ?clean threads in block? i use qtips& brakecleen.
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They permanently elongate.
Lay the threads of a new one up next to the threads of an old one, the only part matching will be that which was protected by the threads in the block.
They are called 'torque to yield' fasteners because you tighten them beyond the elastic range.
You can measure the difference in length as well.
Clean the threads, you can file a head bolt into a tap if you don't have one the right size.
Installing head bolts dry is one of the stranger assembly choices I've seen. if you initial torgue is off, all the subsequent angles are too, although they will usually still be within range.
Lastly, if you get the really cheap head bolts, they don't always work. We had a bag of 50 at about $1.40 each, and 25% of them broke off.
I install head gaskets dry and have good luck that way. if yours is already leaking, I'd be concerned about contamination from that compromising the seal, and i'd probably lift the head enough to dry it and slip a new gasket in there. that would also let you inspect where the failure occurred.
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It's a MLS gasket, not fiber. I don't recall seeing any silicone sealing rings on it, so I figure I have nothing to lose, other than the cost of the head bolts. The gasket cost me $55 + shipping, so I figure it's worth a shot. I paid $20 plus shipping for the German bolts.
If the used bolts measure the same as the new bolts, maybe I'll reuse them and see what happens.
I've read others had luck with the "one at a time method", where it cured their leaks.
-Todd
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i wouldn't do that again with out sticking a new gasket in. if it werent leaking already itd be a different story. but i have messed up the foil around the cylinders before and had to redo a headgasket, just depends how much your time is worth to you haha.
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I reused a mls gasket and got it to seal. That being said it sealed the first time and I drilled out the rivers cleaned it very well and applied copper gasket spray on each surface. I also used arp studs. Like rabbit said, if you have more time then money it won't hurt to try.
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I doubt I put 500 miles per year on the truck. It was perfectly fine with the 1.6. I have no clue why I put a AAZ in it. Not sure if I'll complete the installation of the turbo or TD IP.
I'm gonna try this weekend. If it sits a week or month longer, no worries. I only want to get it running so I can have another running vehicle.
-Todd
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I finally got to swapping the bolts, today. Oddly enough, the new bolts were a smidge shorter than the used bolts. Both sets were the same Viictor Reinz brand and both sets were made in Germany.
I nested the threads together on a new vs. used bolt, and although tight, the fit wasn't prefect. I decided to use new bolts.
About an hour later, I start it up and hear a hissing after shutdown. The head gasket still leaks. Guess I'm ordering a new MLS head gasket.... maybe I'll spray it down with some copper spray for cheap insurance.
-Todd
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mls is harder to seal than a fiber gasket.
did you check to see if both surfaces are flat?
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No, I didn't. This was a running engine, that the PO started breaking down for no apparent reason, after the intermediate shaft froze for a couple seconds in his garage. Engine was immediately shut down when he heard the belt squealing.
His plan was to rebuild it, just to rebuild it. He ended up installing a gas engine that he understood, more. It didn't overheat or anything, so I had no reason to think something was warped.
It turned out being the oil pump. I pulled the main caps and the bearings looked perfect.
I've also heard what you stated about the MLS gaskets. Thought the spray would help.
I also see that Bentley recommends another 90° angle, after running the engine to operating temp IF running a fiber gasket. At this point, I have nothing to lose, so I was considering adding a 45° angle.
Any idea where to get a 1 hole fiber gasket for a AAZ?
-Todd
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I was able to get the extra 45° on the bolts, installed the valve cover, plugged the block vent and started it up. Let it run for a minute, shut it down and didn't hear any hissing... it worked!
Started it back up, sprayed some degreaser on the engine, and started cleaning up. About 5 minutes later, I heard the idle jump, maybe 500rpm. Shut it down and I heard hissing... I guess it didn't work.
Called GAP and ordered another MLS HG. I was told fiber was never available for AAZ and I wasn't going to argue. At least the HG was $20 cheaper than I thought.
-Todd
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If you want to run a fiber gasket just use a 1.6td one.
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fiber wasn't available for aaz, I must have missed aaz in your post. Check both block and head for flatness before throwing the new gasket on.
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The 1.6 TD gasket will work, without issue?
I don't have a machinist straight edge, but could check with what I have.
Why am I not getting notifications of posts, all of a sudden....?
-Todd
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I'm not sure if the cylinder holes in the 1.6 gasket are large enough for the 1.9 pistons.
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That was my main concern.... I see 1.6 engines running the 1.9 gasket, but not the other way around.
1.6 gasket would also be missing the steam holes, but they could be added.
It appears that the 1.6 hydraulic IDI vs. 1.9 IDI gasket's thicknesses, match in relation to notches/holes, but if piston bore won't work, it's a moot point.
-Todd
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Finally got to this today.
Head appeared flat with my non-machinist straight edge. Block appeared the same, although I've never seen a warped block. New MLS gasket with 3 coats of copper spray and 1 extra coat for good luck...
Something I noticed on the paper that came with the gasket was, it was it recommended lubing the threads and under the bolt head to washer, yet it was highly emphatic to not get oil under the "washer to the head seating surface"... not sure what that's about or why it matters...
Sprayed carb cleaner in the head, all bolt and oil drain holes in an attempt to clean any residual oil that could potentially contaminate the new gasket; did this several times. Cleaned the block and head faces at least a dozen times... squeaky clean.
Used ARP Ultra Torque thread lube on the bolts and ran through the torque procedure; added an additional torque spec before the angles. One thing I noticed was absolutely no cracking or popping... the last time I did this with new bolts, I used Mobil 1 TD Truck and it wasn't as silky smooth as using the ARP lube.
I'll button it up and start it, tomorrow... fingers crossed.
-Todd
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I was able to get the extra 45° on the bolts, installed the valve cover, plugged the block vent and started it up. Let it run for a minute, shut it down and didn't hear any hissing... it worked!
Started it back up, sprayed some degreaser on the engine, and started cleaning up. About 5 minutes later, I heard the idle jump, maybe 500rpm. Shut it down and I heard hissing... I guess it didn't work.
-Todd
sure it wasn't pressure escaping from the blocked vent?
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Sir, you hit the nail on the head! After starting the truck, letting it run then shutting down, I wasn't hearing any hissing. I did this several times, in 5-10 minute intervals. Took it on the highway, came home, shut it down and heard hissing.
I was about to park the truck and reinstall the 1.6 that recently came out. Started spraying soapy water over the injectors, glow plugs, head gasket seam etc. didn't see any bubbles. Then I saw bubbles at the plastic CCV tube flange.
Since this is a mixture of a AAZ long lock and 1.6 accessories, I didn't have a way to plumb the puck to the intake. I tossed a cap on it. Once I pulled the cap, no more hissing.
What had me confused is why it took so long to start hissing. Pressure would have built up with a few revolutions.
Anyway, the engine was degreased and I let the engine run for about 30 minutes. No oil leaks at the VC gasket or HG, so that's a relief.
Need to plumb the puck to the intake and fix the leaking CCV flange leak and I have a driveable truck, again.
I still need to rebuild a IP, install the larger camplate, and 10 mm head and install the turbo.
-Todd
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Well that beats another HG!
I had one with enough blowby to shut the CCV.
Smoke, hissing, leaking.....
I didn't want to shut down out of worry about not being able to restart.
At idle, I unscrewed the oil cap to see how much blowby there was.
It still had enough pressure to rip the cap out of my hand, bounce it off the hood, and shoot so far off the side of the road I wasn't able to find it ever.
Made it home though.
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Yeah, tell me about it. When I heard that hissing, it felt like I got kicked in the nuts! Thankfully, I collected my wits, before I made any irrational decisions.
I covered the puck outlet with my hand and didn't feel a lot of pressure. I'm thinking the CCV tube seals when cold, but once warmed up, the o-ring or a crack opens, leading to the hissing.
-Todd