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Engine Specific Info and Questions => IDI Engine => Topic started by: pyro7890 on December 03, 2010, 07:40:25 pm
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i have a 1.6 na 11mm it had a bad head so i bought a rebuilt one and put arp head studs in and made sure there was enough lube on them and tourqed them and i have a coolant leak any ideas as to the problem
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Where abouts is the coolant leak located?
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back right side of the motor
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i think i know what i want to try already but i just wanted to see if other agreed. i am going to take the head off, make sure the head and the block are not warped, chase the threads put a new head gasket on and try again
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i think i know what i want to try already but i just wanted to see if other agreed. i am going to take the head off, make sure the head and the block are not warped, chase the threads put a new head gasket on and try again
Slight distortion should pull out with the studs.
I'd be inclined to check with the head off, for some scoring/divot, corrosion around the water passages.
Maybe it was your block all along, and not you previous head, or maybe the studs cracked the block this time. :'(
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Another possibility is that the block was cracked to begin with (or, at least weak on the rear head bolt). The two places where those 11mm blocks tend to crack is on the right and left rear head-bolt holes.
I hate to be the bearer of bad news, but I'm speculating that a notable leak from a properly torqued head gasket may be due to a crack leading from the head bolt to the water jacket.
I'm hoping I'm wrong.
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I too had a slight coolant leak,after replacing the head gasket on my 1.6NA 11mm
My block has no cracks and both head and block have less then .003" distortion.Gasket surfaces,cleaned immaculate.
I also used ARP studs and torqued to 80 ft lbs and retorqued agian hot.
After searching the forum and asking advice,it was recommended to increase the torque
I backed off each stud 1/4 turn and retorqued to 85 ft lbs(one at a time) in sequence.(I was sweating it,but it took the 85 ft lbs)
coolant leak is gone.
Might be worth a try??
special thanks to those who gave advise .
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Been there doing that :(
I've not had a problem with a 1.6 but currently on 1.9 I'm having the same problem.
I misread the torque specs and tightened them not enough, went back and added 90 deg to all but too late. I have a new gasket sitting here if I ever get the time..
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I remember having this debate with 53Willys a few years back. He was having HG problems with ARP studs. He was afraid to overtorque the head. He had followed the ARP specs to the T. As it turns out, he overboosted and blew the fiber headgasket. But in the process of trying to save it, I pointed out that the OEM stretch bolts finish up somewhere in the 110-120 Ft-lbs range when all is said and done. I thought it would be safe to push the ARPs up to 100 ft-lbs without consequence. I think in the end, he went up to 105-110 ft-lbs and the bolts and block were fine. I'm not sure if the 11mm fact might make a difference in that though.
As noted by others, if you catch some seepage early, you can often retorque and save yourself from redoing the HG.
Probably worth torquing those bolt up to 90: see what happens. Then 95, see what happens. And if it still leaks, try 100 and see what happens. Beyond that, you may still keep going. Worst case scenario, your block is already cracked and you won't risk anything. Best case scenario, you solve your problem simply by adding a bit more (acceptable) torque to the nuts.
Good luck.
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I think I'm correct in thinking that a solid bar increases in strength by the 4th power of it's radius. So a 10 % increase in diameter gives 40 to 50 % increase in strength, or a reduction from M12 to M11 is 'ball park' 1/3 weaker for the same material...
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I think I'm correct in thinking that a solid bar increases in strength by the 4th power of it's radius. So a 10 % increase in diameter gives 40 to 50 % increase in strength, or a reduction from M12 to M11 is 'ball park' 1/3 weaker for the same material...
I think you may be mistaking this with something else. Tensile strength is what matters here, ART studs being in the 180-220,000psi range. ARP's studs are undercut.. I don't know why they do that, but lets say the 12mm is undercut to 10mm and the 11mm undercut to 9.17mm. Using 180,000psi, the tensile strength of the 12mm stud where it's undercut is 6980lbs, the 11mm studs is 5860lbs, an increase of 19% over 11mm studs.
If you want to figure out the actual force the stud is torqued to, it would have to do with the tangent of the slope of the thread. Add that to the peak cylinder pressures and divide by the studs around that cylinder and you get the max force applied to the studs. Multiply that difference by the elasticity, given their preload and you find out how much they stretch. If that's greater than the amount the head gasket can expand, you leak coolant. Fiber would typically just blow at that point as it's not held together by being squished between the head and block.
But I don't feel like figuring all that out right now ;D
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I think I'm correct in thinking that a solid bar increases in strength by the 4th power of it's radius. So a 10 % increase in diameter gives 40 to 50 % increase in strength, or a reduction from M12 to M11 is 'ball park' 1/3 weaker for the same material...
I think you may be mistaking this with something else. Tensile strength is what matters here, ART studs being in the 180-220,000psi range. ARP's studs are undercut.. I don't know why they do that, but lets say the 12mm is undercut to 10mm and the 11mm undercut to 9.17mm. Using 180,000psi, the tensile strength of the 12mm stud where it's undercut is 6980lbs, the 11mm studs is 5860lbs, an increase of 19% over 11mm studs.
If you want to figure out the actual force the stud is torqued to, it would have to do with the tangent of the slope of the thread. Add that to the peak cylinder pressures and divide by the studs around that cylinder and you get the max force applied to the studs. Multiply that difference by the elasticity, given their preload and you find out how much they stretch. If that's greater than the amount the head gasket can expand, you leak coolant. Fiber would typically just blow at that point as it's not held together by being squished between the head and block.
But I don't feel like figuring all that out right now ;D
It could be that I'm looking at the inch rate for springs, which varies with the 4th power.
Loading with the 3rd power, so is it torsion, and thus tension with the square of the radius? I stand corrected ;D
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thanks every body i love this site :) and also love my diesel
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thanks every body i love this site :) and also love my diesel
Did you fix the leak? If so, how?
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have not tried more torque yet but will post results
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torqued them to 105 and still leaking. iam not sure what to do i am very frustrated thinking of selling since its at least running maybe someone who knows could fix it. i could take the head off and make sure it is not warped i geuss :-\
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Something just occurred to me. Did you install the head with the exhaust manifold installed, or did you install it after you installed the head?
If you installed if before you installed the head, the lower ears of the manifold could be holding the head off the block. I've heard of that happening before. Basically, the flanges of the exhaust manifold project beyond the lower surface of the head. When you install it and don't have the head centered properly, the flanges of the manifold will prevent you from torquing down the head.
Something to check for.
If you hadn't checked the head for warpage before you installed the new gasket, well, that's just dumb.
If you did install the manifold after installing/torquing the head, then I'd go up to 115lbs of torque and see what happens.
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have not tried more torque yet but will post results
I have the 12 m/m ARP's in my 1600 T/D and after the first warm up I retorque to 100 from the initial 85 and then retorque it about every 10,000 mi. or so. Seems like we have the valve covers off a lot anyway for one reason or anoter. ;)
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checked the head, seemed good couldnt get the feeler gauge under but did not check the block
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If you installed if before you installed the head, the lower ears of the manifold could be holding the head off the block. I've heard of that happening before. Basically, the flanges of the exhaust manifold project beyond the lower surface of the head. When you install it and don't have the head centered properly, the flanges of the manifold will prevent you from torquing down the head.
I've tried to do that before :-[
torqued them to 105 and still leaking. iam not sure what to do i am very frustrated thinking of selling since its at least running maybe someone who knows could fix it. i could take the head off and make sure it is not warped i geuss :-\
Consider the ARP studs are fine thread, and don't stretch like the TTY bolts, so you are at maybe 3x the clamping force of a stock bolt.
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i am thinking of buying new head gasket and retrying this, dose anyone have suggestions on what i need to do? my plan is to take the head off and make absolutly sure that the head and the block are not warped. make absolutly sure the thread holes are clean and good. make sure i have plenty of arp lube on my head studs and then i think i will do 3 or 4 torque sequences up to at least 100 ft lbs
any thoughts thanks
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I'm not sure how the ARP lube affects torque, but I just talked a guy through a head gasket job on a 2001 TDI beetle. He was nervous on the last pass, thinking that that torque was too high. He did the 30, then 44 ft lbs. When he did the first 90 degrees, his torsion-bar torque wrench read 95 ft-lbs. Not having done an HG on a TDI, he got nervous and thought that number was too high. I told him that they finish about 110-120, so he should be fine. When I talked with him today, he said on the final pass, they finished about 115-120 all around.
Now, if ARPs lube is something special taht dramatically reduces the coefficient of friction, then you'll have as much or more clamping force at 100 as you would with just WD-40 and 120 ft-lbs.
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arp claims it is the most important part but they also sell it so haha you know how that works. but i think it is good stuff and i am sure it is better than just using oil or wd 40. i am mostly concerned that the block is warped. i have an extra block around but i don't want to sink another 600 dollars into this car i have already bought a new head and the bolts and the new block would have to be re bored with new pistons of course
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The moly is pretty slick, but I don't really think it is any slicker than WD40. It will stay in place tons longer, but WD is very slick. There is a difference between using it and not. IIRC they said 30% more torque on 30w motor oil instead of there lube.
If you buy another gasket coat it with the aviation grade permatex/hylomar and clamp it down good. It should be fine.
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If you installed if before you installed the head, the lower ears of the manifold could be holding the head off the block. I've heard of that happening before. Basically, the flanges of the exhaust manifold project beyond the lower surface of the head. When you install it and don't have the head centered properly, the flanges of the manifold will prevent you from torquing down the head.
I've tried to do that before :-[
torqued them to 105 and still leaking. iam not sure what to do i am very frustrated thinking of selling since its at least running maybe someone who knows could fix it. i could take the head off and make sure it is not warped i geuss :-\
Consider the ARP studs are fine thread, and don't stretch like the TTY bolts, so you are at maybe 3x the clamping force of a stock bolt.
Furthermore you may have squished the 'plastic' gasket away from the sealing area...
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been a while since i was on this thread. so i have been trying to figure out what to do with this blasted engine >:(
i do not think i want to use an mls. this is just a motor to last me until i find a nice turbo diesel motor to build and put in my 81 rabbit ;D
ok so my thought is to get another fiber gasket and put aviation gasket sealer on it and position the gasket better. good idea? ???
i think that some of the problem was that the gasket dose not position it self very well it seemed like it could be way off if you slipped :o
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I'm not sure how the ARP lube affects torque, but I just talked a guy through a head gasket job on a 2001 TDI beetle. He was nervous on the last pass, thinking that that torque was too high. He did the 30, then 44 ft lbs. When he did the first 90 degrees, his torsion-bar torque wrench read 95 ft-lbs. Not having done an HG on a TDI, he got nervous and thought that number was too high. I told him that they finish about 110-120, so he should be fine. When I talked with him today, he said on the final pass, they finished about 115-120 all around.
Now, if ARPs lube is something special taht dramatically reduces the coefficient of friction, then you'll have as much or more clamping force at 100 as you would with just WD-40 and 120 ft-lbs.
With ARP the top threads (where the nut goes on) is quite a bit finer than the block threads so it'll clamp harder with less torque.
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Check your deck surface with a straightedge if you pull the head. Anything more than .005 means you'll have to mill it. Generally, anything more than .009 means you may have to heat the head to straighten it, or mill the surface and line-bore the camshaft holes.
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checked already it was fine around .002 i mostly want to know if the aviation gasket sealer will be ok on a fiber gasket
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shouldnt need sealer on a fiber gasket with .002 warpage.. thats pretty straight..
sealer is more for metal gaskets.
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well when i put my head gasket on with the head off i noticed that the gasket really has a lot of room to move around enough so that the gasket could interfere with the piston projection and also not have an efficient seal for the coolant holes
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Maybe try unscrewing 2 of the studs so that it catches the gasket? I have 0 problems with studs, but made old bolts in to a locator pin before I had them. I just unthreaded when I was done and put the bolts in. I would do it so 1/2 a thread or so is above the block surface on the 2. Just enough to keep the gasket in place until you can tighten the other 8 enough to hold it so you can tighten the original 2. You don't want it to hold the head off the block...you should be able to do this.