head gasket leaking oil after rebuild

[vwsb1974]

I recently rebuilt my 1.6 N/A with ARP Head studs and it looks like my head gasket is leaking. Has anyone had this problem? I followed the torque sequence and finished at 125lbs    

[rumbling_caddy]

Do you use hylomar or copper spray on the new headgasket?

[southernman]

When using the arp studs it is imperative that you've torque them at proper intervals. First torquing occurs at build; second occurs after initial startup where the engine reaches operating temperature and then completely cooled down (you can see a 40% loss of torque during this initial cycle); a third and final cycle at about 500 miles. I torqued mine at 105; 95; 85 ft lbs as final value. After the 3rd cycle, I've rechecked a few times and the torque values remain spot on. Don't get carried away with torque values as studs have a higher clamping force at lower values than studs. Over torquing can pull threads and induce warping, resulting in blowby and/or leaks. For anyone that runs arp fasteners, arp states in all their kits that 3 cycles of their stud kits is required to ensure optimal clamping performance - and I can tell you from personal experience, failure to retorque will result in failure of mating assemblies. Good luck with that engine. Southernman.

[Gizmoman]

Thanks, I went to ARP site and indeed, they do recommend re-torquing after initial run.
From their FAQ

3. Do the head studs only go in hand tight?
The studs should be installed finger tight. Then, when applying torque to the nut, the stud will stretch only on the vertical axis. An undercut shorter stud will have a rate similar to a longer, standard shank stud. This provides a more even clamping force on the head. Because the head gasket will compress upon initial torquing, make sure studs (or bolts) are re-torqued after the engine has been run

Darn, I just got my valve cover to finally seal after three attempts It's weird, cause I could swear that I read on this site that ARP suds didn't need to be re-torqued. FWIW, I followed the instructions in the box to the letter (125 ft/lbs - AAZ 1.9). There was no mention of re-torquing in the instructions.
Thanks for the info.

[theman53]

I personally hate to retorque something after it has ran. All my IDI diesels have block heaters...see where this could be going? I plug the block heater in and let it sit for 24 hours, then cool, then another 24 hours plugged in, then cool. Then I will torque it as I don't like the combustion process to interfere with the seal of the HG. Also, I haven't cyro treated the arp stuff but that is a possibility to use as well, but I take an old HG and torque the head down 3 separate times and loosen it. Why? ARP doesn't say if they distress the studs after machining, how old they are, or really much about them. After machining, welding, forging, etc metal will need distressed as it will have a "spring" like effect to it. Also, if you ever bought there connecting rod bolts, they will tell you in the instructions to torque, loosen, torque, loosen, torque, loosen, and then use them, this is why. They do not say to do that with the HG studs or anything else I have bought from them, but I do. It "could" lead to torque issues or it "could" be the reason 1 or 4 bolts are loose and the rest are fine.

All of that said to say, I never have retorqured the HG studs and I have never had an issue. I think they want you to retorque at 500 miles for the same reason I tighten and loosen them 3 times. I could be off but it has worked for me and I have only had one metal HG have a bit of a leak in the #4 corner. It wasn't a leak but a seap out deal and really only went down the back of the block a fuzz and stopped. I honestly think it was because my machinist surfaced the head for a fiber gasket and I used a metal one.

[Gizmoman]

I personally hate to retorque something after it has ran. All my IDI diesels have block heaters...see where this could be going? I plug the block heater in and let it sit for 24 hours, then cool, then another 24 hours plugged in, then cool. Then I will torque it as I don't like the combustion process to interfere with the seal of the HG. Also, I haven't cyro treated the arp stuff but that is a possibility to use as well, but I take an old HG and torque the head down 3 separate times and loosen it. Why? ARP doesn't say if they distress the studs after machining, how old they are, or really much about them. After machining, welding, forging, etc metal will need distressed as it will have a "spring" like effect to it. Also, if you ever bought there connecting rod bolts, they will tell you in the instructions to torque, loosen, torque, loosen, torque, loosen, and then use them, this is why. They do not say to do that with the HG studs or anything else I have bought from them, but I do. It "could" lead to torque issues or it "could" be the reason 1 or 4 bolts are loose and the rest are fine.

All of that said to say, I never have retorqured the HG studs and I have never had an issue. I think they want you to retorque at 500 miles for the same reason I tighten and loosen them 3 times. I could be off but it has worked for me and I have only had one metal HG have a bit of a leak in the #4 corner. It wasn't a leak but a seap out deal and really only went down the back of the block a fuzz and stopped. I honestly think it was because my machinist surfaced the head for a fiber gasket and I used a metal one.

Thanks for the insight. So if I were to re-torque them, I have to loosen them up first or just check if they are still at 125? Obviously, I'd do them in the proper sequence. How far would I back them off (if needed)?

[vwsb1974]

I did not use anything on the head gasket. I will check the torque on the studs. But what should the value be?

[theman53]

If you don't loosen the studs for retorque it probably wouldn't ever work. The friction you need to overcome to start is probably higher than the torque setting. So for ex. if you have a torque setting of 125 and the fastener is at 108, the friction required to over come 108 is probably higher than 125. Unless you loosen the nut it will never be torqued correctly.

[ORCoaster]

Per Bentley one should loosen the bolts by what, 30 degrees of an arc. or approximately 1/6 of a turn then retorque to proper setting.  Just remember all get loosened in order then all get put back in order.  

I loosen in reverse of the recommended tightening order but I am not sure that is important.  Something tells me it is.  You want the center of the head to come down first and tighen out to the edges.  Think of it as a stick of gum and not a hunk of metal.  You are rolling it inplace with the force of the nuts.  

[vwsb1974]

Ok I will re-torque the studs but what value should I use? I have some time I drove the car this morning so it is cooling off. Do I set them back to 125 or some other value

[theman53]

I would do the value that they recommend for their studs.

yes one at a time and I would use the Bentley torque procedure not the loosen procedure. I would only loosen it enough...maybe the 30 degrees should be more than enough to start it back the other way and not worry about the friction under head to impede the starting torque.

[vwsb1974]

Ok I will do it tonight after it has time to cool off and set them back to 125 one at a time

[vwsb1974]

ok I re-torqued them I will wash it off tomorrow and we will see if it is still leaking. I checked a few of them before I loosened them a bit and all the ones I checked were still at 125lbs.

[wolf_walker]

These things always seem to like to weep oil, drivers rear most often.  I'm a fan of the copper spray stuff on less than perfect mating surfaces.
Opinion varies considerably on such.  Hopefully you don't need it, but if it leaks in 30K miles give it some thought.

[RabbitJockey]

take caution when retorquing an 11mm engine... mine cracked the block 

honestly, i'd recommend leaving well enough alone, if all seems well with the initial torque, leave it alone.