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CRD Head Bolt Research Request: We need your data!
http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?f=5&t=79984		 Page 3 of 7
Author:  geordi [ Fri May 01, 2015 9:24 pm ]
Post subject:  Re: CRD Head Bolt Research Request: We need your data!
Mr. Wilson wrote:
I may have skipped over someone mentioning this so I'm sorry if I'm restating someone else. I assume that everyone here knows that there are 3 different thickness head gaskets available for these engines. You must measure the height of the cylinder sleeve in order to get the correct measurement of the head gasket. The bolts supplied with the oem gasket are tough enough and they come prelubricated. So you should NOT put any oil on the bolt threads. The bolt holes should be cleaned and dryed out before head installation. I have replaced quite a few cylinder head gaskets and have had no problems with leaks. I hope this helps someone.


Welcome to the forum.

The thickness of the head gasket is irrelevant to the use of ARP studs, and also has no bearing on the size of the combustion chamber unless one that is too thin is selected and the head impacts the top of the cylinder liners.

No one has EVER suggested oiling the threads in the block, and nothing at all needs to be done with the holes in the block. I don't know what exactly you mean by "The bolts supplied with the gasket are tough enough" but I suspect you have very little experience with why we are using the ARP studs or the amount of research and engineering that has been done to determine that this is a highly suggested upgrade.

The factory bolts are torque-to-yield bolts, which means that NO, they are NOT "tough enough" for this application, but that they have questionable metallurgy and can AND DO weaken over time in service. You claim to have replaced "quite a few" head gaskets, how many were on the CRD? This design is not similar to many others, and the solutions for this engine have been developed with care and contemplation and collaboration with the manufacturer (VM) and the engineers at ARP.
Author:  geordi [ Fri May 01, 2015 9:27 pm ]
Post subject:  Re: CRD Head Bolt Research Request: We need your data!
olypopper wrote:
Geordi, no professional mechanic should darken the doors at Harbor Freight......imho. If the average guy understood how important a torque wrench is, they wouldn't cheap out. :2cents:


True enough. I was looking for a fast solution for a max-torque-trace only, and got exactly what I paid for from HF: Not much. Manually adjusting the torque wrench to discover the release torque takes a great deal of time that I knew I wouldn't have on this job.

My quality torque wrench worked great for the actual torquing of the studs, and the engine sounds great and is running well again.
Author:  Mr. Wilson [ Fri May 01, 2015 10:06 pm ]
Post subject:  Re: CRD Head Bolt Research Request: We need your data!
Fair enough. I was referring to the cylinder head leaks. And I also have no problems with ARP head studs. Yes the OEM bolts are torque to yield. I'm sure there is a lot of money invested in R&D with any upgrade/performance part. Well aware of this. I have worked on these Liberty CRD engines since they were introduced to the American market in 2005. Yes I am a CDRJ technician. And I have also had quite a few heads off a CRD liberty in the last 10 years. Along with sprinters and cummins. And not one time have I had a problem with OEM head bolts. Now I'm sure there are better parts and designs. I'm not downing head studs. I have installed them. They work well. And head gasket thickness is relevant when doing a cylinder head job. You should always use the same thickness as the old one unless you are replacing a piston and liner. Then you will need to measure the liner height. Might be why people are having problems with coolant leaks after a cylinder head service. That's all I'm saying. I'm simply giving out the information that I've learned by the training chrysler has givin me and the experience I've had working on them.
Author:  olypopper [ Mon May 04, 2015 9:48 pm ]
Post subject:  Re: CRD Head Bolt Research Request: We need your data!
Thanks for your advice Mr. Wilson! I'm glad to have some trained techs on here.....unfortunately, my local Jeep dealership has a retired NASA space monkey working as the diesel tech hence the reason they can't seem to fix anything without a lot of luck.
Author:  Mountainman [ Mon May 04, 2015 11:28 pm ]
Post subject:  Re: CRD Head Bolt Research Request: We need your data!
Mr. Wilson wrote:
Fair enough. I was referring to the cylinder head leaks. And I also have no problems with ARP head studs. Yes the OEM bolts are torque to yield. I'm sure there is a lot of money invested in R&D with any upgrade/performance part. Well aware of this. I have worked on these Liberty CRD engines since they were introduced to the American market in 2005. Yes I am a CDRJ technician. And I have also had quite a few heads off a CRD liberty in the last 10 years. Along with sprinters and cummins. And not one time have I had a problem with OEM head bolts. Now I'm sure there are better parts and designs. I'm not downing head studs. I have installed them. They work well. And head gasket thickness is relevant when doing a cylinder head job. You should always use the same thickness as the old one unless you are replacing a piston and liner. Then you will need to measure the liner height. Might be why people are having problems with coolant leaks after a cylinder head service. That's all I'm saying. I'm simply giving out the information that I've learned by the training chrysler has givin me and the experience I've had working on them.


If you're using the same procedure as the factory, perhaps since you are a human, and not a machine, you are applying more even torque to the head bolts (or am I mislead that the factory uses a machine to torque these heads?). But, if not, and you're only as good as the factory procedure, or the TTY bolts, then I think you will find that they will leak, just like the factory ones, it will just take the same 80-180k miles that the factory torqued heads have taken.
Some of the factory ones have lasted until roughly 200k or so, and maybe some never leak, so unless you've worked on large numbers of them, then you may never hear back about any failures, or maybe they haven't racked up the miles yet :2cents:
Do you use the factory degrees method? I would think that if a guy figured a suitable ft/lbs of torque, that they might last a good deal longer than the factory, at least under light use anyhow. I'm very unconvinced that the factory procedure applies even torque. And then there's the crappy bolts. :POPCORN:
Author:  CGman [ Sat May 23, 2015 10:26 pm ]
Post subject:  Re: CRD Head Bolt Research Request: We need your data!
I'm getting ready to put in ARP studs in the next couple of weeks, but I was wondering about one thing.

Are we assuming the factory bolts are stretching or just loosening up?

Wouldn't we expect to see less break-free torque on the outer bolts to be slightly less if the inner row has just been retightened back to spec values?

Any advice, tricks or time estimates anybody would like to pass along to this shadetree mechanic?
Author:  geordi [ Sun May 24, 2015 3:16 pm ]
Post subject:  Re: CRD Head Bolt Research Request: We need your data!
The problem is that there isn't a "spec value" as such because these are TTY bolts and the factory process says "turn x degrees after reaching 60lbs torque" or something like that, and then turn the bolts another x degrees - So what is the final torque of the TTY bolt? Impossible to know.

What we are seeing (and the point of this research thread) is that the #3 bolt seems to be affected by the heat from the cylinders and the exhaust, and loosens. Whether this is from stretch or rotation - I think it is from stretch - is somewhat irrelevant. The studs won't do either when they are properly installed.
Author:  jws84_02 [ Wed Jun 17, 2015 7:35 pm ]
Post subject:  Re: CRD Head Bolt Research Request: We need your data!
Just got done doing one by one. Mine was not leaking, but did it as I had 3 broken rockers and the rest wore out

All of them broke loose with 80lbs. I wish I would of started lower. And yes the torque wrench was working properly because I tested it on the first stud. I tightened to 100 and then turned the wrench down to 80 and got the clicking until I got back up to 100.

I did all of them at 100, then 110, then 120, then 125, and then I took the middle 10 to 130
Author:  lacabrera [ Thu Jun 18, 2015 6:12 am ]
Post subject:  Re: CRD Head Bolt Research Request: We need your data!
I replaced my head gasket a few months back not because of a leak but for more serious reasons. My findings on release torques was none would release below 110lb. I used new TTY bolts, there has to be a good reason why the factory use them instead of standard studs and nuts. The reason for the TTY bolts is to hold the head down under the pressure of the spring built into the bolt. On older diesel engines that use the stud and nuts you would have to re torque them after about 6000 miles. Because of the complexity of modern diesel engines re torqueing the studs/nuts becomes a major issue hence TTY bolts. They are designed to take up any expansion that happens to metal between hot and cold changes. I feel the ARP studs are a good investment as long as you are prepared to re torque them at some point.
Author:  geordi [ Fri Jun 19, 2015 1:02 am ]
Post subject:  Re: CRD Head Bolt Research Request: We need your data!
lacabrera wrote:
I replaced my head gasket a few months back not because of a leak but for more serious reasons. My findings on release torques was none would release below 110lb. I used new TTY bolts, there has to be a good reason why the factory use them instead of standard studs and nuts. The reason for the TTY bolts is to hold the head down under the pressure of the spring built into the bolt. On older diesel engines that use the stud and nuts you would have to re torque them after about 6000 miles. Because of the complexity of modern diesel engines re torqueing the studs/nuts becomes a major issue hence TTY bolts. They are designed to take up any expansion that happens to metal between hot and cold changes. I feel the ARP studs are a good investment as long as you are prepared to re torque them at some point.


Sorry, that is not how TTY bolts work. The elasticity you are expecting ENDS once a fastener exceeds its elastic range and enters the plastic range. This is where deformation does not return to the original position when force is relaxed. The object is permanently deformed, and further deformation usually (rapidly) leads to failure. ARP studs do not need to be re-torqued in this application (or any other that I am aware of) and this instruction comes direct from their engineering department.

TTY bolts are cheap, and an installation line can be programmed to automatically install them with minimal human intervention and any variances in the metallurgy will be accounted for (or ignored) by the install equipment. This is the primary reason why TTY bolts are selected in any application, except one where predicted failure is a desired outcome - such as break-away engine mountings. You would want the bolts to fail in a crash, to absorb energy in that situation. We do not have that design here with the head.

According to ARP themselves, these studs are reaching 75% of their elastic range in this application, well within the safety margin to remain fully functional and provide some 19,000 psi of clamping force. Not a single CRD has reported a head gasket leak after installation of the studs. The examples of leaking gaskets with the TTY bolts are many.
Author:  lacabrera [ Fri Jun 19, 2015 4:39 am ]
Post subject:  Re: CRD Head Bolt Research Request: We need your data!
geordi wrote:
lacabrera wrote:
I replaced my head gasket a few months back not because of a leak but for more serious reasons. My findings on release torques was none would release below 110lb. I used new TTY bolts, there has to be a good reason why the factory use them instead of standard studs and nuts. The reason for the TTY bolts is to hold the head down under the pressure of the spring built into the bolt. On older diesel engines that use the stud and nuts you would have to re torque them after about 6000 miles. Because of the complexity of modern diesel engines re torqueing the studs/nuts becomes a major issue hence TTY bolts. They are designed to take up any expansion that happens to metal between hot and cold changes. I feel the ARP studs are a good investment as long as you are prepared to re torque them at some point.


Sorry, that is not how TTY bolts work. The elasticity you are expecting ENDS once a fastener exceeds its elastic range and enters the plastic range. This is where deformation does not return to the original position when force is relaxed. The object is permanently deformed, and further deformation usually (rapidly) leads to failure. ARP studs do not need to be re-torqued in this application (or any other that I am aware of) and this instruction comes direct from their engineering department.

TTY bolts are cheap, and an installation line can be programmed to automatically install them with minimal human intervention and any variances in the metallurgy will be accounted for (or ignored) by the install equipment. This is the primary reason why TTY bolts are selected in any application, except one where predicted failure is a desired outcome - such as break-away engine mountings. You would want the bolts to fail in a crash, to absorb energy in that situation. We do not have that design here with the head.

According to ARP themselves, these studs are reaching 75% of their elastic range in this application, well within the safety margin to remain fully functional and provide some 19,000 psi of clamping force. Not a single CRD has reported a head gasket leak after installation of the studs. The examples of leaking gaskets with the TTY bolts are many.

I guess time will tell using the studs. None of my CRD,s with over 220,000 miles between them suffered with head gasket problems. Any one had the studs fitted with over 100,0000 miles on them?
I understand The studs you are using are manufactured for the VW tdi engine not specifically for the VM, I am not saying they are not an improvement but I do stand on what I said that they should be re torqued at some point.
Author:  Dent [ Sun Jun 21, 2015 9:32 pm ]
Post subject:  Re: CRD Head Bolt Research Request: We need your data!
Mileage: 100,000, year 2006, no overheating and no perceived need for the studs. Preventative measure while the car is disabled.

position torque (ft. lb.)
1 122.8
2 113.6
3 129.4
4 112.3
5 111.5
6 99.2 (might be screw up on my part reading torque wrench)
7 140.5
8 112.8
9 126.7
10 126.7
11 109.5
12 113.1
13 118
14 113.2
15 111.4
16 119.5
17 124.1
18 105.6

Not completely sure about #10
Author:  geordi [ Sun Jun 21, 2015 11:50 pm ]
Post subject:  Re: CRD Head Bolt Research Request: We need your data!
Thanks for your data! Interesting that it is the intake side of #4 that shows as the loose one on your engine. That is very curious.
Author:  Dent [ Mon Jun 22, 2015 12:28 am ]
Post subject:  Re: CRD Head Bolt Research Request: We need your data!
geordi wrote:
Thanks for your data! Interesting that it is the intake side of #4 that shows as the loose one on your engine. That is very curious.

That #6 could have been a screw up. The way I was using the torque wrench, if I applied torque, then let off a bit and reapplied, it would have lost the break free value. I thought I was pretty good about that after the first (#10), but I wouldn't bet money on it.
Author:  geordi [ Mon Jun 22, 2015 1:19 am ]
Post subject:  Re: CRD Head Bolt Research Request: We need your data!
Hmm. The joys of Harbor Freight I guess.

I'm going to look into getting the better Snap-On device. I'm doing enough of these, I probably should have it.
Author:  josh61187 [ Wed Jun 24, 2015 11:55 am ]
Post subject:  Re: CRD Head Bolt Research Request: We need your data!
I am going to be changing out my head studs today, when I get off work. I am going to borrow a dial read calibrated torque wrench from work so the numbers should be within +-2%. I will use the methodology stated in the first page. Only one question I am going to make a stop by the flaps on the way home today, what socket size is the ARP head stud bolt?
Author:  geordi [ Wed Jun 24, 2015 12:00 pm ]
Post subject:  Re: CRD Head Bolt Research Request: We need your data!
josh61187 wrote:
I am going to be changing out my head studs today, when I get off work. I am going to borrow a dial read calibrated torque wrench from work so the numbers should be within +-2%. I will use the methodology stated in the first page. Only one question I am going to make a stop by the flaps on the way home today, what socket size is the ARP head stud bolt?


Unless your box is somehow different, the studs should be 14mm 12-point socket and the factory bolts are 6-point 11mm. The factory bolts are the ones that have killed my sockets, so get an impact socket if possible or at least a nice thick wall for those.
Author:  farbedo [ Sun Jul 05, 2015 7:44 am ]
Post subject:  Re: CRD Head Bolt Research Request: We need your data!
Torque values from yesterdays ARP stud swapout:
Rounded to the nearest 10. It was a little hard to see the needle since it was only me. All but #3 were the same. I am going to take the #3 bolt and another to work and check hardness on them just to see.

1 120
2 120
3 100
4 120
5 120
6 120
7 120
8 120
9 120
10 120
11 120
12 120
13 120
14 120
15 120
16 120
17 120
18 120
Author:  geordi [ Sun Jul 05, 2015 11:03 am ]
Post subject:  Re: CRD Head Bolt Research Request: We need your data!
Do you have access to a destructive test rig? Need more bolts to test against? I'd love to know the actual metal characteristics of these bolts. It wouldn't be for any specific purpose other than curiosity, as the application of the studs is already figured out and successful.
Author:  Mountainman [ Sun Jul 05, 2015 12:11 pm ]
Post subject:  Re: CRD Head Bolt Research Request: We need your data!
The latest one I took apart was botched by a dealer 2 or 3 times. I didn't bother to get torque readings because I was sure that they didn't follow the procedure. Anyhow, the bolts were bone dry after only lasting a small number of miles for the PO, no oil had been added to them...
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