Arp head stud question.

Mopargarage · **Posted:** Mon Jun 10, 2019 7:30 pm

After following the arp instructions is it ok to go back and check the torque on them again after 24 hours? Or is there no need?

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geordi · **Posted:** Tue Jun 11, 2019 12:26 am

In this application, that would require disassembly of the top of the engine again, but ARP has concluded that there is little statistically valid reason to do that. Once they are properly torqued according to the directions, they are set for the duration.

TKB4 · **Posted:** Tue Jun 11, 2019 10:24 am

I would assume you mean check it after 24 hours and before reassembly. I finished ARP s on one that was at a quitting point for the day and I did recheck the torque the following day before reassembly and the torque was the same but it wasn't but about 16 hours. It would be nice however, if someone needed to replace rockers etc later that already had ARP s after several thousand miles if they would check the torque on them and report what they find.

geordi · **Posted:** Tue Jun 11, 2019 11:14 am

I realize this is a fairly small sample set to answer for, out of the number of ARP sets sold for CRDs and the number of CRDs out there entirely...

~16,000 CRDs originally sold.
~8,000 still on the road
Several hundred sets of ARPs sold, IDparts would have to chime in about how many they have moved

I ***personally*** have installed ARP studs on close to 60 CRDs now, of the 80 that I have worked on. (the rest were just timing belt or water pump)
For the ones I have worked on: I have not heard of a single subsequent failure of the rockers, head gasket* or studs.

*There have been zero head gasket failures after ARP installation on engines that either passed the cold-engine-test and got a one-by-one stud install, or a completely new gasket from me. There HAVE been two subsequent head gasket failures on engines that had FAILED the cold engine test / showed evidence of an existing leak, but the owner elected to try the studs first.

In all cases, the studs are installed the same way and I have not heard of any problems from ANYONE with the VW stud kits, or the newer (longer) stud kits.

Mopargarage · **Posted:** Tue Jun 11, 2019 2:49 pm

TKB4 wrote:

I would assume you mean check it after 24 hours and before reassembly. I finished ARP s on one that was at a quitting point for the day and I did recheck the torque the following day before reassembly and the torque was the same but it wasn't but about 16 hours. It would be nice however, if someone needed to replace rockers etc later that already had ARP s after several thousand miles if they would check the torque on them and report what they find.

Yeah before reassembly

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Mopargarage · **Posted:** Tue Jun 11, 2019 2:51 pm

So there's no need to do then. Cool I was just curious. I'm waiting on a valve cover/camshaft assembly gasket. So I'm kinda twiddling my thumbs.

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Mopargarage · **Posted:** Tue Jun 11, 2019 5:43 pm

Some pictures of the job. I replaced rocker arm and lifters, I have a new timing belt, replaced the thermostat and water pump, also replaced the rear main seal 400 miles ago. I've been balls deep in this thing lately.

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Mopargarage · **Posted:** Tue Jun 11, 2019 5:46 pm

I also had the head checked out and pressure tested, no warping, no valve seats. Only cost me 160 dollars to do. Can't wait to see how the original head is. I love these so much we have 3 diesel liberties. The 4th one is a parts vehicle. It's where I got the spare head from.

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Mopargarage · **Posted:** Tue Jun 11, 2019 5:47 pm

Mopargarage wrote:

I also had the head checked out and pressure tested, no warping, no valve seats. Only cost me 160 dollars to do. Can't wait to see how the original head is. I love these so much we have 3 diesel liberties. The 4th one is a parts vehicle. It's where I got the spare head from.

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I meant new valve seats

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Mopargarage · **Posted:** Tue Jun 11, 2019 5:54 pm

Repainted the turbo with a dark cast paint.

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TKB4 · **Posted:** Tue Jun 11, 2019 8:35 pm

Looks great! Now if it just runs great!

Mopargarage · **Posted:** Wed Jun 12, 2019 5:08 pm

TKB4 wrote:

Looks great! Now if it just runs great!

It ran and sounded fine before. Just leaked oil and coolant.

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gollygeemister · **Posted:** Wed Jun 12, 2019 10:51 pm

[quote="Mopargarage"]Some pictures of the job. I replaced rocker arm and lifters, I have a new timing belt, replaced the thermostat and water pump, also replaced the rear main seal 400 miles ago. I've been balls deep in this thing lately.

/quote]

The deck on that block is gorgeous. You say the HG was leaking? What did you clean it with?

geordi · **Posted:** Wed Jun 12, 2019 11:23 pm

gollygeemister wrote:

Mopargarage wrote:

Some pictures of the job. I replaced rocker arm and lifters, I have a new timing belt, replaced the thermostat and water pump, also replaced the rear main seal 400 miles ago. I've been balls deep in this thing lately.

/quote]

The deck on that block is gorgeous. You say the HG was leaking? What did you clean it with?

You are looking at the head gasket. These will leak if the bolts are not replaced with studs BEFORE the leak presents itself. After that, you need to pull the engine apart to the pistons and replace the gasket and install studs.

I use copper coat spray sealant in addition, the coating on the gasket itself is not sufficient in my view. Also - I hope you replaced the valves? It would be a shame to do all that work and have it suddenly drop a valve next week...

gollygeemister · **Posted:** Thu Jun 13, 2019 8:44 am

geordi wrote:

You are looking at the head gasket. These will leak if the bolts are not replaced with studs BEFORE the leak presents itself. After that, you need to pull the engine apart to the pistons and replace the gasket and install studs.

I use copper coat spray sealant in addition, the coating on the gasket itself is not sufficient in my view. Also - I hope you replaced the valves? It would be a shame to do all that work and have it suddenly drop a valve next week...

Indeed it is! I'm gonna blame this tiny screen I'm looking at! I used the copper spray-a-gasket on the last one I did as well.

Mopargarage · **Posted:** Sat Jun 15, 2019 8:17 am

gollygeemister wrote:

Mopargarage wrote:

Some pictures of the job. I replaced rocker arm and lifters, I have a new timing belt, replaced the thermostat and water pump, also replaced the rear main seal 400 miles ago. I've been balls deep in this thing lately.

/quote]

The deck on that block is gorgeous. You say the HG was leaking? What did you clean it with?

Yeah it was leaking at the head gasket. This is the second time I've had the head off in 400 miles. Pretty sure the original head is warped. I just de greased the motor before the first head gasket replacement. Then painted everything I could reach whe it was in the engine bay.

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Mopargarage · **Posted:** Sat Jun 15, 2019 8:19 am

gollygeemister wrote:

geordi wrote:

You are looking at the head gasket. These will leak if the bolts are not replaced with studs BEFORE the leak presents itself. After that, you need to pull the engine apart to the pistons and replace the gasket and install studs.

I use copper coat spray sealant in addition, the coating on the gasket itself is not sufficient in my view. Also - I hope you replaced the valves? It would be a shame to do all that work and have it suddenly drop a valve next week...

Indeed it is! I'm gonna blame this tiny screen I'm looking at! I used the copper spray-a-gasket on the last one I did as well.

I took my spare head to my machine shop and the valves were checked. Replaced the seats and it was good to go.

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Mopargarage · **Posted:** Sat Jun 15, 2019 8:21 am

geordi wrote:

gollygeemister wrote:

Mopargarage wrote:

Some pictures of the job. I replaced rocker arm and lifters, I have a new timing belt, replaced the thermostat and water pump, also replaced the rear main seal 400 miles ago. I've been balls deep in this thing lately.

/quote]

The deck on that block is gorgeous. You say the HG was leaking? What did you clean it with?

You are looking at the head gasket. These will leak if the bolts are not replaced with studs BEFORE the leak presents itself. After that, you need to pull the engine apart to the pistons and replace the gasket and install studs.

I use copper coat spray sealant in addition, the coating on the gasket itself is not sufficient in my view. Also - I hope you replaced the valves? It would be a shame to do all that work and have it suddenly drop a valve next week...

The head went to my machine shop and the Valves were checked and they were good only had to replace the seats for them.

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geordi · **Posted:** Sat Jun 15, 2019 12:40 pm

Mopargarage wrote:

The head went to my machine shop and the Valves were checked and they were good only had to replace the seats for them.

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I'm sorry for you if that was the only thing done. The seats aren't the cause of failures and frequently have nothing needed. There is no way to "check" the valves for the failures that happen unless this machine shop has invented an x-ray that can see through metal and see microscopic changes in the metal's structure.

The metal alloy itself fails due to fatigue and extreme temperature which changes the crystal structure within the alloy itself. This happens over time, and the failure happens without warning after around 300 billion cycles or roughly 200k miles.

This is why the advice of the group is that if there is ANY reason to remove the head, replacement of the valves (and deleting of the EGR to lower peak cylinder temps) is highly suggested.

WWDiesel · **Posted:** Sat Jun 15, 2019 1:29 pm

geordi wrote:

Mopargarage wrote:

The head went to my machine shop and the Valves were checked and they were good only had to replace the seats for them.
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I'm sorry for you if that was the only thing done. The seats aren't the cause of failures and frequently have nothing needed. There is no way to "check" the valves for the failures that happen unless this machine shop has invented an x-ray that can see through metal and see microscopic changes in the metal's structure.
The metal alloy itself fails due to fatigue and extreme temperature which changes the crystal structure within the alloy itself. This happens over time, and the failure happens without warning after around 300 billion cycles or roughly 200k miles.
This is why the advice of the group is that if there is ANY reason to remove the head, replacement of the valves (and deleting of the EGR to lower peak cylinder temps) is highly suggested.

Spot on advice!
If you did not replace the exhaust valves, you may be very sorry later on down the road.
If one of the valves breaks off, which there have quite a few that have, there definitely will be a lot of catastrophic engine damage occurring.
Some have even lost/destroyed the entire engine when this happens. (Cracked blocks & destroyed head) :shock:

If you have the head off for ANY reason, please replace all the exhaust valves.
Just cannot understand why anyone would want to take that kind of risk when it is avoidable. :shock:

Arp head stud question.

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