Head gasket time

timothyd · **Joined:** Wed Feb 20, 2019 2:58 am **Posts:** 90

It's time to do the head gasket as I am loosing coolant. I do not intend to do ARP head studs and do not have a large budget for this. Other than this kit will I need anything else gasket or seal wise? Also IIRC the short answer for head gasket now is to do the 2 hole no matter what I have in there? https://www.idparts.com/cylinder-head-i ... -3203.html

I am also looking at other failure points and weighing out what would be worth doing. I am not afraid to dig into the motor again in the future but would like to avoid catastrophic failure. Rockers are almost $400 and if they fail should not cause a catastrophic failure so I do not think I can budget for that but if a valve does fail that would be death for the motor. If I were to do the exhaust valves, what all would I need to order?

TURBO-DIESEL-FREAK · **Joined:** Sat Apr 17, 2010 3:29 pm **Posts:** 1167

What cooling system modifications have you performed, if any?

It is great news that you are not falling for the ARP head stud spin. ARP head studs - nor any fastener, for that matter - will not stop a head from warping, and because they do not stretch to accommodate the greater thermal expansion factor of the aluminum head over the iron block underneath, the head has a far greater chance of cracking instead of merely just warping.

American Racing Products makes parts primarily for racing and competition engines. They are made to keep the head securely fastened to the block AT ALL COSTS, in engines that are not made to last very long. They are therefore unsuitable for most day-to-day transportation, where long term reliability is a primary concern. You can call ARP up and consult with them if readers of this post do not believe me... they do NOT recommend their products for this specific application; the V.M. Motori R428 engine.

You can get ARP head stud kits for the CRD engine through online retailers because those same retailers specify the precise measurements and specifications of the studs required for for the R428 and ARP merely fills those orders... no warranty of guarantee is given or implied. Those kits are ordered by the retailers because they see a demand for them through the online forums, even though those same forums have not made the case for them.

Is there a scenario where ARP head studs can be used in the CRD engine? I am quite sure there are cases where they would be appropriate to use.... typically a highly modified engine producing significantly more power than the stock engine where clamping the head down on the block overrides all other concerns. ARP has never bothered to test or develop head studs for the R428 because there aren't enough engines out there in North America to make the testing and development worthwhile.

thesameguy · **Joined:** Sat Oct 01, 2016 8:24 pm **Posts:** 652

I strongly agree.

Factories use TTY bolts for a reason. They offer superior life for all components involved. I wouldn't buy into the "because they are cheap" logic. People do not want engines coming back for head gaskets under warranty. These systems are highly engineered to provide a specific function and that function is durability. ARP studs are great on cast iron engines that have minimal expansion, but they are quite problematic for daily-driven aluminum and especially on mixed materials engines. Every car made in the last 20-30 years uses TTY bolts *because* they are better for the engines they go on.

I'm not an engineer, but I deal a lot with boosted cars the people who build them professionally. Nobody I have ever talked to recommends non-TTY bolts for stock power levels or even pretty enhanced mills. And I'm talking 2.0l motors making 400 and 500hp.

All that said, my experience doing a head gasket on a CRD resulted in basically a full head rebuild - all new valves, guides, and rockets. This was a combination of feedback from the forum, and examination by a competent machine shop... My intake valves and most of the guides were way out of spec. The exhaust valves mic'd out fine, but I replaced them mostly out of fear. The rockers were 100% intact, but after all the other work it seems silly to stop short. When it comes to delicate and important work, like cylinder head work, I always have a good shop take a look and provide recommendations, and that'd be my advice to you.

I would personally recommend replacing all the exhaust manifold studs and nuts. No point reusing things that are in high-stress areas and whose failure would lead to a lot of work. Not worth saving $30 to end up taking something apart again.

I see your timing belt and water pump was just done, kinda sucks to have to repeat that work. I would personally consider putting a new belt back on there... I hate reusing timing belts, even young ones.

Beyond that, in my project I didn't really find much that was easier to access or sensible to replace with the head off. Like the timing belt, though, I always suggest (on any motor) to replace every gasket and seal you come in contact with. That'd be things like the cam plug washers, the cam seals, intake & exhaust gaskets, camifold gasket, thermostat gasket, and the seals & gaskets for the timing belt covers. Most of that stuff you don't have a choice on, but I always cringe when I see people reusing old stuff that is just gonna fail soon anyway.

TURBO-DIESEL-FREAK · **Joined:** Sat Apr 17, 2010 3:29 pm **Posts:** 1167

I personally believe that the V.M. Motori R425 and R428 engines should be upgraded with an iron cylinder head....

Yes, I know... an iron head would be substantially heavier than an aluminum head. But the benefits of having the head expand at the same rate as the block would far outweigh the weight penalty. We might be able to use ARP head studs and boost power levels while actually increasing reliability.

thesameguy · **Joined:** Sat Oct 01, 2016 8:24 pm **Posts:** 652

Beyond weight a cast iron head that flows like an aluminum head would be physically gigantic. It is very difficult to cast small but strong complex parts in iron. The industry moved to aluminum for small motors because getting the flow rates required for modern small engines basically required going to aluminum. You don't get 100+hp/l flow rates from cast iron. A 2.8l Jeep with a cast iron head would make 100hp on it's best day. Even light trucks all use aluminum now because people expect those figures. Nobody cares what horsepower an ISX makes as that's not it's purpose. But nobody would buy an F250 that makes 30hp/l.,.. 200hp from a 6.2l motor would look silly in 2020.

WWDiesel · **Posted:** Sat Dec 05, 2020 1:06 pm

The key factor for the cast iron block with an aluminum head combo is the coolant flow, it is the great temperature equalizer to maintain balance between the two different metals. We all know aluminum absorbs heat (heats up) much faster than steel, but it also transfers or gives up that same heat much faster to the coolant that is in constant contact with aluminum metal. If the coolant is not moving fast enough through the head when the aluminum gives up that heat to the coolant, the coolant can boil off or flash to steam and create a hot spot where the aluminum is not be sufficiently cooled. This can damage the head and / or head gasket.
(and yes the coolant can boil or flash to steam even though it is under pressure, the pressure only slightly raises the temperature at which it happens)

This is why some members are so vehemently and adamantly apposed to doing anything to alter the critical cooling flow through the aluminum head during the very critical warm up period. Altering the cooling systems on these engines in any manner that can possibly reduce the critical coolant flow through the aluminum head, can have grave and catastrophic consequences over time. It may not be noticeable in the short term, but the long term affects when they do began to appear, it is too late, and are irreversible. Possible leaking or blown head gasket, or worse case scenario, a cracked head or worse.....
It is kind of like playing Russian Roulette with the engine! :dead:

thesameguy · **Joined:** Sat Oct 01, 2016 8:24 pm **Posts:** 652

All of that! And that logic is what got us the reverse flow cooling system on the '92 LT1... Get the heat out of the head as quickly as possible! It just cannot be overstated how important a properly maintained engine is. Everything, top to bottom, needs attention periodically.

WWDiesel · **Posted:** Sat Dec 05, 2020 9:32 pm

thesameguy wrote:

All of that! And that logic is what got us the reverse flow cooling system on the '92 LT1... Get the heat out of the head as quickly as possible! It just cannot be overstated how important a properly maintained engine is. Everything, top to bottom, needs attention periodically.

I agree, now if we could just figure out how to reverse flow the cooling system. What a pipe dream! :ROTFL:

My66dodge · **Posted:** Sun Dec 06, 2020 11:21 pm

I stuck the egr coolant outlet in the middle of the head in the rear port and use 5/8 heater hose to run it to a remote mount cooler with a fan, then back to the engine as it normally does in the water pump inlet. The fan is on a switch for hard driving

Sent from my iPhone using Tapatalk

spoon · **Posted:** Tue Dec 22, 2020 11:37 am

More on that 66Dodge? Photo or a diagram.

My66dodge · **Posted:** Tue Dec 22, 2020 1:45 pm

I would love to do a photo but it is a PITA to upload. There is a coolant outlet in the middle of the drivers side of the head that goes to the egr cooler and you move it to the rear and use bulk hose to run it to the pipe that runs by the alternator. An alternate is if you want to add an aux rad that’s the place to do it like a derale remote mount with electric fans, that’s the loop you put it into so it’s cooled when it gets back to the water pump. I put it on a switch for towing to take off the extra heat

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timothyd · **Joined:** Wed Feb 20, 2019 2:58 am **Posts:** 90

Follow up question on this, should I order the head gasket hole size I have or go straight for the 2 hole? Also does this head/block need any machining when doing the gasket?

thesameguy · **Joined:** Sat Oct 01, 2016 8:24 pm **Posts:** 652

Only a machine shop can tell you if the head needs work... And with the CRD head, there is VERY little to work with.

geordi · **Posted:** Sat Jan 02, 2021 2:16 am

timothyd wrote:

Follow up question on this, should I order the head gasket hole size I have or go straight for the 2 hole? Also does this head/block need any machining when doing the gasket?

As someone who has seen the largest number of these engines as any one person in the USA, I disagree with your decision to not install the ARP studs. At the temperatures these engines operate, any expansion of dissimilar metals is microscopic at best. Race teams use similar designs (multi-layer steel gaskets) and certainly have iron blocks and aluminum heads and operate at WAY higher pressures and punishments than our engines. They use ARP studs for the superior clamping and the known quantifiable performance. This is not conjecture, it is proven by science and results.

But that's only one of the decisions. You should definitely use the two-hole gasket, the risk is not about the gasket thickness, it is about the head contacting the cylinder liners and not allowing proper compression / sealing of the gasket which can lead to leaking. You should also absolutely replace the valves and lap them in - any time that the head is removed, the important thing is the prevention of future problems for the least amount of money possible. Everyone should like that, right?

But there is no material in the head to machine, it is a cast aluminum head and very very thin. There have been some people that have had as little as .003 shaved, but that is not enough to solve any warping (should it be, from thermal abuse) Any more than that, is risking cutting holes in the bottom of the head. You don't need to mess with the seats as they are pressed-in and lapping is all they need. Trying to remove and re-press new has caused cracking in other heads.

thesameguy · **Joined:** Sat Oct 01, 2016 8:24 pm **Posts:** 652

geordi wrote:

any expansion of dissimilar metals is microscopic at best.

If there is no functional issue here, why does the factory use TTY bolts when the point of TTY bolts is to allow for this exact effect? The coefficient of thermal expansion is literally double for aluminum versus iron - it may be microscopic, but everything about engines works on microscopic tolerances.

If you've done a metallurgical analysis on the block & head, we could compute this number. If you haven't, it's conjecture that seems to fly in the face of some highly paid engineers.... and I'm not just talking about VM Motori. Every single mixed-materials engine since the '90s has used TTY bolts to account for this.

CGman · **Posted:** Sun Jan 03, 2021 11:33 pm

thesameguy wrote:

geordi wrote:

any expansion of dissimilar metals is microscopic at best.

If there is no functional issue here, why does the factory use TTY bolts when the point of TTY bolts is to allow for this exact effect? The coefficient of thermal expansion is literally double for aluminum versus iron - it may be microscopic, but everything about engines works on microscopic tolerances.

If you've done a metallurgical analysis on the block & head, we could compute this number. If you haven't, it's conjecture that seems to fly in the face of some highly paid engineers.... and I'm not just talking about VM Motori. Every single mixed-materials engine since the '90s has used TTY bolts to account for this.

Have there been a rash of reports of cracked heads from people that have installed ARP studs?

TURBO-DIESEL-FREAK · **Joined:** Sat Apr 17, 2010 3:29 pm **Posts:** 1167

CGman wrote:

thesameguy wrote:

geordi wrote:

any expansion of dissimilar metals is microscopic at best.

If there is no functional issue here, why does the factory use TTY bolts when the point of TTY bolts is to allow for this exact effect? The coefficient of thermal expansion is literally double for aluminum versus iron - it may be microscopic, but everything about engines works on microscopic tolerances.

If you've done a metallurgical analysis on the block & head, we could compute this number. If you haven't, it's conjecture that seems to fly in the face of some highly paid engineers.... and I'm not just talking about VM Motori. Every single mixed-materials engine since the '90s has used TTY bolts to account for this.

Have there been a rash of reports of cracked heads from people that have installed ARP studs?

Yes, there have been some reports. There have also been reports of people getting cracked heads with TTY bolts, and geordi will probably try to point this out. What he does not seem to understand is that the incredible strength of the ARP head studs INCREASES the chances of the head cracking.

The extra strength that ARP head studs provide to keep cylinder heads clamped down tightly on competition engine is precisely the same thing that keeps the aluminum head from expanding properly under normal operating conditions. Competition engines need the extra clamping force these fasteners provide to keep these engines from flying apart under extreme pressures and conditions. These conditions do not exist with stock engines, therefore a fastener that is designed to provide clamping force to the exclusion of everything else is not needed, or desired for that matter... there are other issues to consider. Even stock engines with some performance modifications do not require ARP head studs; has anyone ever got a recommendation from Green Diesel Engineering to install ARP head studs even with their Turbo kit?

geordi points out that there are racing/competition engines that have aluminum head on iron block architecture and that they use ARP head studs. This is true, but what he conveniently leaves out is that all racing and other competition engines have a common characteristic that virtually excludes them from having a head warp or a head crack... they do not last very long. Cylinder head warping and/or cracking only shows up after many hundreds, (thousands, likely), of heat/cool cycles; a competition engine only goes through a few races before it is rebuilt or it has blown up and therefore will likely NEVER get the opportunity to develop a warp of a crack in the cylinder head.

The problem that armchair engineers like geordi have is that if THEY can not see it happening, then it must not be true. The fallacy in their argument is that they do not research on their own or take measurements to bolster their arguments; they just simply repeat their assertions over and over. I suspect that they actually do not want to do any research because they do not want to find out that they are wrong; that would mean that they are exposed to be the fools the rest of us know them to be. The whole narrative that geordi started on the following two threads would have to be changed...

viewtopic.php?f=5&t=84902

viewtopic.php?f=5&t=79984

... and geordi would end up with egg all over his face.

geordi is a glorified wrench puller; he has no professional training as a mechanical engineer, or training as an engineer of any kind. He seems to feel that replacing parts on Jeep CRDs qualifies himself to the "expert". He claims in his post above that "science" is behind his support for the use of ARP head studs in non-competition CRD engines; the problem with this assertion is that he is conflating the issue of the cylinder head clamping requirements of competition and racing engines with the differing requirements of stock engines.

TURBO-DIESEL-FREAK · **Joined:** Sat Apr 17, 2010 3:29 pm **Posts:** 1167

thesameguy wrote:

geordi wrote:

any expansion of dissimilar metals is microscopic at best.

If there is no functional issue here, why does the factory use TTY bolts when the point of TTY bolts is to allow for this exact effect? The coefficient of thermal expansion is literally double for aluminum versus iron - it may be microscopic, but everything about engines works on microscopic tolerances.

If you've done a metallurgical analysis on the block & head, we could compute this number. If you haven't, it's conjecture that seems to fly in the face of some highly paid engineers.... and I'm not just talking about VM Motori. Every single mixed-materials engine since the '90s has used TTY bolts to account for this.

Again, geordi is making irrational estimations here as he has not actually MEASURED the thermal expansion differences in an iron block and an aluminum cylinder head.

If we are talking about 1 cubic inch of iron verses 1 cubic inch of aluminum; he may be correct stating that the differences are microscopic. However, we are NOT talking about something even remotely that small; we are talking about an engine block that weighs hundreds of pounds and an aluminum head that must weigh at about 50 pounds. The cumulative affect on thermal expansion for pieces of metal that large is significant indeed.

geordi · **Posted:** Mon Jan 04, 2021 3:09 am

Now look who is attempting to prove to everyone how smart he is, yet cannot even be bothered to accurately describe the functions of the ARP head stud or the weight of the head itself.

For the record, the head is 38 lbs of aluminum, the engine is listed at 489 lbs - although I do not know if that is the assembled engine or only the block, or somewhere in between.

But at operational temperatures, the ONLY PLACE in the engine that is over 220 degrees at any point is the actual combustion chamber. The coefficients of expansion may be different, but THAT IS NOT A FACTOR AT THESE LOW TEMPERATURES. The clamping force of the ARP studs has been calculated to be PRECISELY THE SAME as the TTY bolts, there is no chance of cracking the head (and NO there have not been ANY proven reports of a head cracking BECAUSE of the ARP stud installation) - Yes there have been exactly TWO people who did have a cracked head, but this was NOT PROVEN AND NOT KNOWN by them whether the head may have been cracked before or after.

So the clamping force of the factory bolts is 19k psi, as is the ARP studs. The critical differences: The ARP studs apply their force with zero rotational twist of the shaft of the fastener, studs are superior in this. The bolts are twisted from the top and clamp at the bottom, leading to elongated twisting forces down the shaft which can - over time - allow them to back out and lose force. TTY bolts are by design also installed and stressed into the "plastic" range, where any deformation of the material is permanent. SO if there DOES happen to be any coefficient of expansion issues as you continually allege.... The TTY bolts will stretch MORE, and never go back, leading to a progressive leak as they lose tension. ARP studs that are exerting the same 19k psi clamping force are able to do this while the material of the fastener is in the "elastic" range, so they can deform (lengthen) as needed and still return to their original shape, retaining their clamping force the entire time.

If the operating temperatures we were talking about were 500 degrees or more, then certainly the expansion might become a factor. But at less than 220 degrees, expansion of the materials is just not a factor.

Manufacturers choose TTY bolts because they can be installed by a machine that does not need continual recalibration like a torque installation machine would. The Germans use TTY bolts for just about everything on a VW, and it has NOTHING AT ALL to do with material expansion or magical fairy dust or anything else. It's because they can be done cheaper by machine, and that's the fastener that can be done that way. Also, Alf: Shut up.

CGman · **Posted:** Mon Jan 04, 2021 10:47 am

TURBO-DIESEL-FREAK wrote:

thesameguy wrote:

geordi wrote:

any expansion of dissimilar metals is microscopic at best.

If there is no functional issue here, why does the factory use TTY bolts when the point of TTY bolts is to allow for this exact effect? The coefficient of thermal expansion is literally double for aluminum versus iron - it may be microscopic, but everything about engines works on microscopic tolerances.

If you've done a metallurgical analysis on the block & head, we could compute this number. If you haven't, it's conjecture that seems to fly in the face of some highly paid engineers.... and I'm not just talking about VM Motori. Every single mixed-materials engine since the '90s has used TTY bolts to account for this.

Again, geordi is making irrational estimations here as he has not actually MEASURED the thermal expansion differences in an iron block and an aluminum cylinder head.

If we are talking about 1 cubic inch of iron verses 1 cubic inch of aluminum; he may be correct stating that the differences are microscopic. However, we are NOT talking about something even remotely that small; we are talking about an engine block that weighs hundreds of pounds and an aluminum head that must weigh at least 50 pounds. The cumulative affect on thermal expansion for pieces of metal that large is significant indeed.

Geordi shouldn't need to measure any of these differences because the block and the head stay the same whether you use ARP or TTY bolts. Your concern is that the thermal expansion with ARPs will crack the head? (you didn't specifically say) Then the question would be whether the ARPs allows the connection to expand and retract the same as the TTY bolts. Geordi clearly gave his answer.

I know you have created an alternative design of thermostat housing that allows you to replace the standard thermostat easily with whatever temp thermostat you would like, but do you think that is what is going to fix the rash of cracked heads and leaky gaskets that plagues this engine design?

Also, do we have numbers on how many people with stock engine tunes have or have not experienced these issues?

Head gasket time

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