CAT 3208TA head gasket replacement

[Mischief Managed]

My boat is equipped with a pair of 375 HP 3208TA engines that are 29 years old and have about 2000 hours on them. I knew that the head gaskets were a known problem on these engines when I bought the boat and decided to replace them with re-designed parts from CAT over the Winter. The work is complete on my starboard engine and about 70% complete on the port engine. I found that 3 out of the 4 head gaskets had already failed, but none of the failures were catastrophic, yet. If you have 3208TAs, I strongly recommend that you budget some money and time for this work.



I used the opportunity to:

• Rebuild the water pumps, heat exchangers, and transmission oil coolers.
• Add remote cooling system drains and Walker Airseps.
• Replace all the hoses, hose clamps, cooling system gaskets, thermostats, fuel injectors, injection pump seals, zincs, belts, o-rings etc.
• Clean and repaint everything I could without removing the engines

I will also be flushing the cooling systems once the boat is launched.

It's been an interesting project. I was hoping to make a video of the work, but gave up when I ran out of memory on my phone. Feel free to PM me if you need any tips.


Here's a picture of two failed head gaskets stacked. The shiny metal ring is supposed to go all the way around each cylinder hole, it's missing where it has failed and burned away. Three cylinders on this engine had this problem but it had no symptoms except some coolant loss, which may not have been caused by this failure.

 

[PM]

I never considered head gasket R&R as preventative maintenance but some engines have poorly designed parts on otherwise good engines.

Glad the job is going well for you.

pete

 

[Ski in NC]

Yep, good call to do it proactively. I've done a bunch of 3208 head gaskets, some obviously failed with symptoms, some proactively, and the pics show what I saw on tear down. Compression seal rings failed between cylinders. All the engines I did were at 20-30yrs of age, varying hours. All were T or TA versions, never did the job on a NA version.

On one boat head gasket clearly failed. Did both heads on that engine, and recommended to the owner to do the other engine even though it had no symptoms. He did not like that idea, so I did just the failed engine. A year later the other engine did the same thing, different owner. This time I had to lug all my crap 50m to the marina it was then located.

It would have been much less expensive to do both at the same time.

So you 3208TA owners, consider this thread. The old head gaskets really get weak with age.

 

[Mischief Managed]

I broke a head bolt on the first head I installed. It was easy to deal with but even though CAT says to re-use them, all the head bolts are new now. I checked my torque wrench calibration and it was well within the expected range, the old bolt was just weak. I voii up of not find a better head bolt than factory stuff so that’s what I bought. Speaking of factory stuff, CAT parts seem to be reasonably priced and really easy to get. My local CAT dealer can get me anything in 24 hours or less

 

[stiggy]

How many hours would you estimate for the replacement?

 

[Arc]

Now you know those engines front to back.

 

[Mischief Managed]

How many hours would you estimate for the replacement?

If I had to guess, I think I could do the head gaskets and nothing else in 10 hours per engine or less, on my boat, where access is very good. I would need occasional help to lift the heavy bits though. And this assumes all needed parts are on hand.


That said, it's hard to say for sure because I was learning as I went on the first engine and ordering parts as I discovered the need for them. I am also doing a ton of extra cosmetic and preventative maintenance work that is not required but eats up huge amounts of time. For example it takes a solid 6 to 8 hours to disassemble the fuel lines, wire brush them, paint them, and re-assemble them (with lots of head scratching), excluding paint drying time. It's also super time-consuming to remove old gaskets from sealing surfaces.

 

[Mischief Managed]

Now you know those engines front to back.

That was another reason for tackling this project. My wife and I are preparing for long-term cruising and we are going to be as self-sufficient as possible. I certainly hope I won't need to pull a cylinder head in some exotic place, but it will be nice to know I have the skills and tools if I need to. Starting out with a like-new cooling system and new fuel injectors gives me tremendous peace of mind too.



Oddly, one of the most challenging parts of this work was figuring out how to use the CAT parts manual. That is one convoluted and thick book.

 

[ghost]

Cool. I did mine, but it took me a lot longer than 10 hours. I don’t work super quick. Plus, I started by building a support with an I beam over the engine because I could not lift the head by myself, at least not while bent over. I spent the most amount of time cleaning the head and block surfaces and lapping the valves before reassembling. The only PIA, was not thoroughly cleaning the little coolant passageway between the front cover and having to pull it back off to do so. I ordered all new bolts and the guy at cat looked like I had a hole in my head, but I think I recalled that part of the improvements they made were better bolts and a better head gasket, so having everything to current spec seemed a no brained. Way cheaper than my time.

It is rather nice knowing the engine inside and out.

Mine are naturals, and while less problematic it’s not unheard of.

The parts catalog is indispensable, along with reading it fluently and taking into account your serial number. Then finally referencing the parts catalog online for any up to date parts substitutions.

 

[Mischief Managed]

The parts catalog is indispensable, along with reading it fluently and taking into account your serial number. Then finally referencing the parts catalog online for any up to date parts substitutions.

For my engines, the serial numbers have not been very useful with the parts manual, I found that it was necessary to use the "arrangement" code first, then the serial number (only if required) to get to the correct page for each "group". Once I had the part number, I used the CAT website to look up the part and note any supercessions. It's been fascinating work and I plan to put together a comprehensive spare parts kit to make this kind of work possible for me to do in some exotic locale; fingers crossed the spare parts collect dust forever...

 

[auskiwi]

Not just on Cats, had trouble with my port Cummins 6 BTA, 25yrs old 1480 hrs, found head gasket leaking, had to replace head as it was cracked, decided to do stb motor for safety, yes it had started leaking as well, head builder said I had caught it just in time, all back and running after doing injectors, cleaning heat exchangers and servicing aftercoolers and replaced both water pumps, big job, had a Marine mechanic do all the tricky bits but still did a good few hrs in the engine room, am getting too old for this, glad the air con was working well on 30+C days.

 

[Prospective]

So I really admire you guys that can do this level of wrenching on your engines. Obviously you have a fair bit of mechanical experience.

I wondering... do you work from a shop manual that shows you the steps for what needs to be removed/replaced and in what order or do you just rely on your experience?

 

[Mischief Managed]

I wondering... do you work from a shop manual that shows you the steps for what needs to be removed/replaced and in what order or do you just rely on your experience?

I use the factory service manual. It’s good, but assumes you know what end of the screwdriver to hit with a hammer; it’s not for novices. There are a couple of special tools required too.

 

[Mischief Managed]

Not just on Cats, had trouble with my port Cummins 6 BTA, 25yrs old 1480 hrs, found head gasket leaking, had to replace head as it was cracked, decided to do stb motor for safety, yes it had started leaking as well, head builder said I had caught it just in time, all back and running after doing injectors, cleaning heat exchangers and servicing aftercoolers and replaced both water pumps, big job, had a Marine mechanic do all the tricky bits but still did a good few hrs in the engine room, am getting too old for this, glad the air con was working well on 30+C days.

One of my marina neighbors is having the head replaced on his Cummins this Winter. Huh, maybe a common issue.

 

[stiggy]

I use the factory service manual. It’s good, but assumes you know what end of the screwdriver to hit with a hammer; it’s not for novices. There are a couple of special tools required too.

Still trying to track one of those down. Where did you get yours?

 

[Ski in NC]

One of my marina neighbors is having the head replaced on his Cummins this Winter. Huh, maybe a common issue.

Earlier 6BTA's had a cyl head prone to cracking. Came out with a new head with 7mm injector tip, old one had 9mm inj. More cooling flow between valve pockets and injector pocket with smaller tip. Some other fixes. Seemed to work.

Otherwise, the 6b head gasket has been pretty reliable.

 

[Mischief Managed]

Still trying to track one of those down. Where did you get yours?

I got the timing pin 3P-1544 on ebay and the pump puller 6V-4069 from Freedom Racing. I could not find the sleeve tool, but you don't really need it. Just break the old sleeves and use the new ones that come with the gasket kit. You'll be cleaning the bores and oiling the new sleeves so they will slide really easily with no special tool.

 

[FF]

With the head off it might be time to have it gone over.

As a minimum trued to flat .

A cup of gasoline poured in each combustion chamber will show if the valves are sealing.

 

[Ski in NC]

With the head off it might be time to have it gone over.

As a minimum trued to flat .

A cup of gasoline poured in each combustion chamber will show if the valves are sealing.

There is no combustion chamber in the head. It is flat. Not like a gas engine. Combustion chamber is the piston bowl.

If you have the heads off, best to pop valves out and check sealing rings and valve guide wear, look for corrosion on seat and valves, and check flatness. If not familiar with head/valve work, send it out to a machine shop that specializes in this.

If you re-machine the head deck, note that valve seats need to be machined down similarly or they will protrude too much and can contact pistons.

Water tube is no big deal. Head can be lifted without backing off the tube. Once bores are (super!) clean, new tube with new seals and some grease will make it slide like butttah. I just use two screwdrivers.

Replace any corroded head bolts and clean clean clean the bolt holes in block. Check any re-used bolts for stretch and replace those stretched. Test fit each bolt in a hole to make sure it can thread down below seating depth.

Bolt stretch can checked by meshing the threads of a known good bolt with the threads of one in question. If you can see light through the mesh, one of them is stretched. Discard.

I see a lot of semi-corroded bolts when taking these apart. I suspect moisture gets in and as the bolt corrodes, clamping force is reduced. Never found a head or block deck not flat. I think the relaxed clamping force is what causes the gaskets to fail.

And use the correct molybdenum grease to lube head bolt threads and washers. The torque spec gets the right clamping force only if the right coefficient of friction exists on the moving parts, thus use the right lube.

 

[Mischief Managed]

I did not do anything with my valves except check for leaking with brake cleaner and they are all good. At only 2000 hours (and 95% of that at less than 1300 RPM), soft valve springs (don't have to battle much valve float at 2800 RPM max), huge valves (lots of surface area to transfer heat), and a mild cam, they just can't have any meaningful wear, and valve lash adjust margin seems to bear that out. I could not find any valve seals in the parts guide so I did not replace any. Perhaps I'll regret not touching the valves later, we'll see... FWIW, I have a ton of experience with valves in 4 stroke engines.



My decks and heads are quite flat, there was no need to machine anything.


I ran a tap through every head bolt hole twice after cleaning them out with brake cleaner and a shop vac (makes an interesting sludge in the vacuum canister), the threads are perfect. I have a huge jar of the correct moly lube that cost me at least 50 buck at my CAT dealer (because no one else around here sells it), that I used on the threads and washers, and I am using all new head bolts.



None of my head bolts had any corrosion except for tiny specs of rust on the heads of a few of the head bolts that are not under the valve covers.



There's a TSB-like recommendation from CAT to add a condensation drain to the intake manifold to prevent hydro-locking the #6 cylinder. My engines did not seem to have any issues with condensation so I did not do the extra work to add the drain. It involves a lot of aluminum fabrication and welding and I may tackle it next year; the intake manifolds are not that hard to remove. In the meantime, I will be cranking the engines over a few revolutions with the fuel shut off before I start them, after they have sat for more than a day. That way if there is hydro-locking, it will just stall the starter motor and won't bend a rod. I used to crank cold,carbureted, motorcycle engines for a couple of seconds with the choke off for the same reason, except the liquid I was worried about was gasoline not water. Anyone that has run a radial airplane engine understands this routine, crank it until x prop blades go by a fixed spot, to clear the oil from the bottom cylinders, then turn on the magneto. That's why they always seem to take forever to start in movies and TV, and blow a big cloud of smoke when they do start.

 

[Ski in NC]

I've got the same big tub of $50 Cat moly lube. I'll probably include it in my will.

The aftercooler drain is mostly for engines that run at high boost and then pull up to dock and shut down. The natural condensation then dribbles out the drain. Running at 1300 you will not have a condensation problem.

With your duty cycle, valves should be fine. Most of my work has been on sportfishers that run hard and that condensation in aftercooler does havoc on valves. If that was a problem on yours you would see it looking at stems through the ports. And it probably would have flunked the brake cleaner test.

On yours my theory of corroded bolt stretch does not seem to hold. Maybe gasket just relaxes, who knows.

On one engine as I was doing teardown, I sharpie marked one bolt, loosened it a few turns then tightened it to spec. It turned like 60deg further than as found. So something was relaxing.

Sounds like you know what your are doing. Kudos and good luck!!

 

[Mischief Managed]

Well, that was weird, 4 of the brand-new CAT head bolts stretched badly on engine two. The manual says to tighten new bolts to 110 in the right order, then back them all off until they are loose, then tighten to 60 in the right order, then to 110 in the right order. Four of them, all the same size, were clearly going to break before hitting 110 ft-lbs the second time, so I stopped, backed them out, checked them for stretch (they were badly stretched) and threw them away. I ended up re-using some old head bolts after checking them for stretch. I suspect CAT may have some manufacturing issues and would recommend procuring a few spares if you plan to do this work yourself. I wish ARP made a 3208 kit... I might suggest they put one together, I wish I had now.

 

[Ski in NC]

Weird. Never had that happen on a 3208. Maybe Millennials have taken over metallurgy and heat treatment!! But it has been a few years since I did one.

You don't have so much moly lube on bolt that it got in the bottom of the hole? Just needs a light coating. Also not likely as it would squeeze out through the thread clearance.

I also cross-check my click type torque wrench against a beam type with a 1/2" 8-pt socket. Wrench against wrench. Click type can be off!!! Beam type too, but very much less likely.

There also is something about 8-tick mark bolts vs 7-tick mark bolts, but can't remember the details. One is higher strength and different torque value.

 

[Mischief Managed]

You don't have so much moly lube on bolt that it got in the bottom of the hole? Just needs a light coating. Also not likely as it would squeeze out through the thread clearance.

That was the first thing I checked, the bottom tips of the bolt were dry. It would not have made them stretch, regardless.

I also cross-check my click type torque wrench against a beam type with a 1/2" 8-pt socket. Wrench against wrench. Click type can be off!!! Beam type too, but very much less likely.

I carefully checked the calibration of my well-made Norbar clicker torque wrench, it is still well within the + or - 5 ft-lbs that CAT specifies. Once the bolts started to yield, I kept (successfully) re-checking the wrench on bolts that were already tightened to 110 ft-lbs too. That said, it was incredibly obvious when the bolts stretched and they did so nowhere near 110-ft-lbs. I could literally feel them just relax and the torque required to turn them started to drop. When I pulled them out, the stretch was obvious to the naked eye as the top 1/4 of threads were quite distorted. It's as though they forgot to fully heat treat them

There also is something about 8-tick mark bolts vs 7-tick mark bolts, but can't remember the details. One is higher strength and different torque value.

It's actually 6 ticks (95 ft-lb max) versus 7 ticks (110 ft-lb max) and all my bolts are 7 tick. I think the 6 tick bolts were only on really early engines.

 

[Pat T]

Great thread! I will try to do as much maintenance myself on my new to me boat but I don't think I would attempt head gasket replacement. Access not that good in my GB 42. But Walker Airseps seems like the way to go and I think I could do. Could you tell us anything about how you made the changeover?
Thanks.

 

[Mischief Managed]

I needed to buy a 45 degree, 4” silicone elbow and 2 t clamps per engine to mount the air seps. Also had to heat the oil drain fitting on each Airsep and turn it 180 degrees to make it fit right. It’s a tight fit and you need to trim about an inch off one end of the silicone elbow too.

 

[Ski in NC]

Sounds like you got some weak bolts from Cat. I would take them back and let them look at them. Cat is usually very good with QC, they would want to know about this.

 

[Mischief Managed]

Speaking of tools...

I got the timing pin 3P-1544 on ebay and the pump puller 6V-4069 from Freedom Racing. I could not find the sleeve tool, but you don't really need it. Just break the old sleeves and use the new ones that come with the gasket kit. You'll be cleaning the bores and oiling the new sleeves so they will slide really easily with no special tool.

Not knowing what to expect before I started this project, I bought a Maxwood 5146 46MM flat wrench and converted it into what I suspect CAT sold as a special tool for installing the head coolant sleeves, that's no longer available.


The head coolant sleeves for engine number 2 were a little tougher to install than engine 1 (it was colder and the o-rings may have been stiffer) and to avoid breaking them, I ended up using the Maxwood wrench that I had modified to get the sleeves home. It worked brilliantly and was worth the 10 bucks and the 5 minutes time grinding it to fit.


If you are collecting tools for this job, buy every kind of "special" 9/16" wrench you can get your hands on. Get stubby, long, S-bend, offset box end, ratcheting, ratcheting stubby, flex head ratcheting, etc. I think I spent 125 bucks at Harbor Freight getting every set of special SAE wrenches they sell, and I used all of the 9/16 wrenches in those sets on this project. Some of the fasteners are frustratingly difficult to access.



A 7/16" flare wrench is handy. For some reason CAT used steel "brake" lines to move coolant in places and those brake lines have 7/16" flare nuts.


You'll need up to 1.5" open end wrenches, or at least up to 1" and a big pipe wrench.

 

[Capt. Jon]

Maybe I missed it but how are you measuring the bolt stretch? How much stretch are we talking about thousands of a....?

 

[Goldcar]

While I'd love to do this work myself, I do not know how. Anyone have an idea of what this would cost at a yard? Our engines have 4600 hrs and run well. I did just rebuild the risers and exhaust system.