CAT 3208 new knock

$hit definitely happens, but I wish it would have waited a little longer! I would have just bought the fixer upper from the start for 30k less if saw this coming. I want to do as much of the labor as I can but I always have the hardest time with the diagnosis. Maybe I need to quit thinking and just start doing. Thanks for the replies

Sounds like a piston and its liner, doesn't has to be dramatic. Might be possible to hone only that one cilinder to an over-size and replace the piston with a new one that matches the over-size.

Check and double check the cranckshaft bearings and its running surface...... (the found white metal, but can be within tolerance)

Okay now its time to use your plan to get the engine ashore..

https://www.google.nl/search?q=how+...ved=0ahUKEwjM6MzuupDOAhWECcAKHVu0A1wQ_AUIBigB

"There are plenty of good aftermarket parts and also engine rebuilders who will supply you a short block with a warranty."

This is because CAT and many other co simply have parts fabricated for them , and then stuck in a CAT box.

The same "aftermarket" guy may have made the part for CAT in the first place.

For a rebuild price here,

http://www.jasperengines.com/diesel-industrial-engines

Pulled the head and found this guy in the suspected cylinder. Any ideas on what causes this and how to fix it? Is it just as "easy" as a new piston?

Hard for me to tell from the picture, but is that part of the piston top? Is that some melted metal on top? If so what does the top of the head look like?

The thing to do now is figure out what caused the piston to fail.

robs523 said:

Pulled the head and found this guy in the suspected cylinder. Any ideas on what causes this and how to fix it? Is it just as "easy" as a new piston?

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See post #92.

As far as I can tell, it's part of the top of the piston. It was actually stuck to the top of the cylinder when I pulled the head. Looked like it broke off and just stuck at the top so the piston was matching up to it every time, it wasn't floating around in the cylinder space as far as I can tell. I think there'd be more damage and more pieces if that was the case. Top of the head looked fine to me other than being pretty dirty. I'll post pics from my phone in another post.

Here's the head. Too bad I can't just pull the piston and have a V-7 for a few months!

Most probably the injector of that cilinder malfunctioning causing
symptoms like this (over heating). But must see it with my eyes to be sure of the cause...

robs523 said:

Here's the head. Too bad I can't just pull the piston and have a V-7 for a few months!

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no chance.

I know that in europe this is not a financial drama, but also examen the cranckshaft..

Rob are the other pistons okay? What do they look like? Is that cylinder furthest away from the water pump? Hopefully the bottom end is still okay. The experts will chime in soon. Good job pulling the head off. Good luck on the repair.

Busterbrown said:

Rob are the other pistons okay? What do they look like? Is that cylinder furthest away from the water pump? Hopefully the bottom end is still okay. The experts will chime in soon. Good job pulling the head off. Good luck on the repair.

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Thanks. I only pulled one side, and this was the #8 cylinder. The other three cylinders looked fine as far as I could tell. When we were tearing it apart, we did notice the valve to the dripless bearings was pretty clogged up, I wonder how much water could even get in there. Maybe the cooling system has too much crud built up and it over-heated? I dropped the pan a couple days ago and everything appeared normal from a quick look but I also don't really know what I'm looking at, so take that for what it's worth. If the

Maybe a dumb question, but could the piston be replaced without boring the cylinder?

Take the rod cap bolts out and pull that piston. You already have the pan dropped so that works well. If lucky, the cylinder bore can be cleaned up with a light honing and fit a new piston.

How does cylinder bore look? Any deep grooves?

Fingers crossed robs523, hope it`s the easy fix. Sure explains the knock.

For a very common engine it is sometimes possible to order an oversized ring set.

If honed a bit to replace the required lubrication hone marks the slightly larger ring can be fitted , just use the stock ring end gap..

fibers and dust get me thinking about swallowing an air filter

Looks like debris got in cylinder or a big chunk of carbon got loose. Looks like a lot of carbon in there, but photos not real clear.

Get another piston and ringset. Make sure you get the right piston as there are several different ones for different models of 3208.

Plan on pulling the other head and cleaning things up there. Old motor will be glad it got two fresh head gaskets.

Clean all sealing surfaces with a steel scraper, use care to avoid gouging any metal.

Do NOT use scotch brite or similar silicon carbide pads or sandpaper to clean!! Abrasive particles are shed and it gets everywhere and makes havoc.

Figure out what is going on with that rod cap bolt you partially loosened- That needs to be resolved before pan goes back on.

Clean up all head bolts and replace any that are corroded or stretched. To check for stretched bolt, hold two together with threads meshed, any light coming through means one or both are stretched.

Clean bolt holes in block by hand screwing a bolt in each hole with something like wd40. Blow out hole with comp air, repeat until hole is clean and bolt threads in like butttaaahhh.

I usually check the valves by taking a few or all of them out and inspecting sealing surfaces. Sometimes a quick lapping job to verify good contact. Almost always the valves are in really good shape.

thanks everyone. We had the mechanic come take a look today and got some pointers on pulling the engine out. I think I'm going to build a cradle and get the engine in my garage, basically overhaul it over the fall/winter, and put it back in with the goal of fishing next April or May. If I'm really ambitious maybe I'll get to both of them by then. I'm sure I'll be posting a lot more questions via new threads as that process goes on, then who knows, maybe I'll be helping the next person in my shoes. Thanks!

robs523 said:

thanks everyone. We had the mechanic come take a look today and got some pointers on pulling the engine out. I think I'm going to build a cradle and get the engine in my garage, basically overhaul it over the fall/winter, and put it back in with the goal of fishing next April or May. If I'm really ambitious maybe I'll get to both of them by then. I'm sure I'll be posting a lot more questions via new threads as that process goes on, then who knows, maybe I'll be helping the next person in my shoes. Thanks!

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For the second engine I`d subscribe to "if it`s not broken don`t try to fix it". But for the defective engine you do need to establish why it failed, ? cooling system.

Is cylinder bore in good shape? If so with a piston and some gaskets you could be running in a week.

Had my engine bored in the salon If the bottom end looks good you might get lucky with a quick fix.

"get the engine in my garage, basically overhaul it over the fall/winter"

If you do overhaul it , take the reciprocating goodies to a "speed shop" machinist. .

For very modest cost they will balance the crank, match the rod ends and the piston weights.

Take the crank damper (your new one) and the flywheel too.

The factory has "specs" but a machinist doing the work will make the engine smoother than you can believe.

You will need to watch the tach to see if its operating.

Ski in NC said:

Is cylinder bore in good shape? If so with a piston and some gaskets you could be running in a week.

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you guys are killing me. I had myself convinced I'd make it if I didn't get it fixed anytime soon but now I'm looking at every scenario and trying to figure out how I'm going to be fishing in 2 weeks when we have friends in town. The hardest part is that lousy "job" thing that always gets in the way, but now you've motivated me- Quit toying with my emotions!

So an in-the-boat honing seems appropriate, at least it does for a guy that's never actually done it (and should I just get a flexhone???), with a new piston and rings for that cylinder only. Clean up the rest of them along with the heads, put it back together, and see what happens. Then I'll just pray that both motors don't blow up on the same day and I should be good to go.

Hopefully the next pics are of fish!

There is no one difficult step in doing this job, just a lot of steps and each must be done carefully.

Removing piston, honing bore and fitting piston would be best to do with someone experienced helping.

Try to make an arrangement with a local mechanic where he stops by periodically and mentors you. Maybe have him fit the piston.

90% of the work in this job is cleaning things and lugging things around.

I most certainly would not advice to hone out of hand, you end up with an elliptical bore. Find a magnetic drill-stand (rent) to keep it centered and to keep the honing pressure centered in the bore..

Being a diesel, how much piston to head clearance exists? Something will give, maybe the piston just collapsed.
You need to see if the rod is bent and if the crank journal got scuffed - cooked.

Rob get that piston out and post some good photos of the cylinder walls, piston top and sides, rod, crank journal and journal bearings. Let the trawler forum army help guide you through this.

Busterbrown said:

Rob get that piston out and post some good photos of the cylinder walls, piston top and sides, rod, crank journal and journal bearings. Let the trawler forum army help guide you through this.

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Here's the piston. Makes me wonder if maybe an oil home was blocked? Looking at where it appears to have been hot. I'll try to get cylinder pics this weekend. Can't really get pics of the journal very well.

Oil hole, not home

Here's the connecting rod