CAT 3208 new knock

[BryanF]

You need a good hone for this job. Not a flex hone. Google micrometer cylinder hone to see the tool you will need. Then you need someone with experience to run it. This tool will give you a good enough finish to run a new piston on.

 

[Busterbrown]

This is the type of hone that was used on my cylinders. The guy that bored and honed my engine had four more jobs to do the day he did mine. He put a perfect cross hatch hone on my cylinders. He would measure every hole in multiple spots write down numbers on a sheet of paper hone measure hone and so on. He left me a mess to clean up but said the holes were perfect and so far so good. He told he had been working with that bore bar for ten years every day and you could tell.

 

[Ski in NC]

If bore dimensions check out ok, nothing wrong with a quick hone with a glaze buster hone. It remove a tiny amount of metal, almost undetectible with the bore gauge and sets up a decent cross hatch. A proper hone is necessary to take a freshly bored cylinder to it's final measurement, which is not the case here.

To do this right, you should have bores checked with a bore gauge, and to do that right no also need a 4-5 mic and a standard.

But many engines have been put in service with a quick clean with a glaze buster, new pistons and rings as needed.

I'd consider pulling 3L and cleaning up that corroded area. Any sharp areas on that pitting will quickly wear the rings. Some hand work and then measure bore then hone.

This thing is not a Ferrari, you can be a bit sloppy and still get good life. Good chance the 4L was tight in bore to piston clearance.

 

[Edelweiss]

I can feel a definite texture change where that stain is. Nothing extreme, but it is a little rough

Really does suggest there was some water incursion. If not a head gasket or cracked block, maybe the water cooled exhaust manifold is failing, leaking into the exhaust port?

Now you've got a second cylinder that is questionable, unidentifiable after-market piston you may not be able to match, metal flakes in the oil, block and head surfaces need to be cleaned and then trued before gasketing, etc. There may be similar issues with the other side and the rest of the rebuild on this engine.

Not what you want to hear, but I don't know if you're going to be able to do this in frame and not risk losing the engine to another failure down the road.

If it were mine, at this point I would say pull the engine, tear down and inspect top to bottom. If nothing else for just peace of mind.

 

[Martin J]

Did you check the oil level? Have you been pumpimg fuel into the sump and thinned the oil?
Always worth a check if you 've been dealing with a fuel leak etc.

 

[robs523]

Really does suggest there was some water incursion. If not a head gasket or cracked block, maybe the water cooled exhaust manifold is failing, leaking into the exhaust port?

Now you've got a second cylinder that is questionable, unidentifiable after-market piston you may not be able to match, metal flakes in the oil, block and head surfaces need to be cleaned and then trued before gasketing, etc. There may be similar issues with the other side and the rest of the rebuild on this engine.

Not what you want to hear, but I don't know if you're going to be able to do this in frame and not risk losing the engine to another failure down the road.

If it were mine, at this point I would say pull the engine, tear down and inspect top to bottom. If nothing else for just peace of mind.

I just talked to the mechanic that did the rebuild and apparently when the boat was overhauled in 2004, the owners wanted it faster after the engines were rebuilt. The mechanic gave it more rack in the fuel system (? or something like that) to increase the horsepower at the owners request. He's going to give me more info about it that and how to undo it. He also really seemed to remember the job well and had a lot of good info, like cylinders being sleeved, and everything that was done to it to make it as close to new (and stock) as possible for a rebuild. He knows the piston is one of two manufacturers and he's looking into getting a new piston and rings.

He also mentioned the exhaust manifold as a possible leak source. What I didn't ask him but should have is, does that mean I need to replace the exhaust manifold gasket? It's a metal gasket that looks in good shape so I wasn't going to replace it.

I'll send the injectors down to him to check them, then hopefully I can get the parts and be back out with two working engines soon! As much as I like the idea of pulling the engine and going over everything, I'm going to try to avoid that this year. Maybe next winter when I need something to do to keep my sanity on those dark and rainy days, and will hopefully I'll be set up better at home to work on it than I am now.

But what's this business about needing to true the head and block surfaces? Sounds complicated and expensive...

 

[robs523]

Did you check the oil level? Have you been pumpimg fuel into the sump and thinned the oil?
Always worth a check if you 've been dealing with a fuel leak etc.

Oil was apparently pretty dirty even after I changed it, but otherwise seemed good. I'd need to add some occasionally but never noticed thinning, "growing," or a diesel smell. Thanks!

 

[Capt. Jon]

I just talked to the mechanic that did the rebuild and apparently when the boat was overhauled in 2004, the owners wanted it faster after the engines were rebuilt. The mechanic gave it more rack in the fuel system (? or something like that) to increase the horsepower at the owners request. He's going to give me more info about it that and how to undo it. He also really seemed to remember the job well and had a lot of good info, like cylinders being sleeved, and everything that was done to it to make it as close to new (and stock) as possible for a rebuild. He knows the piston is one of two manufacturers and he's looking into getting a new piston and rings.

He also mentioned the exhaust manifold as a possible leak source. What I didn't ask him but should have is, does that mean I need to replace the exhaust manifold gasket? It's a metal gasket that looks in good shape so I wasn't going to replace it.

I'll send the injectors down to him to check them, then hopefully I can get the parts and be back out with two working engines soon! As much as I like the idea of pulling the engine and going over everything, I'm going to try to avoid that this year. Maybe next winter when I need something to do to keep my sanity on those dark and rainy days, and will hopefully I'll be set up better at home to work on it than I am now.

But what's this business about needing to true the head and block surfaces? Sounds complicated and expensive...

Playing with the fuel system without metering the pump is not a good thing. Without measuring the output you have no idea of how much fuel is being pushed. If you can see the part number on the injectors please post it.

As for the exhaust manifold during the rebuild they should be vat cleaned and pressure tested while hot. This will tell you if they leak and need replacing. As for the exhaust gasket it is of a crush type and needs to be replaced.

Trying the head is something that is done when re-working the heads. A good cleaning with a wire brush and then checking trueness with a straight edge and feeler gauges will tell you if they are ok.

Not trying to rain on your parade but you are dealing with an unknown engine of dubious origen. It might be best money spent and cheaper in the long run to call this year shot, take your time remove, rebuild or find a re-build with a warranty.

 

[BruceK]

Taking into account the Sitka location and difficulty of getting help easily, isn`t it worth a simple "fix what looks broken and see how it goes' before a total rebuild? That said, the advice of the man who did the rebuild carries a lot of weight, except his rebuild didn`t seem to last too long...I dunno. One step at a time, I`d say.

 

[Ski in NC]

Rob- Was engine using any coolant while you had it in service?

My vote is to fix what is broken, put it together and enjoy it.

 

[Edelweiss]

I just talked to the mechanic that did the rebuild . . . .
He also really seemed to remember the job well and had a lot of good info, like cylinders being sleeved, and everything that was done to it to make it as close to new (and stock) as possible for a rebuild.

He also mentioned the exhaust manifold as a possible leak source. What I didn't ask him but should have is, does that mean I need to replace the exhaust manifold gasket? It's a metal gasket that looks in good shape so I wasn't going to replace it.

But what's this business about needing to true the head and block surfaces? Sounds complicated and expensive...

So they actually went so far as to machine the block and sleeving all the cylinders? OK, If that is true and the block isn't cracked that makes rebuilding it much more doable.

As Capt Jon said:
The manifold needs to be tanked and pressure tested. There may be an internal crack or rust through point between the exhaust chamber and the cooling water chamber. Cooling water leaks through the crack, into the exhaust port, through an open valve and into the cylinder.

The valves in the damaged cylinder were probably hammered pretty good by the chunk of piston floating around in the cylinder. The head needs to be taken to a shop or mechanic who does valve grinding, valves dropped and checked for damage. The shop will check and true the heads gasket surface if needed (make sure it's perfectly flat). The matching surface on the top of the engine block also has to be cleaned and checked as well, before you mate the head gasket and head to it. Maybe your mechanic can help you with this. If both head and block surfaces aren't true, the head gasket won't seal properly and eventually will fail.

 

[sdowney717]

Seeing that expensive earlier rebuilding, got to wonder why it failed?

Due to them increasing the injector pump volume?
Or piston was defective, or did something like trying to compress liquid fracture the piston.

 

[stone beach]

Seeing that expensive earlier rebuilding, got to wonder why it failed?

Rebuild was a long time ago...anything could have happened since.

 

[robs523]

hello everyone, long time, no post. I replaced two injectors- the one on the broken piston was bad and one I managed to tweak trying to get it out of the head and ruined it. Put the new piston on, new rod, new rod bearings, and new rings. I filled it with oil and coolant, made a couple of rookie mistakes (oh yeah, the filter I took off two months ago wasn't ever replaced...) and got it started up. The good news is that I know I shouldn't have a chunk of piston flying around in the #8 cylinder. However, unfortunately, there is a knocking sound that sounds very similar to the knock that started all of this 3 months ago. If any mechanics want to come visit Sitka and work, I can pay in fresh king salmon and halibut! I guess it's back to the drawing board, starting with the valve lash again and checking the rest of the injectors. It's been a journey to say the least

 

[Baker]

Ugghhhhhhhh!!!!!! Sorry to hear that!!!

 

[BruceK]

Oh no! That`s tough. I hope you nail it, somehow.

 

[Busterbrown]

Rob when I saw your post today I was hoping for good news I was a little sick to my stomach after reading it I hope you can find someone to help you out and get everything worked out.

 

[robs523]

Rob when I saw your post today I was hoping for good news I was a little sick to my stomach after reading it I hope you can find someone to help you out and get everything worked out.

thanks, it will all work out eventually. Honestly it's becoming a little comical at this point, but I sure do drink a lot more than I used too...(just kidding). I think it was harder the first time because that was prime fishing and boating season and we missed most of it this year, so it's actually a little easier to handle now that summers over, even though it would be a great boat to go hunting for a few days. I can still say I'm learning a lot every time I do something on it, and I'm forever grateful for all the help I've received here! I'll go back tomorrow or Friday and mess around with it again and see what happens.

 

[Ski in NC]

Go back through the valve lash checks. It is easy to get a pushrod out of position when putting the rocker shaft on and that can cause a bent pushrod or other grief. Spin each pushrod to make sure it is straight when valve is closed and rod unloaded.

 

[River Cruiser]

Did you have all the injectors cleaned & tested? I always replaced the injectors anytime I got as deep into one as you did, rebuilt injectors are cheap insurance. Have you cracked the nut on the high pressure lines while it's running to try to locate the cylinder with the problem? Good luck

 

[robs523]

Did you have all the injectors cleaned & tested? I always replaced the injectors anytime I got as deep into one as you did, rebuilt injectors are cheap insurance. Have you cracked the nut on the high pressure lines while it's running to try to locate the cylinder with the problem? Good luck

I only tested the injectors on the side I took apart. In hindsight I should have pulled the other 4 but my objective was to get it fixed and back together, I definitely had some tunnel vision after a couple months. But, I took it out Sunday and put a few hours on it and it seems like it's running good. Looks like the knock was valves, now I just a need a couple of oil changes and hopefully it will all be behind me.

A huge thanks again to everyone here, if you're ever in Sitka give me a shout!

 

[Busterbrown]

That's good news. I hope the quick fix works out for you. Keep an eye on your engine temperatures and don't let them over heat.

 

[Hawgwash]

09-21-2016, 03:34 PM----------------22-02-2017, 10:45PM.
What happened in between?

 

[robs523]

well, I still feel like there's a knock and white smoke but I haven't been out past the fuel station since October. If it's not just my imagination, it's definitely nothing like it was when the piston broke, hopefully valves just still not adjusted right or something easy. And I will be the first to admit that I might just be paranoid. I've been down to the dock a few times and had it running for a while and it seems good, so I am going to go for it once I get the chance and take it slow and easy to start. We've had some unexpected circumstances make it hard to do much of anything over the past 4 months, combined with the winter weather, work, and a vacation and I haven't had much of a chance to try to get out yet.