overheated 4bt

[Shannon Ritzert]

Late last summer, I had an idler pully bearing seized up, slung a belt, then I had a major overheat.  

I pulled the exhaust manifold, turbo, and head.  I bared the head, and block, and didn’t have any warpage.  As you can see, the pistons were not melted down.  There was some surface rust, and cylinder scaring.  Against my judgement, my partner on the boat just wanted to put everything back together so he could use the boat.

I installed a new head gasket, did valve overhead.  I visually inspected the turbo for cracks in the cooling jacket, installed the exhaust manifold with new gaskets, and the turbo, also new gaskets.  I put the cooling system back together, and a new belt with idler pully and hardware.  I filled the cooling system with new coolant, and within a few minutes I heard coolant leaking out of the exhaust out of the back of the boat.

My best guess is that the exhaust manifold is cracked.  I really won’t know until I pull it back down.  The unfortunate part is, I just installed that new exhaust manifold in the spring.

At this point, I am going to remove the engine, and inspect/ pressure test everything, and do the job the way  it should have been done in the first place.

A few years ago, I purchased an engine from a friend of mine that works for Cummins.  If I remember right, the engine shows to have been in a piece of machinery.  My question is, can I use this engine as a short block?  I understand that I will have to swap out the fuel pumps, injectors (hopefully they are the right diameter) exhaust/ intake manifold.  The engine I will use for a short block is 4b.

 

Pictures attached…. Thanks a bunch!

Topic

[Shannon Ritzert]

My machine shop told me:

Block is the same

Crank is the same

Rods are the same

Heads could be different

Cam could be different

Pistons are different

[Shannon Ritzert]

I have my engine pulled down (CPL 741  4bt)  This engine will need to be bored, or sleeved.  

 

Does anyone know if my block on the CPL 591 is the same block?  I pulled it down as well, and the block is in immaculate shape.  I am hoping to put new pistons in that block.  I am also hoping to use any other parts that are in better shape on this block such as bell housing, timing plate, and possibly the head if they are the same as well.

 

I am about to call the machine shop that I use too, and see if he has the answers too.

Thanks

[Shannon Ritzert]

Francis

I appreciate you very much.  I actually replaced this manifold last year with a new one that SBMAR had on sale.  That’s the biggest bummer to me is to replace new stuff.

So, I replaced the old manifold because you could see the bolts between the head, and the manifold.  I thought this was because it was rusted out, and on the verge of failing.  I was wrong on that, as the old manifold was just designed that way.  I don’t know if that makes sense or not, but bottom line, I have a usable good manifold.

I am with you, and  figured the piston is galled, or melted over the ring.  When I pull the engine down, I will more than likely do main, and rod bearings, new pistons and rings.  I am hoping that the cylinders are honeable.

 

I do have a question or 2 on cpl numbers.  The parts manual that I purchased from SBMAR says it is for 591, and 741, which I have both of those engines.  Tony mentioned looking in the cpl book or on qsol.  It looks to me like you have to be a dealer to use qsol, am I mistaking on that.  Is there a reference for non dealers?

 

Thanks guys,

I’ll post updates, maybe it will help someone out in the future

[Francis Valerio]

Shannon

sorry to hear that about the blow-by.  Do you have a serviceable 4BT exhaust manifold to use?  They are available but not common tho since the unit is older.  I have one that has a slight crack that could be repaired if you can not locate one.  I do advise you to get a new one but I would give it to you if need it.

The blow-by might have been caused by the overheat…unfortunately and got the rings to stick.  The rings stick from the piston melting and or carbon build up.  Piston melting can be caused by a few different problems (overfueling or overheating, timing etc…to name a few).  Carbon build up can be cause by similar symptoms.

 

Hopefully the block is OK and you can get away with a new piston, rings and hone.  These are tough little engines but not indestructible.

 

Please let us know how you make out and any questions you may have.  This is the place to go for help and there are plenty on here that will try

[Shannon Ritzert]

I don’t know if there’s an issue with the forums, or if its my end, but the post’s are jumbled up, not in order.

 

I ended up pulling the turbo, and filling the water side up with water, and no leaks there.  I then pulled the exhaust manifold, and filled the water side up with water, and have a crack where the number 4 cylinder port is.

 

I had the old manifold, and out of curiosity put everything back together, and have major blow by, so I’m going to have to do an engine rebuild.  I’m guessing at the very least number 4 piston is galled, and rings are stuck.

[Francis Valerio]

Like I said in earlier post. Unbolt turbo and REMOVE the exhaust manifold. Tape up one end nice and tight and then fill other end with coolant or water. See if anything leaks out.

If it holds tight then look closely at the gaskets. One by the turbo and the other at the front of the exhaust manifold. These gaskets are only installed ONE WAY. The coolant passages on the gasket are slightly different sizes and the orientation of the gasket is of extreme importance. If installed incorrectly it WILL leak.

If you installed the gasket with hi-temp RTV then it is possible that the RTV was preventing the coolant from leaking out (temporarily), but when she got put under load and up to operating temperature the gasket blew out the RTV that was sealing it. This is just a theory. I dont think this would have cause your overheat unless she lost a significant amount of coolant.

1 user thanked author for this post.

Tony Athens

[donald roth]

There’s a second turbo gasket under the blank on top of the exhaust manifold that can be easily overlooked.  A pressure test would have shown it.

[Shannon Ritzert]

After the overheat, we were leaving a trail of coolant coming out of the rear exhaust port while running home.  Running on the one good engine, the overheated engine was shut down.   At this point, I figured at the very least I smoked a head gasket.  

After inspection, and re-assembly, coolant runs out of the rear exhaust port without even running, or starting the engine.  I am assuming coolant is running out the exhaust manifold (it is cracked)  then our of the turbo, then the mixer, then muffler, the out the port.  

I am heading down to the boat on Wednesday, maybe I will have better answers.

Does that clear up your questions?

[Francis Valerio]

Just to be clear

When you re-assembled the engine (in your first post). 

 

At what time did you have the coolant just pouting out the exhaust?  Was that BEFORE you drove the boat for the first time after assembly? or was it AFTER you drove the boat for the first time?

If that was before then i would have to say you have an assembly problem

 

You need to at the very least tear down what ever you initially did and inspect carefully.  Let us know bc this could be interesting…dont worry bc we have all made mistakes….especially the honest people…

[Shannon Ritzert]

Correct, coolant pours out of the exhaust without even starting it.   I spent a day pulling it down, cleaning off old gasket material, and inspecting everything, and getting everything ready to put back together.  Keep in mind, that  I tackled this project the first week in October, and I am just getting back to it, so I will do as well as my memory serves me.

I remember when installing the head gasket, that I intentionally tried to install it incorrect.  If I remember right, the head gasket will only go on one way and all the coolant jacket ports, and cylinders will align that way.  I’m pretty sure the head gasket also has the right direction stamped in it like most head gaskets, but I don’t remember

Obviously the exhaust manifold gasket fit any way you put them on

I do know that the turbo gasket, goes on a certain way, and I was aware of that while installing the turbo, However, the thought did cross my mind after coolant just pouring out that I possibly could have put it on wrong.  I started doubting myself in other words.

The only thing that makes sense to me is a crack in the turbo housing, a crack in the exhaust manifold, or a turbo gasket.  This engine got hot quick. 

This engine got hot quick.  I slowly throttled up to about 2250 rpm, made sure both engines were in sync, and checked egt, boost, and temp gauges.  My son asked me if I seen the flying fish bust out of the water, and I looked at him and said I missed them.  I looked back down to check my course and rpm, and my egt, and temp gauges were maxed, so literally like 5 seconds.  I don’t know the temperatures that these components can withstand, but past 1800 on egt, and past 250 on engine temp.

 

Anyway, I’ll double check the turbo gasket when I pull it down, and I am going to build a plate to pressure test the exhaust manifold, and turbo, and we shall see what comes of it all.

[Francis Valerio]

If you filled the system with coolant and then soon after you “heard” it leaking out the exhaust???

This happened without you even starting it???  You have NOT run the engine since you slapped it back together, right?

For that kind of coolant to be leaking out it sounds like it would have to be a huge crack or blown out gasket at the elbow maybe??? or something along those lines

Sounds a bit crazy, do you think you may have installed a gasket incorrectly? or forgot to put one in somewhere. 

I would take the exhaust manifold off and put it on the bench and fill it with coolant and see what she tells you and ditto for the elbow

[Shannon Ritzert]

That makes sense being not turbo.  I never considered a different compression ratio.  I was thinking worst case scenario possibly a different cam

 

Do you have a guess on what is cracked, something you see more often that other things?

 

Thanks again

[Tony Athens]

For 100% sure the 0591 has higher compression pistons, among other things. 

[Tony Athens]

Are you sure this is a 4BT?  Your data tag says  4B to me…….No TURBO ??   only a 50-50 on the block–you need an experienced mechanic to measure all   

 

Knowing the CPL of the other engine would be paramount in this.  Then you just look in the CPL book or on QSOL

[Author]

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