3208 Cat Blow back through intake

I am looking at a '93 motor yacht with twin 3208's. Engines only have less than 100 original hours. Yea, I know, but 1 owner had med issues caused the low hours.
It is my first documented one owner vessel I have seen.
Here is my question,, with that low of hours, is it possible the rings are not seated yet ?
I can see blow back huffing from the intake breathers on both engines while running. There are no noises and the engines are running smooth.
I suspected maybe the intake valves may not be sealing completely, and it may get better with some running.
Also there is some smoke while running and did not clear up. Not a lot of smoke but some.
I am a little scared of signs, but it may be a jewel in the rough, just not sure if it is worth the chance.
Any insight would be appreciated.

Valve adjustment?

David

Greetings,
Mr. 01. 100 hrs on a '93? I am by no means a mechanic but there could be a LOT of problems with a motor that has essentially sat idle for 24 years or, as you say, a jewel in the rough. Engine survey, engine survey or hard evidence that the motors were put to bed properly and still, an engine survey.

Given the non use, the rest of the boat should be in absolutely pristine shape. At least I would hope so. What's the story on her if you don't mind? Stored ashore or afloat?

It is all a guessing game at this point, especially for us who have not seen the maintenance records during this layup. I'd guess all seals, O rings and gaskets are well dried out.

To assume non used 25 year old engines will be OK is a huge risk. Price out a 3208 rebuild and offer accordingly if you are willing to suffer the aggravation of losing a boating season. a good price would help alleviate this pain. Or worse yet be stuck somewhere not fun because you took the risk.

I agree with Sunchaser. You are taking a pretty significant risk. Your offer/purchase price should reflect that risk. I bought a 2001 boat with 300 hours. We were unable to do a proper sea trial(boat came out of the water at the yard and the survey was cancelled at that point and deemed unseaworthy at that point). I had written it off and mumbles something to my broker that I would pay half of our survey price. I didn't think much of it but my broker called me back and said he will take it. I gambled, and it paid. But I still don't think I got the deal of the century. It was a good deal. The engines have served well...with my love and care. They have not been without issue though(fuel cooler rupture). But I have put 800 hours on them and I expect them to produce many more!!!

If the price is right...
As engines run, carbon is built up behind the rings. As the rings and sleeves wear, more carbon fills any space and helps keep the rings tight. A very long running engine can have as much as a fourth of the ring groove filled with carbon. It's possible running the engines at a mid rpm, under load, for a long period will seal any ring problem.
Smoke could come from several problems, not just rings. An engine that sits can rust bare metal surfaces. Seals get hard and allow oil to leak past valve guides. Rusted valves and seats don't seat properly, etc.
If the price is right, run the engines with a little smoke. It may get better.

Thanks for the replies.. the boat has been sitting in the water for the entire time,,, and the engines have just been sitting according to the family members, no special prep.They do look extremely clean and no signs of repaint, new gaskets etc. That is what bothers me,,, all the pencil zincs are new now,,,, but no records of how long ago they were replaced before now. They may very well have been the original ones.
I wonder how bad the coolers, manifolds might be if they were not replaced periodically.
I am impressed with the lack of corrosion in the engine room, it is almost non existent.
I keep telling myself this is a sign of the engine condition,,,, not sure I am listening to myself though.
The family says the man passed away and the boat has set since 2008. That is a long time with no maintenance.
We did however dive the boat and the zincs were almost gone, but no signs of pitting on the struts or props so maybe they just were replaced at some time since 2008, not sure how long they would last just sitting.
The boat is sitting behind a residence and I am told electrolysis is not as bad as it would be in a marina with lots of boats.
Almost forgot,,,, no the rest of the boat is not pristine,,,, usual water damage under a couple of windows, not bad but needs attention, windshield leaked and ruined the Jennair cooktop, all appliances are dated and need replaced, also electronics.
Still wrestling with the decision,,,,,,,

So we can assume the engines hadn't ran meaningfully for 10 yrs or so??
Were you the one to start them or had someone else got them going before your visit?
Regardless, any damage that might result from starting after standing that long has now been done.
No corrosion in engine room is a good sign, hopefully the internals will have been even better, so if they are running they are probably going to be ok .....but they are still old engines and should be considered as such regardless of the hour meters.

I think with that much uncertainty, I'd want the seller to back the survey cost and spell out if you find anything mortal (like massive corrosion or rot) they are paying the tab. it's a boat buck or more and a day of your time.

When you say blowback through intake- Do you mean flow out of the vent tubes hooked to the rocker covers? Or do you mean blowback from actual air intake? This can mean two separate issues, first being blowby and second meaning leaky valve or leaky head gasket.

Are these turbo engines or NA?

Yes the 3208 turbo engines have set for aprox 8 years. The family had all fluids changed, engines and ZF trans. Then replaced batteries and had the diesel mechanic that replaced fluids, start them. I was not involved,,, might have pulled injectors and spun them over first to get oil pressure before firing them, but that was not done. Oil pressure is good now and oil looks new,,, of course. So an oil analysis is useless in my mind now.
The blow back is coming from the intakes. As if the intake valves are not quite seating. They both start immediately so the valves are not leaking bad enough to lose very much compression. And the blow by is not huge,, just slight puffing. Still concerning to me.
Rocker cover / crankcase blow by is very little. Makes me tend to rule out the rings, although like I said earlier,, there is some smoke, but not a lot.

Survey and lots of contentions would be great,,,, but the price would no longer be a deal. The family just wants to settle the estate and not be bothered with a lot of potential issues,,,, and the price reflects that.

Another issue just came up,,,, NO STEERING !! Both helms do not move the rudders, the wheels just spin. No fluid in the reservoir. Searched but can not locate the rudder cylinders to see if the seals are leaking, or maybe a hose. Fluid had to go somewhere,, I do not think it evaporated. Looked on both sides of the rear bed, floor nightstands and no access I could find. Huge SS water tank under the bed, but that is it, looks like holding tank under the water tank, no hoses in the bilge or any fluid that we could see. I know they are under there somewhere,, can't believe they are this hard to find,, I would think the rudder shaft seals and cylinders should be accessible for maintenance.
Maybe under the bed / water tank but behind the holding tank ?
May have to dive it again and measure C/C of the rudders to figure it out,,,,, King size bed, so maybe they are under it.

Sounds like the problems are mounting up. Holding tank inaccessible, yikes! Why not keep looking at other vessels? You can always come back to this one again.

Crankcase blow by on no load doesn't tell you much....can only be judged under loaded condition.
Are you sure there isn't a crankcase vent led to the turbo intake and this is crankcase blow by you are seeing??

You might be getting a bargain.... but I would price in a full overhaul of both engines plus whatever else you might think is wrong with the boat. Focussing on engines here but everything else has sat for a long time too. Not a good thing.

I would suggest if its a good price and you like fixing stuff yourself it may be a good buy.....but if you will need to pay others to fix everything and you don't have free time then maybe a goodbye is more appropriate!!

Risk needs to be balanced by a potential reward.

Yes, you guys are right,,,, several issues already, and I don't own it yet. I have looked at several others and they all had some issues.
No one gets rid of a perfect boat. I am spending more time trying to make an educated guess on this one because of several factors,
Large boat with two staterooms, one a King size bed.
Low, Low hours, good or bad.
Aluminum fuel tanks, out in the open and accessible. Previous had steel encapsulated.
Very good looking hull, no crazing or cracks, upper helm and aft hardtops
Davit for dingy
Engine room has lack of rust and corrosion, very prevalent in others I looked at.
I am getting off track for this thread, but trying to explain why I am so enthusiastic about this boat, and not demanding a survey or walking away fast.
What I am looking for here is maybe someone with experience in a similar situation, and the outcome after running a set of engines that have set for a long period of time, good or bad.
I appreciate all the responses, It helps to consider several peoples opinions and thoughts on any subject.
If any drawbacks on this boat, it is the lack of a side helm door.
I have considered the overhaul scenario, this boat does not have a lower helm door. I am a machinist so a little concerned about removing an engine or generator out the back through the aft deck door. I know it is done all the time, but I am a hands on type of guy and intend to do most all of the work at a DIY marina. Reaching in that far from the rear looks like a cumbersome job.

Can you post a vid of the puffing with audio? I know that engine very well and have troubleshot numerous similar issues.

Are these turbo/aftercooled (355,275,425,435 hp)? or just turbo/no aftercooler (260,300,320 hp)?

Leaky valves are easy to check for, take rocker shafts and injectors out, then shoot shop air into injector holes. If it does not stay in the cylinder, you found the leak.

They are 375 HP turbo 3208TA's,,,
May get a vid, but will be a couple of weeks. Family is out of town.

My boat (an '88) was sold to the second owner in '99 with 120 hours showing. 3 years later it was re-powered with a slightly newer version of the same engine (Volvo turbo TAMD41P). I don't have the logs from that period so I don't know why but potentially it could have been from Years of Non-use that finally caught up with it.....Dunno, Just my guess...

I wish the logs were available for this vessel. Looking at the house this boat is parked behind,, it seems he should have had plenty of $$$$ to keep up with the maint even though it was sitting. But when sickness hits, who knows what they are thinking,, boat was probably the least of his worries. Very, Very sad.

I'm thinking of a holding tank with 10 YO cement in it.

You are doing it right, balancing the plus and minus aspects of the boat, not getting carried away.
The engine uncertainty is why buyers get mechanical surveys. But Ski`s offer may help you decide to continue or look elsewhere.
Holding tank location is certainly "sub prime". Does it predate the water tank, or was there nowhere else it could go?

The holding tank looks to be fiberglass and glassed between the stringers,,,it all looks original, at least it does not appear to be an add on.

Following up on Ski's thoughts, the worst case scenario for the engine might be a burnt valve or a blown head gasket. Nothing that has been said so far makes me suspect the piston, rings, crank or main bearings.

So even though it might be a few bucks for a valve and head milling job it wouldn't be the end of the world. I'll bet you could do both heads for a couple of boat bucks each.

And it might be as simple as a valve adjustment.

David

I have ruled out a head gasket,,, since both engines are almost exactly the same amount of blow back. And it is minimal.
So I found it hard to believe they both have blown head gaskets, also there are no bubbles in the coolant, or milk in the oil.
I am wondering if anyone has noticed this blow back on their engines. I know any of the truck diesels I am familiar with always had air cleaners with filters on the intakes,, so you could not see any blow back, even if it was present. I guess boats only have spark arrestor screens.
I thought about valve adjustments, but again with both engines being identical and such low hours I did not think they would be tight. I found the lifters are mechanical and set at .015 so I think for them to be tight it should take a lot of hours for the valves to seat into the heads that far and get tight enough to not seal.
You are right,, valve jobs would not scare me, and the smoke issue may require at least valve stem seals. But they would be easy without removing the heads.

Just sitting , with out DA Book procedure to pickle the engines, my guess would be the cylinders are pitted from rust.
Perhaps the valve seats too.

If the engine starts and runs mostly OK I would run it at least 100-200 hours to let the rings seat against the cylinders, and the valves to settle.

I would use straight oil , not multi weight , and keep my fingers crossed.

Slightly lower compression pressure from pitting would require a more frequent oil change to get rid of blow by.

Until the white smoke with the engine warmed looks like the mosquito control vessel , or the oil consumption gets too high to afford, the "what me worry" concept might have decades of good cruising before replacing the engines.

Oil consumption and engine reliability are two different concepts.

Even a quart of oil lost per hour would take a long time to repay for an R&R .

A possible cause of puffing would be stuck valves. Removing valve covers for a look see would be my first suggestion.

bayview said:

A possible cause of puffing would be stuck valves. Removing valve covers for a look see would be my first suggestion.

Click to expand...

Not much opportunity for a stuck valve on a diesel. It certainly can get stuck, but it won't stay stuck long. With piston at TDC there might be 0.050" between the piston top and the closed valve. If valve is stuck open, it will get hit and either close or break something.

A badly leaking intake valve will make a sharp audible noise out the turbo air intake. A leaky exhaust can often be heard all the way out the tailpipe, depending on what mufflers are used.

Really need a vid with audio to go further..

Thanks.

I am leaning towards your thoughts FF, The smoke is minimal as is the blow back so I am inclined to think the valves are just not quite sealing and hopefully some run time at a medium RPM may help all.
There is no sound at all coming from the intake or exhaust like you would expect from a bent valve or tight valve adjustment. With the low hours and from what I find the lifters are mechanical and .015 settings. I tend to think they have not run enough hours to have the valves seated enough to take up the clearance.
(I Hope)

Both engines may have been set up (or set upon)by the same" mechanic".

At least a lash check would be in order.'

First thing I would do is purchase "Da Book", the repair manual.

Yes,,, will definitely stick a feeler gauge to see what they look like while the cover is off. Also hope there was enough residual oil on everything when it was fired after sitting so long,,, going to look for scuffing on any of the wear surfaces.
I have access to DA book. .015 is the valve spec.