Posted: June 27 2011 at 22:49 | IP Logged

Hi Bennett,

Yes, you may be a mechanical engineer and your temperature numbers may be correct (to a point) but you are running blind.  You didn't see the part and therefore can't say what it was made of. 

No mechanical engineer would mistake aluminum for steel or stainless steel. Aluminum has a much higher reflectivity. Cast steel is out because it is also magnetic.  Most stainless steels are also slightly magnetic.

High temperature Al/Si alloys are commonly used in turbochargers for temperatures up to 750F.  I think the problem with your theory is that while some parts of a turbo may reach 1000F that part doesn't.

Pete37

Posted: June 28 2011 at 10:00 | IP Logged

Hi Mark,

Subject: Disaster in the Making!

Yes, if you have cast iron risers, you have a disaster in the making!  Run, do not walk, to your local mechanic and get those risers replaced.  If the outer shell of one of those risers ruptures it will blow black exhaust smoke into your engine room which will then be sucked into the engines fouling up every part of the engine that uses air. And both engines will be screwed up.  Even the block will have to be cleaned.  The entire interior of the engine room will be covered with black soot.  And all of this happens in the 60 seconds or so it takes before the engines die.

That's what happened to me and cleaning up the damage cost $22,000.  Don't let it happen to you!  I've mentioned this several times on the forum but apparently it doesn't sink in to the conciousness of many of the owners.

Pete37

Posted: June 28 2011 at 10:21 | IP Logged

Hi Mark,

If you have cast iron risers, you are way past the "Having it checked status".  At 14 years those risers definitely need to be replaced.  Checking them isn't simple.  The exhaust hoses are a bear to remove and sometimes have to be cut off.  Replacing them costs about $150 per engine.  For two engines it will take a mechanic about 4 hours at a cost of about $300-$400.  The risers themselves cost about $900 each.  Plus there is about $200 for miscellaneous clamps and gaskets.  You are looking at somewhere between $2600 and $2700 in repairs.  But if you procrastinate and your riser blows you may be facing $22,000 in damages.  Welcome to the joys of boat ownership.

Pete37

Posted: June 28 2011 at 12:04 | IP Logged

Hi Mark,

I have not had a problem with condensation or water in the forward port fuel tank or in any of the fuel tanks. Have you checked the seal on the deck port fuel fitting?

I change fuel tank settings while underway without changing speed or shutting down the engines.

Posted: June 28 2011 at 13:44 | IP Logged

I still have not been able to get the port fuel tank change-over valve to move by lubricating, prying up under the handle and fiddling with the stem sticking thur the stairs. Did get the starboard one working well with that method however. Will look at it a little more this week end but am not planning tearing the assembly out (yet). Still getting more imput and I want to enjoy the Fourth of July holiday with family and friends.

I may just use the boat with the fuel valve stuck as is untill after our usual July and part of August cruising schedule. With the port fuel change-over valve locked on the forward tank (of course it's not locked on the larger aft tank) I will have enough fuel using only the forward tanks to reach enough destinations, especially going slower. The down side is topping off the fuel more often and not being able to take advantage of the best fuel prices. However, at this point I don't want to take a chance on missing cruising time by getting delayed taking the fuel change-over assembly apart and not being able to fix it, or get exact repalcement valves or a have time to install a new set up.

This brings up two possible problems. Most important, is that port valve stuck so that fuel will not be able to flow to the engine??? That valve moves about 1/8 inch each way and feels like it is hitting something that keeps it from turning further. It locked up when I  tapped the top of the valve slightly and I am pretty sure it was in the positon of the forward tank. Not sure of the internal design, but I doubt tapping the valve could hinder fuel flow. Of course I could run the port engine at idle in the slip and see if it runs out of fuel and that would answer that question. Anyone have any idea on how long the engine would take to run out of fuel if the valve were to be shut off?? I assume there would be enough fuel in the line to start the engine...

The other consideration is the running of the generator. The generator draws form the port aft tank and therefore I would think it is connected directly to that tank and would not be effected by the stuck fuel change over valve. So the port aft tank could be used and filled to kept the generator running. Is this correct??

Posted: June 28 2011 at 14:51 | IP Logged

Dave,

The valve should not interfere with your generator, it is separately plumbed.

A short term solution so as not to affect your cruising range would be to temporarily bypass the valve.  Just get a couple of barbed nipples and attach your feed and return lines from the port main directly to the engine feed (or Racor) and return line.  Bronze nipples would be best.  Also, plug the openings on the valve so you don't introduce debris.

John

Posted: June 28 2011 at 16:01 | IP Logged

Hi Bennett,

Subject:Turbos

I do not know what your turbos are made of.  I haven't seen them and wouldn't dare comment on them.  But I do know that the turbine housings on my engines are made of aluminum and have found out that Al/SI turbine housings are commonly and routinely used for diesel engines at temps up to 750F.  Apparently that includes my turbos.  My mechanic also agrees that the turbine housings are aluminum.

Why do you contend that my turbos must be made of steel when you haven't even seen them?

There is no indication that the physical structure of the old turbo housing was affected by high temperatures and new replacement turbos are still being made of aluminum.

I should also point out that gas temperatures are not directly related to structure temperatures.  A turbine handling 1000F gases is not necessarily at 1000F.  And the engine which also handles 1000F gases is not at 1000F.  Remember also that in our engines the exhaust gases flow through a three foot long water cooled exhaust manifold  and may be well below 750F before they get to the turbos..

I have never said that the turbos failed due to bearing problems although statisically that is a very common cause of turbo failure.  Nor have I said that rust was a problem (although others have).  My feelings and the mechanics feelings are that the turbo was stopped by the buildup of carbon near and on the turbo exhaust fan housing as witnessed by the large chunks of carbon found on and in the riser cavity.

Pete37

Posted: June 28 2011 at 17:36 | IP Logged

Hi All,

Subject: Exhaust Gas Temperatures

I did some sluething and found some data that explains why aluminum is acceptable for a turbo.

Exhaust gases leave the cylinders and enter the water cooled exhaust manifold at about 1000F.  They then pass through the three foot long exhaust manifold and enter the turbo at somewhere in the high 700s.  They pass through the turbo and enter the exhaust elbow at about 725F.  This number is from the J&T Owners Manual. 

After passing through the exhaust elbow and being mixed with exhaust water they enter the exhaust pipes at somewhere in the low 200s.  The exhaust pipe is rated at only 250F so the exhaust must be somewhat below that.

The key fact is that the exhaust leaves the turbo at 725F which is below the 750F at which aluminum turbos are commonly run.  So an aluminum turbo is consistant with the exhaust temperatures encountered in a 6V92 diesel.

All of these temps are at full throttle.  At lower rpm they are much less.

Pete37

Posted: June 28 2011 at 21:43 | IP Logged

Hi Bennett,

Actually, I don't have to prove anything.  The J&T Owner's Manual, Section 1, Table 1-4 proved it for me.  My apology, the number for the exhaust temp I gave you is slightly wrong.  The 725F for exhaust temp was for a 671TI.  The correct number for a 6V92TI is actually 690F (35 degrees lower than I thought).  And that's well below the 750F that Al/Si turbos run at.  Would you like a copy of the table?

In view of this I doubt that any marine 6V92 turbos are made of steel.  Aluminum casts and machines much more easily than steel and is therefore much cheaper to produce. And turbo manufacture is very price competitive.

Sorry that you got caught on the loosing end of this discussion.  But it's no big deal.

Pete37

Posted: June 29 2011 at 00:15 | IP Logged

Hi Bennett,

Yeah, the picture shows something but I doubt it's rust.  Aluminum doesn't rust.  In thinking about your statement that your turbos were made of steel it seems possible that somehow you got turbos that were designed for 6V92 truck engines.  Truck engines don't have water cooled manifolds so the exhaust gases go into the turbo at much higher temps which would require the use of steel.

Another thought to contemplate is the fact that at full throttle the exhaust gas temps are only about 700F.  At full throttle (2000 rpm) you are burning 40 gph while at 1400 rpm you only burn about 14 gph.  That's only 1/3 of the fuel so the exhaust temperatures might be as low as 300F.  And at 300F the exhaust chemistry is entirely different than it is at 700F.  So in order to figure out what's going on you need to be a chemist as well as a mechanical engineer.

Pete37

Posted: June 29 2011 at 11:18 | IP Logged

Hi All,

Here is a first cut on the list of Connie maintenance jobs Mark wanted.  It covers only the main engines:

	Replace oil filters	Yearly in Nov
	Change oil	Yearly in Nov
	Replace Racor fuel filters	Yearly in Nov
	Replace on engine fuel filters	Bi Yearly in Nov
	Replace exhaust elbows	Every 6 years
	Replace Raw Water Pump Impellers	Every 2 years
	Fan Belts	Every 5 years
	Check and/or replace engine zincs	Every year
	Check battery water level	Every month
	Check battery condition	Every use
	Engine water level	Every use
	Engine oil level	Every use
	Exercise all thru-hulls	Monthly
	Exercise fuel valves	Monthly
	Replace batteries	Every 6 years
	Check water freeze point	Yearly in Nov
	Check & adjust shaft logs	Monthly
	Check bilge pump operation	Monthly
	Clean bilge	Monthly
	Clean air cleaner element	Monthly
	Add fuel treatments	As needed

This is only a first cut.  Perhaps some of the readers can add some items I've overlooked.

Pete37

Posted: June 29 2011 at 18:29 | IP Logged

New Topic: "Waterfalls"

This afternoon after arriving back on the boat, I found that today's thunderstorms and HEAVY rains had caused a flood on the flybridge that ran through the hatch and into the upper salon.

On my 85 model, there is one drain on the forward starboard side of the FB that has to take off the water from this portion of the FB deck, which is covered by a bimini, but no curtains.  The drain appears to be open (used a coat hanger to confirm it is open).  However, in a windblown downpour, it appears the one drain cannot handle the rainwater load and backs up/overflows the curb of the hatch, generating a waterfall.

Does anyone else have this issue?  Are there any drains under the FB dashboard that also drains this area that I need to confirn are open?  Has anyone drilled added drain openings to prevent such an issue?

Any thoughts are appreciated.

Jim 

Posted: June 29 2011 at 22:49 | IP Logged

Hi All,

Subject: The Fat Lady Has Sung

Well, it’s all over.  The “Fat Lady” has sung.  My Connie is up and running.  Arlene and I took her out for a 20 mile test cruise to Rich Neck and back.  Everything worked fine.  The bill from Bob (the mechanic) had been emailed to my computer when I got back.  I’m poorer but somewhat wiser.

Here is what Bob had to say:

“Service call to marina in Kent Island to work on a Chris Craft boat with twin 8v92TA Detroit engines. Complaint port engine is smoking black. Talked with Mr. Minott about the problem, he thought the engine might need a tune up. I first removed the air filter housing and checked the turbo charger for any damage or blockage. The turbo charger was very hard to turn; this is part of the problem. There was a heavy buildup of carbon between the turbine housing and the turbine wheel; this stopped the turbo from turning.”

I’ve been told by some members of the forum that it was everything but a carbon buildup.  They never saw the turbo but they’re sure it couldn’t be a carbon buildup.  Why?  Basically because they’re afraid that it could be attributed to slow speed running.  And that threatens their lifestyle.

Well, perhaps it could be attributed to slow speed running.  And in fact it probably was.  However, I’m not saying it was.  But I’m scratching my head and wondering “What caused that carbon buildup?”  I don’t want and can’t afford a repetition of this problem 300 engine hours from now.  And I doubt that you guys want to deal with this problem either.  Denying that it exists doesn’t accomplish anything.

There were, however, some silver linings to this otherwise dismal and expensive experience.  I’ll talk about them in my next post.

Pete37

Posted: June 30 2011 at 01:05 | IP Logged

Jim,

I have port and starboard drains (I'm guessing they are about one and a half inches) on the flybridge immediately at the base of the helm and also a pair right under the helm storage area. The aft area of the flybridge deck behind the side fiberglass support walls are open all the way around to each other that acts as a giant run off drain.

I believe your helm and storage area are different from mine and yours has the starboard console set up. If your arrangement has the helm on an angle (mine is straight across) it could act as a dam. Only one drain seems inadequent. Your flybridge flooding may have been due to wind or a forward slooping deck along with the heavy rains. Does water flow forward on the f/b deck when you hose it down? Unusual weight distribution (fuel tanks?) causing water to run forward may be a factor.  

Posted: June 30 2011 at 10:48 | IP Logged

Hi All,

Subject:  The Silver Linings

I said in my last post that there were some silver linings to the breakdown of the port turbo.  I’ll discuss them here.

First, as you all know I’ve been having a lot of problems with transom soot.  And it’s been gradually getting worse.  But now, after repair of the turbo the engines are running exceptionally clean.  There’s no visible smoke.  Of course, we only worked on the port engine.  We didn’t do anything to the starboard engine.  So if the starboard engine had been smoking it still would be.  But it’s very difficult to determine where the smoke was coming from.  It’s possible that all the smoke was coming from the port engine.

Whatever, the engine exhaust is now basically smoke free and therefore I wouldn’t expect any more transom soot.  It’s too early to be sure but time will tell.  So perhaps the mystery of where transom soot originates from is solved.  It’s basically due to a malfunctioning turbo.

The solution for transom soot may be simply to have your turbos overhauled.  Unfortunately though, that isn’t a cheap process.  Turbo rebuilds cost about $1000 each and the mechanics labor is probably at least $500 for a total of about $2,500.  How long will a turbo rebuild keep you exhaust clean?  Don’t know; time will tell.

The other bonus of the turbo overhaul is that now both engines run at the same temperature.  Prior to the overhaul the port engine was consistently running 5 to 10 degrees warmer than the starboard engine.   I had assumed that this was due to instrument error but now after turbo repair they are running at the same temp.  So apparently, in addition to creating soot, the malfunctioning turbo was interfering with the operation of the engine and causing it to run hotter.  With the turbo fixed it should be running more efficiently.

How long will all this last?  Again, don’t know; time will tell.

Pete37

Posted: June 30 2011 at 10:57 | IP Logged

Hi Jim,

Sorry to hear of your waterfall problem.  I'm not too familiar with what the offset instrument console does to your drainage probem.  I've never had the waterfall problem.

Sounds to me like you are going to have to rig some sort of canvas to solve the problem.  It doesn't have to be side curtains  but it obviously needs to divert the water overside.

Good luck, I'm sure youwill find a solution.

Pete37

Posted: June 30 2011 at 12:24 | IP Logged

Nice job Pete

BTW, old rusty exhaust eblow restricts water flow.  Less water flow = less cooling.  less cooling = higher reading on your temp gauge.  New clean elbow = more water flow.  ect...

Posted: June 30 2011 at 20:30 | IP Logged

Hi Allen,

You don't seem to have the slightest comprehension of how a thermostatically controlled  cooling system works.  Or even that our 6V92 systems are thermostatically controlled.  Only a fool argues with a fool.  I'm not going to argue with you.

Pete37

Posted: June 30 2011 at 20:47 | IP Logged

To:  Pete 37.   As excessive carbon build-up was in the turbo, could there be an injector ( 1 or more) problem?

Fly Bridge.

Posted: June 30 2011 at 21:01 | IP Logged

Hi Fly Bridge,

Yes there could have been some injector problems too.  Initially, I thought a tune up  was needed.  But we seem to have obtained very good results without a tune up. I don't think an injector problem would have shown up as carbon at the turbo.

Pete37

Posted: July 01 2011 at 12:16 | IP Logged

Grey Goose and Allen;

Folks who respond to you with a statement that "boats don't have radiators" [like OTR trucks] when you raise a point (ironically on the cooling system), then a few weeks later posts a message that AGREES with you, and then removes it when he realizes his "error" is always "right".

Jim

Posted: July 01 2011 at 13:05 | IP Logged

Hi Bennett,

We know from the picture that the exhaust elbow wasn’t severely restricted so your hypothetical case of complete blockage is rather extreme and doesn’t apply in this case.  We don’t have a complete or even serious shutoff of exhaust water flow.

Minor blockages of the exhaust system water flow have no effect on the temperature of the engine block.  The thermostat just opens slightly wider and compensates for the reduced flow.   But Allen doesn’t seem to understand this very basic fact as demonstrated by his statement:

“Nice job Pete,

BTW, old rusty exhaust eblow restricts water flow.  Less water flow = less cooling.  less cooling = higher reading on your temp gauge.  New clean elbow = more water flow.  ect...”

This equates raw water flow directly to engine temperature and also implies that I am a fool for not knowing that.  It prompted my response to Allen:

“You don't seem to have the slightest comprehension of how a thermostatically controlled cooling system works.  Or even that our 6V92 systems are thermostatically controlled.”

I think that this is correct and fully justified.

The dictionary says fool means “a person with little or no judgment, common sense, wisdom, etc.”  Not knowing how the cooling works is acceptable but making statements that engine temperature is directly related to raw water flow without understanding how the cooling system works shows a complete lack of judgment.   So the fool definition fits Allen’s statements.

And since Allen doesn’t seem to understand even the most basic principles of the cooling system it would be pointless to argue with him, i.e. “Only a fool argues with a fool.”

Pete37

BTW:  I found the exact model number of the turbo (Air Research XT18A rebuilt by Detroit)) and called an Air Research distributer.  The turbine housing could be either aluminum or cast iron.  Both are used. Cast iron (used in trucks) is more common.

Posted: July 01 2011 at 13:32 | IP Logged

Hi Jim,

Subject: Boats Don't Have Radiators

You're right.  If I ever made the statement "boats don't have radiators" it's been erased because it isn't in the archives.  But it sounds like a perfectly valid statement so I'll say it again "Boats don't have radiators".  What's wrong with that statement?

Pete37

BTW: Grey Goose & Allen are the same person

Posted: July 01 2011 at 15:58 | IP Logged

Hi Allen,

Subject: Gripes

I can't answer all your gripes but I can answer the ones you mention:

1.     Proposition:  Restriction in the flow of seawater could affect the freshwater temperature of your engine.  Answer: In your post you said temperature was directly related to flow.   In reality a minor restriction would have no effect.  Complete shutdown of course would.  But we have not had any complete shutdowns.

2.     Proposition: 240v electric is single phase.  Answer: The 240 volt electric you get from the 4 wire dock plug has two 120 volt phases phased 180 degrees apart.  Popular terminology however is single phase.

3.     Proposition:  Your turbo is cast iron.  Answer:  No my turbo housing is aluminum although many turbo housings are cast iron.  The manufacturers say that both aluminum and cast iron are used. Cast iron is magnetic and I tested the housing with a magnet.  It is definitely not magnetic. You haven’t even seen my turbo so I don’t know what you base your premise on.  Frankly, I don’t know why it is any of your business.  It is what it is and its warranted  by the manufacturer.

4.    Proposition:  An extended swim platform would be safe.  Answer:  Whether it’s safe or not depends on how much it’s extended and what the loads are.  However, the loads and extensions you proposed were way beyond what any swim platform manufacturer would warrantee.  And if you get some backyard mechanic to build one for you it may turn out to be unacceptable to your insurance company.  No one prevented you from building it.  We just pointed out the hazards.

Pete37

Posted: July 01 2011 at 16:20 | IP Logged

I'm gonna quit trying...  apparently you don't understand how this statement and your recent "aluminum doesn't rust" statement makes it appear you believe we are all morons without any intelligence or common sense.  Count me out...

Jim

Posted: July 01 2011 at 16:31 | IP Logged

Hi Jim,

My "Aluminum doesn't rust." statement was only to counter statements by others who claimed the turbo was jammed by rust rather than carbon.  It's obvious and I thought everyone would accept it as obvious.

I guess the "Boats don't have radiators." attack which is also a pretty obvious statement fizzled.

Sounds like you don't like the use of obvious statements to nail down a point.  It's a fairly common tactic in debates and I thought you would recognize it as such.

Hope you have found a solution for your waterfall problem.

Pete37

Posted: July 01 2011 at 17:45 | IP Logged

Speaking of judgment, with all that Allen has posted here do you really think he doesn't understand that the cooling system has thermostats? Nothing in his statement warranted your vitriolic response.

Your frequent insults do not promote the mission you proposed on page one: “to exchange ideas.” Instead, they instigate hard feelings, discourage helpful dialogue and cheat the members out of the opportunity to learn from each other.

It is possible to disagree with an idea (or even ignore it) without being disrespectful. Some of us do it all the time. I'm afraid that our dialogue will soon become a monologue and I don't think that is the kind of forum you envisioned.

John

Posted: July 01 2011 at 21:20 | IP Logged

Hi John,

I get a stream of snide comments and insults from Allen.  Most of them I just swallow with no comment.  But once in a while I fire back.  Allen should cut out his sniping and concentrate on exchanging useful ideas.  Since you are not on the receiving end of these comments and insults you probably don't notice them and can afford to be statesmanlike. 

It's not so easy for me.  Some of his ideas are dangerous to both life and property.  I have to discourage these concepts and when I do the snide comments and insults resume.

I think Allen knows the engines have thermostats but he doesn't know what they do or how they work.  Frankly he doesn't have much knowledge of anything to do with engines.  That's'not a crime but he should keep his comments to what he knows about.

Pete37

Posted: July 01 2011 at 21:39 | IP Logged

Wow...I'm a newcomer to these posts and I'm amazed at how harsh some of you sound.  Gosh...aren't we just trying to solve problems, learn new stuff, and generally communicate about our CC's?  This isn't a contest, guys.  I DO learn alot from MANY of you, but can't we just be a little nicer to each other?

Just my thoughts....

Lisa

Posted: July 01 2011 at 21:52 | IP Logged

Lisa, I agree!!

Fly Bridge.

Posted: July 01 2011 at 22:11 | IP Logged

Hi All,

I've noticed that a number of Catalina owners are now posting on our forum.  The Catalina group has a lot more posts than our forum.  Of course there are about 10 times more Catalinas than Connies. Wonder what the attraction of our site is? Perhaps it's because we have more tech data.  Or perhaps they are thinking of moving up.

Pete37

Posted: July 01 2011 at 22:35 | IP Logged

Hi Lisa and Fly Bridge,

I guess the reason that our forum sounds more strained is that Connies are expensive to run and a naive owner promoting bad data can cost the owners a lot of money (not to mention the grief).  Typical costs to run a Connie are $10K to $30K.  Very few get by for less than $20K and there are a lot who whiff more than $40K.

The cost of running a boat goes by the cube of the length so a 50' boat costs about 4X more than a 32' boat.  I guess you can be be more relaxed when your yearly costs are only in the $2.5K to $7.5K range.

Pete37