Considering 1991 420 Sundancer w/T CAT 3208 TAs

[33Degrees]

Hello,

I was wondering if anyone would give thier two cents about purchasing a 1991 420 Sundacer. It is powered by twin 3208 TA Cats. It is very clean and "appears" to be well maintained.

It will of course be fully surveyed, but I was wondering if this boat fits the profile of some of the hull problems Sea Ray had in the past?

What are your thoughts on this boat with that engine combination?

I would love to hear from owners of this or similar boats!

Thank you,
~33

 

[BonBini]

I cant give you much input on the hull and such, but I can give you a little insight on the Cats.

Check the maintenance and service records carefully. Those early 90’s fuel nozzles should have been changed. Regular scheduled valve clearance adjustments (important). A guy that pushes a 3208 hard all the time will beat the valve keepers rite out. At 2600 they’ll run for ever. A seasoned Tech will know what to look for during service. Higher hp models like the 375’s will white smoke when cold, even leave a sheen of fuel on the water, Nature on the Beast. These are old school motors that were built to run sulfur fuel and old school oil. They need a lubricity additive to the fuel and old fashion DEO with the bad stuff in it.

And welcome to CSR…

 

[mmcguire2002]

Wait for Frank...he will chime in shortly. Listen and learn. Then say thank you. ;-)

 

[FireIsland1]

I spent alot of time running those boats. 2 friends had them. very solid and alot of room. engine room access is good, sound levels ok, one had a generac generator sucked big time. It handled well with good speed. both owners loved them

 

[Boatingnut]

It is a great handling boat. No prop pockets, so handling around the docks is great. The props really get a good bite.

First off, get the engines checked by Cat. These are some great powerplants that will last a long time if you do the maintenance on them. How many hours on the engine? If they are at 1000 or above, the aftercoolers should have been pulled and cleaned.

When you sea trial, check what tachs are installed. If they are the Teleflex tachs that came with the boat, don't trust them. Bring a photo tach device to check rpms. If they have digital tachs (Aetna's, for example), then you can use those. Bring some hearing protection if you plan on going into the engine room to check RPM's.

2400 rpm at cruise, 2800-2850 WOT, and around 3000-3100 in neutral. Check the engine information plate for specs. It is located on the aftercooler. If they don't spool up to 2800 or above, you need to find out why and how long it has been like that. The Cats don't take well to being overloaded.

At 2400 rpm, expect a little dark smoke. I can barely see my smoke when running, but it is there. A bit of white smoke when they fire up, more if it is cold outside. When you start them, they should fire immediately. If they crank, there is a problem. You should barely be able to get your fingers off the switch because they fire so quickly.

Other than that, I am not aware of any chronic problems with the early 90's 420/440. Great boat.

 

[Pietro]

Welcome to CSR!
Great boat and great engines, for sure!!! :thumbsup:

Ron, do you mean I can cruise at 2600??? That would be nice!

What is DEO??? Should I put something in my fuel???

 

[BonBini]

“Turning 2600 forever”…The 3208 was widely used by Cat. Towards the end of it’s run, the 01Z(marine), 02Z(truck) and 03Z(machine) were all roller cam engines with virtually identical valve trains. The truck and machine ratings were 2600. These things ran road planers, tree harvesters, wood chippers, exc. They fired up a first light and ran at 2600 rpms till dark, only shutting down to low idle for lunch or to change operators. In these harsh dirty environments, the rings wore out before anything else. I seen a few worn out over heads (beat out valve keepers and warn rocker tips) in higher rpm marine and a few others in dump truck engines that ran down into gravel pits regularly!

“DEO” (diesel engine oil) “the bad stuff” the zinc, heavy lubricating elements that the DPF’s (diesel particulate filter) don’t like. The unmolested 3208 has no valve guide inserts. The heavy metals better lube the valve stem to guide. Stainless guides are available and the heads can be drilled to accept them.

“Fuel lubricity additive” The sulfur that once was in fuel actually lubed the injection pump barrel to plunger clearance. Cat came out with some stuff a few years back. I believe it does more than just add lubricity. A gallon treats something like 350 gallons of fuel. The replacement injection pump parts have been re designed with a lubricating land cut in so they can better run with the green fuel.

All diesel engine manufacturers are going through the same growing pains. 3208’s are simple engines compared to the emission friendly engines of today. They’ll run well enough… I’m just posting on how to get the very best out of them....

I hope that wasn’t too much.

 

[docofthebay]

I bought Tobnpr's '85 390EC several months ago and it has the 3208s and they are fantastic!. Boatingnut is correct, just a bump of the key and they fire up instantly. I dont think I've ever heard them turn over as they crank so instantly. There is some smoke so expect to wash your transom frequently. At 2400 RPM I get 25 MPH and about 1 mpg. I've recently been experimenting with 2200 rpm and 21 to 22mph and I believe this is actually returning a better seat of the pants measurement of fuel use/mpg.
BonBini; is it OK to cruise at this speed (2200)? I've been told and Cat specifies 2400, but the boat is fully planing at 2100 and if its OK to run the engines long term at this speed, then I will on the long fishing or cruising trips of 100- 200 miles a day. Cat literature gives a fuel burn rate of 12gph per engine at 2400 so this measures out to 1.05 mpg at 25 mph, and fuel burn at 2200 is 9 per engine/18 total gph at 21 mph for 1.16 mpg--10% better for only 4 mph slower.

 

[docofthebay]

Welcome to CSR!
Great boat and great engines, for sure!!! :thumbsup:

Ron, do you mean I can cruise at 2600??? That would be nice!

The CAT product literature shows the fuel burn at 2600 to be around 16 to 16.5 gph (per engine) at that speed compared to 12gph at 2400. That s a 33 to 35% increase in fuel flow for just 200 rpm increase. 2700 burns 18.8 gph and 2800 burns 21 gph. On the other end, fuel burn at 2000 is only 6 gph.

Ron can answer about the long term effects on the engines of cruising at that speed, but I think the fuel economy goes way down as you pass 2400.

From your your restoration thread, you showed that you have floscans for fuel management. Could you post sometime the real world fuel flow at each 100 rpm??? The figures I listed above are from published CAT literature but your accurately measured burn rates would be wonderful.

 

[Pietro]

Welcome to CSR!
Great boat and great engines, for sure!!! :thumbsup:

Ron, do you mean I can cruise at 2600??? That would be nice!

The CAT product literature shows the fuel burn at 2600 to be around 16 to 16.5 gph (per engine) at that speed compared to 12gph at 2400. That s a 33 to 35% increase in fuel flow for just 200 rpm increase. 2700 burns 18.8 gph and 2800 burns 21 gph. On the other end, fuel burn at 2000 is only 6 gph.

Ron can answer about the long term effects on the engines of cruising at that speed, but I think the fuel economy goes way down as you pass 2400.

From your your restoration thread, you showed that you have floscans for fuel management. Could you post sometime the real world fuel flow at each 100 rpm??? The figures I listed above are from published CAT literature but your accurately measured burn rates would be wonderful.

:smt038 First, let me tell you that it’s good to see that Mike’s 390 is still around here somehow!! But, where is he???

For now I can only tell you that with full diesel and water tanks, five people aboard, calm sea I checked 25 KTS @2500 RPM , 60 litres/hour = 15.90 GPH per engine full load. So 16.5 @ 2600 looks reasonable.

My boat is going on the hard tomorrow…so I will be able to check fuel consumption again in some 6 months…I’m sorry… but I will do! It will be interesting to work out the best speed/fuel/range combination.

 

[Boatingnut]

2400 is cruise rpm, period. This number is not debatable. Run at higher rpms for extended periods of time at your own peril. Diesel longevity has much to do with how much fuel you push through them. Docofthebay points out that you would use 33-35% more fuel at 2600 vs 2400 rpm. Run like that all the time, and you will just kill them faster. Not that complicated.

I have run at 2100 to 2200 rpms for extended periods, mostly due to sea conditions. I suspect that how the boat is riding at any given rpm will give you the answer to whether or not it is good or not. I have had to stuff the tabs and run at those rpm's before, and have no issues staying on plane, with no increase in smoke. There is not a standard answer to that question.

 

[Pietro]

2400 is cruise rpm, period. This number is not debatable. Run at higher rpms for extended periods of time at your own peril. Diesel longevity has much to do with how much fuel you push through them. Docofthebay points out that you would use 33-35% more fuel at 2600 vs 2400 rpm. Run like that all the time, and you will just kill them faster. Not that complicated.

2400? 2600? :huh:

I've always cruised at 2500... smack in the middle :grin:

 

[BonBini]

Docofthebay: I really don’t see where running at a lower rpm will physically do any harm. By throttling back your reducing the engine load!

Boatingnut: At this point I don’t see where 2400 rpms is any type of optimum running range. My philosophy has always been turn slow and make torque. Many 3208 applications turned lower rpms continuously with out any problems.

FWIW... I dug up the below information...

"The recommended cruising speed of the engine is 300 to 400 rpm below the rated speed of the engine. Operating at the recommended cruising speed will help to provide the maximum engine service life and the most economical operation"

 

[Boatingnut]

BonBini: No issues with running lower rpms, provided the efficiency of the hull, speed and gpm are at optimum levels. No issues at all.

But, run continuously over 2400 rpm at your own peril.

 

[BonBini]

boatingnut: thanks for clarifying the 2400 and below. I did dig through some old O/M manuals “85”/”89”/“98“... 85 recommends 2400-2500... 89 recommends 2400 but refers to it as a maximum continuous running rpm… 98 goes back to 2400-2500. An interesting read in the 85 manual is, run wot for about 4 mins, take a tach reading, then cruise 300 - 400 rpms below. That could be a 2550 cruise rpm!

I believe what is meant by it all is continuous duty running a High Performance Marine needs to be a few hundred rpms back from rated. Pending on how heavy the load and how much hp the engines are pushing. If at 300 rpms back they begin to heat up, then one needs to throttle back another hundred…

Pietro: What I am saying about 2600 is that the overhead will hang in there. If at 2600 to see your temps creeping up, then you’ll need to throttle back.

 

[Pietro]

boatingnut: thanks for clarifying the 2400 and below. I did dig through some old O/M manuals “85”/”89”/“98“... 85 recommends 2400-2500... 89 recommends 2400 but refers to it as a maximum continuous running rpm… 98 goes back to 2400-2500. An interesting read in the 85 manual is, run wot for about 4 mins, take a tach reading, then cruise 300 - 400 rpms below. That could be a 2550 cruise rpm!

I believe what is meant by it all is continuous duty running a High Performance Marine needs to be a few hundred rpms back from rated. Pending on how heavy the load and how much hp the engines are pushing. If at 300 rpms back they begin to heat up, then one needs to throttle back another hundred…

Pietro: What I am saying about 2600 is that the overhead will hang in there. If at 2600 to see your temps creeping up, then you’ll need to throttle back.

Ron, thank you!

My CATs reach 2800 quite easily and they do not seem to overheat at 2600, but I want to check better.
What is the right run-for-ever temperature?
Should I check it on the gauges on the engines rather than on the Teleflex gauge on my dash?
Is there any other temperature I can check with my IR gun??

 

[BonBini]

Pietro: I don't know what you've got for a gauge package but I'm sure you've got water temp. It would be really good if you could monitor the engine oil temp. There are some temp strips that you could stick onto your oil filters, but an actual gauge would be better.

Internally there are some cooling jets that spray engine oil to the bottom of the piston domes for cooling. As things heat up from loading your engines too hard too long, the oil cooler cant cool the oil any longer. First the oil temp climbs, then the jacket water temp. I believe there may be a spot at the oil cooler for a sending unit, but I'm not 100% sure at the moment!

 

[Pietro]

Pietro: I don't know what you've got for a gauge package but I'm sure you've got water temp. It would be really good if you could monitor the engine oil temp. There are some temp strips that you could stick onto your oil filters, but an actual gauge would be better.

Internally there are some cooling jets that spray engine oil to the bottom of the piston domes for cooling. As things heat up from loading your engines too hard too long, the oil cooler cant cool the oil any longer. First the oil temp climbs, then the jacket water temp. I believe there may be a spot at the oil cooler for a sending unit, but I'm not 100% sure at the moment!

No oil temp. gauge, but I want to see if I can fit one!

That's great, yet another winter project :grin:

 

[33Degrees]

Hey guys, thank you for all the responses. I didn’t want to jump back in too quick because I still have a lot to figure out!

BonBini:

Yes, it looks like I will be able to get my hands on all the records and service logs. The boat has only been owned by two people, the current owner for the past 6 or 7 years. The owner is selling to move up and can’t fit two boats in his private slip in front of his nice Newport Beach home (the problems some people have!)

This boat was very well maintained and no expense has been spared. He used it to travel off shore to a fishing spot about 100 miles out then stayed for a day or two, so he wanted a reliable boat. It’s in great shape (but I understand this is only part of the story).

I’m having an engine survey and sea trial on Monday. I’m bringing the CAT tech out on the sea trial to make sure the CAT’s are evaluated under load and I can get some solid RPM / temperature data.

Thanks everyone for the discussion on RPM’s – this is my first diesel, I still can’t believe the numbers – this boat will be about ½ the cost to run as compared to my last 30’ gas boat! (I understand there are more costs than just fuel, but still…)
I have run other peoples diesels for years, both twins down here in Southern California and a couple of larger single screw trawlers up in the Pacific North West (love the San Juan’s). Maybe I was always afraid to do the math!

MMcGuire2002:
Where or who is Frank? Good resource for….?

FireIsland1:
The genset is a newer Kohler. Glad to hear the boat handled nice, thanks for the input.

BoatingNut:
Thanks for the note on the lack of prop pockets. When your post came in I was literally trying to find information on the hull. I had trouble even finding pictures of the boat on the hard, so thanks!

On your suggestion I took your advice and am spending the money to bring in a reputable CAT tech. They are VERY proud of their drive time and mileage charges – geesh – so much for my excitement on the lower running cost as compared to my gas boats!

The boat does have ALL new instrumentation and electronics and that includes a set of Aetna’s. Thanks for the tip on the hearing protection – I didn’t think of that.

I did fire the boat up from cold (well, what we in Southern California call cold) and it was just as you said – fired right up, some white smoke and a slight sheen… then cleared.

Tender / Dinghy:
Currently – the boat does not have a tender or davit (the owner opted for an actual bow mounted life raft because of how he used the boat – off shore fishing) and the life raft will not go with the boat ( I have no need for it, I need a tender).

I’m looking to put the Roskelley Olsson ST-275 davit, a Caribe C10 with a 20 HP motor (Tohatsu, Yamaha or Honda – any input?) I’m going with a 20 HP because over at Catalina Island a strong solid tender comes in very handy, it won’t just be used in no wake harbors.

Thanks guys – if all goes well on Monday with the engine survey and sea trial, it will come out of the water for the full survey on Wednesday!

Thanks again for all the help –
~33 Degrees

 

[docofthebay]

"Where or who is Frank? Good resource for….? "

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