13 Meter 6-71TI Sea Trial Results - Interpretation (major rebuild looming?)

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DRM
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13 Meter 6-71TI Sea Trial Results - Interpretation (major rebuild looming?)

Post by DRM »

I´m new to the forum and would appreciate any advice provided.

I´m considering purchase of a 1989 Trojan 13 Meter Internal Express. Same owner for for 28 years.

Boat dry weight 24,000 lbs, length 43´, beam 16´3".

We just finished sea trial. Hull and structure is sound, mechanicals and all systems functioning. My concern is for expected engine longevity before a major rebuild is required.

Engines: Twin DD 6-71TI J&T 450 HP 1,611 hours each.

Clean bottom and clean props: Boat was hauled out immediately before sea trail and entire hull was pressure washed and cleaned. Props were also cleaned and were in good condition. Boat had apparently not been used in any meaningful way for two years due to owner illness. Fuel filters were presumedly that old.

General performance: Cold started (w/out block heaters turned on) w/o issue, white smoke for approximately 3 min. No running smoke after warm. Within normal operating temperature range on all components during test run of approximately 1.5 hours. External indications of good maintenance, hoses, air intakes, turbos. No significant blow-by. Smooth running. Responsive.

Issues/Concerns: Engines failed to achieve maxim performance specs.
-Max WOT under load only 2100 RPM port, 2200 RPM starboard. Specs call for 2500 RPM
-WOT no load 2400 RPM port / 2500 RPM starboard. Specs call for 2700 RPM.
-Maximum speed, WOT 27 mph (GPS measured), the surveyor indicates that this is 5-6 mph less than expected.
-Oil analysis, all metals within specs, except elevated iron in port engine (93 ppm), broker attested approximately 100 hours on oil. Surveyor's interpretation is that oil test results are "good".

Propeller: Michigan prop, four blade, bronze / nibral 28 x 31.

My basic questions are "Should I be concerned with these results?" and if so, "What options should I pursue to confirm status of engines?"

I am presently looking into a (i) visual cylinder wear ring inspection via air box, (ii) compression test. I have been advised (by surveyor) to be cautious regarding compression test as he has seen damage to injectors due to removal for the test.

I understand that the low peak RPM can be due to number of causes, such as fuel, fuel delivery and filter, calibration of tachometers. However, the failure to hit expected speed suggest that it is not a faulty reading from the tachometers. Could this be an issue with prop size (however, failure to reach WOT specs w/o load suggests otherwise)?

Are there any additional test or causes that should be investigated before purchase? I like the boat, but not if I can reasonably to expect that a major rebuild is just around the corner.

Any advice you can offer will be much appreciated.

Much thanks in advance.

Dan

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RWS
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Re: 13 Meter 6-71TI Sea Trial Results - Interpretation (major rebuild looming?)

Post by RWS »

how full were the tanks - fuel, fresh water, waste?

How loaded was the boat with gear?

RWS
1983 Trojan International 10 Meter
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Re: 13 Meter 6-71TI Sea Trial Results - Interpretation (major rebuild looming?)

Post by prowlersfish »

Start with checking the tachs as no load is down too . Bottom and runing gear clean ? Recc a real engine survey by a DD guy . Air box covers should be be pull and rings, pistons and cylinders checked not cheap .
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Re: 13 Meter 6-71TI Sea Trial Results - Interpretation (major rebuild looming?)

Post by DRM »

RWS and Powlersfish:

Thank you for your responses.

Fuel tank was approximately 1/4 full (100 gallons). Freshwater tank was essentially empty, hot water heater was drained and waste tank was empty. The boat was loaded with all normal gear. Four adult males (approximately 900 lbs). All cabin furnishings (full size side-by-side refrigerator/freezer, oven, etc) and deck chairs, ropes, chain/anchor. No additional gear was on board.

The hull, props and shafts had all just been pressure washed and scraped in the presence of myself and surveyor, to the surveyor's satisfaction.

Oil was low in trim tab reservoir and the bow cold not be brought down during planing.

Iron reading for PORT engine is labeled “serious" (93 ppm) in the oil analysis, all other wear metals and physical properties are with normal ranges.

Blowby was tested by surveyor and found to not be an issue. Engine temperatures were also tested and all were within range.

So, am I interpreting your recommendations correctly?
1. Retest engine WOT RPM using a laser pointer digital tach
2. Visual inspection of rings, pistons and cylinders through the air box

Is it acceptable for the RPM test to be done WOT with no load at the dock, or does a proper test require it to be under load at full throttle (given the previous under load and no load tests)?

If the digital tach shows that the actual maximum engine RPM is within an acceptable range, the issue of failure to gain expected top speed remains.

Does passage of these two tests (even without maximum achieved speed) suggest that the engines are sound and that I need to look to prop, or fuel system (or forced induction) issues to address the top speed? If that is the case, is this something that can be addressed after purchase with a reasonable expectation that the resolution will be relatively minor, or would you recommend that corrections to achieve expected maximum top speed be made as a condition of sale?

Apologies for the additional questions, however, I would like to avoid a $40,000 major rebuild mistake.

Once again, thank you for your input.

DRM

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prowlersfish
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Re: 13 Meter 6-71TI Sea Trial Results - Interpretation (major rebuild looming?)

Post by prowlersfish »

How much smoke for 3 minutes ? The 4 671tib's ( 485hp) on my dock smoke pretty good for a few seconds and clear up My Cummins smoke some till warmed up in gear . My future 671ti's ( 450hp) are almost smoke free . Yes you can test the tach at the dock engine warmed up . If the boat has been sitting the iron can be from some cylinder rust .
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Re: 13 Meter 6-71TI Sea Trial Results - Interpretation (major rebuild looming?)

Post by DRM »

The startup white smoke from both engines was equal. Upon cold start, it was initially rather billowy. It dissipated within about 30 seconds to a much less dense constitution with an appearance more resembling steam. By 3 minutes, essentially no trace of white, transitioning to a rather normal looking very light, to invisible, grey / black. Only sign of any smoke during operation was on hard acceleration and that was not pronounced. No sign of smoke (of any type) during cruise speed or WOT.

The boat has been generally unused for two years. It’s longest journey for at least 5 months was about 400 yards from the owners private dock to the adjacent marina to be shown for sale. It had not left the dock since very early spring. Hopefully that would explain the elevated iron.

For some certainty, the RPM and visual cylinder inspection seem to be essential. Do you or anyone else know of an appropriately qualified DD engine surveyor/mechanic in the Baltimore/Annapolis area or how I might go about finding one?

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Re: 13 Meter 6-71TI Sea Trial Results - Interpretation (major rebuild looming?)

Post by DRM »

From the experience of members of this forum, I would like to Impose on you all for answers to the following:

1. What is the ideal propeller for a 13 Meter International Express with 6-71TI 450’s (The boat I’m considering is running Michigan prop, four blade, bronze / nibral 28 x 31).

2. What is your WOT top speed (and RPM) and cruising speed (and RPM) with 6-71TI’s performing to expected standards.

Answers to these questions will help in determine next steps. Thank you.

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Re: 13 Meter 6-71TI Sea Trial Results - Interpretation (major rebuild looming?)

Post by prowlersfish »

I don't recall other 13 meter expresses on here . Anyone ? Beacon marine may have some factory info . But factory numbers tend to be optimistic .
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Re: 13 Meter 6-71TI Sea Trial Results - Interpretation (major rebuild looming?)

Post by RWS »

THIS SHOULD SHED A BIT OF LIGHT ON THE ISSUE:

YOU WILL LIKELY HAVE TO CUT AND PASTE

RWS

https://books.google.com/books?id=5eirA ... at&f=false

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https://books.google.com/books?id=3ntfR ... at&f=false
1983 Trojan International 10 Meter
Twin Yanmar 315 Turbodiesels
Solid Glass Hull
Woodless Stringers
Full Hull Liner

Trojan International Website: http://trojanboat.com/

WEBSITE & SITELOCK TOTALLY SELF FUNDED

DRM
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Re: 13 Meter 6-71TI Sea Trial Results - Interpretation (major rebuild looming?)

Post by DRM »

Thank you prowlersfish and RWS ... these are very helpful and interesting. I’m having the engines evaluated using a digital tach and scope of the cylinders, rings and pistons later this week. Hope everything checks out, the more I read about her the more I like what I have seen of her. Thanks again. I will post the results of the evaluation.

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Re: 13 Meter 6-71TI Sea Trial Results - Interpretation (major rebuild looming?)

Post by willietrojan »

1600 hrs is not a lot of hours for those DD's engines. Since the RPM's seem to be pretty close between both engines I would think it's more running gear than anything else. My parents owned a 40 Egg harbor years ago with 6-71 JT's and WOT was 2400/2500 and 1900 to 2000 was her crusing RPM giving it about 18 knots

What is the cruising RPM and Knots?
WillieTrojan (Owned F32, Willpower in Kinsale, Va)
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Doc Holiday
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Re: 13 Meter 6-71TI Sea Trial Results - Interpretation (major rebuild looming?)

Post by Doc Holiday »

I'd give Bob a call with your hull number and see if they have the original seatrial. Do this today to give enough (John) Leed time. Expect to pay something but you don't need the whole owner's manual. That way you have a starting point of specs of when the boat was new.

Phototach is a good purchase for this boat or any other potential buys.

No-load speed being low points to the governors. (springs not as tight after 30+ years seems normal)

She's probably over-propped for the now older engines but not trimmed correctly can noticeably reduce rpms.

You didn't have much weight on for the sea trail. I run almost 2 mph slower topped with fuel and water than 1/3 fuel tanks.

Did the oil analysis say that it was 15/40? If so, that's a problem. Did the broker say it's a hundred hours since the last oil change? That makes the problem longer. Make sure you tell your DD guy about the oil.

Look at the coolant too. How long since that was changed?

There's a reason the article had a 13M with 8-92's. 6-71's are fine for the Bay and shorter trips but I think mid to upper 20's (mph) WOT are what you can reasonably expect with those engines.

Hour-wise: I know a guy that had over 3000 hours on his 11M 671TI before overhaul. Mine had 1200; primarily because was she wasn't used enough.

Good luck! It's tough to spend a fair amount of money for a boat you ultimately decide isn't right. But $40k to 50k over the next couple years is a lot more! Though, rebuilt DD's in a Trojan will give you peace-of-mind that's... almost worth it! haha

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Re: 13 Meter 6-71TI Sea Trial Results - Interpretation (major rebuild looming?)

Post by DRM »

Willie and Doc. Thank you for your reply and apologies for not replying to you sooner, I have been away.

It seems that the rpm discrepancy was due to poor calibration of the analogue tachs. Throttle seems to have been opening fully and it appears that trim (and possibly prop) are likely candidates.

Willie, cruising speed was about 17 knots (19.5 mph on the gps) at about 1600 rpm on the analogue tach. It’s good to know that you both have experience that suggests these engines can have a substantially longer interval between rebuilds. I suppose most of the experiences shared online tend to be those of premature failure. I’m hearing from others also that these are more durable.

Doc, that is good advice ... I will look into getting the original sea trial and owners manual. The broker asked the owner about time and hours on the oil and indicated 2 years but only around 20 hours. I realize that this is quite critical and that with that few hours the oil sample may not be reliable. I have also been told by a DD specialist (below) that the iron level (93 ppm) is not high for these engines and that the act of sitting (with an open valve on a cylinder or two) can cause cylinder wall rust and high readings.

The coolant resistors were low and I have no idea when it was last changed. Yes. I noticed the 8-92s in the boat the article described.

I was fortunate to have found a person in the area that specializes in DD and has been recommended may times on a few different forums. He was also the person recommended by my initial surveyor. I gave him the oil analysis results and told him the time and number of hours (even though the analysis defaults to 100 on the report when hours are not known). He didn’t seem to be concerned about the results. I had him do an evaluation of the engines last Friday.

Using the digital tach he confirmed that the analogue tach was off by 300+ rpm on the port engine and 200+ rpm on the starboard. The actual rpm achieved on both engines was in excess of the 2700 wot no-load rating (more than 2750). Fuel delivery pressure was tested and found to be within parameters, as was boost.

He also performed a test that I was unaware of previously. It involved sequentially loading each injector (one at a time) to full throttle while the five others were at idle. You both may be familiar with this technique. He then listened to the sound of the ping from the added fuel load detonation as that cylinder worked against the idle fuel load of the other five cylinders to increase engine rotation. As I understand it, the sharpness (tone) of the ping indicates the degree of individual cylinder blow by (assuming a full fuel load from the injector).

All cylinders in the starboard engine checked out, the port engine displayed indications of a weakness in three cylinders. However, when the engine reached full operating temperature it functioned normally, suggesting that either ring seals bedded or that the injectors provided increased fuel delivery when warm.

The results were a bit inconclusive for the port engine, but given its functioning when warm, the absence of smoke during these tests, inconsequential actual crankcase pressure, the ability to exceed the wot no-load test, and extrapolation of the erroneous analogue tach reading to the actual rpm during the previous under load test, it seems that both engines were actually achieving the loaded wot expected rpm during the sea trial.

The DD specialist suspects that the top speed issue was likely caused by improper trim (as you suggested) and potentially less than precisely tuned or appropriate props. He has indicated that the only way to tell is another sea trial with the trim tab hydraulic lines replaced and close observation of possible smoke under load, possible injector replacement (on the three cylinders that showed weak full throttle performance while cold), and observing each engine’s responsiveness individually under load.

I had inquired about a visual inspection via the air box and he indicated that he has found the air box cylinder inspection to be less reliable and subjective given his assessment of these engines present operating parameters (indicating it is useful for confirming more catastrophic issues, but much less so for diagnosing more subtle issues) and that he has found the ping test more reliable from his experience, combined with a well designed sea (load) test. I am having him take the boat out next week to perform more tests for tuning and final determination purposes. His expectations are that the issues with the port engine are serviceable.

I am also having the oil replaced with the correct single grade. I understand that it is possible that the port engine ping test issues could be related to the viscosity of the 15-40 oil when it is cold.

Your responses were very helpful and I was able to use the suggestions you provided to help clarify the situation with the DD specialist. He is optimistic given what he found in operation, combined with the statistics recorded for the first sea trial, that both engines and the boat will perform within specifications once tuning adjustments are completed and that they can be expected to continue to do so.

I will post the results of the second sea trial.

Again, the your responses were/are much appreciated and I apologize for not having provided a detailed response or to have thanked you for yours before now ....

Take care.

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Re: 13 Meter 6-71TI Sea Trial Results - Interpretation (major rebuild looming?)

Post by Doc Holiday »

That is good news! Good luck with the purchase and thanks for the follow-up.

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