'77 Luhrs 28 ft. diesel repower SPLASHED!

[g1sammons]

Re: '77 Luhrs 28 ft. diesel repower SPLASHED!

the 7.3 is not a ford motor its a international ford just used it
so might be a international and gm war
was a great motor but much more weight and is often used in marine aps so would have some advantages but just to make more power would be much easer to boost presure at this pointe rather than a complete enginge replacement
just food for thought

 

[Luhrs28]

Re: '77 Luhrs 28 ft. diesel repower SPLASHED!

Another aspect I have to keep in mind is how much torque my Paragon transmission and 1.25" propeller shaft can take. I think the tranny is rated for good bit but I'm not so sure about the prop shaft. If I have to change to a 1.5" shaft that's a lot of work. (shaft log, cutlass, prop, coupling, etc.)

Thanks for the continued interest in my boat!

 

[parrisw]

Re: '77 Luhrs 28 ft. diesel repower SPLASHED!

A 7.3 powerstroke would be way cool in a boat, they were the reliable powerstrokes, you just have to take great care of them, I have one in a truck, tons of power with a good exhaust and intake setup, and a good aftermarket computer chip. Stock I believe they are 450ft lb's of torque, it is very easy to get them over 700ft lb's of torque.

 

[Luhrs28]

Re: '77 Luhrs 28 ft. diesel repower SPLASHED!

700 ft.-lbs? I'm picturing the motor mount bolts ripping right out of the stringers!

 

[parrisw]

Re: '77 Luhrs 28 ft. diesel repower SPLASHED!

LOL. Yup, would be fun for a few seconds anyway. I'm guess my truck with the chip on full, its a 6 position switch to select the amount of extra HP, plus an high idle setting, is making close to 700ft lb's. The injectors in my truck are the smaller first ones, 90cc, step up to stage1 160cc, and look out, 1000ft lb's is not out of the question, but then you need to start doing mechanical upgrades like head studs, bigger turbo, now you start getting into some serious coin though$$$$$$$$

 

[QC]

Re: '77 Luhrs 28 ft. diesel repower SPLASHED!

Luhrs,

Been thinking about your desire for a couple of knots here and commenting on engine choices, but I don't think we have what your current speed and RPM are . . . have you run her wide open yet? GPS yet?

Also, can you tell me what your RPM is with the throttle hammered in neutral? (gasoline guys please don't overreact to this, perfectly normal thing to do with a diesel, and a valid test).

I am trying to figure out if you are hitting the governor or running out of power ( I am guessing power, but want to confirm). The difference between high idle RPM (hammered in neutral) and WOT RPM in gear may help. Not sure because I don't have specs yet, but can maybe start to help zero in on this with some data.

A point to understand. Peak torque does not really come into play with a marine engine. Especially with semi-displacement hulls. The propeller load curve is basically linear, so you really can't get to peak torque unless you hammer the throttle with her tied to the dock. Climbing a steep swell may get you close too, but still not like most are thinking here in regards to a true planing hull or especially a wheeled vehicle.

On the other hand . . . what does come into play is the desire for higher speed, which requires more horsepower which requires one of two things: an increase in RPM or an increase in torque at the existing RPM or both . . . If you increase torque at the existing RPM you need either to increase pitch or change gear ratio. If you simply increase RPM, torque stays the same and so does pitch and gear ratio, THEORETICALLY.

What I think I am trying to point out is you don't really need to get freaked out about peak torque capabilities of alternative engines, you can get what you want (faster speed) with an engine that will spin faster. Unknown if that can happen with what you have though.

 

[Willyclay]

Re: '77 Luhrs 28 ft. diesel repower SPLASHED!

I am trying to figure out if you are hitting the governor or running out of power

Very interesting stuff, QC!

 

[Luhrs28]

Re: '77 Luhrs 28 ft. diesel repower SPLASHED!

QC: I'm sorry to disappoint you but I still don't have any hard numbers for most of that stuff. I still don't have a GPS. Also I've never hammered it in neutral for fear of sending a rod through the side of the block (or even worse through the hull).

What I can tell you is, depending on how many people are aboard I reach a limit of about 2600 RPM, where giving her more throttle beyond that doesn't gain any more speed. (GM's redline for the 6.2 diesel is 3600 RPM) So I'm thinking I'm power-limited.

My current prop is a 16" X 16". Do you think I should de-prop a little to gain engine RPM? I'm kind of hesitant to do that just because she cruises nice and relatively quiet at 1800 RPM, which I'm thinking must be about hull speed. Although I plan to address the noise issue over the winter by adding mufflers and covering every square inch of the engine compartment with acoustic foam.

Again,....I appreciate everyone's advice.

 

[NSBCraig]

Re: '77 Luhrs 28 ft. diesel repower SPLASHED!

A centrifugal supercharger is just a turbo that runs off a belt instead of the exhaust giving you more options on mounting.

 

[QC]

Re: '77 Luhrs 28 ft. diesel repower SPLASHED!

I've never hammered it in neutral for fear of sending a rod through the side of the block (or even worse through the hull).

This is a very valid test, the only way to confirm that your Governor is doing what it should . . . My guess is that with a 3600 RPM rating that high idle would be about 3900ish. If you had a technician look at her for anything related to power, he'd do that. With a mechanical governor there has to be some slop (Droop) or she would hunt like crazy trying to maintain a specific RPM. It's usually noted as a percentage and my guess a truck engine like that would have around 10% droop. That means she has to exceed full power by 10% in RPM to get full power at rated . . . Oversimplification, but all mechanical diesels have some sort of droop (alternative is called isochronous or zero droop). Basically if you put your boat on a hoist and set the throttle in gear for 3000 RPM and then dropped her in the water she'd "droop" back to around 300 RPM less if the load on the propeller was substantial. With your numbers it would probably hit right there . . . With an isochronous governor (electronic) she'd try and maintain the 3000 if it was set for zero droop and there was enough power available.

Oh and you should do it at the engine by hand and at the helm to confirm that you are getting full "governor control lever" (actually not a throttle) travel.

Gasoline guys, the only thing remotely like this is a rev limiter or cruise control, don't confuse them please. A diesel can be hammered at WOT in neutral all day long. She'll start slobbering fuel out the exhaust maybe, and it is not something you want to do forever, but a blip up there held for 10 seconds to get a reading is done in every shop that still knows how to work on a mechanically governed diesel.

If you only see 2600 then pitching down is in order although I do understand your cruise comment. It will definitely hurt that, but she may have a few more knots in her wheeled right. I am very skeptical of getting much though considering the 150 hp max we are really dealing with here. I am still amazed she planed . . .

 

[coastalcruiser]

Re: '77 Luhrs 28 ft. diesel repower SPLASHED!

hi Lurs just googled this video

this new boat has
twin diesels 240hp 32.7 speed 28.8 @16gph
starting at 99 k

http://www.youtube.com/watch?v=mMjNOobvQ9A

just thinking that you have a reliable boat for so much less money, lot's of talk about turbo etc but
You have half the power of the boat in the video so imo hull speed is your best choice. it's going to give you long range and comfort.

 

[Luhrs28]

Re: '77 Luhrs 28 ft. diesel repower SPLASHED!

QC: HaHaHa planing! Yes if you consider pushing 24 feet of the hull X 2.5 feet deep through the water planing, then yes it planes quite nicely.

That's all good info about the governor and RPM droop. The next time I have her out I'm going to try the WOT test in Neutral. I know the throttle cable is pulling the IP arm all the way, as I've checked that a couple of times.

Another factor is, this late in the season my bottom is probably encrusted with barnacles. But even when I first launched her she topped out at 2600 RPM.

Many thanks again,

Bert

 

[QC]

Re: '77 Luhrs 28 ft. diesel repower SPLASHED!

QC: HaHaHa planing! Yes if you consider pushing 24 feet of the hull X 2.5 feet deep through the water planing, then yes it planes quite nicely.

.02 - .08 of this vid is a very efficient plane if you ask me

http://www.youtube.com/user/Flounder3906#p/u/24/bcDPqqiisyI

 

[Jhudds]

Re: '77 Luhrs 28 ft. diesel repower SPLASHED!

Hey Bert,

Your project lit a fire in my belly and now I want to tackle a resto myself. I spent the better part of 3 hours a couple nights ago reading thru the entire post here and watching your videos. I am thoroughly impressed with your work. Like I said in the other post, I am concidering taking on a 25' open luhrs on as a project for me and my sons. I'm torn as I want to find a flybridge model but all I can find are opens and CC that are worthy candidates. Both are a mere $500.00 so initially these will be more likely full resto from the keel up. But I also found a 26' egg harbor thats mostly complete and actually in the water for real cheap, Needs a little cosmetic work inside and some sprucing up of the electrical system....

Oh the choices! Any way, I'll keep in touch with you and let you know what I decide, I'll do a resto post like you did for all to enjoy if I take the plunge. Keep your eye out for me for a late model Luhrs flybridge in the 25' range for me thats real cheap.I'm in S jersy so i'm close by if you happen to see or hear of something.

I do have a question for you, can you PM me your approx cost for insurance on your boat, I know thats thinking WAYYY ahead of myself, but I wanna get an idea of what my yearly costs are going to be to operate. This will be a fist time inboard large scale boat for me. I've had 14 and 16 footers before that we put in and took out when we used them.

Thanks, and post some more videos!!!! I would really like one showing your cabin layout.

 

[F14CRAZY]

Re: '77 Luhrs 28 ft. diesel repower SPLASHED!

Hey Luhr's...your vessel isn't too different from my Chris Craft Coho so I've read through everything here so far

um just taking a guess here...but i'm pretty sure its ALWAYS a bad idea to put an automotive engine in a boat... its a may be a strong engine but i guarantee its not rated for continuous marine use at peak torque......

Small block chevy's were used in like Camaro's, Monte Carlo's, etc...these 6.2L diesels were used in work trucks...at least that's how I see it lol

Here's some pics of inside the cabin. The wood is in really good shape. No splits or gouges anywhere. It really just needs some cleaning up and new cushion slipcovers.


There's a V-berth up in the bow also but I don't have any decent pics of it.

I'll post a few more in a couple of mins.

Interior looks pretty sharp compared with the mess mine's in

Here's Lynda helping me prime and paint the rear wall of the cabin last weekend. It's plywood........one of the few non-fiberglass areas of the boat.

Lucky...my cabin superstructure is all wood

Yes I plan to do a full white bilgekote job, but I have to first finish glassing over all the defunct thru-hulls.

One thing I'll tell you: after a full day of working down in the engine compartment you're sore all over. You have to kneel and contort yourself into all kinds of weird positions to reach places.

heh I know the feeling of that from doing the stringers in my Bayliner AND being a plumber. My Coho has a crapload of transducers that I'll need to eliminate eventually too

I had to finally come to grips with the fuel tanks this weekend. Believe it or not my boat had no fuel gauge at the control station. All it had was a mechanical float gauge on top of each tank. So to see how much fuel was on board you had to come down from the flybridge, open the engine hatch and stick your head under there and look with a flashlight:

Well I decided that sux. I want to put sending units in so I can have real gauges up on the flybridge. But as you can see in the photo there's no way to get the sending unit in without removing the fuel tanks. And to remove each tank would require cutting out a partial fiberglass bulkhead.

So I took a shortcut:

I know you purists are going to say I should've removed the tanks instead of cutting into my deck, but I just couldn't see spending an extra 20 hours on that. Plus this way if I have a problem with a sending unit at any time in the future I can have it out in 5 minutes.

I did some other shiznitz which I'll show you in the following post.

I'll have to check out my setup and I'll probably end up doing something like you did since I don't think my vessel has fuel gauges either

LOVE your project and reading through your thread. You're doing like I like doing...you can do things properly without having to spend a crapload on "marine" or brand new stuff

 

[Luhrs28]

Re: '77 Luhrs 28 ft. diesel repower SPLASHED!

Hi guys:

Thanks for all the interest in my barge.

I had her hauled for the winter just 2 days ago:

I had a great summer with her. No problems.

You're all going to think I'm nuts but I'm going to repower it with a gasser Chevy 350 over the winter. I like diesel but to be perfectly honest the 6.2 at 154HP just isn't enough for a 5-ton boat. I thought I'd be content with hull speed but I want more knots. I also think the gasser is going to be quieter with mufflers.

So I'm embarking on a whole round of "Phase II" work, including a lot of details I didn't have time for back in June. (new curtains in the cabin, better snacks in the galley, etc.)

I will keep you all posted.

To sum up, I don't see the diesel as a failure. It worked, was 100% reliable and I had a lot of fun with the boat this summer. But I think there was a reason the boat had a 250HP engine when it left the factory in 1977.

Bert

 

[springer59]

Re: '77 Luhrs 28 ft. diesel repower SPLASHED!

Hey burt, cant wait to see what the further adventures of "The Diesel Avenger" brings,this has been a very informative and intersting thread.I had been thinking about the diesel swap for my 25' luhrs, but after owning two trucks with 318's I'm probobly sticking with it in my resto project.Thanks for all the ideas and info again,I've really enjoyed this thread.

 

[archbuilder]

Re: '77 Luhrs 28 ft. diesel repower SPLASHED!

we'll be looking forward to the updates!

 

[Friscoboater]

Re: '77 Luhrs 28 ft. diesel repower SPLASHED!

But you will have to rename her. I love that name,

 

[sqbtr]

Re: '77 Luhrs 28 ft. diesel repower SPLASHED!

Bert

Glad you got to spend some time on the water this year

Don't think I ever asked you where you boat. I've been thinking about the Middle river area on the bay.