'77 Luhrs 28 ft. diesel repower SPLASHED!

[allpoints360]

Re: '77 Luhrs 28 ft. diesel repower - just beginning

Re: '77 Luhrs 28 ft. diesel repower - just beginning

Luhrs28, Fine looking ship! I spent some time on one of these years ago and thought it was solid boat with a deserved reputation.

I would not want to discourage your progress in any way, but I'll tell you what I've heard for many years: it will cost you more to convert an automotive diesel to a marine application than it would cost to rebuilt a marine diesel. It's just one of those sayings you always hear. I have a Cummins Marine in my Delta.

If cost is not an object, then your end result will be a homemade type conversion. I'll just say that most knowledgeable boaters would walk away from a good deal on a boat if it were an automotive engine conversion.

Now is the time to make the best decisions.

Good luck!

 

[RogersJetboat454]

Re: '77 Luhrs 28 ft. diesel repower - just beginning

Re: '77 Luhrs 28 ft. diesel repower - just beginning

Luhrs,
Thats a sweet looking vintage rig!
All the power to you on the diesel conversion. While you can't write a novel about the 6.2's power, you can at least say they are very reliable, and should serve you well. While working at the last shop I was at, we had a gentleman that would come in with a Suburban equipped with the 6.2's big brother, the 6.5. If memory serves me right, she had well into 200K and was still going strong. The auto diesels are just as capable as any other diesel out there. It's usually just lack of maintenance, and the cheaper injection pumps that can be their Achilles heal.

 

[NSBCraig]

Re: '77 Luhrs 28 ft. diesel repower - just beginning

Re: '77 Luhrs 28 ft. diesel repower - just beginning

I'm watching.

More pics!

 

[Luhrs28]

Re: '77 Luhrs 28 ft. diesel repower - just beginning

Re: '77 Luhrs 28 ft. diesel repower - just beginning

Thanks for all the kind replies.

I'm aware that compared to something like a Yanmar the GM 6.2 is regarded as a "throwaway" engine, but in a way that's a benefit. If I blow it up I can get a replacement cheap and easy.

Another thing that makes the 6.2 an easy conversion is the fact that the bellhousing bolt pattern is identical to a Chevy 305/350. GM did that so they could use all their existing transmissions.

I digress, but as an example of how robust diesel engines are, I own a 1981 Olds Delta 88 with the 5.7 diesel. The 5.7 was GM's first diesel and generally regarded as the worst engine ever made. But mine runs great and I commute in it almost 100 miles a day. I just do normal maintenance on it and it keeps on going.

GM took all the things they learned on the 5.7 Olds and incorporated those improvements in the 6.2. Detroit Diesel also helped with the design of the 6.2. So yes it's sort of a throwaway engine but it's a fairly good design in my opinion.

 

[Friscoboater]

Re: '77 Luhrs 28 ft. diesel repower - just beginning

Re: '77 Luhrs 28 ft. diesel repower - just beginning

I think the manifolds are going to be the issue.

 

[Luhrs28]

Re: '77 Luhrs 28 ft. diesel repower - just beginning

Re: '77 Luhrs 28 ft. diesel repower - just beginning

I already have the manifolds. They're off-the-shelf from OSCO. (not cheap, but readily available. I had them 2 days after ordering.)

I'll see if I can post some engine shots later tonight.

 

[Luhrs28]

'77 Luhrs 28 ft. diesel repower - Engine pics

'77 Luhrs 28 ft. diesel repower - Engine pics

Here are some pics of the mighty 6.2 V8:

Note the Ebay alternator and starter, made in China. I hope they work. Also new fuel pump but that's a Carter which is a good one. Still might be made in China though.

I know what you're thinking: You idiot you're not supposed to paint all the hoses and wires! Yeah I know..........I was just being lazy the day I painted it, plus most of that stuff will be replaced with new hoses and wires before it hits the water.

Risers:

 

[Blue Crabber]

Re: '77 Luhrs 28 ft. diesel repower - Engine pics

Re: '77 Luhrs 28 ft. diesel repower - Engine pics

Sweet project!!! I am adding this to my subscribed list to keep an eye on the project!!

Hope everything works out as well as you are planning!

 

[sasto]

Re: '77 Luhrs 28 ft. diesel repower - Engine pics

Re: '77 Luhrs 28 ft. diesel repower - Engine pics

I know what you're thinking: You idiot you're not supposed to paint all the hoses and wires! Yeah I know..........I was just being lazy the day I painted it, plus most of that stuff will be replaced with new hoses and wires before it hits the water.

Not at all......I personally like everything painted white....makes a quick check of the engine compartment easier.

 

[allpoints360]

Re: '77 Luhrs 28 ft. diesel repower - just beginning

Re: '77 Luhrs 28 ft. diesel repower - just beginning

Not at all......I personally like everything painted white....makes a quick check of the engine compartment easier.

That's good advice... paint the engine compartment white while you have the motor out. It makes issues apparent, plus it's just nicer working in a bright engine compartment.

 

[Luhrs28]

Re: '77 Luhrs 28 ft. diesel repower - just beginning

Re: '77 Luhrs 28 ft. diesel repower - just beginning

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.

 

[Huron Angler]

Re: '77 Luhrs 28 ft. diesel repower - just beginning

Re: '77 Luhrs 28 ft. diesel repower - just beginning

Nice rig ya got there

I agree that needless thru-hull fittings need to go ASAP. Hard to imagine folks thinking it's a good idea to drill so many holes in a hull.

Good luck with the project, hope you get on the water by springtime

 

[erikgreen]

Re: '77 Luhrs 28 ft. diesel repower - just beginning

Re: '77 Luhrs 28 ft. diesel repower - just beginning

Excellent project.

How much do you think the conversion of the engine will cost you overall? What kind of running RPM range and fuel economy do you expect from the engine?

Please post your sources for parts, if you would.

For those not familiar with diesel engines in boats, the GM 6.2 isn't the first choice for a new marine diesel engine for a number of reasons (mostly related to being designed for a different use) but converting a used one cheap isn't a bad idea.

The usual gas engine conversion issues aren't a problem if it's an inboard, and fresh water cooled... the heat exchanger contains antifreeze just like a truck cooling system. People use these engines in boats enough that Osco mass produces a manifold/riser set for 'em.

The diesel has far more torque at low RPM than a similar gas engine, and in fact could be a lot smaller than the original gas engine and still drive the boat ok. If he runs it at 60% power most of the time, it'll last many years.

Probably some work will need to be done matching the transmission ratio/engines/props up for good performance, but this is looking to be a really neat power conversion idea short term.

It's giving me some ideas on what to do with the old Bayliner I just got

Erik

 

[Shife]

Re: '77 Luhrs 28 ft. diesel repower - just beginning

Re: '77 Luhrs 28 ft. diesel repower - just beginning

Great project.

 

[Luhrs28]

Re: '77 Luhrs 28 ft. diesel repower - just beginning

Re: '77 Luhrs 28 ft. diesel repower - just beginning

Thanks for all the positive reinforcement guys. I appreciate it.

Erik, I don't really have any budget aside from trying not to blow any more money on it than necessary. The most expensive thing I've had to buy so far was the set of Osco manifolds/elbows/risers ($1300).

I stole the Sherwood G7 raw water pump off the original Chrysler 360 V8 that was still sitting next to the boat when I bought it. I'm going to slap a new impeller in it before testing out on my engine.

I still need to get a heat exchanger from somewhere. One great thing about diesels is their higher thermal efficiency means less load on the cooling system. So I'm figuring any cooling components that work on a Chevy 350 gasser should cool enough for my 6.2 (379 cu. in.) diesel.

Oh and I also need a GM bellhousing adapter for my tranny, since it came with the Chrysler one. I've seen a bunch of them on Ebay.........just have to snag one hopefully cheap.

One thing I'm having to come to grips with is that the starter motor access is going to be HORRIBLE! On the 6.2 engine there's no way to locate it up top like on a lot of the marine gassers. The engine is probably going to have to be lifted 8" to get the starter out. Oh well.........you can't have everything.

By the way I want to say Thanks, as I've learned a TON from reading everyone else's posts. I will try to keep you entertained with pics as things progress. I'll warn you though, it's going to be slow. Rome wan't built in a day.

 

[Luhrs28]

Re: '77 Luhrs 28 ft. diesel repower - just beginning

Re: '77 Luhrs 28 ft. diesel repower - just beginning

I haven't posted in awhile but believe me I've been working on all sorts of boat stuff.

Let's talk trannys. I have the complicated part of my Paragon transmission out being rebuilt by a professional shop, but I decided to overhaul the V-drive section myself, since it's fairly simple.

The original V-drive from my boat had a big crack in the housing so it was toast. I found this one on Craigslist for $150:

It turned nice and free but had way too much slop somewhere inside. I could turn the input shaft 3-4 degrees before it would rotate the output shaft. So I took it apart:

It's a good thing I did as I found this gear's internal splines and the shaft's splines where it sits are 80% gone. The gear can wiggle all around on the shaft.

OK so no problem I'll just call up the guys at Great Lakes Power that sell Paragon and order the gear and shaft. Nope. No longer available.

So in the spirit of "failure is not an option" I'm having a welder heli-arc the gear to the shaft. The rest of the V-drive doesn't have a single problem, so I figure with some good synthetic gear oil I'll probably get through one season with it OK. That'll buy me a year to look for another V-drive. New they go for about $2,500.

I just thought I'd share my V-drive misery with you all. Actually it hasn't been too bad. It's pretty simple to work on.

 

[Isaacm1986]

Re: '77 Luhrs 28 ft. diesel repower - just beginning

Re: '77 Luhrs 28 ft. diesel repower - just beginning

Great Looking Project! I have no idea how i missed this thread.

I think the diesel conversion is a great idea. Someday, I would like a diesel boat as well.

Keep up the fantastic work!

 

[pmillar]

Re: '77 Luhrs 28 ft. diesel repower - just beginning

Re: '77 Luhrs 28 ft. diesel repower - just beginning

I haven't posted in awhile but believe me I've been working on all sorts of boat stuff.

...So in the spirit of "failure is not an option" I'm having a welder heli-arc the gear to the shaft. The rest of the V-drive doesn't have a single problem, so I figure with some good synthetic gear oil I'll probably get through one season with it OK. That'll buy me a year to look for another V-drive. New they go for about $2,500...

Does welding the gear run a risk of ruining the gear's heat treat/hardness? Just a thought...

 

[Luhrs28]

Re: '77 Luhrs 28 ft. diesel repower - just beginning

Re: '77 Luhrs 28 ft. diesel repower - just beginning

pmillar: Maybe it will hurt the heat treating a bit. I'm not sure. Clearly this is a redneck way of fixing it. But I believe heli-arc doesn't really heat up the whole piece. It's more of a localized heat right where the weld is. At least that's my hope.

I would just hunt around for another used Paragon V-drive but they're not easy to find, they're all 30 years old, and idiots on Ebay want $2000 for ones that probably aren't any better than mine. So heck at least if I assemble this one myself I'll know it's good.

 

[NSBCraig]

Re: '77 Luhrs 28 ft. diesel repower - just beginning

Re: '77 Luhrs 28 ft. diesel repower - just beginning

You know kohler builds their motors and then paints them the same way.

Looks good.