Holman Moody Question

[Tom Smith]

Just what does it mean to have HM motor in a Donzi. I know they built race engines for NASCAR and such, but what did HM do to these boat engines. Are they bored, stroked, blueprinted, ported, polished, releived? Just what is it they did to make them so sweet. My 298 runs like a swiss watch, a damm good swiss watch. Tom

[Craig S]

According to the H/M book I have, they were just a marinizer...unless you have something special in the boat.

[Conquistador_del_mar]

Tom,
What are the aquamarine colored reel appearing devices mounted on the transom? Bill

[Tom Smith]

They are electric spools to retract the ski ropes. There are holse in the transome where the ropes go through. I inderstand they were an option back then. They both still work by pushing buttons on the dash panel.

My HM is just a simple 289 but it sure purrs like a kitten.
What does a marinizer mean? Tom

[Ghost]

They are electric spools to retract the ski ropes. There are holse in the transome where the ropes go through. I inderstand they were an option back then. They both still work by pushing buttons on the dash panel.

My HM is just a simple 289 but it sure purrs like a kitten.
What does a marinizer mean? Tom

How cool is THAT?! Never even heard of these before.

[HOWARD O]

How cool is THAT?! Never even heard of these before.

They ARE cool, I had never seen them before either! As Tom says, they still work!

When my brother had his 302 apart, it was in great shape. We were surprised to find double valve springs too. Probably wouldn't see that in anything but a hi-performance engine to begin with. They do have their own H-M intake and exhaust manifolds as well. I would imagine they were built to pretty close tolerances and I suppose they chose their camshaft carefully. Other than that, can't say how much custom work was put into them but my guess is not much. My old one, now my brother's, had the optional 302 with 235 hp. That's not a lot of horsepower for a 302, but the thing sure does run! I think they were built more for longevity than anything else. They churned out quite a few, obviously!

I also think a lot of us "think" they run better than they do for no other reason than the sound of the open exhaust! Just my guess.....

Hey Tom, try writing Lee Holman and ask him directly....see if you get an answer? http://www.holmanmoody.com/

[HOWARD O]

A "marinized" engine is generally an automotive engine that has had marine parts added to it. Brass freeze plugs that don't rust, special marine camshafts designed to provide torque and run in a different rpm range, valve springs are generally stronger and/or heavier, starter and alternator are built for "marine" use and are shielded so as not to have an external spark, special carb designed to internally drain so no fuel gets into the bilge. Many have special fuel pumps too that overflow into the carb. Spark arrestors....but that doesn't really have anything to do with the engine itself. I also believe that true marine engines are built to tighter tolerances as they have to run under a constant load and at the same rpm for long periods of time.

Probably more stuff, but that's about all I know about it......

[Donzi Vol]

How cool is THAT?! Never even heard of these before.

Yeah, we were blown away by those. Really cool stuff. Let me tell you, Tom's boat is one of the rare ones. All original, but kept in good working order by previous owners.

[CHACHI]

I also believe that true marine engines are built to tighter tolerances as they have to run under a constant load and at the same rpm for long periods of time.

Probably more stuff, but that's about all I know about it......
Howard, they are actually a bit looser for reasons stated.

Ken

[HOWARD O]

Howard, they are actually a bit looser for reasons stated.

Ken

Oh, well I suppose that makes sense! Thanks Ken! :wink:

[MOP]

Who forgot pistons the most important change between auto and marine.

[Ghost]

Who forgot pistons the most important change between auto and marine.

In what way and why I am now very curious, if you have a sec. (I imagine is stems from running continuously at heavier loads, so I imagine something beefier, but that's about as specific as it went so far in my head. Maybe forging instead of casting, or something like that?)

Thanks,

Mike

[Rootsy]

Who forgot pistons the most important change between auto and marine.

Actually I would say the "most" important difference between an automotive and marine spec built engine are clearances... Second to that would be some gasket material application. In most cases crate engines don't even differ between the two.

[MOP]

Standard automotive pistons do not last very long, the standard for marine use is Hypernetic a better design that do not grow/malform under heavy loads. One step better is the forged piston, most of us that have done their engines over have switched to forged.

[MOP]

Actually I would say the "most" important difference between an automotive and marine spec built engine are clearances... Second to that would be some gasket material application. In most cases crate engines don't even differ between the two.

I did not elaborate on that as Chachi already mentioned it! Though along with the extra clearance goes a higher volume pump to maintain the support of the oil film, if you open them up you have to feed them! The gaskets only apply to raw cooled engines, F/W cooled can use good quality automotive gaskets.

[Rootsy]

Standard automotive pistons do not last very long, the standard for marine use is Hypernetic a better design that do not grow/malform under heavy loads. One step better is the forged piston, most of us that have done their engines over have switched to forged.

Hypereutectic.

Which as nothing to do with deflection / deformation due to load.

[penbroke]

Hypereutectic.

Which as nothing to do with deflection / deformation due to load.

Sooo... What does it have to do with/mean? I have always wondered but been afraid to ask.


Frank

[Rootsy]

Sooo... What does it have to do with/mean? I have always wondered but been afraid to ask.
Frank

Google is your friend...

HERE (http://en.wikipedia.org/wiki/Hypereutectic_piston)

[penbroke]

Google is your friend...
HERE (http://en.wikipedia.org/wiki/Hypereutectic_piston)

Yeah, I know, thanks. I actually use that expression quite a bit myself...

I was kinda hoping to get your take on it as your explainations tend to be quite through yet concise.



Frank

[MOP]

Hypereutectic.

Which as nothing to do with deflection / deformation due to load.

As usual you are 100% right!

My wording is not always the best when throwing something out there! What I was referring to it is heat expansion difference between between the two types. Talking just good pistons not stock, hypernetics can be fitted tighter forged need to be looser to allow for expansion. Forged need time to heat up and fit the cylinder or will have some slap. The deflection thoughts came from tech school where it was said a stock automotive piston will some deflection/deformation under the loads in marine use which can cause skirts to break. Was the instructor right? I believed him!!!

[vrod02]

laymens terms marine raw cooled pistons get hotter than cylinder walls.So the pistons are smaller more tolerance for the growth. Back to H/M ford engines much different than a car or truck engine unless its a mexican cast or industrial engine.

[Tom Smith]

That shed some light on the issue. I can't speak for anyone elses HM engine, but mine is a dandy. Tom

[dwiggl]

Before I discovered this sight, I email-ed Mr. Holman about the engines. The response was that they were Ford Industrial engines. But that does not explain the HP options & what they did to add HP.
So if they were industrial motaz, does that mean they were just Eaton crate motors w/ some marketing glitz?!?!?! The man was quite the promoter....

As a side note, I had a 1960 Uniflight 28' w/ twin Eaton 312 Ford direct drives. Crappy dual, one lung, side draft carbs from a Packard or something. But she would pull a slalom skier!

[BlownCrewCab]

That shed some light on the issue. I can't speak for anyone elses HM engine, but mine is a dandy. Tom


After I went through your carb it did run very well, Do you still get Junk in your filters? I think the worst part of yours was just old gas, not neccesarily junk/gunk but Low or No octane. Once it ran,it ran perfect.

[Tom Smith]

She is running great, and no crud in the filters. I have picked up a gas smell when it sits idle in the driveway. Not sure where it is coming from but it bothers the heck out of me. It takes 1/2 hour to air it out ( hatch open and blower on) before I will even attempt to start it. Did you guys pressure test the tank. David said you guys replaced all the fuel lines and installed the seaprator. How about the floats sticking? Could that cause that strong gas smell when it is covered up. Tom

[Donzi Vol]

After I went through your carb it did run very well, Do you still get Junk in your filters? I think the worst part of yours was just old gas, not neccesarily junk/gunk but Low or No octane. Once it ran,it ran perfect.


She is running great, and no crud in the filters. I have picked up a gas smell when it sits idle in the driveway. Not sure where it is coming from but it bothers the heck out of me. It takes 1/2 hour to air it out ( hatch open and blower on) before I will even attempt to start it. Did you guys pressure test the tank. David said you guys replaced all the fuel lines and installed the seaprator. How about the floats sticking? Could that cause that strong gas smell when it is covered up. Tom

Well as Mike said, once it was running it ran great...so we pretty much stopped there. By the time we were through with it, it had a rebuilt carb (new gasket and pump kit), new fuel lines, new water seperator, new in-line fuel filters (2) as there was still some gunk coming out, and the tank was completely drained of the old, crappy gas. As for the gas smell, I don't know. Could be a number of things. I never worried about it too much, although it was never really over-powering as I didn't leave a full cover on it.

[Tom Smith]

Thanks David. We'll find that stinking leak. I had one on my hot rod last year and it smelled up my entire garage. Found it to be a loose clamp on the incoming fuel line. Only a drop every now and then, but that is all it took to overpower the garage with fumes. One quarter turn on the clamp screw and the smell was gone.
Got most of the hardware back on the boat. Almost had Howard O as a permanent fixture under the deck. He wiggled under there to pass up the bow light wires and got stuck. I had the olive oil spray bottle at the ready but he didn't want to smell like a salad aso he managed to wriggle his way back out. Howard in a tall guy and rather muscular. We would have had to cut the boat in half to get him out if the old olive oil threat didn't work. Whew! Tom

[BlownCrewCab]

I Personally replaced the hose from the fitting on the tank to the fuel-water seperator, and the hose from there up to the carb. I didn't pressure check the tank. I guess theres a chance of a small tank leak, pressure checking it would be a good idea.

[HOWARD O]

Thanks David. We'll find that stinking leak. I had one on my hot rod last year and it smelled up my entire garage. Found it to be a loose clamp on the incoming fuel line. Only a drop every now and then, but that is all it took to overpower the garage with fumes. One quarter turn on the clamp screw and the smell was gone.
Got most of the hardware back on the boat. Almost had Howard O as a permanent fixture under the deck. He wiggled under there to pass up the bow light wires and got stuck. I had the olive oil spray bottle at the ready but he didn't want to smell like a salad aso he managed to wriggle his way back out. Howard in a tall guy and rather muscular. We would have had to cut the boat in half to get him out if the old olive oil threat didn't work. Whew! Tom

That may have been muscle, but that was quite some time ago! :cool:

[Tom Smith]

If it weren't for you I would never get this boat fixed. I surely appreciate all your help. See ya in a few days and we'll wrap her up. Tom

[HOWARD O]

If it weren't for you I would never get this boat fixed. I surely appreciate all your help. See ya in a few days and we'll wrap her up. Tom

All my pleasure, Tom......I'm enjoying the heck out of it! :hi5:

[Craig S]

[quote=dwiggl;546751]Before I discovered this sight, I email-ed Mr. Holman about the engines. The response was that they were Ford Industrial engines. But that does not explain the HP options & what they did to add HP.
So if they were industrial motaz, does that mean they were just Eaton crate motors w/ some marketing glitz?!?!?! The man was quite the promoter....quote]

That's my take.