SC V6 or MPI V8?

About inboard or outboard motors.

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kens
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Post by kens » Sat Jan 17, 2009 7:45 pm

"There was also a 53CID series"

There were several series of the old 2-stroke Detroits. 53-series. 71-series, and 92-series. all of the 2-stroke detroits had a engine driven blower on them, and that was what they called a NA engine, naturally aspirated. Since they all had blowers, it was natural to have them. The later 'turboed' engines had a turbo on as well, these were TI engines. So, they had the natural blower plus a turbo(s).
The 6V-92 powered a lot of sportfishing boats, and the biggest blower available to a hot-rodder would likely be a 12v92 series.

Denon Osterman
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Post by Denon Osterman » Mon Jan 19, 2009 8:18 am

what would you have to do/how much would it cost to convert something like this? good idea or bad idea?

http://www.enginefactory.com/454430hp.htm

Thanks,
Denon

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Dave Grason
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Post by Dave Grason » Mon Jan 19, 2009 8:33 am

SWEEEEEEEEEEEEET! I want one of those for my old pick up. Then my license plate could read: "SLEEPR."

Converting that engine would be no more difficult that any other auto conversion. Check the Glen-L site for the pieces:

https://www.boatdesigns.com/departments.asp?dept=35

Glen-L may not show all the necessary parts but they DO have them available, I'm sure. They show them in their print catalog.
Denon Osterman wrote: good idea or bad idea?
That would be up to the individual. Not a bad idea, just an expensive one.
Isn't it amazing!! The person that never has the fortitude to pursue his own dreams, will be the first to try and discourage you from pursuing yours.

Denon Osterman
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Post by Denon Osterman » Mon Jan 19, 2009 9:37 am

Caber, thoughts?

Nova SS
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Post by Nova SS » Mon Jan 19, 2009 9:40 am

again just remember that the internal tolerances for a car motor are tighter then a marine motor. If you want long life out of your motor you will have to take that into consideration. That motor looks good but it would have to come completely apart to have some extra machining done to it.

upspirate

Post by upspirate » Mon Jan 19, 2009 9:56 am

Not to mention marine carb,ignition,starter,exhaust,possibly cam,water pump,plumbing,mounts,flywheel

Nova SS
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Post by Nova SS » Mon Jan 19, 2009 10:20 am

upspirate wrote:Not to mention marine carb,ignition,starter,exhaust,possibly cam,water pump,plumbing,mounts,flywheel
Especially since I believe Denon is plaing on a dog house for his Rampage, to cover the motor ,so it will for sure have to have a flame arrestor, marine starter/distributor etc due to the closed space.

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Caber-Feidh
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Post by Caber-Feidh » Mon Jan 19, 2009 2:38 pm

IMHO I would avoid that mystery-re-builder stuff.

A few reasons, mostly $ (no Cheap Jewish-Scotsman jokes, I have heard them all)

First, in a jet you don't need all that junk!
You will be using pump takeoff for cooling, no water pump, You don't need an Air injection Reactor, it will just wreck your exhaust, and so forth.

Besides, I paid significantly less for my 572. Not endorsing any one vendor here, just a "where I buy my junk". Look at Jegs, a GMPP crate motor is top notch, brand new, no rebuild stuff. All GMPP designs, and random production samples are run for a 50 hour WOT dyno test, then run in a destructive abuse test. No rebuilder is doing that.

Just a few examples... http://www.jegs.com/i/GM+Performance/80 ... 3/10002/-1 A great motor, set to start adding the specifics, With this I would add a big oil pan, torker from edelbrock, and a big double pumper and the block-offs. Set to go!

http://www.jegs.com/i/GM+Performance/80 ... 7/10002/-1 454 with all the goodies, alloy heads, roller cam, forged everything. Ebay the water pump, and add as above. Brand new engine, no rebuilt silliness

A little cheaper... http://www.jegs.com/i/GM+Performance/80 ... 4/10002/-1 steel heads, not as hot as above, add same stuff.

Now sometimes you can get a better deal on GMPP engines from local GM dealer, or some of the online places. I was just using these as examples of what you can find brand new, in a nice big plastic bag, unmolested by anyone.

-The only caveat is that with a crate motor you REALLY need a 4-port thermostat. They are a pain to find sometimes, but it just so happens that Glen-L has them http://www.boatdesigns.com/prodinfo.asp?number=91%2D800 These motors are not built loose, and they will need a bit of warm-up time (2-3 minutes under 2000K in 70ish water). Now, you CAN install a thermostat without a 4-port, but a high output motor + performance-pump+ thermostat closed= potential for 100+PSI in the block, and blown hoses. It is a cosmically bad idea to install a thermostat in a jet drive engine with a conventional housing.

You can build your own, usually my choice, but selecting the right parts gets critical, you are entering a field that is not economically forgiving of even little screw-ups.

There is no water pump or pickup in a conventional jet drive installation. I really would use a regulator on the cooling line. Newer engines are allot hardier, but still, they are not designed for 3-digit pressures in the water jacket.

I have NEVER seen a jet install that uses a manual flywheel. Sometimes the flex plate is a frightening sight when the starter is cranking... but it seems to work. (just shim the starter for an additional .010 of clearance ) The opposite is true with V-drives. Are you planning an open-air engine, or hiding it in a hole?

Denon Osterman
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Post by Denon Osterman » Mon Jan 19, 2009 4:15 pm

I'll admit it, I'm confused...

going through the specs, the 502 and 454(first two links) are basically identical, other then the obvious difference in displacement, and the fact that the 454 comes with more stuff...yet it costs so much less. Any reason why?

the 454 w/ aluminum heads looks pretty good. needs 92 octane though...not so good.

want to quickly explain what all 4 ports are for? i get the idea that if i dont have one, pressure can build up internally, bad news for engine...but why exactly is that (might as well make use of the wealth of knowledge on here haha)?

"these motors are not built loose"...i know novass' been saying that the marine engines need to be built loose for temp reasons, does allowing the motor to warm up(which i plan on doing anyway) solve/forego these issues?

"You can build your own, usually my choice, but selecting the right parts gets critical, you are entering a field that is not economically forgiving of even little screw-ups. "...build my own thermostat? or engine. and i definitely don't trust myself with part selection...i would with assembly though.

why does the starter need to be shimmed?

and im not sure about the open-air/hiding it yet...hiding it is more practical/forgiving, but im not really sure it would fit underneath anything anymore :D

Denon

P.S. caber i owe you one...

Nova SS
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Post by Nova SS » Mon Jan 19, 2009 5:14 pm

Denon Osterman wrote:"these motors are not built loose"...i know novass' been saying that the marine engines need to be built loose for temp reasons, does allowing the motor to warm up(which i plan on doing anyway) solve/forego these issues?
I'm intersted in this one myself :)

normally in an automotive application you will shim the starter to get proper clearance between the starter bendix and the ring gear on the flywheel/flexplate. I suspect the extra clearance is to make sure the starter doesnt bind on the flexplate when your starting the boat cause they tend to "flex" at lot when they arent supported by a torque convertor.

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Caber-Feidh
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Post by Caber-Feidh » Mon Jan 19, 2009 6:37 pm

The motor, under heat will suffer from the alloy pistons, and valve guides being "cold". The valve stems, and pistons will be hot, and more-so the first few seconds after you get on the gas. The heat expands the moving parts, decreasing their clearance, and doing damage to the engine. Not a good thing.

there are 2 common ways around the problem, the first is to just build the motor sloppy, and intend it to run ice cold. Easy to do, most common, but it brings a couple of problems with it... engines are more efficient at a warm temp, and oil flows far nicer warm. There is far more of a risk of washing a bearing out in a cold motor (Love that squealing noise!). Although common in muscle-jets, it's not the greatest system to use. Even built-loose engines will suffer from cylinder flaring at the bottom from running too cold. The top of the jug gets hotter from flame contact and runs tighter, and the piston runs true in the bore, the freezing-ice-cold bottom allows the piston to wobble a little with the action of the connecting rod at BDC, the off-square piston causes additional wear to the jug and top ring. Engines with short piston skirts are really affected by the loose piston effect. (read any long stroked motor, like the 383 & 6.0 vortec)

The better, far more professional way to handle the problem is to install a thermostat and allow a bit of warm-up time before you start running the engine hard. The advantages are found in a more efficient motor, cleaner combustion, FAR better seal of the head with a conventional fiber/steel gasket (the head and block expand to a tighter fit) sensors for electronic systems will operate properly... the list goes on. With an alloy head, there is no question, if you don't like warps, you need a thermostat. It used to be hard to find the 4-ports, they are a bit of a relic from long ago. When they are closed they bypass almost all of the incoming cooling water into the overboard dump, the water is still flowing preventing damage to the pump, and the thermostat allows air to escape and the engine fill properly.
Most any commercial built automotive long block will function perfect in a marine app with a 4-port on it.

With a non-thermostat setup in a jet you have a ball-valve to close off some of the water flow, it's a nightmare, and you are always jacking on it. Unlike a conventional water pump, a jet produces ALLOT of variation in flow, and pressure. where you can "warm-up" a regular inboard somewhat easily, you never get a jet to be above 100 at idle, and not be lake-temp at full throttle. Think of the amount of water that comes out of a 3/4" pipe nipple at 100 PSI. That is going to take some heat to warm up! Now that flow at idle will be a trickle. Enough to cool the engine, but just. With a I/O the pressure is going to vary from 4psi to about 10 psi, More or less, that is going to be far easier to set temp with just a ball valve.

The second problem comes from any engine's #1 killer.... Hot oil, or better, way-too-hot oil. With no oil cooler a big motor will heat 9 quarts to 320-330 degrees in 15 minutes. That is bad, really really bad. Installing an oil cooler fixes it perfectly, and it's a must-do... but (always has to be a but) if you are regulating the motor temp by cutting flow on a ball valve, you are also reducing flow through the oil cooler, and it becomes nothing more than so much leaky plumbing. By using a 4-port the water still flows through the cooler at maximum rate... a good thing. Even a cheap cooler will drop scary-hot oil to a nice 220 deg in a matter of a few minutes of slow cruise. (keep your oil above water boil-off temp for the sake of corrosion elimination).

You want a thermostat... you REALLY want a thermostat The loosey-goosey engines are perfect for the extreme end of performance, but they are, like any high performance mod, a big trade-off in reliability and ease of use. Allot depends on your chosen application.

Man, that flex plate wobbles allot. I have never had one shear, but the flex while the first piston comes to compression is amazing. You are dead on, the added shimming keeps the run-out from trapping the pinion gear.

That 454 is a common beast, I have seen more than a few of them in boats, never knew anyone to use premium in them. It is right on the verge of needing it compression wise. It needs to run plugs 2-ranges under stock. If I remember right stock is an R43TS. I use an R40TS in my GMPP 572. The fact your marine distributor doesn't have vacuum advance, and the engine will be running 160-170 rather than 210 degrees will cure most any predetonation problems. (Another reason to like a carb, it's easy to just jet a little richer and cool off the combustion temp)

The difference between the 502 and the 454 is easy, the numbers look cooler on a sticker on your hull!!!! (The testosterone effect :lol: ) For our purpouse it's a mute difference. 48cid isn't that much displacement.

Nova SS
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Post by Nova SS » Mon Jan 19, 2009 7:01 pm

Caber-Feidh wrote:The motor, under heat will suffer from the alloy pistons, and valve guides being "cold". The valve stems, and pistons will be hot, and more-so the first few seconds after you get on the gas. The heat expands the moving parts, decreasing their clearance, and doing damage to the engine. Not a good thing.

there are 2 common ways around the problem, the first is to just build the motor sloppy, and intend it to run ice cold. Easy to do, most common, but it brings a couple of problems with it... engines are more efficient at a warm temp, and oil flows far nicer warm. There is far more of a risk of washing a bearing out in a cold motor (Love that squealing noise!). Although common in muscle-jets, it's not the greatest system to use. Even built-loose engines will suffer from cylinder flaring at the bottom from running too cold. The top of the jug gets hotter from flame contact and runs tighter, and the piston runs true in the bore, the freezing-ice-cold bottom allows the piston to wobble a little with the action of the connecting rod at BDC, the off-square piston causes additional wear to the jug and top ring. Engines with short piston skirts are really affected by the loose piston effect. (read any long stroked motor, like the 383 & 6.0 vortec)

The better, far more professional way to handle the problem is to install a thermostat and allow a bit of warm-up time before you start running the engine hard. The advantages are found in a more efficient motor, cleaner combustion, FAR better seal of the head with a conventional fiber/steel gasket (the head and block expand to a tighter fit) sensors for electronic systems will operate properly... the list goes on. With an alloy head, there is no question, if you don't like warps, you need a thermostat. It used to be hard to find the 4-ports, they are a bit of a relic from long ago. When they are closed they bypass almost all of the incoming cooling water into the overboard dump, the water is still flowing preventing damage to the pump, and the thermostat allows air to escape and the engine fill properly.
Most any commercial built automotive long block will function perfect in a marine app with a 4-port on it.

With a non-thermostat setup in a jet you have a ball-valve to close off some of the water flow, it's a nightmare, and you are always jacking on it. Unlike a conventional water pump, a jet produces ALLOT of variation in flow, and pressure. where you can "warm-up" a regular inboard somewhat easily, you never get a jet to be above 100 at idle, and not be lake-temp at full throttle. Think of the amount of water that comes out of a 3/4" pipe nipple at 100 PSI. That is going to take some heat to warm up! Now that flow at idle will be a trickle. Enough to cool the engine, but just. With a I/O the pressure is going to vary from 4psi to about 10 psi, More or less, that is going to be far easier to set temp with just a ball valve.

The second problem comes from any engine's #1 killer.... Hot oil, or better, way-too-hot oil. With no oil cooler a big motor will heat 9 quarts to 320-330 degrees in 15 minutes. That is bad, really really bad. Installing an oil cooler fixes it perfectly, and it's a must-do... but (always has to be a but) if you are regulating the motor temp by cutting flow on a ball valve, you are also reducing flow through the oil cooler, and it becomes nothing more than so much leaky plumbing. By using a 4-port the water still flows through the cooler at maximum rate... a good thing. Even a cheap cooler will drop scary-hot oil to a nice 220 deg in a matter of a few minutes of slow cruise. (keep your oil above water boil-off temp for the sake of corrosion elimination).

You want a thermostat... you REALLY want a thermostat The loosey-goosey engines are perfect for the extreme end of performance, but they are, like any high performance mod, a big trade-off in reliability and ease of use. Allot depends on your chosen application.

Man, that flex plate wobbles allot. I have never had one shear, but the flex while the first piston comes to compression is amazing. You are dead on, the added shimming keeps the run-out from trapping the pinion gear.

That 454 is a common beast, I have seen more than a few of them in boats, never knew anyone to use premium in them. It is right on the verge of needing it compression wise. It needs to run plugs 2-ranges under stock. If I remember right stock is an R43TS. I use an R40TS in my GMPP 572. The fact your marine distributor doesn't have vacuum advance, and the engine will be running 160-170 rather than 210 degrees will cure most any predetonation problems. (Another reason to like a carb, it's easy to just jet a little richer and cool off the combustion temp)

The difference between the 502 and the 454 is easy, the numbers look cooler on a sticker on your hull!!!! (The testosterone effect :lol: ) For our purpouse it's a mute difference. 48cid isn't that much displacement.
Caber, this is an awesome informative post. Thanks for sharing your information and more importantly your experence.

Nova SS
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Post by Nova SS » Mon Jan 19, 2009 7:17 pm

Caber, you wouldn't happen to have a plumbing diagram for the 4 way thermostat housing?

Denon Osterman
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Post by Denon Osterman » Mon Jan 19, 2009 8:59 pm

Caber, forgive me if this is a personal question, but does this vast wealth of knowledge of yours spring from profession, or merely personal interest? Either way, great stuff...thanks again! Will be going over all of this with my dad on the weekend, so when we've made our decision I'll be sure to let you know so you can help out with specific parts :D

THANKS!!!

Denon

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Mr Hot Rod
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Post by Mr Hot Rod » Tue Jan 20, 2009 9:59 am

Caber, you wouldn't happen to have a plumbing diagram for the 4 way thermostat housing?
Image

Thermostat Kit For Chevy, 455 Olds (Hardin 540-160200)

Here are some installation diagrams :

Plumbing diagram - Thermostat Kit 91-800 (Glen-L Marine Designs)

Installation instructions (CP Performance)

The plumbing gets a little messier when you add oil coolers and turn the exhaust manifolds around
e.g. flywheel forward. Here's the thermostat on the Hot Rod's 283 :
  • Image
____________________
Paul Kane Chelsea, PQ

Building the Glen-L Hot Rod : http://www.boats.chelseacoachworks.com
    Last edited by Mr Hot Rod on Sat Dec 25, 2010 11:47 am, edited 2 times in total.

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