How to determine the hp, on a Mercruiser 5.7?
 

My Monarch, is a 1977 model, and has had the enggine replaced a few
years ago with a Four Star reman. Now, It was origionally rated at
something like 225 hp. or something like that, and there's really no
reason I should think that the reman wouldn't be the same. But engine
rebuilders hafe interesting ways about them, like boring cylinders 20,
30, and even 40 thousands oversize, PLUS the cam may or may not be to
origional specs.

I'm really not that concerned about the hp, because I know it will be
enough to handle the boat. It has for a few years. But I belive Four
Star located in Indianapolis went out of business a few years ago, and
was wondering if seriel numbers might tell the hp rating,t hat is, if
alll the variables were to remain stock. Has anyone ever heard of
putting a marine engine on a dyno right at the prop?

If so, it would be interesting to see what the true rating of this
engine and "R" Drive really are, instead of merely going with what is
on the valve cover decals.?

How to determine the hp, on a Mercruiser 5.7?
 

Tim wrote:
My Monarch, is a 1977 model, and has had the enggine replaced a few
years ago with a Four Star reman. Now, It was origionally rated at
something like 225 hp. or something like that, and there's really no
reason I should think that the reman wouldn't be the same. But engine
rebuilders hafe interesting ways about them, like boring cylinders 20,
30, and even 40 thousands oversize, PLUS the cam may or may not be to
origional specs.

I'm really not that concerned about the hp, because I know it will be
enough to handle the boat. It has for a few years. But I belive Four
Star located in Indianapolis went out of business a few years ago, and
was wondering if seriel numbers might tell the hp rating,t hat is, if
alll the variables were to remain stock. Has anyone ever heard of
putting a marine engine on a dyno right at the prop?

If so, it would be interesting to see what the true rating of this
engine and "R" Drive really are, instead of merely going with what is
on the valve cover decals.?



You ought to be able to get a reasonable idea of the HP just by the RPM
you get with a given prop. Is the prop original?

How to determine the hp, on a Mercruiser 5.7?
 

I've thought about that James, I've never heard of anybody reasonably
hooking a dynomometer up to a prop shaft, but I'm sure it's been done,
in high-performance marine use.
James Sweet wrote:
Tim wrote:
My Monarch, is a 1977 model, and has had the enggine replaced a few
years ago with a Four Star reman. Now, It was origionally rated at
something like 225 hp. or something like that, and there's really no
reason I should think that the reman wouldn't be the same. But engine
rebuilders hafe interesting ways about them, like boring cylinders 20,
30, and even 40 thousands oversize, PLUS the cam may or may not be to
origional specs.

I'm really not that concerned about the hp, because I know it will be
enough to handle the boat. It has for a few years. But I belive Four
Star located in Indianapolis went out of business a few years ago, and
was wondering if seriel numbers might tell the hp rating,t hat is, if
alll the variables were to remain stock. Has anyone ever heard of
putting a marine engine on a dyno right at the prop?

If so, it would be interesting to see what the true rating of this
engine and "R" Drive really are, instead of merely going with what is
on the valve cover decals.?



You ought to be able to get a reasonable idea of the HP just by the RPM
you get with a given prop. Is the prop original?

How to determine the hp, on a Mercruiser 5.7?
 

Knowing the prop won't help. A 5.7 in a 20' bowrider might have a 25"
pitch and the same engine in a 25 ft cruiser would have a 17". There
might be an adapter to hook an engine to a prop shaft. Boring the
cylinders only adds a few cubic inches, 30 over is about 6 cubic
inches. Cam, heads, intake, and carburation have the most effect on
these engines.

Tim wrote:
I've thought about that James, I've never heard of anybody reasonably
hooking a dynomometer up to a prop shaft, but I'm sure it's been done,
in high-performance marine use.
James Sweet wrote:
Tim wrote:
My Monarch, is a 1977 model, and has had the enggine replaced a few
years ago with a Four Star reman. Now, It was origionally rated at
something like 225 hp. or something like that, and there's really no
reason I should think that the reman wouldn't be the same. But engine
rebuilders hafe interesting ways about them, like boring cylinders 20,
30, and even 40 thousands oversize, PLUS the cam may or may not be to
origional specs.

I'm really not that concerned about the hp, because I know it will be
enough to handle the boat. It has for a few years. But I belive Four
Star located in Indianapolis went out of business a few years ago, and
was wondering if seriel numbers might tell the hp rating,t hat is, if
alll the variables were to remain stock. Has anyone ever heard of
putting a marine engine on a dyno right at the prop?

If so, it would be interesting to see what the true rating of this
engine and "R" Drive really are, instead of merely going with what is
on the valve cover decals.?



You ought to be able to get a reasonable idea of the HP just by the RPM
you get with a given prop. Is the prop original?

How to determine the hp, on a Mercruiser 5.7?
 

Knowing the prop won't help. A 5.7 in a 20' bowrider might have a 25"
pitch and the same engine in a 25 ft cruiser would have a 17". There
might be an adapter to hook an engine to a prop shaft. Boring the
cylinders only adds a few cubic inches, 30 over is about 6 cubic
inches. Cam, heads, intake, and carburation have the most effect on
these engines.

Tim wrote:
I've thought about that James, I've never heard of anybody reasonably
hooking a dynomometer up to a prop shaft, but I'm sure it's been done,
in high-performance marine use.
James Sweet wrote:
Tim wrote:
My Monarch, is a 1977 model, and has had the enggine replaced a few
years ago with a Four Star reman. Now, It was origionally rated at
something like 225 hp. or something like that, and there's really no
reason I should think that the reman wouldn't be the same. But engine
rebuilders hafe interesting ways about them, like boring cylinders 20,
30, and even 40 thousands oversize, PLUS the cam may or may not be to
origional specs.

I'm really not that concerned about the hp, because I know it will be
enough to handle the boat. It has for a few years. But I belive Four
Star located in Indianapolis went out of business a few years ago, and
was wondering if seriel numbers might tell the hp rating,t hat is, if
alll the variables were to remain stock. Has anyone ever heard of
putting a marine engine on a dyno right at the prop?

If so, it would be interesting to see what the true rating of this
engine and "R" Drive really are, instead of merely going with what is
on the valve cover decals.?



You ought to be able to get a reasonable idea of the HP just by the RPM
you get with a given prop. Is the prop original?

How to determine the hp, on a Mercruiser 5.7?
 

Personally, I think you ought to replace the engine with a similar vintage
J-79-17. And perhaps
CHECK YOUR SOFTWARE BEFORE YOU CROSSPOST.

R / John

"Tim" wrote in message
oups.com...

My Monarch, is a 1977 model, and has had the enggine replaced a few
years ago with a Four Star reman. Now, It was origionally rated at
something like 225 hp. or something like that, and there's really no
reason I should think that the reman wouldn't be the same. But engine
rebuilders hafe interesting ways about them, like boring cylinders 20,
30, and even 40 thousands oversize, PLUS the cam may or may not be to
origional specs.

I'm really not that concerned about the hp, because I know it will be
enough to handle the boat. It has for a few years. But I belive Four
Star located in Indianapolis went out of business a few years ago, and
was wondering if seriel numbers might tell the hp rating,t hat is, if
alll the variables were to remain stock. Has anyone ever heard of
putting a marine engine on a dyno right at the prop?

If so, it would be interesting to see what the true rating of this
engine and "R" Drive really are, instead of merely going with what is
on the valve cover decals.?

How to determine the hp, on a Mercruiser 5.7?
 

"Tim" wrote in message
ups.com...

I've thought about that James, I've never heard of anybody reasonably
hooking a dynomometer up to a prop shaft, but I'm sure it's been done,
in high-performance marine use.


A decent marine service shop will have one. They are portable and put a
load on the engine shaft using hydraulics. I've seen them at a couple of
shops around here.

Eisboch

How to determine the hp, on a Mercruiser 5.7?
 

John,

I have checked for the cross post. Seeing Ted, BobandCarole, and "Fred"
like to puke their whacked "White only" and other shady journalism, I
thought it would be better to change the subject and ask for some
genuine advice.

That is, unless you really must have "white only" material starring in
your face.and I'm sure you don't.

So I asked a question seeking true information.

Thanks John.
John Carrier wrote:
Personally, I think you ought to replace the engine with a similar vintage
J-79-17. And perhaps
CHECK YOUR SOFTWARE BEFORE YOU CROSSPOST.

R / John

"Tim" wrote in message
oups.com...

My Monarch, is a 1977 model, and has had the enggine replaced a few
years ago with a Four Star reman. Now, It was origionally rated at
something like 225 hp. or something like that, and there's really no
reason I should think that the reman wouldn't be the same. But engine
rebuilders hafe interesting ways about them, like boring cylinders 20,
30, and even 40 thousands oversize, PLUS the cam may or may not be to
origional specs.

I'm really not that concerned about the hp, because I know it will be
enough to handle the boat. It has for a few years. But I belive Four
Star located in Indianapolis went out of business a few years ago, and
was wondering if seriel numbers might tell the hp rating,t hat is, if
alll the variables were to remain stock. Has anyone ever heard of
putting a marine engine on a dyno right at the prop?

If so, it would be interesting to see what the true rating of this
engine and "R" Drive really are, instead of merely going with what is
on the valve cover decals.?

How to determine the hp, on a Mercruiser 5.7?
 

jamesgangnc wrote:
Boring the
cylinders only adds a few cubic inches, 30 over is about 6 cubic
inches. Cam, heads, intake, and carburation have the most effect on
these engines.


Correct. But I suppose in the whole long run, and with exception of
running the drive train on a dynomometer, there's really no way of
telling if the re-man engine is truely build to O.E. origional stock
factory specs, unless the engine was torn down and spec'd out.

Which obviosly isn't worth the hassle.

How to determine the hp, on a Mercruiser 5.7?
 

call around and see who has a prop shaft mounted dyno which should get the
true close HP. Pre 89 5.7's with 4bbl carbs were 260hp at the crank.


"Tim" wrote in message
oups.com...

My Monarch, is a 1977 model, and has had the enggine replaced a few
years ago with a Four Star reman. Now, It was origionally rated at
something like 225 hp. or something like that, and there's really no
reason I should think that the reman wouldn't be the same. But engine
rebuilders hafe interesting ways about them, like boring cylinders 20,
30, and even 40 thousands oversize, PLUS the cam may or may not be to
origional specs.

I'm really not that concerned about the hp, because I know it will be
enough to handle the boat. It has for a few years. But I belive Four
Star located in Indianapolis went out of business a few years ago, and
was wondering if seriel numbers might tell the hp rating,t hat is, if
alll the variables were to remain stock. Has anyone ever heard of
putting a marine engine on a dyno right at the prop?

If so, it would be interesting to see what the true rating of this
engine and "R" Drive really are, instead of merely going with what is
on the valve cover decals.?

How to determine the hp, on a Mercruiser 5.7?
 

Lost In Space/Woodchuck wrote:
call around and see who has a prop shaft mounted dyno which should get the
true close HP. Pre 89 5.7's with 4bbl carbs were 260hp at the crank.

That's a good idea. There is a fairly reputable boat dealership about
thirty miles from me. And I'm going to ask them to do some "check-up"
on the boat this spring when I dig it out of mothball. They just might
have a dyno.

Thanks!