WOT for alpha one

[achris]

Re: WOT for alpha one

...Hmmm! 1.65:1 would that spin the prop faster for lower engine rpm?...

Yes.

 

[MikDee]

Re: WOT for alpha one

I have everything to hook up to my engine and it seems all I will have to do is drill holes to match the flathead. My bolt circle comes out in the flat area of the flywheel surround and will be easy to do once I get it in proper position. The length seems to be almost identical.
The boat had a very heavy 90 hp Mercruiser outboard hanging on the back with all the cables for shifting and throttle installed with a steering wheel and all gauges including a tachometer. It has the power trim controls and I have a complete trim system.
I am looking at using a triangle shaped coupler to mount on my flywheel.
The fuel tank is mounted under the deck in the front. I am sure I will have to clean it.
Why power steering?
My flathead runs best at about 180 degrees. Is there any reason I have to worry about the standard 140 degree thermostat? The water passing through my water manifold will be tempered a lot lower by the amount of water passing through the manifold as shown in my sketch. The engine will be controlled by the thermostats, but with that much water going through the system, it should be quite cool other than inside the engine. By my research, it seems the engine will use a lot less water than the Alpha drive will furnish so there will be a lot of flow through the water manifold and the engine will just use as much as needed. The rest will just go through the water manifold and dump back to the Alpha drive.
Hmmm! 1.65:1 would that spin the prop faster for lower engine rpm?
The max torque of the engine is about 1800 rpm. That is one of the characteristics of Flatheads.
I am sure once I try it with what I have for gearing I will be able to tell right away and change just the gears if needed.

I am sure to get the coast guard involved for all safety features I will need. This will be an all open boat with no enclosure aft of any sort. We will have to see what they say.


Will C

Power steering is for the bulky heavy outdrive. I don't know if you need it? But, I never had an I/O without it. You can run whatever water temp you need, that don't matter.

So, you won't need the Y-pipe on the Merc exhaust if you're not using it, when you take it apart there is a port thru the transom plate for exhaust, but maybe you can use that to discharge the excess water from the cooling system?
To be on the safe side RPM wise, you should use the drive you have with 1:89x1 gearing. Prop pitch over 21" gets hard to find. A 1:65X1 ratio will spin your prop slower, not really what you want. Most of the 4cyl I/O's with 130-140 hp run the 1:89X1 gearing. With a mostly open boat, I'm sure you're good to go!

 

[achris]

Re: WOT for alpha one

Power steering is for the bulky heavy outdrive. I don't know if you need it? But, I never had an I/O without it. You can run whatever water temp you need, that don't matter.

My boat originally came without power steering (a 1972 MC165), the new engine has it. I like it, but it was no big deal to drive without it. A 140 degree thermostat is for saltwater use. Salt water at high temperatures disassociates into acid. Not something you want inside any metal, hence the cooler thermostat. If you're going to be running in freshwater, by all means run the 180...

So, you won't need the Y-pipe on the Merc exhaust if you're not using it, when you take it apart there is a port thru the transom plate for exhaust, but maybe you can use that to discharge the excess water from the cooling system?
To be on the safe side RPM wise, you should use the drive you have with 1:89x1 gearing.

I don't think he has a drive yet, that's why he's asking about ratios.

Prop pitch over 21" gets hard to find. A 1:65X1 ratio will spin your prop slower, not really what you want. Most of the 4cyl I/O's with 130-140 hp run the 1:89X1 gearing. With a mostly open boat, I'm sure you're good to go!

No, a 1.65:1 will spin the prop FASTER then a 1.98:1 for the same engine speed. It's a step down, not an step up.... With the 1.65 you would need LESS pitch than with a 1.98 for the same boat speed at the same revs... And none of the 4cyl engines produce anything like the torque his V8 does. And it produces it at 1800prm, not the 3400rpm of a 4 cyl.

For every engine rev, a 1.98:1 would turn the prop 0.51 revolutions. and 1.65:1 would have the prop turn 0.61 revolutions. ie, the prop will turn FASTER with the 1.65:1....

Chris.....

 

[wilvn70]

Re: WOT for alpha one

Ok! Sounds like I will dump the water through the upper section of the drive with an adaptor where the exhaust bellows connects. That will be easy. I do have a drive that is 1.98 I believe, but I should be able to change the gearing later if needed.
If Chris is right, then I want to have a lower engine speed and a faster prop, So the 1.65 may be better. (.61 over all verses .51) Now I know what to expect and how to adjust later after I have it running. Time will tell. I am just a strong armed old country boy, so I may survive without power steering at least at first.( My wife may dictate having it later as she is just a tiny woman.) I think the flathead will sound a lot better running at a lower RPM. I do know in my 'Rods' it has very high torque at low rpms and sure sounds neat. I am getting rather anxious to play with it. I will be leaving Thailand for my home in Pa, USA shortly. Will C

 

[Scott Danforth]

Re: WOT for alpha one

Im jumping in because I like old hot rods.

regarding the drive, it is almost cheaper to buy a different drive than to change gears

you may want to run a version of drag boat or jet boat headers. they exit out the back over the transom and have the water injection ports in them to keep the exhaust cool (preventing the whole fire thing)

this way you get the cool factor..... and the cooling factor

Bassett Racing Boat Headers

 

[MikDee]

Re: WOT for alpha one

My boat originally came without power steering (a 1972 MC165), the new engine has it. I like it, but it was no big deal to drive without it. A 140 degree thermostat is for saltwater use. Salt water at high temperatures disassociates into acid. Not something you want inside any metal, hence the cooler thermostat. If you're going to be running in freshwater, by all means run the 180...



I don't think he has a drive yet, that's why he's asking about ratios.

I never had an I/O without power steering, so I don't know,,, You would know better Achris.

I thought he said he already has an outdrive with 1:98x1 gearing?

No, a 1.65:1 will spin the prop FASTER then a 1.98:1 for the same engine speed. It's a step down, not an step up.... With the 1.65 you would need LESS pitch than with a 1.98 for the same boat speed at the same revs... And none of the 4cyl engines produce anything like the torque his V8 does. And it produces it at 1800prm, not the 3400rpm of a 4 cyl.
For every engine rev, a 1.98:1 would turn the prop 0.51 revolutions. and 1.65:1 would have the prop turn 0.61 revolutions. ie, the prop will turn FASTER with the 1.65:1....

Chris.....

True, If you have the lower end torque, it's like shifting into a higher gear, overdive.

 

[MikDee]

Re: WOT for alpha one

The exhaust port on the drive is actually quite low on the transom. Changing gearing is a very technical, expensive, major job, I wouldn't advise it.

 

[achris]

Re: WOT for alpha one

...I thought he said he already has an outdrive with 1:98x1 gearing?...

I just assumed from this statement, in his opening post of the thread, that he was looking for a drive and was asking what ratio he should consider...

... but I would like to know what ratio of alpha drive I should use to give me the best prop rpm for an 3700 rpm engine range....

ok, given you already have a drive, with 1.98:1... Put that on and take the boat for a run, so what sort of revs you are heading towards. I would start out with about a 21" prop on that drive. If your target max revs are 3800, then if it's low, decrease the prop size. If it's high, just a little, try and find a 23 or 25" prop. They can be found, but are a bit less common than the 15"-21" range. Most props are in 2" increments, and they change the engine speed about 200rpm per inch of pitch change... If the revs are significantly high, you'll need to change ratio, and given that new gears and the tools to set them up are not cheap, it's more economical to just buy a new upper. Brand new, with 3 year warranty, is about $600... Or you could look for a second hand drive complete, but as it's second hand, you don't know if it used or abused....

Chris......

 

[Outsider]

Re: WOT for alpha one

I hope looking cool and sounding sweet doesn't rip the transom out. It is, after all, an outboard boat that's only 16' ... :facepalm:

 

[wilvn70]

Re: WOT for alpha one

Hi Scott,
My headers are just six upswept zoomie pipes with motorcycle baffles and the engine is mounted in the totally open boat. Nothing will be even close to the engine so I think the exhaust heat will be no problem. I don't have a picture of my header set and engine with me here. I will be setting the engine in the boat in the middle of May and will take some pics and post then. Thanks for your input, I am always looking for and thinking of new ideas. There is an old set of federal manifolds on ebay, but I think they may be off a V60 ford. If the headers don't work as well as I think, then I am sure to go water cooled. But I like the hot 'cool' looking zoomies for my starter.
Will C

 

[Scott Danforth]

Re: WOT for alpha one

If you get inspected on the water, the local LEO may think otherwise on the cool looking zoomies vs water cooled.

its the whole safety aspect of a fire hazzard

 

[wilvn70]

Re: WOT for alpha one

Hi Again Scott,
You got me doing research again. Thanks
I found what I needed to decide on the open pipes.

CFR-2011-title46-vol7-sec18 Engine exhaust cooling.

? 177.970 Protection against hot piping.
? 177.405 General arrangement and outfitting.

It seems if I do what I am planning, it will pass the regulations just fine.
Thanks again for bringing it to my attention.
Will C

 

[wilvn70]

Re: WOT for alpha one

Outsider,
You are right. I have the complete boat the outdrive is out of and am planning to reinforce the Marlin using parts from it and a bit of home brewed ideas.
I remember what we did on my Dads 12' with a 22hp outboard. It was riping the stern out and he remade it with a stronger stern and more bracing.
That is a part of the fun of it, figuring out how it is working and always improving it.
I am more interested in building it than running it a lot. I am sure my kids will take care of that part for me. They are 18 and 25.
At my age, 73 I am much more interested in making it. I have built airplanes, a kayak, hotrods and houses. This seems to get my interest, so why not.
Will C

 

[wilvn70]

Re: WOT for alpha one

Hey Cris,
Got any friends that are into old '30-31 Fords?
I am trying to find a steering box for the RHD two tooth "A".
The one in my hotrod works very well and I am going to build a tudor with the same flathead setup.
Will C

 

[LawHungLow]

Re: WOT for alpha one

FWIW - I have an 18' openbow runabout with the 2.5L and it does NOT have power steering. My wife drives it so i think you and your wife will be able to handle it without power steering. I have an alpha one gimbal ring and bell housing laying around with hydraulics still on it. Let me know if you're interested. you'll need one.

 

[wilvn70]

Re: WOT for alpha one

Hi LawHungLow,
Thanks for the information.
I think I have everything but the triangler shaped connector/coupler for the flywheel.
I think I will lighten the flathead flywheel and drill it for that sort of coupler.
I will be doing an inventory in about a month when I get back. I will keep in mind what you have available.
I think without power steering will work as my wife is quite a strong girl.
Will C