Double Eagle, center console.

Report the performance of your boat, supply as much information as possible (weight, HP, prop, speed, etc.).
Subject: Make the Glen-L design name the subject. If the design already has a posting, add your information to that post.

Moderator: Bill Edmundson

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Mr Hot Rod
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Location: Chelsea, Quebec, Canada
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Post by Mr Hot Rod »

Can I bolt vortec heads onto the old 3.8L, 1983 vintage, and then go on to mount MPI injection on that??
A competent machine shop/engine builder should be able to advise you on that one.
Haven't come up with any V6 info. You might leverage some info from
Mortec's CHEVY small block V8 Casting Numbers :
http://www.mortec.com/castnum.htm
A Page Search for vortec in the Blocks and Heads sections will yield some possible candidates.
Use the part numbers to confirm what you're looking at when crusing the boneyard.
Needless to say that these engines will be commanding higher prices than carbureted engines
and still require marinizing and tweaking . . .
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Paul Kane Chelsea, PQ

Building the Glen-L Hot Rod : http://www.boats.chelseacoachworks.com

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kens
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Post by kens »

THANKS for the links.
I have spotted a donor boat with a 3.8L sterndrive. It is a carb motor, since it is already a marine package, it ought to relatively easy to swap over to MPI. That link to DIY auto mpi looks like a good choice.

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kens
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Location: Coastal Georgia

Post by kens »

kens wrote: I have spotted a donor boat with a 3.8L sterndrive. It is a carb motor, since it is already a marine package, it ought to relatively easy to swap over to MPI.
Update:
I found that motor on Craigslist, and, drove all the way to Ft. Worth to see it. Got it started 1st time in years, and water was coming out of it all over, cracked manifolds, risers, block. Oh well. :cry:

However, I did find a straight-6 for good money a mere 3 blocks from the apartment. I saw this run OK, and nabbed it.

Just recieved another prop; a 16x13 heavy cup. I'll try this as soon as I re-launch the boat. (with original engine still)

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kens
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Post by kens »

Has anybody ever heard of 'negative' slip?
Whatever it is, it seems that I got it.
At the Gathering I ran my 10th prop. A 16x13 #4 cup. I lost 200rpm from a (16x14 #3cup) but the speed is still stuck at 29mph.
But, if you do the math at 13 pitch, it comes up to a negative slip number.
3975 engine rpm and a 1.91:1 gear.
Interesting or what?

upspirate

Post by upspirate »

Ken's,
Have you noticed any difference in performance between the coast with it's sea level elevation and Guntersville with higher elevation affecting the carburetion?

I've noticed differences in the past with my carbureted cars & boats

Also salt vs fresh water?

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kens
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Post by kens »

no , no difference. But, I think it is weird that the last prop dropped 1" pitch for a minor increase in cup, and, lost 200rpm.
But, this current prop is definitely 'hooked up'. It also comes out of the hole like a really big prop; real slow.

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Bill Edmundson
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Post by Bill Edmundson »

I don't know about Ken. But, I notice that my boat sat lower in freshwater. It was about an inch. I forgot my GPS. So I don't know about speed it felt about the same.

The Pitot Tube speedometer is pretty good in salt. But, was way out in the freshwater.

Bill
Mini -Tug, KH Tahoe 19 & Bartender 24 - There can be no miracle recoveries without first screwing up.
Tahoe 19 Build

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kens
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Post by kens »

Of all the prop testing thus far, I never noticed a difference between salt or fresh water, I launch at either one depending on the tides.
But I can say that this boat seems to be a little faster in a light chop, seems that a little air under it loosens it up a little. Last Saturday at Guntersville was not chop, that was still smooth water.

upspirate

Post by upspirate »

kens wrote: Last Saturday at Guntersville was not chop, that was still smooth water.

Yea....not if you were in an 8' boat!!!! :wink: :shock: :roll:

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kens
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Post by kens »

This is weird........
I ran a 16x13 med cup and only got 4000rpm, but a decent speed.
Out of curiosity I ran a Ebay prop I just got, a DynaQuad 4blade 17x14.
turned it 4500rpm, the highest rpm thus far. And, its a 4blade 17".
Speed was off, to 27mph though.
How can I turn a bigger 4blade, faster, than a smaller 3blade?

upspirate

Post by upspirate »

slip& cavitation??? :?:

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Fifty Plus
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Post by Fifty Plus »

The total amount of blade area in the 17" circle is probably less than the 16".
I think that makes for more slip.

Carl

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kens
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Post by kens »

No, the 17" 4blade has 40% more blade area than the 16" 3blade.

That is what puzzles me.

Butch Barto
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Post by Butch Barto »

Ken I would use the prop you have that gives you your engines max RPM @WOT 95 % of the time you will likley run around 3000-3500 RPM or be in a no wake zone at idle speed.The other props you try will have little difference in this range unless you plan to pull nets .

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kens
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Post by kens »

kens wrote:This is weird........
Out of curiosity I ran a Ebay prop I just got, a DynaQuad 4blade 17x14.
turned it 4500rpm, the highest rpm thus far. And, its a 4blade 17".
Speed was off, to 27mph though.
How can I turn a bigger 4blade, faster, than a smaller 3blade?

this wheel had a little vibration in it, so, I had it MRI scanned and tuned. Its blades were not consistant pitch, I had it averaged to be smooth & consistant pitch. I re-ran it and lost 300 rpm and lost 1 mph. How can this be? The shop put a burnished looking finish to it where it was formerly polished.
Does anybody have experience with polishing props? Could it be the surface finish on different props giving me unpredictable results from one wheel to another?

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