E-drive prop help

[Hull #18-83]

Hey guys, looking for some help in selecting the right prop to try. I have acquired a near pristine Volvo E-drive to replace my 280 lower and must now search out new props.

My boat is a 1966 triple hatch 18' powered by a stroked SBC putting out 400HP. The drive is a 270T (hydraulic trim) currently with a 280 lower which will be replaced with the E-drive lower. The current set-up will turn a Bronson built SS 3 blade 14.5"D X 25.5" P left hander about 5,300 rpm at WOT. The 280 lower has a 1.61 : 1 ratio and the standard 17 spline Volvo shaft (I don't mean to preach to the choir, just stating the facts!).

The E-drive has a 1.45 : 1 ratio and uses a 15 spline Mercury style prop shaft. It does not have the taper at the leading edge of shaft, but rather a small (1/16"?) shoulder for the front of the prop to ride against.

The new prop must be an over-the-hub style as the gear case of the E-drive is very slim (about 3.5" at it's widest point). Diameter can not exceed 14.5". And it must be a left hander.

In another post on the board, someone stated that the E-drive was rated for 6,000 RPM by the Volvo engineers. My small block likes RPMs and will happily turn to 6,000.

My rough calculations show that a 22" pitch, coupled with the E-drive will increase RPMs to about 5,600.

Your thoughts please on pitch, diameter, prop manufacturers (Mazco?, Mach?, Merc chopper? or?), max RPM, or? Anyone have any of these props for sale?

Thanks in advance for your assistance!

[BRIAN73]

Jeff,

It seems that we are both in the same boat. I too am looking for a prop for my E-Drive. The ratio of my lower is 1.31. All the props you mentioned will all work. The lower will take 6,000 but the upper will fail as heat builds. I'm pushing 456HP through a 270 upper and a E lower. I plan on being very gentle on both.

Mazco, and Bullet seem to be the best choices. Pitch and diameter are up to you. The E lower likes to have a small wheel spinning at high R's.

Brian

[Hull #18-83]

Brian, what kind of RPMs are you looking to turn at WOT?

[Ralph Savarese]

www.boatpropellers.com/propcalc.html (http://www.boatpropellers.com/propcalc.html)
This has a great prop calculator
Ralph

[Hull #18-83]

Thanks Ralph. That IS a great prop calculator. Joel and Byron Bronson know their props. They built two props for my Donzi. A 22" and a 24" which they reworked to a 25.5". I am currently have the 22" rehubbed to fit the E-drive. Going with the smaller pitch due to the taller 1.45 to 1 drive ratio.

[BRIAN73]

Jeff,

WOT, was a little more than 6,000RPM. The prop that came on my E-drive was a michigan wheel. It has a 12.75 diameter and the pitch was off the chart. It is like the blades are turned in. A Volvo expert told me that the E-drive props were designed to act like a screw, not a fan blade.

If I had 900.00 to spend, I would go with the Lightining ET and shave it down.

Brian

Proud To Own A Volvo

[Hull #18-83]

Brian, do you think that Michigan prop was the original that came with the E-drive? I was told by the Volvo Tech support people that Volvo never built props for the E-drive. Maybe Michigan did!

Any chance you could post a pic of it?

Thank you!

[BRIAN73]

Jeff,

From what I'm told, Volvo didn't make props for the E-lower. They designed the shaft to accept all Merc racing props. My contact at Volvo told me that there were a few different places making these custom props for the E-drive back in the 70'S. The questine is where the heck did they all go?

The ss prop that came with my E-drive has no markings on it any where. The previous owner claimed that he had shown the prop to a guy who worked for Michigan. And yes it was wheel from their custom shop. Who even know's if it's a true story or not.

What I do know is that I've shown this prop to a number of Volvo dealer. Not one dealer had ever seen one or knew what it went on.

I will try to take a picture of the prop tonight.

Check out Props Plus.com

[GEOO]

Jeff,
I ran an E:Drive on my 18 back in 1998 wtih a 383 ci approx 360-380hp. 1:31 ratio, Mazco Prop, RE3 14 1/2" x 26" (ran 76 mph @ 5200 rpm), cut down blade width and 1/4" dia to a 14 1/4" dia. Ran 77-80 mph. I think she spun 5300-5400 rpms. You will need external steering!!! You have to drive the boat several times to find the sweet spot; then the boat takes off. Good Luck!!!

[Andy knuth]

Jeff I am also running an Edrive on my 67 2+3 and have two props i'm not using anymore. I'm running a270 with a higher ratio so I needed a 24" 4bladed cleaver ,work great. I bought the drive about 9years ago off afriend who had a 72 2+3 with the same drive as you.He was running very thinned heavily cupped+polished three blade which he gave me with the drive.He was running 70mph at 5700 with a winsor. not enough prop for me +lots of torque steer. Then I found a 22" 4blade ,lost alot of torque steer but still not enough prop. Istill have those props and willing to part with them.The 24" is nice ,my motor is very torquey .I run 68mph at 5200. My boat is in the registry with pictures.

[BRIAN73]

Andy,

Did you do any mods to the 351? Were their any markings on that polished cupped, three blade?

Brian

[Hull #18-83]

Geoo,

Thanks for the reply! I had seen that you were running an e-drive with a stroker before the arneson conversion. I understand your comment that you reduced the Mazco prop's diameter to 14 1/4" but I am not sure what you mean by cutting down the blade width!
Did you remove metal from the trailing edge of each blade?

Do you think a Mazco RE3 is the best prop for this combo? Others have suggested a Merc Chopper II or a Lightning ET or a Bullet. I have no clue as these are Outboard props typically, and until this new e-drive thing, I have had no experience with this type of prop!

In regards to steering, I DO have the Teleflex Seastar hydraulic system with the helm pump and no assist. Kevlar lines are run to the inside of transom where the steering ram is attached to the tiller bar inside the engine compartment. It has worked VERY well for ELIMINATING all steering torque from my old set up. I did see your comments regarding the e-drive's need for external steering. I'll go easy with it at first to see how she performs.

Thanks from California for any assistance you can provide!

[GEOO]

Jeff,

The Mazco worked the best for me. The blades were cut down to reduce blade area. Not thinned any more.

[Andy knuth]

Brian my351 is 91 block with 69 heads with1.94"in ,1"60 ex. ported ,roller rockers. have a stealth intake 650 mech. holley .Cam is acomp cam EX284H-10 lift is.540 and.544 dur is240 in. and 244 ex. at.050 . Have KB pistons at .020 over. motor is very torquey.Also am running veriable duration lifters from crane to calm the idle down to about 800rpm .5200 rpm is about where it likes to run at WOT.

[Andy knuth]

Oh yeh. Got carried away with the motor.The prop is marked 19P S&S between the blades and 48-77320-24 on the front of the hub. I think its areworked merc prop done by S&S .Its very thin and very shiny!

[Andy knuth]

I had hynautic hydraulic steering inside also untill I moved it outside 5 years ago and eliminated chine walk and 2" of play at the prop . To many pivots between inner arm and drive.