Grand Banks 36 Engine/Prop

[KBiedermann]

Hi all,

I am new to this forum as a proud new owner of a 1984 Grand Banks 36 Classic. Prior to purchasing the boat, I had it surveyed, and it came up that one of the propeller blades was slightly bent. The sellers gave me a credit to buy a new propeller, which I am searching for now.

Can anyone point me in the right direction as to what size prop I need? The boat is powered by a single British Leyland "6N125". It seems that most other 36 Classics are powered by Ford Lehman engines. I was told that this is the original engine, but can't find anything online about the 36 Classic being powered by a British Leyland. Any assistance or advice would be greatly appreciated.

Kurt

 

[Choices]

Post pictures. No telling what you have. No need to buy a new prop, just get that one balanced. I have seen a chart with all the GB designs and lengths broken down by engine, tranny, and prop. Maybe someone will post it.

 

[Comodave]

Welcome aboard. Congratulations on your new boat l. I would take the prop to a good shop and ask if they can tune it up. You will save a bunch.

 

[Blissboat]

Welcome aboard the TF, Kurt, and congratulations on your new-to-you GB 36!

6 cylinder naturally aspirated Leyland diesels were rare in the Grand Banks line - you are right that the 120 hp Ford Lehmans were the typical power choice. Parts for the Leylands can be a bit scarce.

But either way, a propellor that is "slightly bent," as you put it, shouldn't need replacement. A propellor shop can do a lot, even with a prop that's been seriously dinged up. Doesn't matter what kind of engine is at the other end of the shaft.

 

[SteveK]

If you had it surveyed and the size of the prop is not listed in the survey I would question the surveyor. Single or twin boat?
also try this https://vicprop.com/displacement_size_new.php

 

[hmason]

I had a Grand Banks 36 with a British Leyland engine. It is pretty much bulletproof as long as you change the oil on a regular schedule. Brian Smith at American Diesel is very familiar with the engine as they were the North American distributor at one time. Keep in mind that that engine is powering a half a million buses around the world. I think you're lucky to have one. The only part that I know of that is no longer available for that engine is the freshwater pump in the cooling system. I have known of others who had to replace that pump with an electrically driven pump. That is not a big deal and can be accomplished fairly readily. Good luck with your new boat and engine.

 

[hmason]

Just want to add that I owned that GB for 15 years and never once had that engine failed me.

 

[Xlantic]

What is important to determine the diameter and pitch of the propeller for your boat is the engine horsepower and transmission ratio.

I am not familiar with the British Leyland 6N125 but a quick Internet search suggests it is rated to 125 HP. This is effectively the same as the Ford Lehman's 120.

Do you know your transmission gear ratio?

I once used a prop size on-line calculator that was available in BoatDiesel.com but that site is now down. I would think there are other on-line calculators available.

Also a prop shop should be able to calculate the prop size based on your parameters (HP, ratio, displacement, speed, ...). It is not rocket science ...

 

[SteveK]

What is important to determine the diameter and pitch of the propeller for your boat is the engine horsepower and transmission ratio.

I am not familiar with the British Leyland 6N125 but a quick Internet search suggests it is rated to 125 HP. This is effectively the same as the Ford Lehman's 120.

Do you know your transmission gear ratio?

I once used a prop size on-line calculator that was available in BoatDiesel.com but that site is now down. I would think there are other on-line calculators available.

Also a prop shop should be able to calculate the prop size based on your parameters (HP, ratio, displacement, speed, ...)

see post 5

 

[Mainecoast]

The prop on my 36 with a Lehman is 24" 16 pitch, LH rotation