Mercruiser Speedmaster

[Scand]

Does any have the specs of the mercruiser speedmaster III VI V?
Just woundering how much power or torque they could take, and what gear rations were used?

[DAREDEVIL]

The number 3 is rated at 650 pounds tourge , the 3A & 4 is at 750 and the 5 800 !

But that is only because merc did not have any bigger engines in theyr line, back in the day. they can take a lot more with no problem !!!

Hope that helps ?

[Scand]

Thanks, thats just what I was after.
Do also remeber what reduction ratios they had? Did they all share the same spline on the propeller shaft?

[DAREDEVIL]

Originally Posted by Scand

Thanks, thats just what I was after.
Do also remeber what reduction ratios they had? Did they all share the same spline on the propeller shaft?

all the way from 1:33 to 1:68 !!!

1:1 & 1:125 lower the rest is in the top half !!!!!!

I have most parts, NEW..shafts..gears and such . They are the straightcut NET forged gears that even Merc originaly never offered.
A friend of mine here in the US is making them again per merc specs !!! ( just forged which is better ) can get splined or polygon.

[Jim Brooker]

Originally Posted by Scand

Does any have the specs of the mercruiser speedmaster III VI V?
Just woundering how much power or torque they could take, and what gear rations were used?

Have you decided on the Engine. ???
What sort of Engine are you thinking of fitting to Mercruiser Speed-master to, i.e Petrol, Diesel, Power, Torque and RPM, or if you are thinking of running them on the surface.
Here are so many combination's.

[Scand]

Thanks for your help.
I am not looking at running a speedmaster, but I am after some props for a project. I think 3 bladed speedmaster props should be more or less the right size. Do you know the diameter of the propeller boss on these and the spec of the 19 teeth spline?

[Jim Brooker]

Originally Posted by Scand

Thanks for your help.
I am not looking at running a speedmaster, but I am after some props for a project. I think 3 bladed speedmaster props should be more or less the right size. Do you know the diameter of the propeller boss on these and the spec of the 19 teeth spline?

Right Mercruiser Speedmaster, There are two different Propeller Shafts at the prop end. Number 1 is 7.750 ins long and 1.370 OD with 19 spine's and taper for the prop to sit on.
Number 2 is 7.750 ins long and 1.750 OD with 26 spine's and the prop site's on the end of the shaft.
Both props have 6 ins long hubs.
I don't have a engineering drawing.
But I do have a pair of props 18 x 28 3 bladed 19 spines

[DAREDEVIL]

correct, and the props you have would probably help him a lot to get started. I do believe down the road you would want 4 or even 5 blade props, the technoligy cam a long ways since the 80's. lol

[Jim Brooker]

Originally Posted by DAREDEVIL

correct, and the props you have would probably help him a lot to get started. I do believe down the road you would want 4 or even 5 blade props, the technoligy cam a long ways since the 80's. lol

Yes I do know that I am CORRECT. I started rebuilding all the Speed-master unit's back in 1972 and at that time the was only one that did rebuilt them in the UK.
Scand, seems only interested in 3 bladed and 19 splined props at the moment.
Jimmy Brooker

[DAREDEVIL]

1972, lol....wow i was 1 year old..hahahaha

but i do think they only had the Merc II back then not no speedmaster ?!

[Jim Brooker]

Originally Posted by DAREDEVIL

1972, lol....wow i was 1 year old..hahahaha

but i do think they only had the Merc II back then not no speedmaster ?!

I fitted 2 Mk 3 speed-master to a boat with 2 Sabre Diesels 380bhp through step up box's, I had to rebuild them and set them up so we could run them back-wards, I started the boat at the end of 1972 and the boat was called HTS 11 it raced for 2 year and in the end it got a World Diesel Record at 71 mph in 1974. !!!!!!!!!

[DAREDEVIL]

Originally Posted by Jim Brooker

I fitted 2 Mk 3 speed-master to a boat with 2 Sabre Diesels 380bhp through step up box's, I had to rebuild them and set them up so we could run them back-wards, I started the boat at the end of 1972 and the boat was called HTS 11 it raced for 2 year and in the end it got a World Diesel Record at 71 mph in 1974. !!!!!!!!!

Nice, do you have some pictures of the boat ??

[Jim Brooker]

Originally Posted by DAREDEVIL

Nice, do you have some pictures of the boat ??

Here is 1 the only one I have.

http// boatmad.com/forum/attachment.php?attachmentid=2461&d=1104349952

[DAREDEVIL]

Originally Posted by Jim Brooker

Here is 1 the only one I have.

http// boatmad.com/forum/attachment.php?attachmentid=2461&d=1104349952

NICE PICTURE, thanks !!! shame you only have one tho.

[Jim Brooker]

Originally Posted by DAREDEVIL

NICE PICTURE, thanks !!! shame you only have one tho.

I haven't got any more photos of HTS 11 I was never one to take a lot of photos, but here is a very similar insulation, I did a few years later, the only difference is that this boat is 34ft long and engines are further a part, and the step up box's are fitted between the gearbox and engine, these engines are 500 bhp it run just on 80mph.
I did 8 very similar full race boat insulations with Sabre Diesels fitted to MK 3 & 4 Drives from 380 to 600 bhp per engine.

[DAREDEVIL]

Thanks, nice set up and nice boat !

[pain -tera 28]

Originally Posted by Jim Brooker

I haven't got any more photos of HTS 11 I was never one to take a lot of photos, but here is a very similar insulation, I did a few years later, the only difference is that this boat is 34ft long and engines are further a part, and the step up box's are fitted between the gearbox and engine, these engines are 500 bhp it run just on 80mph.
I did 8 very similar full race boat insulations with Sabre Diesels fitted to MK 3 & 4 Drives from 380 to 600 bhp per engine.

Good afternoon Mr Jim Brooker hope all is well in sunny spain. great pic can you tell me the weight of one of them motors regards paul

[Jim Brooker]

Originally Posted by pain -tera 28

Good afternoon Mr Jim Brooker hope all is well in sunny spain. great pic can you tell me the weight of one of them motors regards paul

Paul .. now that's a question the earlier 500 bhp one's without the step up box and the toque converter was around 1200 pounds, the one you see in the photo is just under 1500 pounds as far as I can remember and around 600bhp.

[pain -tera 28]

Thanks Jim woudnt want one on your foot ah just like to know were they the best around at the time ?? and can you tell me how much power they had when they were in the lorreys ??

[gerry.p]

if memory serves me right the 6 cyl D series started off with 120 hp n/a
then ford started playing with Chromard liners and blowers to get the power up,but in the trucks was still a gutless motor,
then Sabre got their hands on it and showed what could be done