Crescent CS500 - Question

[corin_huke]

I have a question for all of you guys regarding the Crescent engines produced in the 70s

We've recently acquired a CS500 which be believe to be of circa 1973/4 vintage

When pulling the engine apart, we discovered that the crankshaft was a little out of the ordinary (so we believe anyway). It's a full circle (disc) crank, but unlike the early full circle cranks, this one appears to be forged rather than machined from a solid

I wonder if any of your guys that own Crescents now, or back in the day, have encountered a similar crank. We think that this is pretty much as it came out of the factory in Uppsala, Sweden and certainly, the motor has never found its way across the pond, so it'll not be the work of Dick O'Dea or others

Just wondered if anyone could throw any light on it

A few photos are attached. Note also that the crank has been balanced somewhere over a period of time. Not sure if this is original Crescent work

Any info would be much appreciated

As with the other Crescent CS we have, we are planning on restoring and racing this is the increasingly popular Classic Hydro series that we have in Europe

[corin_huke]

I thought I'd send you guys some photos of the boat on which we intend to run the Crescent CS

When the original rig was found the thought was to restore the original hull, but after looking at it, it really was in too bad shape - not surprising as it'd been lying in someone's back yard for circa 20 years!!!

Using the original hull, which we think is a Runne from Sweden, as a template a new one was built. It's not an exact copy - a few minor changes were made, ie to make it a little longer, so that it could also be used to run Konig engines from the 70s

[corin_huke]

The boat was finished using a similar style to the rig run by John Rohm, Sweden, back in the day.......

[corin_huke]

The pistons that came out of our recent Crescent restoration project (above engine) were very interesting. On the left is the 'conventional' Crescent piston (a modern day copy) but on the right, the ones out of the motor

We are currently trying to figure out who did this work on the pistons

[Thomas]

Doris, What are those small holes for?

[smittythewelder]

Can't answer your questions, Corin, but what a fun project!! Beautiful cabover, and where did/do you guys get those drape-molded cowlings?

And please tell us over here about your Classic Hydro series. We don't get much input from you Brits or the Europeans except for occasional race results. Photos like yours, of racers working on their equipment in their backyard or shop, or in the pits (look at Wayne Baldwin's shots), are always of interest to us. I wish we could get such photos from racers in Japan and China and anywhere else, but they don't seem to come here much. Only the fellows who race small Stock runabouts in Equador have shared many photos here.

[John Schubert T*A*R*T]

Here is an answer from Dick O'Dea
Thanks for your note, I am sorry for the delay. We have been in IL, as Barb's Dad
passed away and she had quite a few details to handle. We had planned a trip to
Las Vegas over 6 months ago. When we returned from IL we were off to L.V. 2 days
later, and I just got behind in correspondence. I do not know how you reply to boat
racing forum questions, but here are the answers. I cannot see a difference in the crank parts, the large plugs were heavy metal slugs.All the cranks and parts were made in Germany, I believe by( Koben Schmidt) spelling may be off. The small
holes in the pistons skirts are about 1mm in dia. and drilled to lubricate the chrome
cylinders and prevent scuffing. The later replacement pistons were made by Mahle,
and we machined in the transfer port cut outs in the skirt, and the boost port window and oil holes. Some early replacement pistons may have been machined in Sweden

Will do my best to make the reunion.

[BJuby]

Always loved those Crescent engines. Really interesting design. Maybe one day I will be able to add one to the collection.

[Jaybird]

I have several Crescent Class C motors, but no spec information. Can you assist me with this?
Thanks
Jay Young

[John Schubert T*A*R*T]

I have several Crescent Class C motors, but no spec information. Can you assist me with this?
Thanks
Jay Young
I will look in my inspection manuals in a few days. Would you sell one of your Crescents to me. I drove a Crescent in APBA class C Outboard Hydro for Dick O’Dea. Won a lot of races.

[John Schubert T*A*R*T]

I have several Crescent Class C motors, but no spec information. Can you assist me with this?
Thanks
Jay Young
I will look in my inspection manuals in a few days. Would you sell one of your Crescents to me. I drove a Crescent in APBA class C Outboard Hydro for Dick O’Dea. Won a lot of races.

[Albert]

Here is an answer from Dick O'Dea
Thanks for your note, I am sorry for the delay. We have been in IL, as Barb's Dad
passed away and she had quite a few details to handle. We had planned a trip to
Las Vegas over 6 months ago. When we returned from IL we were off to L.V. 2 days
later, and I just got behind in correspondence. I do not know how you reply to boat
racing forum questions, but here are the answers. I cannot see a difference in the crank parts, the large plugs were heavy metal slugs.All the cranks and parts were made in Germany, I believe by( Koben Schmidt) spelling may be off. The small
holes in the pistons skirts are about 1mm in dia. and drilled to lubricate the chrome
cylinders and prevent scuffing. The later replacement pistons were made by Mahle,
and we machined in the transfer port cut outs in the skirt, and the boost port window and oil holes. Some early replacement pistons may have been machined in Sweden

Will do my best to make the reunion.

I know I’m answering an old question here but your spelling on the German crank manufacturer should be kolbenschmidt they still produce a lot of pistons for some oe German auto manufacturers.

[Whiskers]

Just seen this post, Chris Applebee had / has an engineering shop in Rayleigh, he did a lot of work on the c/ shafts, info maybe of use.
I worked for Crescent Marine years ago until Crescent was taken over by Volvo Penta.