Crescent Super C Moto, Talk about rare....r

[Instigator]

These things were bad ass and was my favorite class in my early days of racing.
Can't remember ever seeing one for sale.
They were wicked fast.

http://www.ebay.com/itm/121272568326?item=121272568326&viewitem=&sspagename=ADME:B:SS:US:3160&vxp=mtr

[Phillip Mason]

I love these motors. I still think it is one of th best sounding motors Ive ever heard.

[Mark75H]

There have been a dozen or so sold on eBay in the past 5 or 6 years and about that many sold thru other internet forums as well.

Its hard to find one with functioning ignition and lower unit, they are quite fragile. This one has a second or third generation ignition and US made mid section with Merc clamps, so its a put-together by Dick O'Dea. Dick was the importer and when Crescent stopped making complete motors he built up motors from parts he imported. When parts weren't available, like the mid section and clamps, he had mid sections cast in the US and put Merc clamps on them. Later there was no ignition available at all and he put the belt driven ignition from the 3 cylinder Merc 650/700 on them ... until the Swedish supply of crankshafts was depleted.

It was an excellent design when it was first executed in the early 1960's but the makers packed the cylinders so close (by slightly canting the porting) that there was no room to upgrade when the next generation of porting design came out in the middle 1960's (MZ in East Germany - search Walter Kaaden Ernst Denger MZ Suzuki). Dieter Konig had plenty of room in his motors and the Crescent was done outside of classes where it was the only motor allowed.

[Instigator]

There have been a dozen or so sold on eBay in the past 5 or 6 years and about that many sold thru other internet forums as well.

Its hard to find one with functioning ignition and lower unit, they are quite fragile. This one has a second or third generation ignition and US made mid section with Merc clamps, so its a put-together by Dick O'Dea. Dick was the importer and when Crescent stopped making complete motors he built up motors from parts he imported. When parts weren't available, like the mid section and clamps, he had mid sections cast in the US and put Merc clamps on them. Later there was no ignition available at all and he put the belt driven ignition from the 3 cylinder Merc 650/700 on them ... until the Swedish supply of crankshafts was depleted.

It was an excellent design when it was first executed in the early 1960's but the makers packed the cylinders so close (by slightly canting the porting) that there was no room to upgrade when the next generation of porting design came out in the middle 1960's (MZ in East Germany - search Ernst Denger MZ Suzuki). Dieter Konig had plenty of room in his motors and the Crescent was done outside of classes where it was the only motor allowed.

Thanks for the history lesson Sam. I think you educated us on these in a thread a while back. I was going too try and find it and link it to this thread.
I remember them racing in the 70's and they were by far, the fastest of the "Stock" division. Thinking a Kilo record in the low/mid '90's in its day which was 10+ over the 44 cu.in. 55H D Merc's.

[Mark75H]

I bet its in the 3 cylinder thread. The Screamandfly internal search engine sucks. You can find what you are looking for faster by telling Google or Bing to look for what you want on SnF ... at the same time you can search for info on other sites

I would love to buy this motor, but I don't have what the seller thinks its worth right now and he is in a hurry to cash a few motors out to purchase a new toy for a different collection. :(

I will probably buy one later this year.

[olboatman]

Hey Mark75H I remember watchin these babys when I was younger. I loved their sound also! Do you have an idea what rpm they would spin. Also are those Tilitsons with butterflys. Thanks Gary

[Mark75H]

Alkys used a 30mm Amal and cranked 8,500. The CS/Super C gasoline burners used a Bing, it might have also been 30, but I suspect it was 28mm or 25mm (I have a note that might be the Bing model number and its "8/25/16") and they would spin 7,500

"Super C" is an american nickname for the motors shortened from the "C Super Stock" APBA class they ran in. The factory just called them "CS" for C Stock vs just "C" for the alky version. Stock racing was never as big in Europe as in the US, but the Crescent C in both versions held the European records in their day. In Europe their Stock competition would have been 30hp 30H's at 120 pounds ... the CS Crescent pulled an easy 50+ hp and only weighed 70 pounds ... on alcohol they pulled 80+ hp - better than 1.14 hp per pound.

Like the Chevy Vega car motors these used a chrome directly on aluminum bore

In prototype development the original block had the carbs on the other side. When they first ran it on a boat they quickly discovered that it got a lot of spray in the carbs and the design was flipped over to put the carbs on the left where they were clear of spray. If you look at the Anzanis and Konigs built before the Crescent ... you see that they already had the carbs on the left.

[Instigator]

the CS Crescent pulled an easy 50+ hp and only weighed 70 pounds ... on alcohol they pulled 80+ hp - better than 1.14 hp per pound.

My favorite picture of that motor is in Rusty Raes book showing a guy carrying one to tech at the Stock Nats in Dayton.
Just looks mean.

[olboatman]

Thanks Mark75H for the great info! Gary

[Mark75H]

If you dig deep enough there is even more about the development of these on some Swedish and German language websites. Some of the info comes directly from Gert Lowensin?sp and some of the others actually involved. Henry Johansson and Thomas Martenson been great contributors on the subject of these motors.