OS 300 Radial
#1
Thread Starter

A friend has the OS 300 FR5 SR radial. One head is cracked. Tower is telling him that the part is no longer in production.
My question is: Is their an OS head that will fit this motor ? Maybe one from an old FS .61 ?
My question is: Is their an OS head that will fit this motor ? Maybe one from an old FS .61 ?
#3
Senior Member
My Feedback: (264)
I think you are right, it looks like a OS .61 head to me. If you look at the parts list, the FR300 head contains all .61FS parts.
Your best bet may be to just buy a new or used .61 on epay or here at RCU. I still see these engines up for sale frequently, OS must have sold many of them back in the day.
#4
Senior Member
I don't know what is going on with Tower. Your engine is still offered and is in stock, but no parts. My 120 Surpass II has a bad head,(stripped glow plug) and it is the same head as the 120E which is also currently for sale. The head for that is discontinued. Seems to me that if Tower isn't going to stock parts for an engine, it time they have a very serious fire sale on the ones they have in stock.
Don
Don
#6

Joined: Jun 2006
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From: Reggio Emilia, ITALY
I don't know if they ship to the US, but the head is available through Graupner ([link=https://shop.graupner.de/webuerp/servlet/AI?ARTN=1415.11]Link[/link]).
Radial.
Radial.
#7
Thread Starter

Thanks for your comments, and assistance.
I have another friend, who has the 61FS. We're going to see if the head fits, if a new head for the radial cannot be located.
The link to Graupner is a great place to start.
I have another friend, who has the 61FS. We're going to see if the head fits, if a new head for the radial cannot be located.
The link to Graupner is a great place to start.
#8

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From: Reggio Emilia, ITALY
Forgot to add: the head from an OS FT-120 will not fit (I'm 99% sure).
Just look at the position of the exhaust and intake pipes relative to the pushrod tubes: if you tried to place such a cylinder head on your radial, the intake and exhaust pipes woud be facing forward (more or less), while on the radial the intake is in the back of the head and the exhaust is in the rear right corner.
On the other hand the FS-61 head should fit.
Finally, the Graupner website lists its prices INCLUDING VAT. Orders toward the US should not include this tax, so, if you decide to buy from Graupner, you should pay a price close to 70€, not the 87€ listed. This price, obviously, does not include shipping costs.
Radial.
Just look at the position of the exhaust and intake pipes relative to the pushrod tubes: if you tried to place such a cylinder head on your radial, the intake and exhaust pipes woud be facing forward (more or less), while on the radial the intake is in the back of the head and the exhaust is in the rear right corner.
On the other hand the FS-61 head should fit.
Finally, the Graupner website lists its prices INCLUDING VAT. Orders toward the US should not include this tax, so, if you decide to buy from Graupner, you should pay a price close to 70€, not the 87€ listed. This price, obviously, does not include shipping costs.
Radial.





