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Author Topic: SC .61  (Read 6813 times)

glennb2006

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Re: SC .61
« Reply #25 on: November 15, 2007, 11:21:38 PM »

New bearings fitted, all cleaned out and new con rod, reassembled and fitted onto test bench again with an aero prop, fired up easy and run for half an hour to settle in it again.

Back into the boat tomorrow for round two!!


With luck it will get a run out on Saturday.

Glenn
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glennb2006

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Re: SC .61
« Reply #26 on: November 18, 2007, 01:20:13 AM »

And it ran well for around three hours today, if anything seemed quicker than before. All went well until the receiver decided to die, failsafe did it's work and the end of the day.

Not too worried about the receiver, it wsa secindhand and only stood me a tenner.

Glenn.
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OMRA117

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Re: SC .61
« Reply #27 on: March 27, 2008, 11:37:42 AM »

Slight curve on the topic but though it might be of interest.
I am running a stock ASP 61 for OMRA this year. (made in the same factory as the SC, though higher compression)
Anyway the engine is also V. tight and broke the Conrod on it's first fire up and had to go back to the shop.
Seems to be a good engine if your on a budget (as I am). But it gets me on the water until I can afford a race engine.
I run Formula Irvine 10% nitro 14% klotz, 4% castor, with an OS8 plug.
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BJ

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Re: SC .61
« Reply #28 on: April 10, 2008, 04:07:46 PM »

Hi, been there many times  :'(

what fuel and total oil content did you use?

 may of started a hot potato here, lets see how the thread goes  O0

Gary.

See http://www.justengines.unseen.org/acatalog/Model_Fuel_Info.html on this point - particularly Point 2.
I would not touch SC but have just bought ASP. I think that ASP are the better engine and am running it on Supaglo 10 (I used to use Duraglo 10 with extra castor)
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ids987

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Re: SC .61
« Reply #29 on: April 11, 2008, 12:21:53 PM »

It may have changed now that ASP is on "Series 3", as I'm not sure if the most recent changes have been applied to the SC branded engines. The ASP 61 and SC 61 were previously identical though.
A couple of years ago, I had a SC .61 with shot bearings - which scored the piston and liner, and a ASP .61 with a broken rod. I made one engine out of the pair of them, and I would defy anyone to see any difference in the internals.

Ian
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glennb2006

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Re: SC .61
« Reply #30 on: April 20, 2008, 04:42:57 AM »

The SC 61 story continues, it has run well since the rebuild, but started to get bored with it. So, with "advanced rc model boats" by John Finch in one hand, and engine in the other, I ported it.

For anyone interested, here is the timing data:

Standard: Exhaust 154 deg, Intake 187

My targets, which I achieved, were:

Exhaust: 172 deg, Intake 200.

All measurements were done simply using a degree wheel and a piano wire pointer fixed to one of the head bolts.

I was really easy to do, just took my time with a dremel. I was advised to lighten the piston (Thanks Dave), and after seeing how much metal there is on the standard piston gudgeon pin bosses I can see why my con rod failed. So after much grinding the piston is much lighter.

I have for now left the squish clearance alone, it is measured at approx 0.25mm.

I left the exhasut port "bridge" in place, for no other reason than it was there before I started. The exhaust ports were widened and matched to the crankcase at the extreme edges.

Schneurle and transfer ports were tapered to try to get the fuel "up" rather than "across".

Engine washed off and reassembled. I refitted the stock carb for the tuned motor and removed the restrictor from it.

Back into the boat for some testing, starts as easy as ever, ran it with a 2024 prop, took off and ran OK, revving more easily and higher than before. unfortunately a leaking tuned pipe put paid to any more extended running, so ten minutes is all I have on it so far since the work, and I have not had the chance to play with tuned pipe lengths yet. I think I am slightly struggling to get enough fuel into the engine now too, but more testing soon.

Still running Duralgo 16% nitro.

Has anyone from Elmbridge got any hot set up tips for this motor to take it further that they are willing to share?

Glenn

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OMRA117

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Re: SC .61
« Reply #31 on: September 09, 2008, 01:30:58 PM »

Just to follow up.
The last outing with my ASP 61 ended very sudenly when the carb fell apart as I was starting it, it over revved, and seized.
When I stripped it down the bottom of the piston had broken up and the conrod broken same place as the one pictured before.
The ASP carb is rubbish, it is constantly falling apart!
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andyn

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Re: SC .61
« Reply #32 on: September 10, 2008, 08:07:40 PM »

ASP's, unlike SC's, are not built by the lowest bidder.

I had one for about three days once, it would'nt start, was so tight you could hardly turn it over with both hands, and stopped after about 20s in the air, not good!

I would never have one again, if i was given one it would find a new home rather quickly too...
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