RCM&E July 2005
You cant get much hotter than this one, straight from the Just Engines suite case after their recent factory visit to China, and a brief test run on their test bench.
Another exciting new engine to add to the existing range of ASP engines, at last a single cylinder four stroke of over 120 size and at a decent price.
On close inspection its approximately 4mm longer than a 120sized four stroke but with the same engine bearer width and bolt spacing as a 120, but with a little bit of middle aged spread around the centre of the crank-case, to take up the extra cubes.
This one should hit the spot with most of us that are suffering from a wheezing 120 in the so called 120 sized ARTFs that really could do with a bit more get up and go.
Will it live up to my expectations read on and we will endeavour to find out
ASP FS 180 Strip
Where to start? Lets start the strip by removing the carb and intake manifold, this is done by removing the 2xM3carb retaining cap head bolts. The carb can then be gently eased from the intake manifold. The pressure die cast alloy intake manifold, is retained to the cylinder head by 2xM3cap head bolts, be careful when removing these so as not to damage the fibre gasket. This is a very nicely cast part, and it contains the chrome plated steel pressure nipple that?s sealed by a fibre washer. This is connected to the timed crankcase breather nipple by a supplied piece of silicon tube
The rocker box cover is the next part for removal. Retained to the cylinder head by 2xM2.5 cap head bolts, and pressure die cast from alloy. Once this is removed we have access to the 2 machined hardened steel, rocker arms, adjustable tappets and lock nuts. Tappet, setting gaps are .1mm from cold. The central M4cap head bolt and its locking washer, can now be removed releasing the rocker arm assembly.
The 2 hardened steel pushrods can now be removed, leading you on to the next job of removing the cylinder head.
5xM4cap head bolts retain the cylinder head. Remove these diagonally, working across and around the head, a couple of turns at a time so as not to distort the head, [with the same rules applied in reverse for reassembly] As the head is still under pressure from the 2 machined bar stock alloy, push rod tubes that are sealed to the head and crank case by 4 rubber O rings.
The cylinder head on the 180 is of a very quality. Its been Pressure die cast from alloy, with cast in bronze valve seats and valve guides and has very smooth gas flowed porting, the wedged shaped combustion chamber has been bored and tapped for a long reach four stroke plug, and fitted with 2 hardened steel valves, the inlet being slightly larger than the exhaust. Each valve is fitted with a single valve spring, cap and pair of steel retention collets. Great care must be taken if removing the valves, as the springs caps and collets can fly every where. Sealing of the head to the crankcase is by alloy head gasket. Well that just about wraps up the head.
Cam box cover, Cam shaft and Followers
2xM2.5 cap head bolts retain the die cast alloy cam box cover. The cover is sealed by a plastic gasket, and is fitted with a ball race to support the hardened steel camshaft, with a further bearing for the cam being fitted deep inside the crankcase.
Looking into the cam box at the camshaft, on the face of the cam gear cog there is a timing mark.
Cam timing for the ASP180 is by having the piston at TDC [top dead centre] with the timing mark at 12 o'clock
The pressure die cast back plate is the next part for removal, it is retained to the crank case by 4xM4cap head bolts, and has the carb mounting flange cast on at the top, this as mentioned earlier has been tapped for its 2xM3 carb retaining bolts The back plate sits deeply into the crankcase and is sealed by a plastic gasket. Now its time for the next job, and that?s the removal of the liner piston assembly.
Liner and Piston assembly
As is usual with ASP engines the liner is a very good fit into the crankcase. This makes for excellent heat dissipation so a small amount of heat was applied evenly around the crank-case cylinder fins. The crankshaft was then rotated and the liner raised up just enough to be pulled out by hand. Upon inspection the liner is made from steel, with a retaining lip at the top, Its been Case hardened, then finished by fine
grinding and lapping.
Now lets remove the piston and con-rod assembly, so it?s round to the rear of the crankcase. In the centre of the case Just above the back plate there is a hole. Looking into the hole, align the gudgeon pin with the hole, then give the rear of the case a firm tap into the palm of your hand, and the fully floating hardened steel gudgeon pin along with its PTFE wear pad can then be removed.
The single ring piston is a permanent die casting from alloy, is of the slipper type and fully finished by machining. Internally it has two large webs to support the fully floating gudgeon pin. This has been fully bored, for lightness and is retained at the front by a semi blind hole in the piston. It is fitted with a PTFE wear pad at the rear, to ensure no damage is done to the liner when the engine is running.
This leaves us with the heavy-duty con rod. CNC machined from high tensile alloy. Bronze bushed at both ends, with a single oil hole centrally at the top for the small end, and two oil holes for the big end. Now it?s time to remove the crankshaft.
Lets start from the front by removing the black chemically finished, steel prop-locking nut, prop nut and prop washer. Next in line is the turned from alloy bar stock prop driver, with its helically cut driving face and dirt shield at the rear. It has been cut internally with a slot running axially, this is for the steel woodruff key that retains it on the crank-shaft. These parts out of the way the crankshaft can now be removed with a firm push.
The heavy-duty crankshaft is machined from a single billet of steel. The heavy duty big end bearing has a Dia of 9mm, and is supported by a large fully counter balanced flywheel.
Moving forward the next part of the shaft is for the rear bearing, this has a Dia of 17mm, and is bored with a timed breather / oiling hole that exits into the centre of the shaft. This boring is blind at the front but opens at the rear into the main case. this is to relieve bottom end pressure, and excess oil as the piston descends. This excess oil lubricates the camshaft , valve gear and bearings it then exits the case via the pressure / breather nipple with any excess being recycled through the carb induction manifold as mentioned earlier.
On to the next part of the shaft, this has been cut, with the skew gear drive for the camshaft, and has a plain bearing portion of 13mm Dia. Forward then to the front bearing part of the shaft, this has a Dia of 10mm, and has been cut axially for the steel woodruff key that retains the prop driver. The next part of the shaft has a dia of10mm this is the out put part of the shaft, for the prop now all that remains is the portion that?s been cut with a UNF thread for the prop nut and locking nut. now for the crankcase.
When I was first told I had a 180 four stroke on its way to me, I thought it would be quite a size, but surprise, surprise, the crank-case is just a couple of mm longer and higher than a 120 with bearer and bolt hole spacing just the same.
The 180 Crank-Case is of a very high quality, pressure die cast from alloy with a finish as clean as engines of twice the price. All details are clearly defined with no flash or pockmarks and any machining carried out, is to a very high standard.
The front end of the crankcase is very stiff. With 3 axial webs between the main case and the front bearing housing, that has been recessed for the prop driver. That acts as a dirt shield, for the front bearing. Further stiffening comes from the cam timing chest that is also webbed to the front of the cylinder fins. Each side of the crank case has a very substantial mounting lug, with the left side or exhaust side of the case, containing a timed, chrome plated, steel breather nipple, that is sealed by a fibre gasket.
Internally the case has been fitted with two quality heavy duty bearings, for the crank-shaft, with the front bearing is of the semi sealed type to give protection against dirt ingestion.
The main body of the carb has been pressure die cast from alloy, it is of the push on type using a rubber O ring for sealing. Fitted with a very smooth operating, steel throttle barrel. that has been finished by fine grinding, and has a choke bore Dia of 11mm. Internally the barrel has been fitted with a brass slow running jet that is sealed by a rubber O ring. The barrel is fitted with an steel adjustable throttle lever, that is retained on the barrel by an allen grub screw the barrel is then retained in the body of the carb by a cheese head screw.
The main needle valve assembly is from steel and has been finished by chemical blacking, it is fitted with a very good ratchet device for the fuel needle and is sealed by rubber O ring , the needle has been bored centrally for an extension, and fitted with a retaining grub screw.
Rounding up the fibre washer sealed chrome plated steel fuel nipple, is fitted in a vertical position, giving you the option of reversing the carb, to suite your models requirements.
Silencer and Exhaust manifold
The Exhaust system consists of a chrome finished steel manifold, with a locking nut at each, and a pressed together silencer with an internal baffle.
The front part of the silencer is turned from alloy bar stock, and contains a
steel tank pressure nipple. The rear part, the tail pipe, is also machined from alloy bar stock and has been is pressed into the front. As the engine employs OS 14mm fittings a wide range of silencers and pies are available
At last a budget single cylinder 180 sized engine, the options for over 120 sized engines before this engine arrived were for very either very expensive twins or fitting a 2 stroke.
When the ASP180 arrived on my door step it had been briefly run as mentioned earlier, so I was quite surprised to find it was still very tight and I could not hand start it. But I did not despair as a quick dab with the electric starter had it running instantly and it soon settled down to a very good steady idle. Instant starting was the norm for the whole test from either hot or cold, with excellent throttle response throughout the rev and prop range. The ASP proved to be a good performer and threw props of a larger pitch than I expected, enabling me to try out a couple of super new Hawk Wooden props, that will soon to be available from Flair Models Ltd.
The ASP180 was given a very thorough thrashing taking some 4 hours, and then dismantled showing no signs of wear or of the abuse I gave it, as the photos will show.
This engine will prove to be a top seller being of excellent value for money and I nearly forgot to mention, it has now freed up enough to start by hand.
It will surely prove to be a top seller thanks to being excellent value for money and physically small enough to add much needed 'grunt' to underpowered models/ There's nothing undesirable in terms of it's build quality either.
Configuration: O,H,V Single cylinder 4 stroke, with 2 valves, Steel Liner with single ringed alloy piston. and twin ball race crankshaft
Stated Power: 2.80 BHP
Bore and Stroke; Bore 35.95mm Stroke 29.0mm
Weight; 1040g including silencer
Plug used in test; O.S F
Fuel Used in test: Four Stroke Specially made by Flair Products
5% Nitro, 2% Castor, 15% Synthetic
Average noise test; 82 db @ 7mtrs.
Supplied with; Full English Instructions, 3 x Allen Keys, 2Year warranty
|Size ||Type ||Idle Rpm ||Max Rpm |
|16x8 ||APC ||2600 ||8900 |
|16x8 ||Master ||2600 ||9400 |
|16x10 ||APC ||2600 ||8200 |
|16x14|| APC ||2600 ||7000 |
|16.5x12 ||PROFI ||2600 ||7400 |
|18x6 ||Master ||2600 ||8400 |
|18x8 ||Hawk Wood ||2600 ||8200 |
|18x10 ||Hawk ||2600 ||7800 |
Read Steve Dorling's review of the A.S.P 1.80fs for AMI here
You can find more ASP engine reviews here.