fiery

My Feedback: (2)

I recently picked one if these engines up. Shown below, as delivered.

There was also a 1 cc version.

I have little knowledge of them. Are the 1 cc/1.5 cc engines in this case the last of the A-M diesels? This 'last gasp' production run of the A-M brand engine has not previously been discussed on this forum. There is also mention of a glow variant in the instructions. Has anyone seen or heard of one?

The engine has not been run by myself. I believe it is unrun since first purchased.

Unlike the photograph on the box, where the case is matt bead blast finished, the case has a shiny surface. A pressure die casting. It feels well made and is nicely finished. That said the "R/C carburettor" is a let down. There does not seem to be any attempt to regulate fuel or air at low speed setting. It also has an old fashioned 'split halves' silencer. Guaranteed to leak without rtv sealant applied to the flanges. The silencer inlet aperture is also much smaller than the outlet aperture in the exhaust stack.

I will report in it's running qualities later.

fiery

My Feedback: (2)

Copy instructions posted below.

An article written by Ian Russell on the history of Merco and A-M engines makes mention of this version of the engine. Comments appear in the fourth last paragraph. An on-line copy of the article is linked below. :

http://www.iroquois.free-online.co.uk/merco/merco.htm

chevy43

Any chance you would sell it to me?

I love those...

chevy43

Ok, you should keep it because it is a great engine with a little modification to fix that carb which won't idle...

Mine turns and 8x3 MAS 3,300 rpm idle to 12,200 rpm and an 8x4 MAS from 3,300 to 10,500 rpm.

It is a nice light little engine.

Once you fix that carb it is better than a PAW carb becase that plastic barrel is a nice air tight fit in the carb.

Here is what you do:
Take your modeling knife and cut a tiny notch into the plastic barrel just as it shuts in the idle position. Put it in the part of the barrel you can see when looking down the throat. That serves as the air bleed and stops if from over fueling at idle. Start with a SMALL notch.

Hope that helps.

Trev.

AMB

Fiery muffler looks quite weird is a split design for its entire length?? never saw one like it if that is the case , why would they do that?? martin

ffkiwi

As you'd expect, I have one or two AMs...........................!.....and for fiery's benefit and delight-the 1.5 glow version below-plus some of the others in the 10-15 range! The Mk1s can be distinguished by their more rounded cylinder heads and anodised turned dural tank, the Mk2s have a sharp edge to the cylinder head, and a moulded nylon tank. Mk2s were less powerful, as the exhaust and transfer timing had been reduced (because the cylinder slots were narrower-to reduce the occasional-but rare-case of cylinder sheering in the Mk1s when run hard) Mk3s (my nomencature, to distinguish them from earlier versions) were schneurle and ABC.

A bit of history-which you should all know (or hand back your 'oily hand brigade' membership card!)-AMs were designed and initially manufactured by Dennis Allen of Allen Engineering and marketed by Mercury Models-hence 'Allen-Mercury'-the 10 came before the 15-but both shared the same bottom end (as did the Allbon Spitfire/Javelin, DC Spitfire/Sabre and Frog 100/150[the Mk3 version of the 100]. Allen Engineering also took over manufacture of the Merco engines after their initial introduction, when demand massively exceeded the original 'Model Engine Research Company's ability to produce them. Ca 1971, Allen Engineering stopped manufacturing the A-M diesel range to concentrate on the more lucrative R/C Merco engine market.

Subsequently (and I've not been able to establish EXACTLY when) sometime later, Forrest Engineering took over manufacture of the AM diesels-whether they purchased the design rights and tooling, or manufactured under contract to A-M, or under a licensing arrangement I've been unable to establish. These were all the Mk2 versions-and AFAIK Forrest engineering did not produce the AM35, only the 10,15 and 25-and also accessories such as mufflers.

Later still Premier Plastics revamped the design, modifying the crankcase die to the RH exhaust stack version from the original 360 degree porting, and introduced ABC cylinder technology, and a rather simplistic throttle. Tanks were moulded in opaque nylon and should be black or mid blue depending on the model. I believe Premier also did the 25-but I've never seen one, or even a photo. As with Forrest Engineering, the timeline is a bit vague, the only certainty is that the Premier ones were the last.

One of these days I'll get around to doing some comparative testing on the Premier ones compared to the originals. Some pics below-I don't have all of the Premier versions

ChrisM
'ffkiwi'

Mr Cox

I have some of these, both diesel and glow versions. The diesel one runs alright but the glow version was a weak and sad story. The timing of the crank seems too short and restricted for glow I think, I increased it on mine and got some gain, but it needs more work. The muffler is very small and restricted too. Feels like it was designed for diesel and then converted to glow. The muffler gets very hot (on the glow version) and adjusting the needle with the engine running is a pain...

AMB, yes the muffler is split along its length, just like you would find on the Tatone "peace pipes" etc.

fiery

My Feedback: (2)

I do know that Aurora Mfg. made the A-M 25 and possibly 35, for some time. At some stage they acquired the dies and tooling.

Here is an Aurora built A-M 25. Distinguishable from UK manufacture by the gold anodised cooling jacket and screw-in prop driver.

ffkiwi

Well fiery, I didn't know that....! Some of the early Auroras were Frog based-149, 249-but I wasn't aware they'd done a virtually direct copy of the AM 25....always good to find these things out.

ChrisM
'ffkiwi'

Dan Vincent

The AM muffler is also a perfect fit on a Kingcat .09 diesel or the Glocat version.

fiery

My Feedback: (2)

I'd rather have those awesome looking shotgun pipes. Anyone care to swap? [8D]

ffkiwi

Also useful to know-both my Kingcat and Glocat are sans mufflers, so with that info I can copy an AM one and fit that........actually am expended 'Sparklet' bulb from a CO2 engine filler will do nicely with a little bit of milling and drilling..............

ChrisM
'ffkiwi'

fiery

My Feedback: (2)

Nice use for an old sparklet bulb.

This is the KingCat 1.49 cc diesel with the later Muffler

ffkiwi

yes fiery-I have all the dimensions for that one, so I could-at a pinch-produce one-but the Sparklet option (and I claim no originality for THAT idea) is a lot easier-two holes for the screws plus a milled slot, and a suitable tailpipe ID.........

ChrisM
'ffkiwi'

Dan Vincent

The Kingcat came in standard and deluxe versions. The only difference was the Deluxe version had the exhaust header and an aluminum spinner nut.

My Deluxe version started on the first flip, straight out of the box.

fiery

My Feedback: (2)

I ran the Premier A-M 1.5 cc last week-end.

It started easily and ran, as the photo's below show, but was not happy. 8,500 RPM on a Robbe Dynamic red composite 7 x 4 propeller? Things were not well. I did not persist.

I looked in the exhaust. The exhaust port bridge in the cylinder was not centralised in the case port. Way off in fact. Ah - hah. The cylinder is out of alignment.

The top end was dis-assembled. Off with the three screws, slide off the cooling jacket, and out slips the cylinder. Very nice machine work. No swarf or abnormal detritus found. All clean. ABN P/L set up with a traditonal contra-piston in the cylinder. The contra-piston is brass. Porting appears to be the 'vortex' type, not true schnuerle. Interesting.

Carefully put back together with no issues, making sure not to tear the flimsy paper gasket which seats under the cylinder flange. Line up the cylinder exhaust port centrally in the case port. Alignment of spray bar jet will also be checked. Will bench run it again next week-end, weather permitting. Hopefully all will be well.

AMB

FIERY VERY FANCY EXHAUST TWIN STACK INTO MUFFLER, NEVER HAVE SEEN ONE LIKE MARTIN

Mr Cox

Is really ABN construction?
I'm pretty sure mine are just regular iron/steel construction, but it's been a few years since I last had one appart.

fiery

My Feedback: (2)

Sometimes some sleuthing is required.

Two days after putting the engine back together I stripped and checked the NVA. The spray bay has two jets. Similar to PAW. However, jets are not offset, just drilled straight through.

One of the jets was clogged with debris. A pin through the clogged hole and a quick blow-through and squirt with WD-40 soon sorted that.

Something was still not quite right. Turning it over slowly I was not happy with the bottom end. There was definitely a binding about 20 degrees before bottom dead centre. Also, there seemed to be very little fore-aft play in the shaft.

Time for a bottom end inspection . Off with the nicely made screw-in moulded composite back plate. The moulded screw thread is very coarse. I had it out in a couple of turns.

All working parts appear well made and finished. The piston has very thick walls. Judicious lightening may yield some benefit. Another day perhaps. The connecting rod big end is bronze bushed.

Look closely ... as suspected ... the inner face of the plate was fouling the conrod big-end. It's surface is seriously big-end scrubbed. The back plate was over tightened. Minute particles of black plastic swarf were everywhere, telling the story. The front of the bottom end of the connecting rod had also rubbed away a large patch of the black oxide anti-rust coating on the facing surface of the crank web.

Cleaning out undertaken, the back plate was re-installed, unscrewed 1/8 of a turn back from its original seating. . If it leaks I will skim the inner face of the plate by 0.2 mm.

Bottom end is now friction free. There is 0.15 mm fore-aft play in the shaft, in range and acceptable. Piston fit is still really good. Hopefully the next test run will be successful.

brokenenglish

Derek, concerning thebackplate fouling... For non-engineers like me, a thickish gasket would be easier than removing material, and it's also "adjustable" (number/thickness of gaskets) and "reversible", i.e. you haven't done anything permanent, it can be "undone"!

Mr Cox

On some engine one can also add shims behind the propdriver in order to not hit the backplate.

fiery

My Feedback: (2)

She now runs as intended. Pulling a broad blade 7 x 4 with a rich mixture and a little low on compression showed a steady 11,000 rpm.

ffkiwi

That's more like it-I suspect with a flexi nylon Taipan 7x4 you'd get a bit more still out of it..................

ChrisM
'ffkiwi'

AMB

Fiery nice easy fix sometimes you win one with an easy correction, with that back plate rub running with the brakes on martin