ST-2 Mystery Plugs

[quinnf]

I have an ST-2 powering a 7.5 kW generator.  Was getting it ready for winter and noticed a couple of plugs that I hadn't seen before.  They appear to be lube points, but I'm not sure.  I don't have a manual, or even a diagram of the engine, so I'm in the dark about this engine.  Can anyone tell me what I'm holding in my fingers?

Thanks,

quinnf

[Tom Reed]

Just a guess, would one fill those cups with alcohol and light it to warm the air for cold starts???

[quinnf]

Hi Tom,

I've never heard of anything like that on a high speed diesel, which the ST2 is.  I suspect they're oil cups since they have a small hole in the bottom, but I'm unfamiliar with the anatomy of the engine, so your guess may be better than mine.  I'd like to get a manual for the engine, but they don't seem to be available any longer.

q.

[dcamac1]

The ST/W1,2,&3  workshop manual #027-08205, states on page 51 "Provision is made for a cold start device which is screwed into the machined face above the inlet port."  My ST2 has the same plugs. Associated publications are Operators Handbook ST1,2,&3.....#027-08024 and Parts List ST1,2,&3.......#027-08059. dc

[Tom Reed]

Does the manual say how they are used?

[mobile_bob]

does the plug screw into the intake port?  or..

does it screw into a prechamber ?  from what i can tell the st is a direct injection engine, so it has no prechamber?

what does the end of the plug look like? someone mentions a hole? how big is the hole?

curious that the manual mentions the inclusion of this plug as a cold start device, but no mention how it is used?

i wonder if it screws into the intake, maybe you replace the plug with a glowplug/heater?

the changfa's idi engine's have a similar plug, that is hollow in the end, it fits down into the prechamber, it is used by stuffing it with pretreated (nitrated paper) the heat of combustion causing the paper to start to glow/smoulder which aids in cold starting... i guess the paper is probably tissue and is consumed and causes no issues with wear or other nasty problems?

btw, thanks for asking this question!

reason being is i learned something of use to me today,

some time ago we talked about the possibility of building a single cylinder diesel using off the shelf parts, while a crankcase can be made of welded steel the cylinder head really needs to be cast.

making a casting with water jackets is much harder when the molds must of sand cores, it is much easier to provide for the water jacket if the head can be cast in two parts! an upper and a separate lower! 

no sand cores needed, how cool is that?

and casting one out of aluminum is not outside the realm of possibility for the diyer either, made in two parts i can see how that could be done much more easily.

another thing that makes you go "hmmmmm"

bob g

[quinnf]

Hi Bob,

The white plastic plugs, as well as the steel/iron holes they fit into have about a 1/32" diameter hole in the bottom.  Hole is cylindrical with a taper at the bottom, like it was drilled with a twist drill.  It looks like a liquid is meant to be poured into the hole.  Was thinking it might be an oiling point, but perhaps alcohol or starting fluid is poured in and dribbles into the intake port.  As far as the "cold start device that is screwed into the machined face above the inlet port," it's possible that I'm seeing only part of the setup.  I was mainly concerned that if it was an oil cup, I might be overlooking a maintenance item.

It's a neat engine.  Really sounds like a Diesel!

Re: building an engine, it seems the top end (cylinder/head/piston, conrod) are available for reasonable prices.  Alls you need to do is build a crankcase for it and work out how to oil the bottom and top end.  What we were talking about back then was making a horizontally opposed twin, like a BMW motorcycle engine, but only Diesel.  The balance issue would largely be mitigated by the opposed cylinders.  Certainly a project, but the Wright Brothers built their own engines, so nothing's impossible.

q.

[quinnf]

Ahh, found a manual online.  Regarding the funny little cups, apparently you fill them 1/3 full of regular lube oil and inject the oil before starting when temps are below -10 deg. C.  Purpose is to raise compression and to seal valves/rings with oil in case the engine hasn't been started in a really long time.  That factoid from a kind gent (Combustor) somewhere north of West Australia. 



[Edit:  In case anyone's interested, the manual is online at http://www.winget.co.uk/document/LISTER%20ST%20WORKSHOP%20MANUAL.pdf.  It's worth looking at in case you (like I), can't resist looking up the skirt of a new engine.}