Dyno compression ignition

[Ramon Wilson]

I don't think you are right here Jason - the bypass ports (or transfer if you prefer) should be just below the exhaust ports.

As said checking the timing on the timing calc gives the correct periods in the right place for this type of engine as called for on the liner drawing. What appears to be wrong is the position of the inlet hole in the top crankcase block. The timing as dimensioned will 'run' but turning the liner 180 degress is going to make for some pretty sore fingers

Well that's how I see it 

Ramon

I perhaps should have added. As said before - it's the lower edge of the port that defines the timing period for the inlet - controlled by the lower edge of the piston. Or am I missing something here 

[Jasonb]

Its not so much the relation of port to exhaust that I was commenting on but the fact that on the doubel dyno section from Stricktly IC ( I don't have the smaller drawings) the bypass/transfer is facing the venturi but from the position of the holes in Rod's photo it looks like he has the inlet facing the venturi.

So is one of the liners 180deg out of place? Or could this explain Rod's earlier query about a pusher prop??

J

[tangler]

Jason,

If you look at the errata on page 31 of SIC Apr/May, 2000 : "The cylinder drawings are incorrect. Actually if they were rotated 180 degrees they would be correct". 

The amended drawing is also slightly confusing because the hidden detail, which I presume was dotted on the original drawing, has come out as bold on the reproduction.

Thanks, guys for teasing this out,

Rod

[Ramon Wilson]

Yes I did realise that Jason but I was pointing out that in relationship the bypass position is much closer to the exhaust port (relative to the cylinder flange) than the inlet.

The Double Dyno 'clip' you show definitely has the liner 180 degrees out of phase. As you rightly say Rod has the inlet next the venturi which is where it should be.  I still feel that the inlet position on the block is an anomaly or as Rod states a compromise in production methods of the time - Though the company produced an earlier engine I think I'm right in saying that this was the first commercial diesel engine. Though it is a very old design it shares these characteristics with many other side ports.

To Boot - As the piston rises the inlet port is uncovered by the piston skirt allowing fuel in - as it descends the inlet closes and the transfer (bypass) opens just after the exhaust has cleared.

Looking at Rons drawings yet again though I can see nothing untoward on the timing layout - its Strictly I/C that appears to have it wrong.

I missed Rod's earlier query about a pusher prop - as a side port engine's timing is symmetrical about the centre line they will run equally as well forwards or backwards - was that it?

Rod - I know what you mean - hang on to that surplus metal as long as possible 

Regards - Ramon

[Jasonb]

Thanks Rod. I had not seen the correction in SIC which would explain the reason you had it the other way round to what I had seen, I'll let you both get back to the workshop now which is where I'm about to head.

There is a note in one of the SICs that the ports don't line up too well with the case but its as the original was.

J

[Ramon Wilson]

Jason,

Is that 'Double Dyno' twice the original physical size or twice the capacity? - it was on the list for a 5cc version - perhaps I'll do the DEEZIL instead at some stage.

A bit of over time is on the cards for me too tonight   

Ramon

[tangler]

Ramon,

You should have a pm.

Cheers,

Rod

[Jasonb]

If Rod's pm does not answer the question this sould

[Ramon Wilson]

Thanks Rod and Jason - 16cc now that could prove to be a bit of a finger ripper 

I'll keep to the 'fives' 

Ramon

[tangler]

Crankshaft next:

This is my starting point:



I've got a collection of large bolts, I always pick one up when I see one.  I mounted the hex end in the 3 jaw, turned the shank down to 1/2" and put a centre in.  These bolts turn quite nicely, a bit tougher than mild steel which, I think, makes them quite suitable for crankshafts.  The bolt was then turned around,  mounted in the 1/2" collet, the hex turned away and a centre put in this end



With a bit of dead reckoning from the OD I put in a centre for what will be the crank pin.  On the other engines with overhung crankshafts that I've made, I've always used a separate pressed in crankpin but I don't think there is really enough meat in the web to do that with the Dyno.



The following was guided by Ramon's Super Tiger build here :http://modelengineeringwebsite.com/Super_Tigre_5.html.  Many years ago I made one of these Keats type angle plates http://www.collegeengineering.co.uk/KeatsAngles.htm.  I've never actually used it before.  For the moment, I've left the shaft over size at 1/2" to provide better support.  So, bolted to the mill table



I milled away most of the meat around the embryo crankpin



The whole assembly was then removed from the mill and bolted to a faceplate in the lathe.  I centred the crankpin using a wobbler, which is simply a length of silver steel with a point on one end and a centre hole in the other, supported by a centre in the tailstock.



I had a bit of difficulty getting a fine finish on the crankpin.  There isn't really enough length to do any post turning operations on this rather small diameter without risk of barreling.  There are a couple of score marks remaining, which will help with oil retention . 



I now needed to turn the crankshaft down to size and thread the end.  The drive pin is tapped into an area of the web that will be cut away later, as I was reluctant to drive on the rather slender crankpin.



The main part of the shaft was turned down to be a running fit in the crank bearing. Again, getting a good finish was a problem until I tried Jason's suggestion of using a CCGT tip for the finishing cuts.   The original Dyno uses a prop driver with a taper that matches one on the cranshaft.  I prefer to use a separate tapered splt collet that goes over a parallel on the shaft because it allows for better control of the crankshaft end float.  The Dyno thread is 4mm but I have cut a 3/16 BSF (32tpi) thread to 3/4 depth and finished it with a die.

 

This is a far as I want to go for the moment, I can still return it between centres if I need to do any further work.

[Ramon Wilson]

Nice work Rod  but may I offer a word of caution?

Given the material is of 'unknown quality' and not looking particularly tough (hence the possible difficulty of getting a finish)  I would not personally use the 'drawn' type Phosphor Bronze for the big end bush - basically that's the 'coppery' coloured type bronze. It is not intended for use as bearings on unhardened  material and will pick up very easily, which could ruin that bottom end - if it does pick up you would have one hell of a job getting the con-rod off the pin 'in situ'.

Though I do use it myself I'm always concerned about this - all the shafts are EN24T and highly polished on the pin but the worry is never that far away..

Without looking I can't recall if the crankcase bearing is sleeved - if it is then the same thing goes - either use the 'cast' yellow bronze or cast iron - you won't have the potential galling problem with either.

Hope you don't mind my 'oar poking' 

Hope too, to see you Sunday - if I can help with material for the above let me know

Regards - Ramon

[BronxFigs]

HELP! Re: Tangler's posting # 92.....

Could someone be good enough to post drawings/renderings showing  the "corrected" port locations, etc. for the T. Maciag- "DOUBLE DYNO" engine that was serialized in Strictly IC Magazine.  As noted, even the corrections were drawn wrong and then printed wrong by Strictly IC.  It's confusing.

Thanks for any help.

Frank

[tangler]

Given the material is of 'unknown quality' and not looking particularly tough (hence the possible difficulty of getting a finish)  I would not personally use the 'drawn' type Phosphor Bronze for the big end bush - basically that's the 'coppery' coloured type bronze. It is not intended for use as bearings on unhardened  material and will pick up very easily, which could ruin that bottom end - if it does pick up you would have one hell of a job getting the con-rod off the pin 'in situ'. .....

.....Without looking I can't recall if the crankcase bearing is sleeved - if it is then the same thing goes - either use the 'cast' yellow bronze or cast iron - you won't have the potential galling problem with either.

Thanks for the warning.  On my previous engines I've used silver steel (unhardened) for the crankpin in PB.  The crankshaft bearing is sleeved with CI, I'll now use the same for the big end bearing. Ta.

Frank,  if you look back to the end of page 4 of this log (# 59) you'll see an extract from the drawings showing the correct ports and passages - just multiply  by 2 for the Double Dyno (I think)

cheers guys,

Rod

[BronxFigs]

Rod-

Thanks for the help and for noting the corrected drawings.  Too confused to realize that what I needed was already posted.


Frank

[BronxFigs]

Rod/tangler
Ramon
Jason...et al.

THANKS!...for all the interesting comments re: porting hole locations, timing events, bearing/bush material, etc.

I have a keen interest in following along with this photographed, engine-build.  The documentation, photos and explanatory comments all help to clear up many confusing (to me) details regarding the DYNO....especially confusing are the porting locations on the cylinder.  As noted in comments, either the Strictly IC drawings (Double-Dyno) were unclear, and/or the porting holes in the original drawings was an anomaly.  So at this point, I am dazed and confused.   I have some rather amateurish questions concerning the positions of the porting holes, but for now, I will just sit back at watch as the rest of the engine takes shape.  Then, I will ask for more clarifications from the Masters.  Maybe it shouldn't, and maybe it will ultimately not matter, but he misaligned induction porting still gives me concerns.

A hint at where I will be going and why I need your brain-power, and collective help.    At some point in the near future, I will start to seriously consider building a steroidal version of Ted Maciag's "DOUBLE-DYNO"....but scaled-up, in physical size.  (As in some other cases, maybe size will matter). This gigantic engine will be used for display, and maybe will run occassionally at shows etc.  Size and weight will NOT be a factor. 

 Last year when I joined this forum, I was encouraged to think outside of the box, and was gently guided to follow my endeavors to build some scaled-up versions of vintage diesel engines.  I want to use the drawings for the "DOUBLE-DYNO as a point of departure.  Not wishing to hijack this thread, I will say no more.

tangler/Rod....Love watching the DYNO build.  Thanks for the inspiration.


Frank