Author Topic: piston from "re playing with the old . . ."  (Read 463 times)

mikenash

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piston from "re playing with the old . . ."
« on: June 10, 2019, 11:08:28 AM »
Hi guys

In the other thread I have rambled about barrel and piston . . .

But the piston has a bunch of inscriptions and I thought knowledgeable folks might like to shed some light?

It says:

Piston says, maybe

008 – 0.4025

WELLWORTHY

BLQA 403101/1/0.40T

And see pics attached?

It came up so clean it suddenly occurs to me to wonder if it's an alloy piston?  It's cold and dark and raining out and the engine's 200 metres away so I'm not going out with a magnet now in the middle of the night . . .

Couple pics here, anyway

Cheers

Hugh Conway

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Re: piston from "re playing with the old . . ."
« Reply #1 on: June 10, 2019, 04:39:37 PM »
I don't know about the piston but......
The photo of the crankcase, rod, piston, etc: is it from some nearly parallel universe where things are a mirror image of things here?
I know it's early, but I have had my coffee.
Cheers
Hugh
JKson 6/1  (Utterpower PMG ) Off-grid
Lister 6/1 Start-O-Matic engine......running with PMG
1978 Royal Enfield (glutton for punishment by Indian iron)
1963 BMW R-27 project

BruceM

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Re: piston from "re playing with the old . . ."
« Reply #2 on: June 10, 2019, 06:30:16 PM »
Good catch, Hugh. That exhaust valve lifter (and everything else) is on the wrong side.  Some photo trickery here.

mikenash

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Re: piston from "re playing with the old . . ."
« Reply #3 on: June 11, 2019, 09:50:14 AM »
Or-righty.  Some image processing snafu?  Try this one

BruceM

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Re: piston from "re playing with the old . . ."
« Reply #4 on: June 11, 2019, 05:01:37 PM »
A rare convertable model. Marvelous.

mikenash

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Re: piston from "re playing with the old . . ."
« Reply #5 on: June 12, 2019, 03:22:03 AM »
Doctor Google says the numbers on that piston mean “40 thou” oversize

I don’t know enough about bores to make a judgement, but it LOOKS like a chrome bore

Is there any way, do we know, that Lister “back in the day” would have supplied cylinders with oversized bores, chromed?  Perhaps as a “rebuild” item?  I can’t imagine so as, if you were going to buy a new cylinder, you’d buy a standard one?  Unless they were some sort of “reconditioned exchange” item whereby a cylinder with a worn bore was rebored and re-chromed?

Certainly it’s the nicest 2nd hand bore I have ever gotten my hands on

I’m interested to know if anyone has information

Cheers




38ac

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Re: piston from "re playing with the old . . ."
« Reply #6 on: June 12, 2019, 11:54:17 AM »
Hi,
Sorry for being late with this info but the piston is the alumininum 8/1 type as can be seen via the ring arraingment which differs from the cast iron piston ring package. Could be the picture but it looks to have the typical top ring groove wear that must be corrected to have compression restored to spec. If all is well otherwise you can widen the groove to accept a spacer.  Yes Lister did indeed rechrome the bores after reboring oversize. They also attached a nice tag. My 10/2 is 40 over and is re tagged to state so.
Collector and horder of about anything diesel

BruceM

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Re: piston from "re playing with the old . . ."
« Reply #7 on: June 12, 2019, 03:07:58 PM »
After 38ac points it out, I can see that the top ring groove does seem to have a dark shadow that the others don't. 

mikenash

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Re: piston from "re playing with the old . . ."
« Reply #8 on: June 12, 2019, 05:31:33 PM »
Hey Guys, expertise in action, thanks

I get up and go to work in the dark and rain; and come home from work & go inside with an armload of firewood in the dark and rain at this time of year - the engines a couple of hundred metres away out in a paddock under the macrocapa tree which was the mounting point for the chain block to get it off the trailer and to lift off the head and barrel - so I haven't been out for an inspection.  Perhaps this weekend

But, yes, a re-chromed +40 thou cylinder-and-piston makes good sense

I wonder if you can use a part of an old oil control ring as a spacer?  In fact you can probably buy spacers - the machinist here will know, I'm sure.  A worn top ring & leaking compression would explain why it looked superficially good but was taken out of service as 'getting hard to start" too

I will investigate

Thanks for your expertise

Understanding that the (very slight) lip in the cylinder has to go, I bought a hone the other day - yet to arrive - off TradeMe.  So whatever we do with the top ring it has to survive OK.  There will be a "good practice" answer here - would we machine the groove so that it's "square" and place a spacer below the top ring?

Cheers

38ac

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Re: piston from "re playing with the old . . ."
« Reply #9 on: June 12, 2019, 08:38:37 PM »
Yes, the scraper ring part of a 3 piece oil ring is a perfect spacer. The wear in the land is down thus typically a very light cut is taken on the top, just enough to true it, then widen the groove as needed by removing material from the bottom
Collector and horder of about anything diesel

mikenash

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Re: piston from "re playing with the old . . ."
« Reply #10 on: June 13, 2019, 07:35:16 AM »
There are three machinists in our city . . .

I went to the first, who are race-car engine builders etc, and they told me "You have to get a proper spacer, you can't re-purpose something else.  We'll have to see what's available . . . ."

The second one is just around the corner from work and I use him all the time for trimming pump impellors, modifying sprocket blanks etc etc - he sorta looked at it and said "It's a piston"  I explained what was needed and he's like "well, if you can source a spacer and tell me what the clearances should be . . . ."

The third shop is full of dismantled truck engines and old V8s and resurrected WW2-era tiny flathead English four-cylinder engines.  He said "We just need to find the right sized scraper of an old oil-control ring and . . . "

He's the man, I think.  I just emailed Rob at oldTimerEngines to see if he has a dead piston with an intact oil-control ring hanging off it . . .

Progress

And thanks for all the advice  :)

dieselspanner

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Re: piston from "re playing with the old . . ."
« Reply #11 on: June 13, 2019, 11:00:47 AM »
Nice story, Mike.

And good know that there's others like us out there somewhere.

We are not alone................

Cheers
Stef
Tighten 'til it strips, weld nut to chassis, peen stud, adjust with angle grinder.

BruceM

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Re: piston from "re playing with the old . . ."
« Reply #12 on: June 13, 2019, 02:51:32 PM »
There's only one machine shop in the rural area where I live. He doesn't know what to do without full shop specifications he can have for his computer, and still I know he's had plenty of claims against them for botched work.  We call it the "White Mountain Shuffle"; rural area and services of laughable quality, with screw the customer attitude.


mikenash

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Re: piston from "re playing with the old . . ."
« Reply #13 on: June 14, 2019, 08:05:44 AM »
Interesting stuff

THe helpful chap at OldTimerEngines wasn't able to help in this case, so I emailed a few others after a google around

The old Bedford 466/500 diesel has an almost identical bore to a 40 thou over CS.  Bedfords were extra common here until the '80s or '90s and there are still bits & pieces in wreckers yards or shops with older stock

So I emailed a few places asking for a spacer or a oil control ring I could take a scraper from.  Got the response below from a chap named Chris Bowden from a company called Bowden Engine Parts way up in the north of our North Island.  Very helpful chap

" . . . Hi Mike,
 
I think it might be your lucky day.  I have one only ring groove insert WS232 (as shown on my website).  You can have this for $9.80 plus freight $6.00 = $15.80.
 
And by the way, the insert should NOT be fitted to the bottom of a compression groove.  It should be fitted to the top of the groove.  You will then have your machined lower face for the compression ring to seal on plus the ring is kept lower and away from any ridge that might be present . . . "

So there we are a (hopefully suitable) part and advice, just like that

We'll see what the machinist has to say . . .

Cheers