Author Topic: Top end specs ??  (Read 7084 times)

biobill

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Top end specs ??
« on: October 29, 2006, 12:05:50 PM »
  Anyone know what the ring end gap and the piston/cyl clearance should be on a 6/1 ?     Thanks, Bill
Off grid since 1990
6/1 Metro DI living in basement, cogen
6/1 Metro IDI running barn & biodiesel processer
VW 1.6 diesels all over the place
Isuzu Boxtruck, Ford Backhoe, all running on biodiesel
Needs diesel lawnmower & chainsaw

GuyFawkes

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Re: Top end specs ??
« Reply #1 on: October 29, 2006, 12:49:32 PM »
4 thou per inch of bore will rarely put you wrong, so 0.004 x 4.5  = 18 thou

don't forget to stagger the gaps around the piston.

there is SUPPOSED to be some blow by and leakage, if you make everything too precision you end up with excessive ring / barrel wall pressure = worn rings and bores in short order.

====================

when people do stupid things and accidentally put diesel in a petrol engine, especially tuned engines like japanese motorbikes, many think provided they only ran a moment or two, or flushing the tank, is enough, it ain't, if you got ANY diesel into the engine, eg you cranked it, you get diesel sitting in the rings, and this detonates and blows the rings apart.

to a lesser extent this happens in a badly maintained diesel engine too, eg cranking to start, and is is why ether / wd40 and all those spray start things "addict" engines, in other words totally fuck them in short order.

======================

As another aside, someone on these forums has been running without an oil scraper ring, this is also fatal for the engine for exactly the same reasons, you do NOT want lube oil getting under the top rings.
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Original Lister CS 6/1 Start-o-matic 2.5 Kw (radiator conversion)
3Kw 130 VDC Dynamo to be added. (compressor + hyd pump)
Original Lister D, megasquirt multifuel project, compressor and truck alternator.
Current status - project / standby, Fuel, good old pump diesel.

biobill

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Re: Top end specs ??
« Reply #2 on: October 29, 2006, 03:16:26 PM »
  Thanks GuyF
 That spec is piston/ cyl clearance (seems really loose) or ring endgap (seems a bit tight)?  I ask your patience, my experiance has been with things that wouldn't idle at lister speeds, used a piston made from some light weight shiny metal, and had much shorter lifespans.                                            Bill
Off grid since 1990
6/1 Metro DI living in basement, cogen
6/1 Metro IDI running barn & biodiesel processer
VW 1.6 diesels all over the place
Isuzu Boxtruck, Ford Backhoe, all running on biodiesel
Needs diesel lawnmower & chainsaw

GuyFawkes

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Re: Top end specs ??
« Reply #3 on: October 29, 2006, 05:13:32 PM »
18 thou is ring gap for 4.5 inch bore.

put a ring 2 or so inches down the bore to measure.

=============================

Piston gap is something else ENTIRELY.

Piston is oval when cold, so where do you measure?

What you do is measure the bore for ovality

wrap the piston in a sheet of A4 100 gsm paper, it should still slide down the bore easy, when you get to thicker gasket paper it should not slide, piston / barrel gap is something you need to learn from experience

You aren't running genuine lister are you, so YMMV

no chrome bores, so if you hone the cylinder you need to wash it out THOROUGHLY, on a lister(oid) that means this process is done with the barrel removed and away from the engine, lint free cloth and then old newspaper, both wetted in paraffin / kerosene are good for wiping bores.

Make sure piston / bores / rings etc are surgically clean before assembly, and then oil everything with fresh oil on assembly, if you don't oil rings etc liberally you'll have no compression when you try to start, so it will blue smoke like a bitch for 5 minutes, so what

Make sure bore isn't too "lipped" at the top, or ovaled (that's where the torque goes inside the engine) on not perpendicular to the crankshaft

Make sure rings can rotate and gudgeon / wrist pin retainers are WELL seated

No point having the head off and not stripping and cleaning valves / guides / springs / collets / seats / comet too

Never forget to clean ALL fasteners with a brass brush and run a correct #3 tap and die over all threads or your torque settings will be wrong

Grease alll gaskets, never use stick shit

pull and clean injectors and check spray pattern when head is off too, anneal copper rings before using again

(dowty washers are good for leaky banjo fittings, get em from hydraulic supply shop)




this is as dirty as a bore should be before assembly before oiling



This piston, apart from being damaged, is WAAAY too dirty to put back in, piston should match bore visually



How to check ring gap



--
Original Lister CS 6/1 Start-o-matic 2.5 Kw (radiator conversion)
3Kw 130 VDC Dynamo to be added. (compressor + hyd pump)
Original Lister D, megasquirt multifuel project, compressor and truck alternator.
Current status - project / standby, Fuel, good old pump diesel.

listerdiesel

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Re: Top end specs ??
« Reply #4 on: October 29, 2006, 05:57:53 PM »
  Anyone know what the ring end gap and the piston/cyl clearance should be on a 6/1 ?     Thanks, Bill

There are three ring sizes/types:

010-04018 is the most popular, with ground periphery and lapped sides.
Width is 0.125"
Depth is 0.153" +0.00" - 0.007"
Nominal FREE gap is 0.53"
Installed gap is 0.012" to 0.020"

010-04065 is a chrome-plated version (0.005" to 0.007")  same details as above but slightly larger gap at 0.018" to  0.023"

102-00014 is the older and wider ring.
Width is 0.185"
Depth is 0.156"
Nominal FREE gap is 0.53"
Installed gap is 0.012" to 0.016"

Peter

biobill

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Re: Top end specs ??
« Reply #5 on: October 29, 2006, 06:14:11 PM »
18 thou is ring gap for 4.5 inch bore.

put a ring 2 or so inches down the bore to measure.

=============================

Piston gap is something else ENTIRELY.

Piston is oval when cold, so where do you measure?



Quote

   Guy, again thank you. no incomplete answers from you.
On the stuff I've worked on the measurment was taken perpendicular to the wrist (grundion?? over there)pin a couple mm up on the skirt to get size for boring then cyl was honed to fit and the clearance checked with a long feeler strip. Apparently this has little or no application in a removeable sleeve engine, it's already been done and you're not going to hone it smaller if you don't like the fit.     Bill
Off grid since 1990
6/1 Metro DI living in basement, cogen
6/1 Metro IDI running barn & biodiesel processer
VW 1.6 diesels all over the place
Isuzu Boxtruck, Ford Backhoe, all running on biodiesel
Needs diesel lawnmower & chainsaw