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Author Topic: heads off the 6/1, should do gaskets, right?  (Read 9554 times)

tyssniffen

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Re: heads off the 6/1, should do gaskets, right? - UPDATE from OP
« Reply #15 on: May 29, 2019, 05:07:09 PM »
So, thank you everyone for the continued advice.

It might not be clear that this tear down is from from compression loss after 200 perfect run hours or so, almost certainly due to carbon build up.   I believe my 'squish' at TDC is already good.    I did check it, and while I to improvise, it's close to .025"   

Once I got the cylinder on - no head, no bolts - , just turning it over I can hear the body 'breathing' a ton more than before.  I think I'm good, and it was stuck ring(s).

I guess the question continues to be:  should I *replace* the copper head gasket, or just reuse the one that was there?
6/1 with 2 tank for WVO.  pushing power into off-grid house battery bank, in winter.

BruceM

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Re: heads off the 6/1, should do gaskets, right?
« Reply #16 on: May 29, 2019, 09:19:59 PM »
+1 Rapping on the valve is normally effective at dislodging a bit of carbon on the valve seat. Decarbon is normally a 1000 hr. job.  I have never had an exhaust valve stick, nearing 3K hrs.

Valve and injection timing will affect carbon build up, as Glort mentioned, if you haven't checked those closely already.

My memory is that the Listeroid bump clearance should be 0.050, but I may be wrong.

You can try to reuse the gasket by spraying it with the copper paint for head gaskets. I'm cheap and have done that successfully. 

 








ajaffa1

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Re: heads off the 6/1, should do gaskets, right?
« Reply #17 on: May 30, 2019, 09:57:05 AM »
If you have a composite, copper faced gasket, it is probably best to replace it. They aren`t very expensive and having done all the hard work involved with your rebuild it would be a shame to have to do it all again because you have had a leaking head gasket.

In the past I have annealed solid copper gaskets and reused them, copper work-hardens over time and warming them up will return them to their original soft condition.

I`m unclear as to whether your engine has radiator cooling or a cooling tank, these engines were never designed for a pressurized cooling system like modern motors and the gaskets will leak unless you take exceptional care. I always use a variety of gasket sealants on every engine I rebuild, regardless of how flat the surfaces appear to be.

Glort is always advocating that you set up a water injection system, this will alleviate the carbon build up problem. I would recommend using rain water rather than tap water depending on how much limescale you have in your local water supply.

Pretty sure that Bruce is right about the bump clearance being around 50 thou, so you will need to shim the cylinder block up from the crankcase a little.

Let us know how you get on,

Bob

38ac

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Re: heads off the 6/1, should do gaskets, right?
« Reply #18 on: May 30, 2019, 12:23:24 PM »
Bump clearance is .045-.050 if the engine has a change over valve and .075-.080 if it does not. If your valves seats are recessed as most are with high hours starting will be easier if you stay at the minimum or even .005" under minimum.
Collector and horder of about anything diesel

ajaffa1

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Re: heads off the 6/1, should do gaskets, right?
« Reply #19 on: May 30, 2019, 12:57:33 PM »
Thank you 38ac for confirming the bump clearances, the cylinder needs raising by about 25 thou with shims.

Glort, I have wondered for a while if the coking problem is caused by oil blowing up past the piston rings. I suspect that these old engines were designed with generous piston ring clearances because they were intended to run with cold crankcase temperatures during short runs. The problem being that during a longer run the engine and oil will eventually heat up and the piston rings grow to provide a better/tighter seal, thus short runs will always burn more sump oil. Another likely culprit could be a damaged diaphragm preventing the expulsion of oil fumes from the crankcase as the piston travels downwards, this could result in a positive crankcase pressure and excessive oil being pumped upwards through the rings and being burned in the cylinder. A sure sign would be if there is oil leaking out from around the crankshaft main bearings behind the flywheels.

I still believe Glort is right that the cost of implementing and running a water injection system is so small that it should be mandatory on any system expected to provide reliable long term service.

Bob

veggie

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Re: heads off the 6/1, should do gaskets, right?
« Reply #20 on: May 30, 2019, 02:44:41 PM »

I'll readily admit, I would not have thought there would have been much problem with diesel causing Coking in any engine that 
The 1000 hours Bruce mentions in vehicular terms at an average of 60 KMH would be 60K Km.  No one would expect to tear an engine down that quick due to coking or anything else so the question would be why do these engines need it
?

My theory on that is because the Listeroids are a slow speed engine which run at a fixed speed.
With automobile diesel engines (like my truck) the speed and load constantly varies and sometimes I even rev it a bit higher than usual to blow the "snot" out.  :)
Secondly, many listeroid systems use a large evaporative water storage tank for cooling.
This can result in many hours of running at temperatures that are less than optimal.
If the tank is too large, the engine can run for a long time without ever reaching 190f, creating an environment for soot buildup.
With stationary diesels, it's probably important to get them up to operating temperature as quickly as possible (Just like in a diesel automobile with a thermostat).

Just a thought.

Veggie
« Last Edit: May 30, 2019, 03:35:40 PM by veggie »
- 6/1 GM90 Listeroid - Delco 33si Alternator
- Changfa R175 - Lease/Neville Alternator
- JiangDong R165 Air cooled - 2 kw
- Changfa S195 (Waiting for a project)

BruceM

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Re: heads off the 6/1, should do gaskets, right?
« Reply #21 on: May 30, 2019, 03:59:59 PM »
I reduced my bump clearance for my elevation of 5600 ft.  By the book, which I can't recall.  That may be a factor. 

I do think the cool running of the CS is part of the carbon issue. Water injection is pretty easy for a stationary setup.  I like my gravity and intake vacuum drawn setup.  I'm using well water (rain is a rarity here) so it will be interesting to see how that goes.  I'm adding 20% methanol in the winter, 10% in spring and fall.




ajaffa1

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Re: heads off the 6/1, should do gaskets, right?
« Reply #22 on: May 31, 2019, 09:15:40 AM »
Hi Veggie, I think you are probably right about carbon build up being a mixture of cold running temperatures and slow RPM. I have wondered for a while about buying one of the thermostat kits that are available here: https://www.stationaryengineparts.com/Lister-CS-Thermostat-Kit.html

This should allow the engine to reach optimal running temperature quicker but won`t do anything for the cold crankcase temperatures, has anyone tried to install an electric crankcase oil heater? These are regularly fitted to back up generators in hospitals and other essential service providers, when the engine is not running they have a life support system that maintains them at running temperature to ensure instantaneous start in the event of a blackout.

Bruce, our old mate Glort adds a little regular gasoline to his WVO in winter, this helps it light off in cold weather. If you were to buy E10 (10% ethanol gasoline mix), you could add water to it and give it a good shake, the water will absorb the ethanol and then settle to the bottom. You can then decant off the water ethanol mix to use in you water injection system, while the gasoline  remaining should be good for any other equipment you have. Probably cheaper than buying methanol.

Bob

Willw

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Re: heads off the 6/1, should do gaskets, right?
« Reply #23 on: May 31, 2019, 02:07:04 PM »
Re: quick engine warm-up. I recall reading somewhere about putting a valve in the lower water pipe so that flow into the engine can be adjusted to achieve quick warm-up as well as stable engine temps.
That is how I have mine and it seems to work well.
Daily driver '97 GMC W4 tipper on WVO/Kerosene mix.
6/1 clone standby generator.
Too many projects.

BruceM

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Re: heads off the 6/1, should do gaskets, right?
« Reply #24 on: May 31, 2019, 05:01:44 PM »
Bob, the methanol is free to me, left over from a 2 hp Honda outboard I modified to run as a pseudo diesel on methanol using Mark Cherry's Smartplug invention.  A racetrack in a nearby town sells it pretty cheap.
 




BruceM

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Re: heads off the 6/1, should do gaskets, right?
« Reply #25 on: June 01, 2019, 05:51:26 AM »
Yes, Mark Cherry was legit, he just couldn't sell his idea to the automotive industry. He had a contract with Darpa as part of the "one fuel forward" research program.  My version of his original patent worked fine in my Honda 4cy outboard running methanol. I only had to apply current for starting. Increasing compression and getting enough fuel flow (double the normal gasoline flow rate) from the carb were challenging, but it did work quite well.

In his later versions Mark Cherry was varying the current to the platinum element to adjust ignition timing. 

I don't know if it's possible to run a gas engine on oil using his method.  I know he had success with aqueous fuels (less refined alcohol), with the benefit for very low NOX due to all the water and the lower combustion temps.  Again, no interest from industry.


veggie

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Re: heads off the 6/1, should do gaskets, right?
« Reply #26 on: June 20, 2019, 05:40:17 PM »
tyssniffen,

When you re-assemble the head, consider spraying the head gasket on both sides with Permatex Copper Gasket coating.
Its adds additional sealing for the water passage ports.
Here's how I did mine ...
- 6/1 GM90 Listeroid - Delco 33si Alternator
- Changfa R175 - Lease/Neville Alternator
- JiangDong R165 Air cooled - 2 kw
- Changfa S195 (Waiting for a project)

BruceM

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Re: heads off the 6/1, should do gaskets, right?
« Reply #27 on: June 20, 2019, 06:09:30 PM »
+1 I've used the same copper spray when reusing head gaskets.  It does work.

Water passage sealing is a big problem for Listeroids with liners, with a protruding lip. Best to address head and cylinder top flatness, and lip protrusion if you're having problems with leaks. The protrusion of the liner causes concave warping of the head, which causes insufficient pressure at coolant passages.

The stock Rajkot copper/asbestos gaskets with asbestos soaked with Permatex aviation gasket sealer is the best for the bad head/liner protrusion situation; I tried everything before finally fixing the problem. Copper spray does also help seal the water passages. Combined it was still only a 400 hour solution before leaks.

The best fix is to reduce the protrusion to under 0.005 inches (5 mils) and flatten the head and cylinder top.  I used the classic farmer fix- sandpaper with spray contact cement on plate glass on non-slip foam shelf liner on cast iron saw top. 

Lots of elbow grease to flatten the concave head but it's doable.  A file and careful work for the liner protrusion prevents another concavity.




mikenash

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Re: heads off the 6/1, should do gaskets, right?
« Reply #28 on: June 20, 2019, 07:35:31 PM »
+1 I've used the same copper spray when reusing head gaskets.  It does work.

Water passage sealing is a big problem for Listeroids with liners, with a protruding lip. Best to address head and cylinder top flatness, and lip protrusion if you're having problems with leaks. The protrusion of the liner causes concave warping of the head, which causes insufficient pressure at coolant passages.

The stock Rajkot copper/asbestos gaskets with asbestos soaked with Permatex aviation gasket sealer is the best for the bad head/liner protrusion situation; I tried everything before finally fixing the problem. Copper spray does also help seal the water passages. Combined it was still only a 400 hour solution before leaks.

The best fix is to reduce the protrusion to under 0.005 inches (5 mils) and flatten the head and cylinder top.  I used the classic farmer fix- sandpaper with spray contact cement on plate glass on non-slip foam shelf liner on cast iron saw top. 

Lots of elbow grease to flatten the concave head but it's doable.  A file and careful work for the liner protrusion prevents another concavity.

Hi Bruce and others

I have just been reading up on this as I'm interested in head and base gasket sealing at the moment

I would guess in a metric environment that liner protrusion is more like a tenth of a millimetre?  If it's five thou?

Cheers


BruceM

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Re: heads off the 6/1, should do gaskets, right?
« Reply #29 on: June 21, 2019, 01:18:46 AM »
6 mils or 0.006 inches is the thickness of a standard sheet of copy paper. 
I'd shoot for 0.1 millimeter = 4 mils or a shade under.  More protrusion just means more leaks at 200 hrs+.

What I used was a feeler gauge next to the lip, and then ran my fingernail back and forth to determine if I was down to the feeler height yet. 

One thing to check carefully is that the cylinder liner isn't being held up by some sloppy machining of the liner or cylinder.  You may be able to rectify that with some careful dremel work. If you are having the machine shop do it properly, and the cylinder looks good, then they will cut the shoulder of the liner.  I used a file to take down the protrusion, with a feeler gauge to test regularly all around and a lot of patience. I smoothed it with a disc sander.

No worries at all for the Lister clones or originals- they have no liner thus no protrusion.