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Message |
    
frank_n
New member
Username: frank_n
Post Number: 1
Registered: 03-2012
| | Posted on Friday, March 16, 2012 - 10:18 am: | 
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recently showed Renault RC8D cylinder and piston to 3 diesel/engine machine shops. Opinions ranged from rebore + oversize piston to honing + rings should do it. Question ..how close to spec (piston gap,ring gap) do I have to be for combustion to take place. No glow plug,no compression release set up. Head reworked and pressure tested. Cylinder has some small pitting can feel with finger nail. Having honed gas engines before doable in my opinion. Diesel at 450 500 psi. not sure fudge room?  |
matt_morehouse
Senior Member
Username: matt_morehouse
Post Number: 109
Registered: 12-2009
| | Posted on Friday, March 16, 2012 - 10:47 am: |
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I would say if you are getting 450-500 psi you should be good to go.
I certainly would hone and put new rings in before going the rebore/oversize route. What does the manual say about tolerances? |
frank_n
New member
Username: frank_n
Post Number: 2
Registered: 03-2012
| | Posted on Friday, March 16, 2012 - 03:02 pm: |
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Sorry, I'm not getting 450 500 comp. test..but that is where it should be. Manual specs piston to cylinder clearance .035-.055mm and mine is more like .13mm. (I can place a .229mm feeler gauge between piston and cylinder on one side so .229/2=.13mm). In your opinion with new rings and honed cylinder should I be able to obtain combustion all else be good? |
matt_morehouse
Senior Member
Username: matt_morehouse
Post Number: 111
Registered: 12-2009
| | Posted on Friday, March 16, 2012 - 03:36 pm: |
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I guess it depends on how you will be using the engine. Will it be a "show" or a working engine? If for show I'd go the hone/ring route. If for work I'd go the re-bore route. |
frank_n
New member
Username: frank_n
Post Number: 3
Registered: 03-2012
| | Posted on Friday, March 16, 2012 - 04:13 pm: |
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Ok Matt so you think I should be able to get her running but not produce a whole lot of power. Engine is in a sailboat and I have outboard as main aux. Parts are available but $$$. Even when new only 8hp. and under powered. I will take your advice and hone and replace rings. She ran before head gasket blew and pushed boat at 4 to 5 knots. So with new rings, clean cyl. and reworked head she should be much better than before. Thanks for help and will let you know out come...cheers Frank |
matt_morehouse
Senior Member
Username: matt_morehouse
Post Number: 112
Registered: 12-2009
| | Posted on Friday, March 16, 2012 - 06:37 pm: |
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How much does the boat weigh and where will you be sailing?
Here's a good link for sailors <www.paracay.com> |
frank_n
Member
Username: frank_n
Post Number: 4
Registered: 03-2012
| | Posted on Friday, March 16, 2012 - 10:40 pm: |
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boat weighs 7500 lbs. NYC Hudson river and has about a 1.5 to 2.5 knot tide at any given time not to mention currents. |
matt_morehouse
Senior Member
Username: matt_morehouse
Post Number: 113
Registered: 12-2009
| | Posted on Friday, March 16, 2012 - 10:59 pm: |
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No problem. Not much wind, small seas, shore is near, I would think you would be OK.
Now if you were thinking on taking her offshore... |
jimdereynier
Senior Member
Username: jimdereynier
Post Number: 58
Registered: 08-2007
| | Posted on Saturday, April 28, 2012 - 10:24 am: |
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Multi-weight engine oil for an overhauled Sabb Diesel.
I have a valve job, new rings and sleeves in my 2H Boat engine. The manual calls for SAE 30 weight diesel engine oil. Shell still makes it but this is getting scare. The same oil is used in the clutch housing. Given the new rings and cylinder sleeves, Would you move to a multi-weight diesel oil? |
jimdereynier
Senior Member
Username: jimdereynier
Post Number: 59
Registered: 08-2007
| | Posted on Saturday, April 28, 2012 - 10:55 am: |
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How long does it take to seat rings?
Some place else on this site Matt says to seat the new rings by running the engine under a load. I can tie off on the dock. What RPM- the Sabb 2H book specifies 16 HP @ 2000 RPM, 18 HP at 2250 RPM ( In 12 years, I have never run the engine above 1500) |
jimdereynier
Senior Member
Username: jimdereynier
Post Number: 60
Registered: 08-2007
| | Posted on Saturday, April 28, 2012 - 11:12 am: |
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How to preserve a spare engine outdoors in New England.
I have a spare Sabb 2H or 2 G that I use to rob parts. I no longer have room in the shed so the engine sits on a pallet with heavy boat plastic sheeting under and over it. I filled engine with clean oil, will put diesel fuel in the pump and injectors. Not sure about the engine water jackets- I use to have antifreeze in them but no longer have an exhaust manifold. I saw something that Matt wrote that on the MD3B about using Kerosene . |
