hello to all
looking for some good advice from the very experienced cape dorians here.
heres the story. mystic rose, hull #122, 1979 cd30k appears to be in trouble. she has been putting out white smoke and spitting out some fuel in her exhaust for about the last year. had a local reputable diesel shop look at her about six months ago, and they recommended new injectors. we did that.
engine is a md7a, by the way, and starts within 5-10 seconds and seems to run just fine, max rpms is about 2300.
new injectors did not solve problem. still got white smoke and fuel in the exhaust. as i am preparing to move to rock hall on the chesapeake this summer and plan to sail her up from south florida, i want to make sure she will make it (best i can). with the fuel not being totally burned i am using almost twice what she should i think.
anyway, now i go talk to the service manager (same company) we check a few thing like air intake and clean fuel, and all of that looks ok. mechanic comes out and goes into cockpit locker to access fly wheel (v drive), spins the flywheel with his hand for a few minutes and says "low compression" i say do we need to do a compression test, he says "waste of your money" "if i can turn your flywheel this easy you got low compression".
now, he seems very competent and well meaning, and they are a very reputable company, so we continue to talk. he recommends either a rebuild or a new engine, and they will look into options and get me quotes.
here are my questions:
should i insist in a compression test? or is a freely turning flywheel good enough evidence?( as i said, engine starts good and runs good, but i dont like dumping fuel in the water or all the smoke)
if we conclude that we need to repower or rebuild, what are the various options and your experienses with replacement engines?
what fits best? runs well? and ( i know this is a stupid question) costs the least?
i tend to believe the mechanic, but i would be very interested in your collective thoughts. what say ye?
darrell randolph
mystic rose
low compression?? is it time to repower??
Moderator: Jim Walsh
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Ben Thomas
- Posts: 215
- Joined: Feb 5th, '05, 12:17
- Location: 82 CD30 Milagro Hull #248
low compression Volvo
Darrel, on my old Volvo MD7A there was a compression release bar aft of valve cover, if you lifted this it would release the compression in cylinders and you could spin the engine like crazy. I am a trusting soul... but I would want to see the flywheel spun for myself with this lever in its running position. Best of luck Ben
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Carter Brey
- Posts: 709
- Joined: Feb 5th, '05, 12:02
- Location: 1982 Sabre 28 Mk II #532 "Delphine"
City Island, New York - Contact:
Engine woes
Low compression sounds like a logical conclusion. But what's causing the low compression? I'm trying to imagine things that would cause it without meaning a rebuild is necessary. I was also thinking of a compression release bar as Ben mentioned. Silly, but worth looking into.
Also, what about:
bad valve clearance?
bad valve seating?
leaky cylinder head gasket?
I'm sure others more knowlegable than I will chime in.
CB
Also, what about:
bad valve clearance?
bad valve seating?
leaky cylinder head gasket?
I'm sure others more knowlegable than I will chime in.
CB
Compression
I agree with making the test myself. If the mechanic was small enough to fit into the locker and able to spin the flywheel without releasing the compression release, the engine would not start, or would be pretty ragged. Crawl in and do it yourself, but check the release first.
Now as to what to do. Considering the engine will be coming out and the age, you would want to consider a fairly extensive overhaul. No sense in doing it again in a few years. Not too many mechanics are going to do a valve job with the engine in place.
As to replacing it. A rebuilt will cost a lot less. It sits on the same beds, no surgery required. Replacing with new will 90% of the time mean "a bucket of boat units" to adapt the boat to the new engine.
It is your call, you have a big trip ahead of you and you want reliable power. Also Volvo mechanics are scarce, and expensive, along the Ditch. I would rate the options:
1. Good overhaul
2. Rebuild
3. Replace.
Anyway Good Luck on your endeavors and I know it is a bit early, WELCOME to God's Country for sailboats.
ps Been there/done that (rebuild/replace) even if you do it yourself, ain't cheap.
Now as to what to do. Considering the engine will be coming out and the age, you would want to consider a fairly extensive overhaul. No sense in doing it again in a few years. Not too many mechanics are going to do a valve job with the engine in place.
As to replacing it. A rebuilt will cost a lot less. It sits on the same beds, no surgery required. Replacing with new will 90% of the time mean "a bucket of boat units" to adapt the boat to the new engine.
It is your call, you have a big trip ahead of you and you want reliable power. Also Volvo mechanics are scarce, and expensive, along the Ditch. I would rate the options:
1. Good overhaul
2. Rebuild
3. Replace.
Anyway Good Luck on your endeavors and I know it is a bit early, WELCOME to God's Country for sailboats.
ps Been there/done that (rebuild/replace) even if you do it yourself, ain't cheap.
Jim Davis
S/V Isa Lei
S/V Isa Lei
Compression gauge
A compression gauge is a fairly cheap instrument $10.-$20. dollars
First disconnect connections that provide electricity to your glow plugs.You want to be able to turn over your engine with the starter without starting the engine.You then remove one of your glow plugs and insert the compression gauge tip into glow plug hole. Hold firmly while someone cranks over engine 6- 10 times using starter . Remove gauge from hole and record reading . You might want to redo the process just to make sure you had everything right the first time. Someone on this board should be able to tell you what normal spec readings for compression on the Volvo are and what deviations are allowed before considering you have bad compression.
good luck.
First disconnect connections that provide electricity to your glow plugs.You want to be able to turn over your engine with the starter without starting the engine.You then remove one of your glow plugs and insert the compression gauge tip into glow plug hole. Hold firmly while someone cranks over engine 6- 10 times using starter . Remove gauge from hole and record reading . You might want to redo the process just to make sure you had everything right the first time. Someone on this board should be able to tell you what normal spec readings for compression on the Volvo are and what deviations are allowed before considering you have bad compression.
good luck.
Running Just Fine, right?
I keep thinking of that line, "it seems to be running fine." Bad fuel consumtion and fuel out the exhaust, points to injectors. White smoke? It's not overheating right? It's not steam?
If it is steam then the cooling system need attention. But why the fuel out of the exhaust? Your running at the same RPM's as always, right? I used to run at 1800 and on one trip, trying to make good time, I ran at 2100 and my fuel economy was cut in half.
Take your time on this. Maybe get another opinion and do your own compression test, but dog gone it all, your engine might not need replaced. After all, it seems to be running fine!
One more thing, the local reputable shop recommended something that did not cure the problem. They just lost a little of their credibility, whether that's fair or not!
If it is steam then the cooling system need attention. But why the fuel out of the exhaust? Your running at the same RPM's as always, right? I used to run at 1800 and on one trip, trying to make good time, I ran at 2100 and my fuel economy was cut in half.
Take your time on this. Maybe get another opinion and do your own compression test, but dog gone it all, your engine might not need replaced. After all, it seems to be running fine!
One more thing, the local reputable shop recommended something that did not cure the problem. They just lost a little of their credibility, whether that's fair or not!
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marv brinn
- Posts: 202
- Joined: May 13th, '05, 09:43
- Location: CD 27 1982
ENGINE
doesnt sound good . if you can spin the flywheel that means you have no compression.I would call mack boring those guys are great and can walk you thru a diagnosis.
none
I seem to remember that the compression release just opens up valves to relieve compression.. the manual gives some specs for adjusting the compression release lever if i remmber correctly.. i think you may also need to check your valve clearance which is recommended every 50 hours in the manual.. pulling off the valve cover is no big deal on the MD7A and it's easy to check the valve clearance.. turn over the engine a few times and make sure the valves close completely..i've done it numerous times.. check out some of these things before you think engine replacement... turning the engine over for 5 to 10 seconds seems excessive and does suggest a loss of compression.. i think the valve clearance is supposed to be .014" but someone please correct me on this i no longer have a Volvo and am speaking from memory
engine diagnosis
Since rebuilding the engine is going to be a real pain in the rear.... especially the part where the wallet is located, I suggest the following proceedure. Money spent diagnosing the problem is definitely not wasted. Here is the proceedure I would suggest.
1. Adjust the valves.
2. Turn the engine over by hand (with out the compression released). Use a large rachet on the nut holding the crank pully. Do this slowly and listen at the intake and exhaust. If you hear hissing then thats a sign the valves are leaking. Take out a preheater or injector and put your thumb over the hole while someone turns the crank. It should without question push your thumb off the hole.
3. Check the compression with a gauge, as this is the most difinitive test. Do both a dry and wet test. For a diesel the minimum necessary to run is about 325psi dry and you should get about 500 psi wet. This is way beyond what a cheap automotive compression gauge will do. They are usually only good for 150 psi. This test is really something to hire a mechanic. The gauge just costs to much.
4. White smoke is often caused by water getting into the combustion gases. The most likely suspects are the water cooled exhaust manifold followed by the water injector elbow and finally the head gasket. Change the oil and send off a sample for an analysis. If it comes back with water or high sodium then you have a good lead where to look. It only costs $25 from Blackstone Labs. Water getting into the cylinders from a bad exhaust system will result in a loss of compression over time. Rust staining on the cylinders is a clue. If you have a bore scope then you may be able to see whats going on inside your cylinders.
I remember hearing that Volvo engines have a sleeve in the heads where the injectors pass through the water jacket. If this fails then water gets into the combustion chamber. My memory is a scarry thing to rely on so check it out first.
Blowing excess fuel out the exhaust or black carbon floating in the water during start up is usually an indication of poor compression.
I rebuilt my engine in place and found it much cheaper than the other two options. I only spent about $1500 to rebuild a 3 cylinder Westerbeke.
Good luck and let us know how it turned out.
Boyd
s/v TERN
CD30 MkII
Fort Lauderdale, Fla.
1. Adjust the valves.
2. Turn the engine over by hand (with out the compression released). Use a large rachet on the nut holding the crank pully. Do this slowly and listen at the intake and exhaust. If you hear hissing then thats a sign the valves are leaking. Take out a preheater or injector and put your thumb over the hole while someone turns the crank. It should without question push your thumb off the hole.
3. Check the compression with a gauge, as this is the most difinitive test. Do both a dry and wet test. For a diesel the minimum necessary to run is about 325psi dry and you should get about 500 psi wet. This is way beyond what a cheap automotive compression gauge will do. They are usually only good for 150 psi. This test is really something to hire a mechanic. The gauge just costs to much.
4. White smoke is often caused by water getting into the combustion gases. The most likely suspects are the water cooled exhaust manifold followed by the water injector elbow and finally the head gasket. Change the oil and send off a sample for an analysis. If it comes back with water or high sodium then you have a good lead where to look. It only costs $25 from Blackstone Labs. Water getting into the cylinders from a bad exhaust system will result in a loss of compression over time. Rust staining on the cylinders is a clue. If you have a bore scope then you may be able to see whats going on inside your cylinders.
I remember hearing that Volvo engines have a sleeve in the heads where the injectors pass through the water jacket. If this fails then water gets into the combustion chamber. My memory is a scarry thing to rely on so check it out first.
Blowing excess fuel out the exhaust or black carbon floating in the water during start up is usually an indication of poor compression.
I rebuilt my engine in place and found it much cheaper than the other two options. I only spent about $1500 to rebuild a 3 cylinder Westerbeke.
Good luck and let us know how it turned out.
Boyd
s/v TERN
CD30 MkII
Fort Lauderdale, Fla.
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Parfait's Provider
- Posts: 764
- Joined: Feb 6th, '05, 13:06
- Location: CD/36 #84, Parfait, Raleigh, NC
berthed Whortonsville, NC
Check the Bed
Seems to me that you are a long ways from knowing what really is wrong, but when you get to the point where you are considering pulling the engine, whether for a rebuild or replacement, be certain the bed is solid inside and out. If it isn't, you might want to rebuild it to fit a different engine.
Keep on sailing,
Ken Coit, ND7N
CD/36 #84
Parfait
Raleigh, NC
Ken Coit, ND7N
CD/36 #84
Parfait
Raleigh, NC
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Matt Cawthorne
- Posts: 355
- Joined: Mar 2nd, '05, 17:33
- Location: CD 36, 1982
Hull # 79
Tell us about the white smoke.
Is the white smoke continuous or just when the engine is cold and under heavy load?
Fuel consumption and smoke and partially burned fuel in the water are often a result of owning a barnacle farm on your prop. Have you checked that recently?
While 5-10 seconds to start might not seem too bad, you are in Florida, and I am guessing that the temperature is a little warmer there than in Rock Hall. If you run your batteries down you will not get the same cranking speed and starting will become a major problem. If you are going to move your boat north before it gets warm you risk not being able to start due to colder temperatures and reduced cranking speed.
Many good ideas were presented above for evaluating compression. Whatever you do, make certain that the engine is reliable before you start off on your trip. It would be a shame to mess up a perfectly good adventure with some unreliable equipment.
Matt
Fuel consumption and smoke and partially burned fuel in the water are often a result of owning a barnacle farm on your prop. Have you checked that recently?
While 5-10 seconds to start might not seem too bad, you are in Florida, and I am guessing that the temperature is a little warmer there than in Rock Hall. If you run your batteries down you will not get the same cranking speed and starting will become a major problem. If you are going to move your boat north before it gets warm you risk not being able to start due to colder temperatures and reduced cranking speed.
Many good ideas were presented above for evaluating compression. Whatever you do, make certain that the engine is reliable before you start off on your trip. It would be a shame to mess up a perfectly good adventure with some unreliable equipment.
Matt
thanks for all the ideas and recommendations
to answer a few questions you all have posed, the white smoke is continuous and does not change. it is definitely smoke and not steam. i have now been in the locker myself and while i can rotate the fly wheel by hand, it is not as easy as the first mechanic said.
i do not have glow plugs in this engine, so if we do a compresion test it will have to be through the injector nozzle openings. someone asked if the prop or bottom could be barnacled up. the boat just came back from being bottom painted, and i do have a diver that cleans the bottom and running gear every month, so i dont think this is an issue.
today , the manager came out to look at the engine and the space available to work, because he was led to believe the engine would have to come out even to remove the head (mechanis covering their butts). anyway, very nice guy, after looking at it for a few minutes, he says, "you see what i have to deal with". what he meant is that his guy painted a picture much worse than it really was.
so, the plan now is for me to remove the head (to save the $800.00 or so in labor costs) and then for him to return and examine the valves and the cylinders. if it appears that the valves alone are the cause of the low compression a valve job would be in order. on the other hand, if the cylinders are worn and contributing to the loss of compression, smoke, and unburnt fuel being exhausted we have a decision to make. pull engine and look into overhaul or rebuild, or consider repower. i presume cost will be a major factor in deciding.
in thinking about the eventual outcomes and trying to be prepared, i would appreciate any further comments from this board, as well as suggestions about what engine options i might have in this boat should it come to that. i know there has been alot of repowering done out there, so share your thoughts, please. this is a cd30 ketch.
thanks for all your help
darrell
mystic rose
i do not have glow plugs in this engine, so if we do a compresion test it will have to be through the injector nozzle openings. someone asked if the prop or bottom could be barnacled up. the boat just came back from being bottom painted, and i do have a diver that cleans the bottom and running gear every month, so i dont think this is an issue.
today , the manager came out to look at the engine and the space available to work, because he was led to believe the engine would have to come out even to remove the head (mechanis covering their butts). anyway, very nice guy, after looking at it for a few minutes, he says, "you see what i have to deal with". what he meant is that his guy painted a picture much worse than it really was.
so, the plan now is for me to remove the head (to save the $800.00 or so in labor costs) and then for him to return and examine the valves and the cylinders. if it appears that the valves alone are the cause of the low compression a valve job would be in order. on the other hand, if the cylinders are worn and contributing to the loss of compression, smoke, and unburnt fuel being exhausted we have a decision to make. pull engine and look into overhaul or rebuild, or consider repower. i presume cost will be a major factor in deciding.
in thinking about the eventual outcomes and trying to be prepared, i would appreciate any further comments from this board, as well as suggestions about what engine options i might have in this boat should it come to that. i know there has been alot of repowering done out there, so share your thoughts, please. this is a cd30 ketch.
thanks for all your help
darrell
mystic rose
MD7A
Here are a couple places to start. Good luck and looking foreword to seing you on the Bay.
www.bluemoment.com/manuals/Volvo_MD6A_MD7A_Workshop.pdf
and
http://www.volvo.com/volvopenta/global/ ... e/inboard/
www.bluemoment.com/manuals/Volvo_MD6A_MD7A_Workshop.pdf
and
http://www.volvo.com/volvopenta/global/ ... e/inboard/
Jim Davis
S/V Isa Lei
S/V Isa Lei
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Matt Cawthorne
- Posts: 355
- Joined: Mar 2nd, '05, 17:33
- Location: CD 36, 1982
Hull # 79
white smoke
That smoke could be from leaky valve stems or from worn rings. The low compression could be from valves or from worn rings. Your approach of trying the head is reasonable, but you may feel that you are forcing yourself to continue with the existing engine if you do the head and it turns out to be the rings. Good luck. See you in Rock Hall this summer.
Matt
Matt
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M. R. Bober
- Posts: 1122
- Joined: Feb 6th, '05, 08:59
- Location: CARETAKER CD28 Flybridge Trawler
FWIW
I mentioned your situation and ...
Fordham Marine in Jacksonville, Florida is very highly recommended by a local sailor who ran into trouble a few years ago while transiting the ICW. They are Volvo specialists. If Jacksonville is local, you may want to chat.
Good luck,
Mitchell Bober
Sunny Annapolis (60F in January, huh???), MD
Fordham Marine in Jacksonville, Florida is very highly recommended by a local sailor who ran into trouble a few years ago while transiting the ICW. They are Volvo specialists. If Jacksonville is local, you may want to chat.
Good luck,
Mitchell Bober
Sunny Annapolis (60F in January, huh???), MD
CDSOA Founding Member