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Rebuilding TAMD41A, convert to 41B or 41P ?

CASTLE_CAPE

Regular Contributor
I have twin TAMD 41A's that are getting tired and due for rebuild.
Supposedly B's and P's smoke less when cold due to different pistons and injector tips-spray pattern.
Is B or P better?
What all parts need to be changed? Piston/liner kits and injectors. Anything else?
The parts schematic I looked at has the same part number for cylinder head for A & B .
I have already modified the air cleaners and PVC system.
Any changes to injection pump?
Thanks
 
Went thru the same question with my B when getting the full rebuild. The A version has the exhaust damper valve which does cause issues when it malfunctions. Don't know if this is an main source of excess smoke, but owners are more apt to disable or remove this from their As than do the repair.
On my B version we deglazed the cyls and installed new rings, because my main issue was leaks and a one minor bent piston rod due to a prev owners folly.
I do not think the B pistons and liners are available, just the P version, which I was told was a very minor change and maybe helped somewhat with the startup smoke.
The main change was a redesigned fuel injector pump. I can't comment on its improved performance, as I just went with my pumps.
I prefer my engines B version over the P because.... the heat exchanger is plumbed with brass pipes with changeable o rings, instead of the expensive volvo penta only hoses.
I have the metal air cleaner housing, which I prefer over the smaller plastic P version. I did remove and discard my oil breather canister and purchase the newer P valve cover with the hose connection fitting. Also installed racors on this line to clean up the engine compartment. This is plumbed bach to welded fittings on the air cleaner. The valve cover is installed in the middle position to avoid issues wit the engine install angle which may cause minor oil pooling.
As far as smoke, if any its only during early spring I get a few moments of light smoke at start up, which diminishes quickly when the engine temp rises. If I winter start I get a ton of smoke but it does clear quickly. Only th A version has glow plugs, the B version and P do not have the glow plug option. As for the rest of the season there is maybe a whisp of smoke at start up for maybe 30 sec to a minute.
Smoking during start up could be leaking injectors. Smoking while running is most likely injector condition or pump or setup of the timing.
As for different injector spray patterns ... my trusted mechanic showed my diff brands of engine injectors with different hole patterns. The advice was not to worry about this as the fuel gets atomized under pressure and should not make much difference.
The only way to get away from smoke is to go electronic with the new computerized models, which opens up a different type of topic discussion on reliability and cost of repair and life expectancy of the cpu and availability of stock of these parts. I am happy with my twin 41Bs, with what little smoke I might have. When running there is no smoke, which is the important factor.
 
Thanks for the help! Both of my A's smoke a lot. The colder the temp the worse it is.
They never completely clear up, it is a white colored smoke, I use no lube oil or coolant, they start easy and run like sewing machines. I have the aftercoolers apart now and the turbos off, I am not
getting upper RPM's or turbo boost , turbos were fairly coked up with soot . The glow plugs don't work so I have never used them. Injectors were rebuilt last spring, it helped a little, no where close to what I was hoping for. After coolers were surprisingly clean, I would get black smoke when revving up the engine while trying to get up on plane, but no black smoke at lower RPM's .
I'm trying to decide if I should rebuild these or get different engines and keep my out drives. Maybe Yanmars, still researching.
I need to do a compression test, I think that is the root of the problem, they smoke more than a good running "A" should . The local VP mechanic, who is pretty sharp, says he thinks the compression is good since they start so easy and use no lube oil.
What is the exhaust damper valve? Is that the linkage thing on the turbo? I do not have that on mine. After re reading what I typed I can see that a compression test is the next step, then have the injection pumps gone through.
I should add that I have dry exhaust and keel cooling. No salt water in the system anywhere.
Except the out drives, which are DP-B's . So it is easy to keep track of coolant levels .
Thanks
 
If your engines are easy to start.. eg within 3 turns or revolutions, then compression should be maybe not be on the list of possible issues (I think).
Now... not being a mechanic I don't know if the A model has diff piston design then B or P that might cause smoke... you will have to figure
that one out.
My transom with my DP drives gradually soot up a little. Deposits are mostly on the top of the drive cover that is out of the water. I assume
this is normal. What I do not think is right is the smoke you report during acceleration and not getting your max rpm at WOT.
I have assumed the smoke was mostly during startup.
What props are you using? I have A4 props and I am maybe under propped with a light load and just about right overloaded, but still no smoke
when I accelerate.
Check condition of hull and props. What props are you using and what is the length and weight of your boat? Is it a planning hull design?
 
Lots of white-ish smoke on the first start up of the day. It has that unburned diesel stink to it.
It will not clear up from idle / high idle at the dock. When I leave dock and bump RPM's up to 1,300-1,400 it smokes white, a lot ,then slowly clears up after 5-8 minutes. Starts after that, but same day, there is no out of the ordinary smoke.
Props are A-3's , bottom is clean, it is a planing hull, 36' X 12.5' aluminum, weighs around 12,000 lbs. I can get up on plane with full throttle, engines turn 3,800 or more then back off to 3,000 and get an easy 17-19 knot cruise .
The back smoke is a recent thing,it starts at about the RPM the turbos should start making good boost, since the after coolers are clean I am going to send the turbos to a rebuilder and see what they say. My plan is a compression check, both engines, possibly send the injection pumps off to a pump shop if compression is good. I will also install turbo boost gauges, and vac. / psi gauges on my racor filters. When I pulled the injectors last spring there was no signs of water being burned , the tips were a little sooty and not polished looking like they had been "steam cleaned" .
If compression test is "bad" I will pull the engines in the fall and rebuild them using B or P parts .
Thanks for reading!
 
The Volvo turbos are well known for excess tip clearance developing on the exhaust side. You may well have low boost, so worth checking. I did a pair of KAD32 turbos a year or so ago and all they needed doing was to have a new exhaust housing 'insert' installed. This isn't however a Volvo fix (say "we can sell you an expensive new turbo" in your best Swedish accent), so you may need to hunt for someone who does this.
 
Thank You, I will ask the local (Seattle) turbo shops if they do that fix, it sounds good to me.
In the past I have spent days researching non Volvo parts rather than pay Volvo prices.
 
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