2 x TAMD41A - low RPM @ WOT

FARSCO said:
To give you motivation...after fixing it I went from 3100 to 3900 revs! (Slightly under propped I know)
Click to expand...

That sounds great!

After removal i can see daylight through the join at the bottom of the housing. There is also a weld repair around the drain plug hole. I am thinking of just replacing the housing as I couldn't guarantee the the drain plug seal will do its job due to this repair and I would love to be able to totally rule the housing out if I put it back on and am still short on power. I think it will be worth it for piece of mind. You can see the pics of it on the thread:

http://www.ybw.com/forums/showthread.php?515933-Volvo-TAMD41A-Aftercooler-Housing-and-Cover

So, part number 861657? Is there any reason that I can't just use bolts for the top cover? The studs are 6 quid each and I need 12. Am I missing something? I reckon I can reuse everything else.

https://www.marinepartseurope.com/en/volvo-penta-explodedview-7745920-26-20517.aspx

Also, are marinepartseurope the place to go? I would like speedy delivery so I can get this thing back on ASAP.

Excitement building...

D.
 
Volspec in Essex are showing they have it in stock. £296 inc vat and delivery

I can’t see why you couldn’t reuse the studs.....if you can get them out. You could probably source alternative studs and dome nuts much cheaper anyway!
 
Great - ropewalk marine are getting me a quote for delivery as well so one or the other will do nicely..

I am just noticing that the original diagram for the TAMD41a lists part number 984733 as the housing as well as 861657. Surely there isn't more than one version of this one the shelf at this stage of production?

I wonder will it be a straight swap. I guess we will soon find out!
 
Oh dear - copy and paste error!

Housing part number 859354 on the diagram above? Confusing - however, on other sites I see that 861657 supersedes all previous versions so I guess we will be good to go.

I found a shop nearby that will remove the existing studs for me after work (all being well). If not I am sure they could point me in the direction of replacements. I will get them to remove my snapped drain plug as well. Surely bolts would also work? Any reason for studs and nuts on this?

I am no engineer...

Cheers farsco.
 
I would guess it’s to minimise the chance of a bolt getting stuck in the housing body and snapping off.

By using a stud, you can spray the nut and free off much more easily.
 
A
bowler said:
Oh dear - copy and paste error!

Housing part number 859354 on the diagram above? Confusing - however, on other sites I see that 861657 supersedes all previous versions so I guess we will be good to go.

I found a shop nearby that will remove the existing studs for me after work (all being well). If not I am sure they could point me in the direction of replacements. I will get them to remove my snapped drain plug as well. Surely bolts would also work? Any reason for studs and nuts on this?

I am no engineer...

Cheers farsco.
Click to expand...

With studs drop the cover over them fit the pipes and diagonally tighten the studs ?
 
FARSCO said:
Or just buy a pack of 20 studs for £4!

https://www.ebay.co.uk/itm/5mm-M5-D...s-Screws-A2-304-Stainless-Steel-/322378872280

Not sure if they are M5 but gives you an idea anyway
Click to expand...

Too right - it's the principle of the thing!

I found a machine shop who said to bring the new housing in and they will measure up the necessary studs. Sadly, they were not keen on removing the old ones to measure in advance or remove my snapped drain plug from the core so it's staying where it is (maybe I need to find another machine shop).

Got the housing delivered all in for £284 - not too bad. Cheers also Scotty - cross tightening makes sense.

Should be here in two days, then hopefully get the studs on Friday, then bang it in on Saturday all being well.

D.
 
Interesting reading regarding twisting forces. Shouldn't think it would matter too much on this aftercooler. However, as farsco says nuts are easier to remove than bolts. I ended up getting studs that are 32mm and open nuts. Will do the job nicely.

Looks like all the stuff will arrive tomorrow so hopefully will know this craic this weekend.

Quick question, what kind of sealant for the intake manifold?

D.
 
bowler said:
Interesting reading regarding twisting forces. Shouldn't think it would matter too much on this aftercooler. However, as farsco says nuts are easier to remove than bolts. I ended up getting studs that are 32mm and open nuts. Will do the job nicely.

Looks like all the stuff will arrive tomorrow so hopefully will know this craic this weekend.

Quick question, what kind of sealant for the intake manifold?

D.
Click to expand...

Volvopaul said generic engine gasket maker compound type stuff when I asked him.

Mine was black....that’s as much as I thought about it at the shop :):):)
 
Well, AC fitted and water tested. Some progress but still down a bit. Engine now revs to 3600 and the other is up to 3800 so I am happy that we have progress at least.

I checked high idle again. 4200 on the SB engine , 4300 on port although these seem to change by 100 rpm every time i look! Perhaps time for a phototach at those rpm.

On the water with one out of gear and the other flat out i get 2700 out of the port and only 2200 from SB. Not surprising the turbo whistle is way more pronounced on port but i guess that is to be expected. Also, a friend of mine had a look over the stern during the test and noted that that SB engine was pumping out less black smoke than the port. Could that suggest some fuel starvation?

Another thought. I noticed when i had the air filter off that there is a slight resistance on the intake side of the SB turbo turbine. It spins with no play but it does not 'run on' for longer a second or so. Perhaps that suggests something? Anyways, pressure guages should be here soon so i can get some readings as volvopaul originally suggested.

In the meantime at least they are both in the correct range according to the engine manual.

Any other simple checks I can do in the absence of an engineer?

D
 
You could check the throttle cable fully advances the injection pump arm.

The rev gauges could easily be out by 200 rpm.

Bit of turbo wear maybe...but how far do you want to go down the rabbit hole!

You also said one was running warm, have you had the exhaust elbows off?

Personally, I would put some hours on them. Now both are getting hopefully, full air, things may clean up and improve with use. Certianly on my old boat (61a’s) that was the case. Ran much better after 10 hours blasting about.
 
FARSCO said:
Bit of turbo wear maybe...but how far do you want to go down the rabbit hole!
Click to expand...

Ha ha - all the way to the bottom!

Nope, have not had elbows but may pull them off for a looksee. Will also try to put some hrs on them. The turbo may not have much use over the last few years.

On a different note, i can confirm that volvo 'green' has changed significantly over the years. My engine is now 2 tone!

D.
 
Hello again all.

Just resurrecting this thread to get some additional input. As stated above, I was having some low rpm issues with one my my two TAMD41As. Over the off season I had the injectors done, props checked and refurbed, valve clearances set, new fuel filters (primary and secondary) including replacing the actual Racor housings, new air filters and exhaust elbows off and cleaned. I also installed VAS edition Bluetooth boost gauges. The lower RPM engine also had a new lift pump as I had a spare kicking around. N.B. I still need to clean the port AC core.

On a positive note, both engines are near enough doing the same thing for the first time. Both max out at 3750-3800 on my tachs after a minute or so at WOT according to my dash gauges. I photo-tached them at WOT and they are both actually around 100 rpm lower. In terms of EGTs and all those scary things, how concerned about this should I be?

I know to get my extra rpm I may need to check a number of things:

Firstly fuel supply. I reckon I can do this by running from a separate tank bypassing all fuel system component up to the lift pump. Currently I can't see any black smoke at cruise at cruising rpm (3200 rpm approx).

Secondly, to check the turbos does anyone have any figures for boost psi vs RPM for these engines? Currently each engine makes about 2700 rpm on its own (according to dash tach so maybe less) with just 14psi of boost (assuming gauges are accurate).

Lastly, could removing layers of old anti-foul for a super smooth bottom help? Or could a clean alone give me the extra 200rpm? The boat is slimey underneath as it is in fresh water but no significant growth.

To summarise, 2 questions really.

1) How bad it is to run the boat with this type of RPM in the short(ish) term? Or more importantly, how stressed should I be about the numbers?
2) What would you focus on first in term of trouble shooting. Would the fuel system be the obvious choice?

Cheers in advance.

D.
 
I’d say you have a good result There , old boat and engines .
Safe margin is max attained rpm and drop back 200 you can run at that all day as long as water temp is ok .
 
bowler said:
Hello again all.

Just resurrecting this thread to get some additional input. As stated above, I was having some low rpm issues with one my my two TAMD41As. Over the off season I had the injectors done, props checked and refurbed, valve clearances set, new fuel filters (primary and secondary) including replacing the actual Racor housings, new air filters and exhaust elbows off and cleaned. I also installed VAS edition Bluetooth boost gauges. The lower RPM engine also had a new lift pump as I had a spare kicking around. N.B. I still need to clean the port AC core.

On a positive note, both engines are near enough doing the same thing for the first time. Both max out at 3750-3800 on my tachs after a minute or so at WOT according to my dash gauges. I photo-tached them at WOT and they are both actually around 100 rpm lower. In terms of EGTs and all those scary things, how concerned about this should I be?

I know to get my extra rpm I may need to check a number of things:

Firstly fuel supply. I reckon I can do this by running from a separate tank bypassing all fuel system component up to the lift pump. Currently I can't see any black smoke at cruise at cruising rpm (3200 rpm approx).

Secondly, to check the turbos does anyone have any figures for boost psi vs RPM for these engines? Currently each engine makes about 2700 rpm on its own (according to dash tach so maybe less) with just 14psi of boost (assuming gauges are accurate).

Lastly, could removing layers of old anti-foul for a super smooth bottom help? Or could a clean alone give me the extra 200rpm? The boat is slimey underneath as it is in fresh water but no significant growth.

To summarise, 2 questions really.

1) How bad it is to run the boat with this type of RPM in the short(ish) term? Or more importantly, how stressed should I be about the numbers?
2) What would you focus on first in term of trouble shooting. Would the fuel system be the obvious choice?

Cheers in advance.

D.
Click to expand...
Hi, sounds like everything is within spec given the probable error tollerence of your measuring equipment.

Www.solocoastalsailing.co.uk
 
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