Tamd41a exhaust solenoid

[colhel]

Morning! Does anyone know what activates the exhaust solenoid on Tamd41a? Ie, is it engine temp, rpm or throttle position etc? Also what position would the solenoid be in for the flaps to open? When the solenoid arm pushes out it pushes against the top of the lever on the exhaust elbow.

 

[andy59]

Had a read on boatdiesel Colin and the consensus is ditch the old elbow and fit one from the 41b, they don’t think the flap does much and you’re old one could be partially blocked , (steam).

 

[colhel]

Thanks Andy. Keep me posted if you're heading this way ?

 

[oldgit]

Nothing fitted to my 41B.
The cylinder head/pistons were modified to reduce the smoke.
Aftermarket elbow for 41B around £200 from ebay,

What's the difference between Volvo AQAD41A's & AQAD41B's?

 

[colhel]

Thanks OG. A new elbow is more thsn likelythe next move. I have tried prising the exhaust tube so I could investigate inside the elbow but its well and truly stuck, so when we're back home I'll try again.

 

[colhel]

A quick update.
Yesterday I fixed the flaps in what I assumed was the open position. Leaving the River Dart I opened the throttle and she wouldn't rev higher than 1500 rpm so I then fixed the flaps in the opposite position and what a result! Engine responsive and sounds much free'er and steam drastically reduced.
Now in Salcombe.

 

[andy59]

Good news Colin ? enjoy salcombe ???

 

[volvopaul]

Morning! Does anyone know what activates the exhaust solenoid on Tamd41a? Ie, is it engine temp, rpm or throttle position etc? Also what position would the solenoid be in for the flaps to open? When the solenoid arm pushes out it pushes against the top of the lever on the exhaust elbow.

Small micro switch on injection pump .

 

[Rappey]

I had to look at this thread as flaps on the exhaust system ?
I know how the mercedes amg ones work and why, but what are they meant to do on a boat ?

 

[colhel]

Small micro switch on injection pump .

Thanks Paul.

 

[colhel]

I had to look at this thread as flaps on the exhaust system ?
I know how the mercedes amg ones work and why, but what are they meant to do on a boat ?

In the exhaust elbow there's some flaps operated by a solenoid to restrict the flow of exhaust gases to reduce smoke on a cold start.
This engine has always been steamy but lately its been getting worse but the engine temp have been normal so the exhaust elbow was possibly the culprit. On Saturday I checked the solenoid was working, which it was, so resovled to remove and clean the elbow after our holiday. Dartmouth on Monday and it was lashing down with rain all day, so I thought it would be a good time to at least remove the pipes and attempt to clean the elbow in situ. The exhaust tube was well and truly stuck so I gave up, it was then I noticed the lever that links the solenoid to the spindle that turns the flaps was loose and I couldn't get the solenoid to operate. So rather than risk having the flaps closing I wired them into (what I assumed) was the open position. Leaving the Dart I opened the throttle, and nothing so dived below and fixed the lever in the opposite position. Result, the engine is running the best it's been in ages ?

 

[oldgit]

The elbows do have a certain lifespan.
Recently on my boat the bolt holding the stainless clip holding the exhaust elbow failed.
Removed and inspected old elbow, which externally looked good, shiney paint etc.
The outer cast iron casing literally fell to bits on removal. Stainless clip was more or less holding it all together.
Engine was not overheating although much of the internal channeling was resticted by corrosion.
Early warning , rust stains on elbow or on bilge floor immediately under exhaust.
Fairly easy job to do to refit new elbow and new clip, only pig is sometimes releasing short flexible exhaust hose from elbow.
On mine the angled stainless tube connecting to main exhaust did need some attention.
Ps. Did use a smear of exhaust paste twixt turbo and elbow.
Pix from a exhaust elbow swap on a Princess 33 with AQD 40A Same corrosion problem.