Jump to content

Featured Posts

Posted

*I have a video of the gearbox in a link at the bottom. 

 

So I bought this boat last fall and I need some help fixing the gearbox. The boat has a Coventry victor WD3 engine (1938), and a Perfekta no. 5 gearbox, I can find very little on this gearbox so it makes it more difficult to fix myself.

 

Do you have any advice on how I can clean the gearbox, because in the current state it looks very dirty and rusty, and I don't think is good for running it. Of course I will fill it with the proper oil when running it but I would like it a little cleaner before using it. I thought of letting it sit in diesel for 2 hours but I don't know for sure if that is the right thing to do. Do you have advice on cleaning the gearbox.

 

Secondly, I ran it for a little while a few months ago and it I noticed it wouldn't properly enter neutral gear unless I forced the prop shaft stuck. Otherwise the prop shaft would spin along even in neutral. I looked around the internet and found that often some bolts have to be adjusted, but I don't know which. Do any of you know how to fix this issue.

 

I only have the video below of my gearbox, but I have also posted the manual and blueprints I have found on the internet.

If I was unclear in any of my explanations, I apologize, please comment if you have questions or want clarification. Thanks in advance.

 

https://imgur.com/a/RJrvW2w

Gearbox wd3.jpg

keerkoppeling blueprints.pdf

Posted

I think @truckcab79 might have a Coventry Victor.

 

 

Posted
43 minutes ago, Ltvel said:

Secondly, I ran it for a little while a few months ago and it I noticed it wouldn't properly enter neutral gear unless I forced the prop shaft stuck.

Its very common with mechanical gearboxes for the output shaft to rotate slowly when the gearbox is in neutral. The gearbox internals are subject to vibration from the engine and it only takes a bit of movement for one of the forward or reverse clutches to drift into weak engagement, and the shaft rotates. It can't transmit significant power like this and can easily be stopped by a foot on the propshaft.  But a bit of a nuisance all the same when you think the boat is stationary in midstream with the gearbox in neutral and you find the prop is slowly rotating and pushing you somewhere you don't want to go.

Posted (edited)

That looks very like what I know as a BMC B type gearbox, but I think it may be a Parsons design. The only thing I don't understand is the oil recommendation, that looks more like the engine oil recommendation. I am all but sure the reduction box uses SAE 80 gear oil, and possibly the same or SAE 30 engine oil for the gearbox.

 

I assume that you want to clean the inside of the gearbox but unless you strip it totally down and wire brush I would not bother in case whatever you used affected the clutch plates and brake band. Fill with oil and run to allow the oil to take off whatever rust that wants to fall off. It will look a lot better when soaked in oil.

 

There are two adjustments on that box, one having two adjusters and another having three. However, I am not sure that there are not missing parts from the astern adjusters. Does the gearbox select and actually drive in astern.

 

I also get the impression that the ahead adjustment is very slack, if so that would NOT explain holding in gear. I just hop a clutch plate or the brake band friction material is not breaking up because slack adjustment is more likely to result in slip, not drag. maybe it is rust that will wear off.

 

Astern adjustment:

I can't remember all the details but here is a general procedure. The astern adjusters and the two square heads on either side, close to the top of the box near the cover that you have taken off. The large hexagon outer sleeves are just lock nuts.

 

Hold each square and loosen the lock nuts. Screw each square in by half a turn and in equal amounts while you keep putting it in and out of astern. You will see the brake band tighten and loosen on the astern drum. Eventually, it will be impossible to move the lever into the fully astern position. Then gradually loosen each adjuster until you can get full movement and I THINK you will feel a detent that clicks as the lever moves into full astern (don't hold me to this). If so, this is to do with the shape of astern wedge that you can see moving as the lever moves. Once you feel the adjustment is correct, run it and move it in and out of astern. If the box drags in astern with the lever in neutral, slacken each adjuster a little until the dragging just stops. Then hold the squares and lock up the lock nuts. Please note that the adjusters on your box do not seem to be evenly adjusted.

 

Ahead:

There are three (I think, may be four) adjuster bolts with lock nuts on the toggles pivoted on the back of the clutch drum. The procedure is similar to astern adjustment. There is one at 12 o'clock in your video, I expect the others will be at 4 and 8 o'clock.

 

This time loosen the locknuts and then tighten each adjust in turn by one flat (one sixth of a turn) while moving the lever in and out of ahead. Adjust each bolt evenly. After adjusting all three bolts check the movement of the sleeve that is around the output shaft. When fully in ahead the toggles should allow full movement of the sleeve with the end of the toggles all but sitting against the flange at the end of the sleeve.

 

Ensure the locknuts have been tightened and the run it while moving the lever in and out of gear. If the box slips then tighten each adjuster slightly, if the box drags slacken them slightly, but ensure equal adjustment.

 

I hope this helps.

 

 

 

 

 

FWIW, the instruction for this box was in the back of the original BMC 2.2 Commander manual with the yellow card cover, I have not seen one for well over 50 years and I have yet to find an online version.

 

@RLWP do you have a manual or will you add anything to this for the OP.

Edited by Tony Brooks
  • Greenie 2
Posted (edited)

Alright thanks a lot for your detailed explanation. 

I just have one question following your advice, which part did you mean when you said. "close the top of the box near the cover that you have taken off"? Which part do you want me to close, or do you mean the flywheel opening where the starter usually goes?

WhatsApp Image 2025-02-04 at 22.02.20_958fa2f2.jpg

Edited by Ltvel
Posted (edited)
52 minutes ago, Ltvel said:

Alright thanks a lot for your detailed explanation. 

I just have one question following your advice, which part did you mean when you said. "close the top of the box near the cover that you have taken off"? Which part do you want me to close, or do you mean the flywheel opening where the starter usually goes?

WhatsApp Image 2025-02-04 at 22.02.20_958fa2f2.jpg

 

I seem to have missed out a "to", sorry. Close to the top of the box.

 

You can see the square reverse adjusters almost level with the front two cover bolt holes.

 

I just checked, I did write "close to"

 

I should have said that there is another "adjustment" right in the centre in the bottom of the box. It is not something you want to mess with because it is just the support and centring device for the reverse brake band.

 

Edited by Tony Brooks
Posted

I n I have remembered another aspect of ahead adjustment. It is very important that each ahead adjuster is adjusted equally, so use the gear lever to slide the ahead sleeve cam into the toggle so they almost touch the cam. Then use a feeler gauge between the cam and each toggle to ensure the gap between each toggle and cam is equal. If not, then adjust the relevant adjuster until they are all equal. Once that is done adjust as detailed in my earlier post.

Posted
16 hours ago, Tony Brooks said:

 

 

@RLWP do you have a manual or will you add anything to this for the OP.

 

I don't, unfortunately

 

Richard

Posted
16 hours ago, Ltvel said:

Alright thanks a lot for your detailed explanation. 

I just have one question following your advice, which part did you mean when you said. "close the top of the box near the cover that you have taken off"? Which part do you want me to close, or do you mean the flywheel opening where the starter usually goes?

WhatsApp Image 2025-02-04 at 22.02.20_958fa2f2.jpg

 

I agree with others that the box has distinct similarities to some manufactured by Parsons.

However, after a bit of time searching, I have not been able to turn up anything that is in any way close to a match, so don't think I an help any further.

Posted (edited)

I seem to recall that we have discussed this sort of box before. I have also been checking things and now think that it is not a BMC DCB, (B type), but a BMC DCA (A type) used on smaller engines (I have never seen one in real life).  The DCB had a cast rectangular top cover, I think this one is round pressed steel. The adjustment won't be much different though. I think it may have been used on the Vedette petrol engine.

Edited by Tony Brooks
Posted
43 minutes ago, Tony Brooks said:

I seem to recall that we have discussed this sort of box before. I have also been checking things and now think that it is not a BMC DCB, (B type), but a BMC DCA (A type) used on smaller engines (I have never seen one in real life).  The DCB had a cast rectangular top cover, I think this one is round pressed steel. The adjustment won't be much different though. I think it may have been used on the Vedette petrol engine.

Also on the Coventry Victor 14hp petrol engine which I once had, but direct drive with no reduction gear.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.