BMC/Parsons

[Djh]

Hi Tony. Absolutely spot on. Inspected the whole thing and the reduction box will need to be removed to continue dismantling. Will require a puller and a bigger socket than  I have to take coupling etc off the back. The backing plate for the brake drum has moved back so  I can see the clutchplates but need to complete the aforementioned before  I can properly inspect them. Learning a lot more about mechanical gearboxes than  I ever wanted to know. Thanks to input from the forum I'm getting there. I suspect that I might be heading down the hydraulic route as the probable engineering bill is mounting up. The delta lockdown here is not making things any easier and with Christmas looming and summer holidays thereafter it might be a long winded process. Never mind  I didn't expect to be using her this summer anyway.

[john.k]

Simple rule....if you have your own machine shop ,you can fix anything......if you are reliant on others ,then you need to able to buy spares and find an instruction book. 

[Djh]

Ain't that the truth. My late father was a diesel engineer. Trained in the RAF during the the war. Should have paid more attention and asked more questions.

[Tony Brooks]

7 hours ago, Djh said:

Ain't that the truth. My late father was a diesel engineer. Trained in the RAF during the the war. Should have paid more attention and asked more questions.

 

I very much doubt that would have made any difference in this case. I also doubt you will find a manual or anything other than second-hand spares and  even that will take a lot of doing. I was working on them about 55 years ago and they were considered an old design then. I suspect a second hand PRM or Velvet Drive hydraulic box will end up costing not a lot more and will be far easier. I am not sure about what other boxes are available where you are but I would avoid a TMP hydraulic box. Self Changing Gears hydraulic boxes are/were very good. Arguably more robust than PRM.

[Djh]

Thanks for that Tony. I have the possibilty of a PRM 307?. Was rebuilt and then did less than 100hrs but has been sitting in a container for about 5yrs. Cost £750. Still have to find bellhousing, make adapter plate and lengthen propshaft, because the PRM is about 12" shorter than old mechanical box but could well be the way to go. Would certainly make maneuvering in and out of my marina berth a lot easier. I will continue dismantling the old box ,just for the hell of it, and possibly will be able to give it away for spare parts or something.

[Tony Brooks]

I think that you must have a flywheel housing because the intermediate plate and the gearbox body bolt onto it. I suppose the engine change could have involved bolting the intermediate plate onto the gearbox and then some other form of gearbox mounting fabricating to support the box clear of the engine but without a photo I can't be sure. If you do have the flywheel housing then you need an adaptor plate and a drive plate. Note the marine flywheel housing is not normally  a bell housing like you have on a vehicle. It is often more a ring about 3 to 4 inches deep with  the rear feet on it.

[Djh]

My apologies Tony I used the wrong terminology. The existing housing did accomodate the flywheel and stubshaft, with the intermediate plate,that included a plunger type oil pump bolted to it, feeding oil through an internal gallery to the central bearing mounted on the stubshaft. That housing was for a Commodore and basically fitted where it touched. That will all have to be replaced with a new setup. Lancing Marine Marine still make a housing for the 4/98 and they are sending me a template to see how well or not it mates up to the back of my motor. They mated it to a velvet drive but should also fit PRM okay. Just went into the back of the boat and took a quick pic of the intermediate plate and oil pump.

[Tony Brooks]

Pity the intermediate plate (shown) only fits where it touches otherwise a bit of removal of surplus parts (pump, bearing and oil seal) careful marking out and drilling would probably produce a "not too bad" adaptor plate but it would probably have to be reversed.

[Djh]

The intermediate plate is okay it's the housing that's the problem. The holes don't line up with the holes in the block. They even resorted to trying to drill new holes, one of which went through a water gallery which they blanked off. Still, there were only 4 bolts holding the whole shooting box together.

[john.k]

You should be able to find a #3 SAE truck housing quite easily in NZ.....the same housing will also be on the 6/98 in any number of Leyland trucks (Boxers).....same flywheel too,if you need one...(The UK market Terrier had the 4/98,the Oz market Terriers had a Mazda Perkins 6)

[Djh]

Thankyou. I will start ringing around wreckers in the morning. I suspected that might be an option but didnt know which truck models would have been compatible. I will let you know how I get on.

[john.k]

You may be better off on a NZ vintage truck forum.

[kiwiSteve]

On 16/11/2021 at 23:42, Djh said:

Thankyou. I will start ringing around wreckers in the morning. I will let you know how I get on.

?

[Alan de Enfield]

2 hours ago, kiwiSteve said:

?

 

He is obvioulsy going to 'send out the boys' to stand on the rocks signalling that it's safe to proceed, but, once they do and get grounded, the 'wreckers families' all troop down to the wreck to disassemble the engine and gear box to remove the 'prized piece' (the intermediate plate housing)