Hi ! New member with gearbox drama

[balmoralbob]

Hi all, am searching for answers to gearbox problem, we are currently restoring our 1962 44' timber bridge deck cruiser and have suffered a seized Perkins engine (exhaust riser let go into manifold), am well underway with stripping engine onboard and rebuilding in situ (difficult but not impossible). The problem I have is : on removing all gearbox mounts and bolts (Paragon velvet drive box) have found the gearbox main shaft into the damper plate appears seized on spline and having a lot of trouble freeing box. Any ideas as to how this can be achieved? Have approx. 15mm opening at top of bell housing and am thinking of oxy torch thru gap and heating damper plate at spline to try and release gearbox shaft? Damper plate will obviously need replacing so not to concerned there. What does everyone think? Am running into constant seized/rusted obstacles all caused by previous owners lack of maintenance, had 3 weeks removing head from 1 stuck head stud so am getting used to these type of problems. Any help greatly appreciated.
Cheer's
Steve

 

[KD3PC]

Since it looks as if you will be replacing the paragon or at least rebuilding it....I would spend a few bucks on the best penetrating oil/spray you can get and hose it down, wait a couple of hours and spray again over the next few days, let it work and then work the shaft with a wrench or bar and see what you get.

Torch would be my last choice, but might work.

 

[Sovt]

Just went thru this myself. Paragon 23 transmission with a Perkins engine.
I ended up drilling a 2" hole at the 1:30 position on the adapter plate and by using a custom bent wrench managed to back out the bolts. Drilling the hole was a pain (use lots of cutting fluid) but backing out the bolts went fairly well. The light in the picture is a LED that I bought at Radio Shack. It just slid into the bolt hole below the hole I cut. Made getting a wrench on the damper plate bolt much easier.

I tried penetrating fluid, heat and prying no luck.

Good luck

Mike

 

[balmoralbob]

Thanks for replies, drilled hole in adaptor plate and discovered Allan head bolts, not what I was hoping for, as motor is seized cannot turn flex plate so now have the fun of trying to undo hidden bolts under gearbox. Diabolical....

 

[kloudie1]

Steve, PB Blaster and time and hardwood wedges to pry it apart while keeping the transmission perfectly centered so that the shaft is not binding in the hole? The running wear will have machined a little relief in the shaft which can act as a keeper.. making sure the shaft is not binding by wedging equally around the case gap and twisting the case against the frozen plate .. twist clockwise and counterclockwise .. may get the thing to move? Good luck with it!

 

[Sovt]

The paragon manual calls for inserting 3.5" bolts with the heads cut off into the engine block to guide the transmission out.

Sorry for your troubles. It's been my experience that seized engines are almost always the result of piston rings rusting to the bores. While the above suggestions may be valid you can do damage to the thrust bearings in the engine and transmission if you apply too much force in separating them.

I would suggest that you remove the engine head and use a penetrating liquid to try and free up the engine so that you can get at the Allen screws. A little patience and elbow grease is less likely to cause damage that you might regret down the road.

I have a number of manuals for paragon transmissions and perkins engines if you need them.

Good luck

Mike

 

[balmoralbob]

The paragon manual calls for inserting 3.5" bolts with the heads cut off into the engine block to guide the transmission out.

Sorry for your troubles. It's been my experience that seized engines are almost always the result of piston rings rusting to the bores. While the above suggestions may be valid you can do damage to the thrust bearings in the engine and transmission if you apply too much force in separating them.

I would suggest that you remove the engine head and use a penetrating liquid to try and free up the engine so that you can get at the Allen screws. A little patience and elbow grease is less likely to cause damage that you might regret down the road.

I have a number of manuals for paragon transmissions and perkins engines if you need them.

Good luck

Mike

Thanks Mike and everyone else for the replies, have tried hex head sockets today but bolts are just about in line with gearbox so next to impossible to get head in properly let alone the ones under gearbox. Head has been off now for 6 weeks and thoroughly soaked with PB Blaster- result - zilch movement of pistons, so no chance of turning motor over. Have cut a section out of top of bell housing to try and access rear end of shaft (motor side of flex plate) but to no avail, just a bigger useless hole that accesses nothing really.Am thinking heat now on flex plate at centre where shaft passes thru and cool rapidly, may expand and contract enough to free shaft?
Steve

 

[Sovt]

Oh boy.
Keep us informed as to how you make out

Mike

 

[balmoralbob]

Greetings !! Happiness has descended on the " Nereides" today with the freedom of the gearbox, thanks to my technical brilliance ( and the gas axe), I now am staring at 1 x free gearbox ready to be fitted with a new flex plate. Worked out quite well really, plate would have needed replacing anyway and after closer inspection of end of shaft, gearbox would never have come free without this radical removal method. Have attached pic of end result.
Cheer's and thanks for all the advice,
Steve

 

[balmoralbob]

Flex Plate Query?

Hi, gearbox and flywheel housing all off now ready to lift motor but am trying to find a supplier for new flex plate. No markings on old one but it is 26 tooth spline approx. 33mm shaft coupled to a6.354 Perkins flywheel. Have tried several USA suppliers and either dont reply or say thanks for interest but no reply?? We buy a lot of gear from US and always great service but this seems to be something no one is interested in supplying ? Any idea's on good supplier or even part no.?
Steve

 

[Sovt]

Re: Flex Plate Query?

Try PYI
http://www.pyiinc.com/index.php?section=rd_marine&action=marine-damper-plates