Crankcase Joint-Prep and sealing

[greg brillus]

How do you tell when your Vincent is leaking oil badly............when your rear brake shoes have got more oil on them than the insides of your engine....hey at least the oil is centrifically cleaned...this is an almost guaranteed way to stop your "Brakes Squeeling" even with Shadow drums....!!!

 

[riptragle1953]

The Japanese bikes have dead flat CNC prodded horizontalally split cases ...... unlike the Vin which was sorta machined true, warped, bashed, crashed and God knows what else.

 

[b'knighted]

was that a 60 year old R1 Yamaha?
Did Vincents leak when they left the factory?
I have heard that the factory found some cases to be porous so they came up with a painting system for the engines to seal those that were not good enough for Rapides and sold them as Shadows. The die-cast D engines did not suffer porosity so did not need their crankcases painted.

 

[A-BCD]

so my oil-tight 1948 Rapide is in fact, superior to a Black Shadow !! But then I always knew that................................( after all, the VOC was formed for owners of Series B Rapides )

 

[b'knighted]

That is true Brian. Have you considered painting the A black?

 

[Big Sid]

For a porus spot in the crankcase this often works . Drain sump dry . Wash super clean the surface thought to be oozing through . Spray several times directly the area with contact cleaner , directing the spray right into the pores up close . Blow dry well immediately . Apply medium Loctite over the surface liberally . Let sit overnite . This will often wick in and harden in the pores , it can effect a permanent cure if the cleaning was good . Done it . Sid .

 

[A-BCD]

That is true Brian. Have you considered painting the A black?

A Series A Black Shadow ?? I thought I might have some porous crankcases, but after more work on sealing the pushrod tubes, I seem ( whisper !! ) to have got the A twin almost oil-tight !!

 

[b'knighted]

From the fact that you fitted replica A pushrod seals on your B they must be good. How do they work?

 

[Hugo Myatt]

was that a 60 year old R1 Yamaha?
Did Vincents leak when they left the factory?
I have heard that the factory found some cases to be porous so they came up with a painting system for the engines to seal those that were not good enough for Rapides and sold them as Shadows. The die-cast D engines did not suffer porosity so did not need their crankcases painted.

I seem to remember reading many years ago that the insides of Vincent crankcases were treated with isinglass to prevent porosity.

 

[Big Sid]

There is a modern technique used on fresh castings that has them submerged in a special fluid that like a thin Loctite wicks into the pores and totally seals up any porus areas , in fact I think Loctite sells such a fluid .
Sand castings unlike die castings tend to have poorer flow of the metal into complex shapes and did have such problems . Die casting has the molten metal pressure forced into the hollow form , while the earlier sand mold is simply poured into the form .
It was quite common , and I personally saw this in early Ducati 750 twin cases . Was evident in engine no. 10 in frame no. 3 that we rebuilt . There were areas that had been heliarced over to seal the surface . Vincent had this problem in a few early motors way back as did Ducati in this 1970 motor , this one purchased right from Ducati by the owner who rode it all over Europe for 43,000 miles . Brought back on the deck of a ship the bores and rings had rusted solid .
Berliner began selling these in 1972 but a few left the factory as far back as 1970 . Sid .