This whole post is very interesting, especially since this weekend I acquired a set of chopped cases. I really like what you have done with this engine. I like how you used the original type primary cover. I want to do that also. Probably I will use a Triumph 5 speed gearbox, because I have one. What would make it easier would be if I had the bit that someone cut off the Vincent cases years ago. Does anyone have one of those? Or were they all scrapped. Also I am going to need a primary cover. It could be an awful one also.
Crank Case Inspection
- Thread starter Pushrod Twin
- Start date
At least availability is not the problem see Spares Company
Hi Nigel, how much engine did you get with your cases? A 5 speed Triumph box is a good choice, Roy Robertson uses one in his Egli racer. Does the Triumph box have a splined or tapered input, clutch, shaft? I recall some having tapers which I am not a fan of, but if you can obtain a shaft which will take a Norton Commando clutch, life becomes a little easier. The Commando clutch, as you can see, uses the Vincent chain size but is 1 tooth bigger bringing it 0.062" closer to the crank. There is quite a bit of enthusiasm on the forum for belt drives & I believe that belts with teeth both sides are now available if you wish to drive a power generation device off the back.
I had a friend who arranged chain case castings which allowed me to cut the diaphragm out with out conscience. However, they were cast using an original & not enough allowance was made for shrinkage, the first one only just cleaned up!
Can you put up pics of your cases, I dont quite understand what you mean by "the bit that some one cut off"? Some have had parts, or all, of the chain casing cut off the side of the crank case, some of those have used modified Comet parts to reclaim them. If you mean the gearbox end of the casing, I may be able to help. I have some new castings which could be welded on, but after considerable deliberation I chose not to take the risk of losing my original engine cases by welding & distorting them. I understand that it has been done successfully? 30 years ago when I started this project new cases were totally out of the question & I couldn't afford, or find, complete used ones! Besides, I now have the satisfaction of reclaiming a couple of sets of original cases and giving them another life. Keep asking questions, I am happy to help. Roy
I had a friend who arranged chain case castings which allowed me to cut the diaphragm out with out conscience. However, they were cast using an original & not enough allowance was made for shrinkage, the first one only just cleaned up!
Can you put up pics of your cases, I dont quite understand what you mean by "the bit that some one cut off"? Some have had parts, or all, of the chain casing cut off the side of the crank case, some of those have used modified Comet parts to reclaim them. If you mean the gearbox end of the casing, I may be able to help. I have some new castings which could be welded on, but after considerable deliberation I chose not to take the risk of losing my original engine cases by welding & distorting them. I understand that it has been done successfully? 30 years ago when I started this project new cases were totally out of the question & I couldn't afford, or find, complete used ones! Besides, I now have the satisfaction of reclaiming a couple of sets of original cases and giving them another life. Keep asking questions, I am happy to help. Roy
Roy
I got very little with my engine. but I already had some cylinder heads. I have a few other small things leftover from the 48 Rapide I just put together. I have an oil pump and an the drive worm. I am going to buy a Terry Prince crankshaft assy. I also bought two 90 bore cylinder kits with billet muffs and Venolia pistons. The 90 X 90 engine appeals to me as the standard Vincent combustion chambers seem to have been designed for a larger bore than the original 84mm.
I haven't had any trouble with the Triumph tapered gearbox shafts, and I have a couple of Triumphs that are pretty fast. The tapers don't wear the way splines do. I had to replace the center of my Norton clutch because the splines were worn. It is funny how on the Norton they have a taper on the end of the crankshaft and a spline on the gearbox shaft and on the Triumph it is the opposite. I think the best combination might be to have tapers on both, probably you would prefer splines on both. I have a few Triumph crankshafts with worn output splines.
I like the idea of the double sided belt. I have been thinking that way. I notice with the smaller Norton gearbox you had lots of room for a small alternator. I think I will use the Kubota permanent magnet type alternator either driven in the original way by a chain or by the belt with the outside teeth. When those are used with the standard cases and offset drive has to be arranged. I have one of those on my 48, it is called a McDougallator. I think if it was driven directly instead of being speeded up a bit it would still put out enough power. The Triplex chain is good also, I will have to see if a T140 Clutch will fit. It seems not much different than the Norton one.
The cases I have look a lot like the ones you have but the back of the case is not milled flat as yours is. I think I can make the necessary connection for the gearbox with a special G50 plate and by welding an inner primary back on. It would be really nice if I could find one of the inner primary parts, the part on the drive side case that was cut off. That would avoid having to mill one from solid.
I don't want to weld on my timing side case, but I think I can weld onto the drive side without causing much distortion. I have a 400 amp TIG welding machine and lots of welding experience. I am going to have to line bore the cases as they are not a matched set, so I will do that after all the welding. All the alignments have to be established and I have to re deck and bore the holes for both cylinders, to flatten them, but also just so the bigger liners will fit.
http://s901.photobucket.com/user/tricatcent/media/photo 2_zpsgjebn4oo.jpg.html?sort=3&o=0
I got very little with my engine. but I already had some cylinder heads. I have a few other small things leftover from the 48 Rapide I just put together. I have an oil pump and an the drive worm. I am going to buy a Terry Prince crankshaft assy. I also bought two 90 bore cylinder kits with billet muffs and Venolia pistons. The 90 X 90 engine appeals to me as the standard Vincent combustion chambers seem to have been designed for a larger bore than the original 84mm.
I haven't had any trouble with the Triumph tapered gearbox shafts, and I have a couple of Triumphs that are pretty fast. The tapers don't wear the way splines do. I had to replace the center of my Norton clutch because the splines were worn. It is funny how on the Norton they have a taper on the end of the crankshaft and a spline on the gearbox shaft and on the Triumph it is the opposite. I think the best combination might be to have tapers on both, probably you would prefer splines on both. I have a few Triumph crankshafts with worn output splines.
I like the idea of the double sided belt. I have been thinking that way. I notice with the smaller Norton gearbox you had lots of room for a small alternator. I think I will use the Kubota permanent magnet type alternator either driven in the original way by a chain or by the belt with the outside teeth. When those are used with the standard cases and offset drive has to be arranged. I have one of those on my 48, it is called a McDougallator. I think if it was driven directly instead of being speeded up a bit it would still put out enough power. The Triplex chain is good also, I will have to see if a T140 Clutch will fit. It seems not much different than the Norton one.
The cases I have look a lot like the ones you have but the back of the case is not milled flat as yours is. I think I can make the necessary connection for the gearbox with a special G50 plate and by welding an inner primary back on. It would be really nice if I could find one of the inner primary parts, the part on the drive side case that was cut off. That would avoid having to mill one from solid.
I don't want to weld on my timing side case, but I think I can weld onto the drive side without causing much distortion. I have a 400 amp TIG welding machine and lots of welding experience. I am going to have to line bore the cases as they are not a matched set, so I will do that after all the welding. All the alignments have to be established and I have to re deck and bore the holes for both cylinders, to flatten them, but also just so the bigger liners will fit.
http://s901.photobucket.com/user/tricatcent/media/photo 2_zpsgjebn4oo.jpg.html?sort=3&o=0
I am a fan of splines, I had bad experiences with R series BMW's with tapers on gear box out puts. They dont stand the shock of bump starts! Splines shouldn't wear if they are kept tight on the shaft.
My cases were cut differently to yours, obviously, & I was able to mill them flat. I see yours have the rear top & bottom of the primary area cut out. The rear case casting I have may be the answer to your desire to weld on the inner primary edge. I am off to the NZ Section VOC rally tomorrow, bags are packed, will gas the Guzzi on the way home from work after lunch and off ! I will take pics for you next week when I get back.
That little alternator ran the lights the night we started it & the lights didnt dim at idle so we figured it was keeping up. A Kubota should do the same.
90x90 does sound attractive, where did you buy the barrels & slugs? Are they nigusil plated or iron linered? I have a pair of cut cases labeled HRD like yours, late '48, #1398, but they are a low mileage, only raced for 1 season, matched pair. They are also machined up, 90% ready to be built, same as the pair in this article.
If you are an experienced welder, I am sure you dont need me to remind you to preheat the cases before welding & keep them hot all through during the process. It makes a huge difference to shrinkage & distortion.
Are you considering electric start? I am keen to fit something to the B cases, but havent worked out how yet.
My cases were cut differently to yours, obviously, & I was able to mill them flat. I see yours have the rear top & bottom of the primary area cut out. The rear case casting I have may be the answer to your desire to weld on the inner primary edge. I am off to the NZ Section VOC rally tomorrow, bags are packed, will gas the Guzzi on the way home from work after lunch and off ! I will take pics for you next week when I get back.
That little alternator ran the lights the night we started it & the lights didnt dim at idle so we figured it was keeping up. A Kubota should do the same.
90x90 does sound attractive, where did you buy the barrels & slugs? Are they nigusil plated or iron linered? I have a pair of cut cases labeled HRD like yours, late '48, #1398, but they are a low mileage, only raced for 1 season, matched pair. They are also machined up, 90% ready to be built, same as the pair in this article.
If you are an experienced welder, I am sure you dont need me to remind you to preheat the cases before welding & keep them hot all through during the process. It makes a huge difference to shrinkage & distortion.
Are you considering electric start? I am keen to fit something to the B cases, but havent worked out how yet.
I have made a pdf (18MB) of the photos that Pushrod Twin has posted. It can be downloaded from http://s000.tinyupload.com/?file_id=03363783151414128789
PT
I can see that the way your cases were cut is a lot nicer than the way mine are done. By welding I can correct some of that.
Probably the rear casting you have would simplify what I want to do with my bike. When you get a chance send me a picture and maybe I can arrange to purchase those bits from you. I like the way you went. The other way would be to put a Commando primary on, but then you are committed to a crank driven alternator, and you have to give up the ESA which I like.
I know what you mean about splines but tapers are really good too. There are as many bad examples of each. On BMW airheads the splines on the rear drive wear out, almost the same set up on Moto Guzzis almost never wears out. The trouble with spines is once there is a little wear tightening the bolt on the end won't actually take the play out, especially when there is a reversing load. At work we often use to connect a Gates Poly Chain pulley onto a spline hydraulic motor shaft, a split tapered insert, tapered on the outside, and involute splined on the inside. When the pulley is pulled down the taper squeezes the whole thing together and nothing moves.
The 90 bore kit I have was purchased from the estate of the late John McDougal who was one of the f0remost Vincent experts in our area (Vancouver Section) There are a lot of experts around here though. It has Maughans billet cylinder muffs and iron liners. Those parts still have to be fitted together. It has some forged Venolia pistons that are around 11:1 compression. Tony Cording has the identical stuff on his Comet and it works really well. I think that John took the compression down to about 10.5:1 on Tony's engine by fitting compression plates. I think that is about what I want to aim for as well.
What kind of Guzzi do you have? I have owned two, a 850 Lemans and a V11 Lemans. They were great bikes.
I can see that the way your cases were cut is a lot nicer than the way mine are done. By welding I can correct some of that.
Probably the rear casting you have would simplify what I want to do with my bike. When you get a chance send me a picture and maybe I can arrange to purchase those bits from you. I like the way you went. The other way would be to put a Commando primary on, but then you are committed to a crank driven alternator, and you have to give up the ESA which I like.
I know what you mean about splines but tapers are really good too. There are as many bad examples of each. On BMW airheads the splines on the rear drive wear out, almost the same set up on Moto Guzzis almost never wears out. The trouble with spines is once there is a little wear tightening the bolt on the end won't actually take the play out, especially when there is a reversing load. At work we often use to connect a Gates Poly Chain pulley onto a spline hydraulic motor shaft, a split tapered insert, tapered on the outside, and involute splined on the inside. When the pulley is pulled down the taper squeezes the whole thing together and nothing moves.
The 90 bore kit I have was purchased from the estate of the late John McDougal who was one of the f0remost Vincent experts in our area (Vancouver Section) There are a lot of experts around here though. It has Maughans billet cylinder muffs and iron liners. Those parts still have to be fitted together. It has some forged Venolia pistons that are around 11:1 compression. Tony Cording has the identical stuff on his Comet and it works really well. I think that John took the compression down to about 10.5:1 on Tony's engine by fitting compression plates. I think that is about what I want to aim for as well.
What kind of Guzzi do you have? I have owned two, a 850 Lemans and a V11 Lemans. They were great bikes.
I just tried to drag and drop a photograph onto this email and got an error so I think it must be a server problem. Perhaps try again later.What has happened here? I cant work out how to post pics, has something changed or my forgettery working better than my memory?
