Vincent 1360

worntorn · Apr 14, 2014

I finally started to assemble the permanent engine for my Project bike. I built the bike a couple of years ago using my OZ Rapid engine as test engine. The OZ Rapid had to come apart for painting anyway so it was an opportune time to borrow the engine.
Before investing any money in a new engine I wanted to see if the bike was worthwhile. It turned out to be my favourite to ride, even did one 600 mile day with little fatigue, so the parts orders went in. It took nearly two years to assemble the parts since much of the stuff is one off.
For a standard Vincent engine you could likely have all the pieces sitting in front of you in a/week or two.

Unfortunately, when the 102 mm stroke crank arrived it was running out 4 thou on one side and two thou on the other. Acceptable for a/new/Harley according to my reading, but the Vincent factory specs call for less than 2 thou runout, so I had a go at improving things. The 8 lb lead mallet had no effect even with one man holding and the other giving it a/big windmill two handed blast.
This crank is much like those Vincent built for the high performance Picador drone aircraft engines. When developing those engines they learned that the stock crank was not suitable for constant high rpm.
Terry Prince designed my crank and had it built by a/machine shop in Australia.
It has oversized mainshafts and an oversized big end pin plus a 12 ton interference fit vs 6 ton for the standard crank
I spent about two days getting it to run with a half thou TIR ea side. It finally moved after squeezing it with 14 tons in/the hydraulic press.

Glen

Crank now running true, the drawers await me

bwolfie · Apr 14, 2014

Looking forward to more on this, very cool stuff. I'm :mrgreen:

worntorn · Apr 14, 2014

Hi Brent

I actually started on it in mid January but went away for holidays in the first half of February then got talked into a complete Bathroom Reno here at home, that killed most of March.

First up was to deal with the problem of sealing the mainshaft. Original Vincents did not have a seal between the crankcase and the primary housing. They have four mainbearings in total, two per side. The outside bearing on the drive side is a ball bearing. It's outer race is held in place by two heavy circlips and by the interference fit in the case. The inside bearing is a roller bearing an butts tight up to the flywheel. There is about a 5/8" gap between the two bearings and this is take up by a scroll which runs inside of a hardened outer distance piece. The scroll runs with about a half thouclearance to its outer,so it holds some of the oil back, and worms most of the rest back. A little gets thru to lube the ballbearing and this oil then carries on out to the primary.
After awhile the primary gets over full and needs to be drained. This also makes for a high level of oil consumption. By the midfifties Paul Richardson had come up with an after the fact seal housing and seal to deal with the issue. On standard cases the seal carrier gets mounted on the outside face of the ballbearing housing. Hole are drilled and tapped into the face.
In my cse, with much larger than standard mainshafts and bearings, even though these cases are greatly thickened around the mainbearings there wasn't quite enough meat to do this.
I spent quite awhile agonizing over this issue. Finally I came up with something that was quite simple and should work fine.
Here is the area where the seal needs to be

These Molnar cases are about three pounds heavier than original cases. Most of that weight is increased thickness around bearings. With this dim. bearing in a standard case, there would be no wall remaining!
Below the area where the webs are the cases are solid and about 1.25" thick. The cast webs were milled down to get a uniform flat support area for the seal holder. A flange was formed on the holder so that it could attach directly to this thickened up area of the crankcase.

A light tap fit over the housing. This will give backing to the ballbearing which is maybe not necessary, but won't hurt.
The ball bearing locates the crank axially, the rollers take the thrust. The rollers sit in material which is thick and solid right out to the case perimeter.

worntorn · Apr 14, 2014

Finished seal housing

Fast Eddie · Apr 15, 2014

worntorn said:
Hi Brent

I actually started on it in mid January but went away for holidays in the first half of February then got talked into a complete Bathroom Reno here at home, that killed most of March.

First up was to deal with the problem of sealing the mainshaft. Original Vincents did not have a seal between the crankcase and the primary housing. They have four mainbearings in total, two per side. The outside bearing on the drive side is a ball bearing. It's outer race is held in place by two heavy circlips and by the interference fit in the case. The inside bearing is a roller bearing an butts tight up to the flywheel. There is about a 5/8" gap between the two bearings and this is take up by a scroll which runs inside of a hardened outer distance piece. The scroll runs with about a half thouclearance to its outer,so it holds some of the oil back, and worms most of the rest back. A little gets thru to lube the ballbearing and this oil then carries on out to the primary.
After awhile the primary gets over full and needs to be drained. This also makes for a high level of oil consumption. By the midfifties Paul Richardson had come up with an after the fact seal housing and seal to deal with the issue. On standard cases the seal carrier gets mounted on the outside face of the ballbearing housing. Hole are drilled and tapped into the face.
In my cse, with much larger than standard mainshafts and bearings, even though these cases are greatly thickened around the mainbearings there wasn't quite enough meat to do this.
I spent quite awhile agonizing over this issue. Finally I came up with something that was quite simple and should work fine.
Here is the area where the seal needs to be

These Molnar cases are about three pounds heavier than original cases. Most of that weight is increased thickness around bearings. With this dim. bearing in a standard case, there would be no wall remaining!
Below the area where the webs are the cases are solid and about 1.25" thick. The cast webs were milled down to get a uniform flat support area for the seal holder. A flange was formed on the holder so that it could attach directly to this thickened up area of the crankcase.

A light tap fit over the housing. This will give backing to the ballbearing which is maybe not necessary, but won't hurt.
The ball bearing locates the crank axially, the rollers take the thrust. The rollers sit in material which is thick and solid right out to the case perimeter.

Hi Glen,
This is gonna be a pretty awesome motor!
Just out of interest, what cams and CR are you using? I think I recall you saying you we're using TP squish heads too?
I see you're running a double sided belt, which I assume is to drive something like an Alton alternator?
I ran this set up and had a failure. PG 'sorted it' but I never managed to get him to tell me precisely what he'd done to cure it! It seems to me that the distance between mainshaft and alternator shaft centres are really crucial with this set up. A chain will allow a lot of expansion and contraction and still have plenty of teeth depth left to engage adequately. But, if a belt has the centres too close it will 'crush' the belt. If to far, too much stress will be put on the ends of the teeth. Iether of these will, of course, lead to failure. And in getting this right, one has to take into account not only the crank case expansion, but also the belt pulley expansion.
I'm thinking you may have thought this through though, and am interested in your comments.

worntorn · Apr 15, 2014

Eddie, the cams are a new profile from Terry Prince, his MK5. I think in reality it is more like MK20 because Terry has experimented with many different profiles, most of which did not make the cut.
The MK 5 is, as far as I know, the first computer generated Vincent cam profile. Fritz Egli Jr, who is Terry's godson, did the design using the Mercedes Formula 1 cam development program when he was lead engineer on that team a couple of years ago. Terry gave him all of the Vincent valve train data and the desired rpm range for Max power. With all that info plugged into the program it produced the MK5 profile. Terry got an immediate improvement in power from this cam as compared to all of his other cam profiles, all of which are 105s and were known to be good cams.
One of the things learned was that there was no point is lifting the big Vincent intake valves beyond. 440". Terry's long running MK4 race cam lifted to. 480" but the MK5 s make significantly more power and only lift to. 440", which is easier on things as well.
This is still a very high lift. Standard MK 1 Vincent cams lift just. 315" and the Lightning cams, or MK2 s as they are known, lift. 343".
Terry, being the hotrodder he is, has his own versions of MK1s, 2s and 3s, all with higher lift and different timing than stock.
For this kind of lift (.440") on the Vincent it is essential to use special curved followers and RD race springs. Standard springs become coil bound at about. 380" lift.

The compression ratio with this setup is 10.5 to one, two plug heads, bathtub shape combustion chamber , 38 mm inlet ports, D shaped exhaust ports., 41 mm Dellorto Pumper carbs.

Interesting info on the belt, I will add a post on that shortly. :shock:

Glen

swooshdave · Apr 15, 2014

I'm not sure I have enough money to even afford to read these posts. :mrgreen:

worntorn · Apr 15, 2014

One of my Vancouver clubmates figures this Special will be worth about fifty bucks when all done. He's not too fond of specials :roll: Another has told me that I have ruined an original Vincent, even tho the bike has zero original Vincent parts in it. Guess he just didn't care for it.
There is a fair old bit of snobbery in North America about non original Vincents within the club, tho strangely not from the boys in England (or Europe), they are all pretty keen on it and want to see what it can do . Could be that the inventive British minds handle non conformity better than those of us in the Colonies!

Glen

gtsun · Apr 15, 2014

Those "snobby" old farts are missing the joy of heart mind & soul you will have blasting through some mountain road on this amazing bike. If I had an original Vincent I would do my best to leave it as stock & unmolested as possible but that's not what yours is so ignore the negative ones & laugh all the way past 150mph !!! How fast will something like this go anyway???

worntorn · Apr 15, 2014

Roy Robertson built a similar bike at 1272cc which currently holds a UK speed record for his class at close to 170mph.
Roy feels this engine should do more, but I would not attempt that on a public road, it would have to be on a track somewhere, or perhaps at Bonneville.

Glen

ashman · Apr 15, 2014

I just love it, keep it up Glenn you are doing a great job and its great reading and seeing the pics and having a one off bike is a great frill.

Ashley

Fast Eddie · Apr 16, 2014

Those cams sure sound interesting Glen! I used 105s and 10:1 CR and PG was very impressed at the Dyno figures over his 'usual' spec of 8:1 and MKII cams. So, if yours are even better, that'll be impressive.

I support the 10.5:1 CR Glen, as I was convinced mine could easily have handled it higher than 10:1.

Those ports and carbs sound bloody big mate... You'll be incurring the wrath of many an expert with those! It'll be interesting to see how they work out.

One other thing I forgot to mention about the belt tolerance issue, is that getting the measurements between alternator and mainshaft spindles too tight also knocks out the alternator bearings pretty quickly!

It's true what you say about most Brit Vin folk, contrary to popular myth, they tend to be quite interested in, and supportive of, mods in general. There is still the odd one who thinks that NOTHING done by the factory could ever possibly be improved upon, but most are quite sane!

worntorn · Apr 17, 2014

Eddie, thanks for the warning, I'll have a good look at the alternator pulley position when setting up the primary.
This was a first for Bob New by in that he made the primary ratio the same as standard Vincent. In the past he has worked to standard belt lengths which only allowed a ratio somewhat lower than standard Vincent. This time he made up the drive, fitted the components to an old damaged set of Vincent cases he uses for this. The cases are fitted with dummy shafts. With the pulleys mounted he measured the belt length needed and ordered accordingly. He also charged me extra for doing all of that, but the result should be a proper fitting belt and an easier load on the gearbox. I decided to get a spare belt as these will not be something that is readily available.
Next off was to drill and tap screw holes for staking the inner mainbearings to prevent rotation of the outer races. The screws used are coutersunk head type. After the bearing is shrunk into place a Dremel tool was used to grind a very small recess for the edge of the screw head where it protrudes into the bearing race. Pattern blueing is used for this as the recess should be just enough to let the screw tighten down fully without actually touching the bearing. If it binds on the bearing at all it will squeeze the outer race out of round.
Glen

Fast Eddie · Apr 17, 2014

worntorn said:
Eddie, thanks for the warning, I'll have a good look at the alternator pulley position when setting up the primary.
This was a first for Bob New by in that he made the primary ratio the same as standard Vincent. In the past he has worked to standard belt lengths which only allowed a ratio somewhat lower than standard Vincent. This time he made up the drive, fitted the components to an old damaged set of Vincent cases he uses for this. The cases are fitted with dummy shafts. With the pulleys mounted he measured the belt length needed and ordered accordingly. He also charged me extra for doing all of that, but the result should be a proper fitting belt and an easier load on the gearbox. I decided to get a spare belt as these will not be something that is readily available.
Next off was to drill and tap screw holes for staking the inner mainbearings to prevent rotation of the outer races. The screws used are coutersunk head type. After the bearing is shrunk into place a Dremel tool was used to grind a very small recess for the edge of the screw head where it protrudes into the bearing race. Pattern blueing is used for this as the recess should be just enough to let the screw tighten down fully without actually touching the bearing. If it binds on the bearing at all it will squeeze the outer race out of round.
Glen

Nice attention to detail Glen. More evidence that this will be a cracker when its done! Please do keep us all posted. And I mean step by step, don't just wait till its done. We want the nitty-gritty, step-by-step detail!!

worntorn · Apr 17, 2014

I'll try to put in as many details as possible. I realize now that I should have taken a few more photos for explanation purposes.
Next was to fit the transmission inside the cases. The gear cluster is a Quaife/Surtees 5 speed set. It was binding in a couple of spots so a small amount of material had to be removed from the cases . I used a die grinder for this.
On pushing the cases together with gear set in place, the gear change was free and easy right up to the last ten thou squeeze up. Ten thou gap left between the cases and everything worked fine, tighten beyond that and the gear change tightened up.
After determining that the ratchet shaft bevel gear was running to tight to the cam plate pinion, it was back in the mill to remove 10 thou of material from the ratchet shaft bevel gear mount face. This gave proper fitting between these two small gears.
Unfortunately I did not take a close up of the gear and its mounting boss.
The ratchet shaft mounting boss can be seen in the photo, more or less under the milling cutter.

worntorn · Apr 17, 2014

I left out a step.

The bearings were installed in order to fit the transmission. This photo also shows the ratchet shaft bevel gear mentioned in the last post. The area under the gear is the area I removed 10 thou from in order to get the gear change working. The mill did most of it but there was an area that had to be done by hand. For that I used a razor sharp wood chisel to cut the aluminium, then fine emery to finish. The finished flat is the bearing surface that the gear pivots on.

acotrel · Apr 17, 2014

My brother has recently built a couple of historic speedway sidecars which are Vincents. He commented that they are a bit of a nightmare - every bolt etc seems to be a 'special'. In the olden days the owners would have been entirely at the mercy of the dealers. Looking at your posts, I can see what he means. It all looks like lovely stuff, however definitely not for beginners. Is your crank a special, or is it possibly a Ducati crank ?

worntorn · Apr 17, 2014

The crank is a one off, supplied by Terry Prince, same as he had constructed for his Bonneville sidecar racebike. 102 mm stroke, oversized shafts and pin etc.

Vincents are complicated, but when you start hotrodding things it gets even moreso, I am finding.

Glen

worntorn · Apr 17, 2014

The mainbearings for the engine and the trans case bearings all came from the local bearing house, except for one small roller bearing on the outboard end timing side crankshaft. Regular Vincent bearings are all inch bearings, but this engine has larger mainshafts which are metric. The inch bearings are always a bit tough to get, but I thought the metric rollers would be easy to find and cheap. They were neither!
Only F.A.G. makes them in c3 clearance, E service , machined brass cages. Two hundred bucks each!
The little roller could not be supplied in C3 by the bearing house, so I ordered one at great expense from the club. While expensive, they do endeavour to supply the proper C3 bearings. Unfortunately the bearing that arrived was stamped c normal.
Hoping for the best, I fitted it, but it proved too tight. My friend and expert Vincent engine builer John Mcdougall helped me out by lapping the tight bearing. This is no small job as he had to make precision fit sleeves for his manrel, since my bearings are larger than standard.
The sleeves are a very close rolling fit in the outer race of the inner mainbearings and a push fit on the mandrel. The cases get fully bolted together, the mandrel runs from one side to the other and the lap is located at the end where the small tight roller bearing outer race is. When all finished the tight bearing is made perfectly round, in line with the other mainbearings and at proper running tolerance.
John does all Vincent mainbearings this way, that way they are truly aligned and round. The factory never did this, they just used c3 bearings and shrunk them in. This was good enough for 100,000 miles, so I am happy with the C3 method I used on the other bearings.

worntorn · Apr 17, 2014

The inner races of the inner pair of roller bearings butt tight up to the flywheels. This means that the outer races must be made narrower to create clearance between the edge of the outer races and the flywheels. A surface grinder is ideal for this job, however I do not have one of those.
With the race dialed into the lathe and taking light Ten thou cuts with lots of coolant, the carbide cut the hard outer race very nicely.

Vincent 1360

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