Do I need a refresh?

[Monkeypants]

I've not had great luck with the V3 seals. Fitted two full sets and one half set to three bikes a couple of years ago and am slowly working my way back to stock seals. I have had three broken valve cover seals to date, one of which required dropping the engine down to change back to stock type.
The Chicago section gaskets are very good.

Glen

 

[greg brillus]

Kenny, A couple of things to watch out for.....in the picture of the cylinder, it is not quite clear enough, but it looks to me as though the oil feed hole is above the lower most marks left on the bore where the rings stop at bottom of their travel...If this is the case you need to remedy this, as this is a common issue that is basically feeding oil into the rings and not bellow them. This will result in oil usage without doubt. The other thing is to make sure on assembly that the piston ring gaps are set apart....I usually set them up 180 degrees apart from one to the next and diagonally across the bore. That is so the gaps are in line with the hold down through studs. It is not good if the ring gaps are in Line with each other, once again not quite clear enough in your photos......Cheers....Greg.

 

[KennyNUT]

Thanks, Al, Martyn and Greg.

Martyn, I don't remember the explanation of your bike being a smoker, sorry to hear that, however, it sounds like you have a masterpiece on your hands, now. In fact I may have come across you on "You tube".

Congratulations on a stunning bike. Great work. I do wish I had some engineering talent in my veins! Never mind I try to make the best of what I have got

Yes, all has gone well so far on this little adventure, which is officially my "Winter Project".

After a busy day in the garage and carefully packaging everything up last night I sat with some of the bike's history and found that the piston that went in in 1980 (34 years ago ) as described in my first post in this thread was an oversize +0.020 ". The piston I found is as described and is +0.040" so I think the liner is original and just honed to accept the next oversize piston which is the "nearly new one (500 miles ago?)" that I encountered. When the rebuild begins I will ensure the gaps in the rings are 180 degrees apart, thanks for the observation, Greg. Its something I checked when I lifted off the barrel and liner. All was well.

I spoke with Simon Linford today and he will check all components in the head and review the condition of the liner. I have sent him pictures of the piston and will await any further request. He will also check the position of the oil hole in the liner which he highlighted as a problem sometimes, too. There is an indentation on the outside of the liner to indicate where that hole should be and it is positioned in there, so hopefully is correct. I will ask for the metering wires to be removed as once the head is checked, and rebuilt all should be well, should it not?

I actually put in the same photo of the liner twice in post #46. the second one is below and shows that indentation with the oil hole now on the top side:

Again, very nice condition (obviously without measurements) and honing marks obvious.

I guess there will always be differences in opinion over gaskets and seals. I just found the V3 advert in the August edition of MPH (must track down the later ones). It looks interesting but expensive at $85 AUD for the Comet. I have ordered the GASKET SEALANT - RHODORSIL from the spares company as well as stock (Mmmm) gasket replacements. Should I use one or other or both? Happy to absorb your advice on that. For the oil lines over the top of the engine, I was proposing to use fresh copper washers and a tiny drop of RHODORSIL on the top part of the bolt threads.

As suggested, I will retain all invoices as proof of "folding" spent. Of course that will be on a need to know basis only .

If I get a message from Simon Linford, I will update you guys and keep the thread going, if it is of any interest. After all, we don't have confirmation of the issue just yet!

Cheers, Kenny.

 

[nkt267]

I do wish I had some engineering talent in my veins! Never mind I try to make the best of what I have got]

Hey you can use spanners just like the rest of us. I do have some machining abilities but as you are doing , there are things that I have to get done by specialists.
The 'indent' in the liner is so that the hole in the liner can get it's feed from the horizontal slot at the rear of the crankcase opening . On the earlier bikes it was found that the hole in the liner was too high and oil fed between the rings instead of below the oil ring. The hole was lowered on later bikes and a slot was cut upward so that the hole again got it's oil feed . Own a Vincent for a long time and talk to lots of people and you end up (said I never would be) a Vincent anorak..John

 

[KennyNUT]

Hi John,

Thanks for pointing out the indent's source of oil to the piston/barrel. Sounds like the position of the oil hole has to be very accurate. Simon will measure it, so I am sure he will confirm one way or the other. When you say early, how early? This a 1950's machine.

(Just testing how anorakish, you are )

Best wishes, Kenny.

 

[KennyNUT]

Hi John (again),

I was checking through some favourite threads for classic bikes and found this and thought of your response.

http://www.britbike.com/forums/ubbthreads.php?ubb=showflat&Number=217887&page=all

I remember the first time I read it. I was rooted to my seat like reading a great book.

This is the sort of engineering attention to detail that I am in awe of just because of the sheer skill and patience involved.

I hope you enjoy it.

Kenny.

 

[nkt267]

1951 according to my anorak---Know Thy Beast..must have books Know Thy Beast and Vincent Motorcycles by Paul Richardson..John

 

[KennyNUT]

First Impressions from Simon Linford:

Liner is pristine and the oil hole is in the correct place. Looks like it has done 500 miles or less. Unmarked and fine.

He also said of the piston that you would expect carbon build up on the piston and so liner and piston look to have been done 500 miles or less ago. Simon did comment on the piston in that it does not have 3 holes drilled under the rings fore and aft, something that he expected to see and helps with excess oil removal from the barrel. I may call Omega who made the VOC piston and ask why some pistons have holes and some don't.

Any ideas technical gurus?

Of the head, Simon commented that it was in great condition, overall (upon visual inspection). He said something about the valve seat guides or seals?? I wish I had clarified
Also, he will take the head apart and take a closer look.

Any thought's?

If I have deteriorated or missing valve stem seal, could the vacuum on the intake pull oil down the intake valve guide and into the combustion chamber, causing smoke in the exhaust? Would a weak spring do the same?

 

[nkt267]

Valve stem seals were never fitted to a Vincent, but you can fit new guides that allow seals to be fitted. This should eliminate any oil passing the valve stems. Vincents seem to have quite a generous amount of clearance for valve stems. On the guides I have fitted the seal fits in a recess in the top of the guide under the locking ring. The are made of Viton..John

 

[davidd]

I have never used stem seals and I have not had any oiling problems from the valves. The lower valve guide is quite short and you have to make certain that the oil is not pooling around the guide and then running down the stem when the combustion pressure is low. I am sure that Simon will check this.

I have never drilled the oil hole in the cylinder, but many have without any problems. Most oiling issues are caused by rings.

David