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Lead free valve seats

Puddle jumper

Well Known and Active Website User
Non-VOC Member
Hi Gang,
What are your views on lead free valve seats, do I need to change the original valve seats if they are in good condition and would you recommend changing the valves as well ?

Cheers Paul
 

Ken Tidswell

Well Known and Active Website User
VOC Member
Hardened valve seats and valves

Given that the automotive industry and the petroleum companies care nought for old bikes or cars, and put allsorts of oxygen containing compounds in their formulations for emission control and injection systems. And may go even furthur in the future on formulation,You can use additives to mitigate the effects of modern fuel on valve seat recession, or even modern two stroke ashless oil. But the valves sold by Vinparts are made by a Formula 1
part manufacturer are are a better shape than the originals with regard to flow.
You pays your money and make the choices, also the time to get the job done is now, I speak as an independant observer and have no commercial interest, in any spares manufacturer. If you use the bike for short distances and keep off the freeways and motorways , don't use them much, them the additive should suffice. I have bought a set for a 636 Comet currently in a foreign land and in the process of being fitted for the same. If i should live so long.
 

timetraveller

Well Known and Active Website User
VOC Member
I'm with Mr Boggler on this. On the ex-Cecil Mills bike I used Millers Additive and Octane Booster for several years and found that I was having to slacken off the tappets. I was only doing about 6,000 miles per year. Bill Turner from Hove, who does a lot of miles and used to regularly travel between Hove and Liverpool stuck with it for several years and then changed his valve seats. The old ones were warn about half way through. I still have one here somewhere if anyone would like a photo. In the VOC we have one member who has a PhD in automotive engineering and he did some calculations a few years ago into rates of valve seat wear. It seems that there is a combination of valve seat pressures, revs, temperatures etc which can be used as input to the equation to work out under what conditions maximum wear will occur. Guess what! A Vincent twin at normal motorway speeds, 3,500 rpm, is right in the worst place for rapid wear. This might explain why when this problem surfaced over here we had some of our American friends telling us it was not a problem as they had theoretically been limited to 55 mph for years. Both my experience and Bill's suggests that if you are going to keep up with modern traffic and do several thousand miles a year then, whenever the bike is apart, take the time to insert lead free seats.

How did I know that mine were wearing? I have a habit of turning the engine over a few times with the valve lifter used to get the oil circulation started and then just testing the compression on both cylinders before I try to start it. Just as well as every few months I would find that the compression was not what it should have been and slackening the tappets cured the problem. :)
 

john998

Well Known and Active Website User
VOC Member
Valve seats

Being a tight Yorkshire man I have used unleaded from it first appearing.
Neither of my bike have suffered any problems with seat eroding, over something like ten to fifteen years. Admittedly my average mileage is only around 3000, split between the two machines. I feel that unless you have a machine with an iron head and no inserts it is not a problem. John.
 

roy the mechanic

Well Known and Active Website User
VOC Member
valve seats

According to K.T.B. exhaust seats are made from austinetic iron, the same as used by Jaguars. I have literally hundreds of clients using unleaded feuels super+regular. If there were problems I would have ques of head jobs. As none of them have materialised I can only assume that there is no need to worry on this score. The majority of vin mettalurgy was worked-out pre ww2[pre leaded ] Don't worry, be happy! Roy.
 

clevtrev

Well Known and Active Website User
VOC Member
According to K.T.B. exhaust seats are made from austinetic iron, the same as used by Jaguars. I have literally hundreds of clients using unleaded feuels super+regular. If there were problems I would have ques of head jobs. As none of them have materialised I can only assume that there is no need to worry on this score. The majority of vin mettalurgy was worked-out pre ww2[pre leaded ] Don't worry, be happy! Roy.
Having worked on several hundred heads, I have NEVER seen an austenitic seat in the exhaust position, inlet yes, most of them,only the later ones having bronze. Only ever seen bronze for the exhaust seat.
And if you do fit lead free seats, increase the amount of interference, as they do not expand at a similar rate to bronze, and have been known to drop in.
 

Ken Tidswell

Well Known and Active Website User
VOC Member
unleaded valve seats

As far as I am aware only early heads were fitted with austenitic iron, I have only seen one pair of heads with same.I am using Castrol additive. But if you are using old guides in the head the oil may do the trick, but the coke formed from the combustion of the oil when thick enough detaches itself, and will sometimes lodge between a closing valve and the seat. This hammers the bronze seat and causes indentations . a poor sealing ovf the valve.
 

timetraveller

Well Known and Active Website User
VOC Member
If you want your valve seats to look like this then by all means stick with leaded ones. Otherwise fit lead free items. This is one of Bill Turner's and was not the worst but it the only one I can find to take a picture of.

PIC_0823.JPG
 

roy the mechanic

Well Known and Active Website User
VOC Member
valve seats/time traveller

looks like it came out well[nice one] , I would personally ,have refaced that seat ,it looks in the pic to be too good to replace. It appears from the colour to be made of some sort of bronze, which should have suffered better on unleaded. not knowing the history of the motor makes further comment difficult. Roy.
 

timetraveller

Well Known and Active Website User
VOC Member
Remember, this was not the worst one. Yes there are people who would have re-cut the seat and then what happens is that the valve gets pocketed, the gas flow is rubbish, you lose tappet clearance and might end up having to have short push rods made and finally the valve spring retaining cap (ET37) will at some stage hit the inside of the ET24 inspection cap causing the valve no longer to seat properly. An exaggeration? Sadly no, I have seen all these things on Vins.
 

roy the mechanic

Well Known and Active Website User
VOC Member
valve seats/time traveller

If re-cut with 3angles and carefully re-sphered the gas flow will not turn to sh-t. Itake your point about shorter push rods etc. You obviously have a greater experience of this product. Best Regards ,Roy.
 

Prosper Keating

Well Known and Active Website User
Non-VOC Member
All I can say is that I have never experienced valve seat problems with unleaded fuel with any of the old motorcycles I have ridden since leaded fuel was phased out, including iron-headed singles and twins. Many British machines were designed to run as well as possible on low grade fuel.

The only significant changes I have noticed with unleaded fuel of the kind sold at pumps across the EU for the past decade or more are slightly hotter running, a nasty sensation on the skin when one washes one's hands in petrol after a roadside repair and a marked absence of sparrows and other small birds from urban centres, suggesting that they know how much more harmful to the health this stuff is than the old stuff.

I did have problems with Niton-tipped carburettor float needles in Amals and Bings because the additives in 95-grade unleaded made them sticky. A change to 98-grade cured this. However, I gather that 98-grade is due to disappear. Another irritation is the tendency of unleaded to "go off" much faster than the old leaded fuel. I have also found it necessary to remove water from float bowls far more frequently than previously, although this may be due to filling stations economising by not cleaning out their storage tanks as often as they used to.

In summary, I would say that I believe that my motorbikes used to run more sweetly on leaded fuel but that they run satisfactorily on unleaded 98, including the ones with tuned motors, as long as one retards the ignition by a couple of degrees or so. But I have never had a problem with valve seats and am inclined to view the whole valve seat recession thing as a bit of a scam. If it ain't broke, don't fix it. Having a replacement valve seat come loose at speed - or even at a standstill - isn't much fun.

Paddy Keating
 
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timetraveller

Well Known and Active Website User
VOC Member
Why would Don Canard think that using lead free seats is "a bit of a scam"? I do not sell seats or replace them for money. The photograph shows what happens if you use a twin for long distance commuting at normal motorway speeds for ten to twenty thousand miles a year. My own mileage was much less at about 6,000 miles and I still had to slacken the tappets at intervals of a few thousand miles. Each person should do whatever they think is right for their usage of their bikes but do not say you have not been warned if you do a rebuild without replacing the valve seats with unleaded items and then have to strip the whole thing down again to replace the seats.
 

Prosper Keating

Well Known and Active Website User
Non-VOC Member
The comment wasn't directed at you. I was recalling the scare tactics deployed by many interested parties in the automotive industry in general. As for having to haul engines down after rebuilding them, it's not a problem I have encountered and, as anyone who knows me can tell you, I put some serious mileage on my machines.

Lighten up...

PK
 

john998

Well Known and Active Website User
VOC Member
Valve seats

Hello, the wrought aluminium bronze exhaust , and iron inlet seats in my limited experience work fine. Both of my bikes do not need any adjustment to slacken off to allow for seat recession. If the seats need replacement then fit modern lead free inserts, if not leave them till they do.
Having made that statement, always remember never make a definitive statement about Vincents, even after forty years you never stop learning about them!
 

Alan J

Well Known and Active Website User
VOC Member
Valve seats.

A complex problem!! I had a Truimph spitfire and was told leave it alone!!-unless you drive like a maniac!! I have a shedfull of Morini's as some of you know. I put some wonder "stuff" in one of them,but nothing in the others- so far no valve seat problems!! My view is if you need to take your heads off- change the exhaust seats-otherwise leave things alone!! [but what do I know?]:confused:
 

timetraveller

Well Known and Active Website User
VOC Member
I'm light man, I,m light, or do I mean Je suis ligere, mon ami? The question that arises from all this is why do some bikes suffer from this and others do not? Clearly some bikes have all bronze seats and some have hard inlets and bronze exhausts. Round here all the local Vin riders have had to replace their valve seats or do not use their bikes over significant distances. I would typically cruise at about 3,500 rpm with odd bursts above that for overtaking. Bill was about the same. I do not want anyone to incriminate themselves but I imagine that in France one is using about the same engine revs. So why the difference? I know that my diesel cars seem to go better on French and Spanish diesel than they do on supermarket diesel here. Could there be a difference between French and English unleaded? With the insular UK view it is generally assumed that French petrol is inferior to UK but really this dates back several decades. How about now? Do we have an expert in the club on the quality of various fuels and if so will they let the rest of us know what is happening? We are looking for facts now chaps, not opinions. :)
 

Comet Rider

Well Known and Active Website User
VOC Member
UK fuel quality

Hi Norman,

These facts apply to UK supplied petrol only!

Most petrol will come from a single source, such as the Buncfield depot near to Hemel Hempsted, which is run by BP. Tankers for all retailers (Supermarkets, Shell Esso etc) fill up with the same base petrol, which will comply with the appropriatre ISO standard, then the fun begins:mad:

The supermarket petrol, will then just leave site and go to the appropriate supermarket for us mugs to buy. Shell BP etc have their tankers goto another filling station (on the depot site) where adatives are put into the tanker.

So if you want reliable running I would always goto a known brand (Shell, BP, Esso etc) rather than a supermarket. A point of caution to note is that a local car dealer has put the disclaimer in his warranty documentation, that the warranty is null and void if you use supermarket fuel...:rolleyes:

Buyer beware

Neil
 
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