Classic cars forum & vehicle restoration.

ukdave2002 · Joined: 23 Nov 2007 Posts: 4104 Location: South Cheshire

I was prompted to post this after viewing First Bedfords posts on LPG conversion. Someone mentioned that LPG is an "un-leaded" fuel so all the same precautions regarding valve seat accelerated wear should be observed.

I personally know folk that run old crocks that were built from the thick end of 100 years ago through to the 80's , some have had hardened valve seat conversions.. others have not.... some have had valve seats re-cut but not had hardened insets fitted. I guess non of the cars do a high millage, but all have been run for the last 10 years or so on unleaded, non of them have valve seat wear problems, in fact I have never met anyone who has or knows of someone who has actually had a problem with un-leaded fuel!

I'm interested in hearing if the wider audience on the forum has experienced un-leaded valve seat related problem's .

Cheers

Dave

Phil - Nottingham · Joined: 01 Jan 2008 Posts: 1252 Location: Nottingham

No problems - all depends on useage eg sustained high revs motoring, lead memory and whether valves have been reground since to remove it. Your engine is very unlikely to have hardened seats but then will not be high reving (3000+) anyway
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Jim.Walker · Joined: 27 Dec 2008 Posts: 1229 Location: Chesterfield

Can I refer you to the Canley Classics website? Canley Classics supply lots of parts and advice for Triumph cars, but much of the advice is applicable to other makes. I quote:- "the best way to convert your Triumph to unleaded fuel is to fill the tank with it".
As I have said elsewhere on the forum. If you do suffer valve regression(pocketing) it will be so far in the future you will have saved far, far more money than it will cost to have hardened inserts fitted. In your LPG posting I mentioned my experience with BL 1800s on LPG. My advice - don't worry about it! If valve clearances don't close up it isn't even happening!
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First Bedford · Joined: 11 Dec 2009 Posts: 107 Location: Darlington, Durham

forum has been good in helping me decided whether to add an LPG system. Not going to bother.Will run truck on unleaded, as you say it wont be high mileage or high revs.Will let you know of any problems.

Uncle Alec · Joined: 14 Jan 2008 Posts: 734 Location: Manchester

I am fortunate with the RMs inasmuch as the steel from which the head is cast has been proven over many years and much mileage to withstand the use of unleaded without any modification.
If you do experience any problems with the exhaust valves pocketing, the remedy is exactly the same as if you were converting as a precaution, i.e. machine the seats out to take hardened valve seats. So you aren't losing anything by just going for it.

peter scott · Joined: 18 Dec 2007 Posts: 7117 Location: Edinburgh

I'm not aware of any problems with unleaded and having ground in the valves I haven't had any lead memory to rely on.

I think you can run into serious problems puting inserts into heads that were never designed to take them. Namely breaking through into the water passages and the risk of seats subsequently falling out if not properly fitted.

Peter
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Jim.Walker · Joined: 27 Dec 2008 Posts: 1229 Location: Chesterfield

Peter is right and unless you intend putting more than another 50,000 miles on your engine why bother with inserts? You could well find if you do that kind of mileage it is not necessary anyway. Save your money!
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Quote from my late Dad:- You only need a woman and a car and you have all the problems you
are ever likely to want". Computers had not been invented then!