requires "valve master"???

[Budgie]

I've just seen an advert for a moggy fairly close to me that states on the add that it needs a "valve master". Excuse my ignorance but what on earth is a valve master???

[LouiseM]

Castrol valvemaster is an additive to add to the petrol if you don't have an unleaded head, although depending on how you use the car it isn't a necessity providing you adjust the valve gaps regularly.

[Budgie]

Ah right that makes sense thanks Louise.

[drivewasher]

so I wonder why you need to adjust the valve gaps regulary?
Perhaps it's because with no lead residue on the valve seats especially the exhaust ones from leaded fuel the seat softens under the extra heat and the force from the valve spring snapping the hard valve into the hot soft seat closes the valve clearance gap so it needs re setting (opening). The need to reset clearances more frequently should sound alarms as to why.

It's like the heel on the points wearing, as the heel wears the points gap closes and needs re adjusting to compensate. Eventually (if the contact tips lasted long enough) the heel would be worn completley away and the points wouldn't open

If you don't convert to harder valve seats or at least use a historic vehicle approved lead additive (Castrol Valve Master is one of the few that is) then it's only a matter of time, granted a lot, before trouble begins.

The reason many say they have done hundreds of miles on unleaded without either is on an engine thats already done many thousands of miles on leaded petrol over the previous years, there is a lead residue absorbed into the surface of the internal steel works that take thousands of miles to wear out especially on low demand work like around town and @ lower speeds. Hence the "If you don't do mny motorway miles or thrash the engine it'll be alright." It just takes longer for the damage to show!

[bmcecosse]

The regular check of gaps (3000 miles....could be 3 years for many!) is to check if the gaps are reducing, and to reset them to 15 thou. Yes - if they are regularly closing up then the seats are eroding. Worst case - after many thousands of miles - hard seats can be fitted - along with new hard valves. The ONLY additive with tetra ethyl lead is 'Tetra-boost' and it's not inexpensive. All the others contain various mixtures of sodium/potassium compounds - and a large dollop of hocus pocus..... What they do is to slightly improve the octane rating of the fuel -which helps to delay the onset of 'pinking' which is harmful to the pistons. Just check/reset the gaps.....it's not arduous, and should be done anyway as part of routine maintenance!

[drivewasher]

My point exactly, meaning that the gap is reducing because the valve head is hammering itself into the hot seat. The normal maintenance checking of valve clearances as in the manual/schedule is to compensate for a LARGER gap than should be, caused by wear of components NOT in the combustion chamber itself. IE valve stem to rocker arm wear & follower to cam lobe wear.
In my book constantly having to open a valve clearance up means valve seat problems. Because if you didn't keep checking & opening gap back up then the valve would not close causing an even more almost instant burn out.

But I am still amazed how many drivers just keep blowing a tyre with a nail in it up rather than sort the issue out.

[minor65]

Additive = total waste of money

[drivewasher]

Additive = total waste of money

Yes probably is.
The way I see it is with a leaded head use a good TESTED lead replacement most aren't! The ones that have credability have been tested and approved by FBHVC Castrol Valve Master is one of them.
Use vehicle normaly as you choose,either with or without lead replacement additves, then when the time comes as it will eventually when the lead compounds protective effect is worn away, have the head repaired/reconditioned to use on unleaded.

[bmcecosse]

The FBVHC tests were a farce - don't rely on them! They no way replicated the use our cars get - not even the 'daily drivers' I repeat that the ONLY one worth having is Tetraboost. It really does make 'leaded' fuel if that's what you want. And I disagree about the 'Manual' checks - the gaps were always needing to be opened up! I've been doing this for 50 years!.. When the gap disappears - burned valve follows almost immediately. So - just check/adjust the gaps and all will be fine. My own cylinder head - which definitely had no 'lead memory' if such a thing exists - hasn't closed up the gaps in 8 years of hard motoring (summer only ). I decided to open the gaps to 18 thou last year - when a 'backfire' sometimes developed when running hard in the then hot weather.

[drivewasher]

Iv'e just read through the tetraboost site and I'm gonna order some on Monday. At the moment I have 3/4's tank full of 1999 vintage 4 star, smells loverely in the tank and from exhaust when she's running

I'm wierd I know lol...