New Valves or not

[jamcarr2]

Whilst the head is off should I take the opportunity to fit new valves or leave them alone till something goes wrong
john

[new to this]

John

may be a good idea to have the valve guides/seats checked for wear

Dave

[jamcarr2]

Thanks Dave I suppose now is the time whilst they are off I will look up the nearest place tomorrow
john

[flying farmer]

Exhaust valves usually wear worse, but I often find they all need doing together, and the guides will need doing if the valves are worn.

You may be lucky and find they have been done before and don't need doing again, it has happened to me on one of my engines.

Neil

[jamcarr2]

Thanks Neil ,I am guessing I need to take them in to a specialist to have them checked and its not a job I can do myself
John

[flying farmer]

Thanks Neil ,I am guessing I need to take them in to a specialist to have them checked and its not a job I can do myself
John

Start by looking at the valve stems, if there is any sign of a step at the top of the stem between the bit that goes inside the guide and the bit that doesn't then the valve is worn and the guide will be also. The amount of side to side movement of the valve in the guide is also a good indication, with new valves and guides there will only be a few thou of sideways movement.
Valve guides can be replaced at home but it takes a lot of time to grind in the new valves when new guides are fitted, so unless you really know what you are doing I would suggest you get it looked at professionally.
If you take the stripped head and the old valves to an engineering works they should be able to tell you what needs doing.

Neil

[DJT]

Have a close look at the neck of the exhaust valves near the collet groove. If the number 155524VL is marked there they are suitable for unleaded and don't need changing unless worn or damaged.

If unmarked then it all depends whether they have been replaced with unleaded aftermarket valves or cheaper ones.

FWIW I have stripped a couple of pairs of heads recently, including the ones I took from my engine (20,000 miles of non-additive unleaded during my ownership) and all the exhaust valves were marked as above and suitable for re-use.

[f100stepside]

I have just had mine taken apart and looked at. All the exhaust valves were in need of replacement and two of the guides had a little sideways play. The new valves are only £4.00 odd each, so not too expensive to do the lot. Jonathon

[jamcarr2]

Thank you all for the advice ,as it doesn't involve a hammer or a spray gun I think I will pop along to the experts ,a chap I worked with many years ago owns a machine shop so it would make sense to visit him .I am surprised that I got the heads off on my own so better not bush my luck

[edd]

Thank you all for the advice ,as it doesn't involve a hammer or a spray gun I think I will pop along to the experts ,a chap I worked with many years ago owns a machine shop so it would make sense to visit him .I am surprised that I got the heads off on my own so better not bush my luck

That made my chuckle as it does involve a hammer to drift out the guides. I did mine myself however at my disposal was my friends engine recon workshop with heater wash tank and lots of drifts. I replaced all my valves as I wanted to keep the shims within tolerance most workshops will charge for resurfacing the valve which takes about 1 minute .
edd