Inlet valve oiling

[ajsm18]

Hello,

I'm just checking before setting the inlet valve oiling adjuster on my 1947 Model 18. The head has had a lead-free exhaust valve seat, re-cut inlet seat, new valve and guides. When I first put it back together, the exhaust valve nipped up so the people doing the work eased the guide and advised me to check the oiling. The oilways have been cleaned out and a new needle valve and lock nut fitted, I think!

As I understand it, only the inlet valve has any adjustment? The Fred Neill book states half a turn from fully closed. Is that about right? How does one know what is correct?

On the subject of cylinder head torque readings. Is that so critical on an iron head? I can't see that the difference between 25 ft lb and 35 would distort an iron head, or would it? Just to be safe, I've torqued my new bolts to 40! I hope I'll be OK. The head and barrel surfaces have been cleaned up as I've also had a rebore and new piston. However, the compression won't bear my weight yet (15 stone). Is that because nothing is bedded in yet?

Sorry for the questions. Since being a teenager (now 53), I seem to have lost all confidence and want to "do it right", rather than bodge!

Thanks in advance
Mark

[SPRIDDLER]

As I understand it, only the inlet valve has any adjustment? The Fred Neill book states half a turn from fully closed. Is that about right? How does one know what is correct?

Only the inlet valve has its own oil feed because the valve stem is in the path of and being washed by petrol being 'sucked' into th'engine. Half a turn open is a good starting point. I've read that if the valve 'squeaks' it's too dry; if you get smoke or heavy oil consumption it may need to be closed down 'a bit'.
I've alway set the oiler at 1/3rd open and never had nipping up, squeaks nor smokiness. In reality I don't know quite how you can be sure that smoke and heavy oil consumption is due to the inlet valve oiler setting rather than worn bore/valve guides, drips etc.

As far as cyl head bolts are concerned I see no reason to second guess the workshop manual. In fact overtightening (to your 40 ft/lbs "just to be safe") may only result in stretched and weakened bolts, not to mention the obvious risk of stripping the thread or shearing the bolt.

The cause of the zorst valve nipping up may be overheating due to a weak mixture, retarded timing or air leaks at the zorst or the carb manifold or over-zealous running in. There 'shouldn't be' any need to ease the guide, but of course we can't assume that pattern parts are perfect.
There is an outside chance that the new zorst valve seat has not been fitted correctly with regard to the angle of the new valve guide resulting in poor compression although it may take a while until the new piston and rebore have been run in.
Make sure that the new valve guide hasn't migrated on its own further into the zorst port throat (although I believe pattern ones have circlips now?).
Just a though but from memory (I no longer have my '47 Model 18) it's important that the holes in the valve guides line up with the feed holes in the head casting. But I guess you knew that anyway.
If you get really stuck I could take some measurements from a pair of NOS guides and valves which are lurking somewhere in my shed.
There are several knowledgeable members in your Hants section who would be only too keen to suck wisely through their dentures whilst attempting to assist/depress you.

[Malleon]

Mark,
If the 'compression' won;t take your weight on the kick start, make sure that the valve lifter is correctly adjusted, and thus allowing the exhaust valve to close.

[ajsm18]

Hello,

Thanks for the very helpful replies, certainly some more things to check.

The engine work has been carried out by a reputable vintage engine rebuilder who advertises in the VMCC journal so I hope the work is good! Of course, the parts used may not be brilliant as they are pattern parts, I can't really tell.

Anyway, I got the carb back on after carefully lapping in the float needle and there certainly seems to be a lot of compression now! If anything, the valve lifter isn't helping much. I think that, after standing for several months, the oil has drained into the crankcase. Either that or I have lost the knack of kicking over an old British single!

I'll get to play with again at the weekend and, hopefully, will be able to get it to start.

Thanks, again, for all the help

Mark

PS I do need to try and get along to the Hants branch, although I live much closer to the old Wessex section. Not sure if they are still in existence, though...