Rebuilt engine firing on 2 cylinders

[Oxford Jack]

Yes the cam followers all appear to be dropping, at least when the engine was turning over, but I have not observed them while the engine was running. Thank you for the thought I will bear it in mind

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Thanks Ivor I have not previously come across that device, I shall see if I can obtain one.

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Ivor, where did you find those tools? Are they a hone or just a cleaner, I cannot find them at the moment and do you have an idea on appropriate size please?

[Ruairidh Dunford]

If you are unable to locate a valve guide cleaner (new to me too), then a 9/32" reamer is what you require.

If it is sticking I would definitely remove that valve and ream.

[Oxford Jack]

Thanks R, I will get one

[Ivor Hawkins]

Hi Ruairidh and Jack, valve guide cleaners are readily available on Fleabay or Chometrader is doing a two piece set for a tenner, I’ve used them before and they work a treat.

[Ruairidh Dunford]

Great spot Ivor - thank you!

[Oxford Jack]

Removed Number 6 valve, see attached photos. It was again stuck up in the guide. I think I shall have to remove and clean them all to be happy it will not happen again. It is barely detectable with a finger nail, but if the engine has been built with close tolerances then I suppose the heat will soon cause the valve to stick. There is no sign of anything in the guide itself.

       

[Tony Press]

As I noted:

When I first obtained the Austin Seven Standard Sports/Latrobe, the engine. which had been rebuilt twenty years abo by renowned Club expert the late Bob Booth, had stood for ten years. 
All the exhaust valves were stuck. After an engine rebuild with new exhaust valves and guides plus a bore hone the car ran well.

When I asked Bob about his valve stem clearances he agreed they were too tight 

[Bob Culver]

If an engine has stood for a long time the valve chest would become very dry. Nevertheless the degree of scuffing is surprising against cast iron when not much force available.
Brief running would not work oil to the guides. Nevertheless seems unlikely to seize unless an interference developed.
If awkward to remove the valve cover, oil squirted toward the valve head as each is open would find its way down. Valves on moderns with seals must run quite dry.
The guides are 9/32. .2813. For the Mini and predecessors the BMC A engine new clearance was 1.5 to 2.5 thou for inlets and 2 to 3 for exhaust, based on bores up to .5 thou over the exact.
I assume all own inch micrometers, these now being very cheap. (The 25.4 conversion is exact so Metric is fine) Those with lathes can make test pieces for bores. Otherwise a rod can be hammered flat and filed to just enter, then measured. Callipers not sufficiently accurate, despite readout. Drill shafts are undersize.
Guides are less liklely to be damaged if pulled into place. Whatever is used should not contact the inner diameter. Austin inlet valves were originally slightly thicker than the exh. Now I understand same used for both, which means inlet can be a trifle generous clearance.
Normally the reamed guide when fitted still gives enough clearance. New reamers cut slightly oversize so if reamed in place can produce generous clearance esp for inlets. Reamers cut smaller and give better finish if lubricated.
Clearance can be assessed from the degree of rock. By drawing the extreme positions the multiplying factor can be figured.

[Oxford Jack]

An update for those interested.
After troubles and tribulations, various, I found that honing the valve guides with an old valve stem and fine paste, polishing the valve stems with 1200 grade paper and oil was the solution. I had bought and tried a suitable sized ream, which almost fell down the holes, which is why I fell back on honing.
Sadly Ivor the valve guide cleaner you recommended seems not to be available (no reply from the company concerned). One of the difficulties was in refitting the valve cotters, they are little buggers when working over the wing of an RP even though I removed the manifold. They hide in the most awkward places!
In all I had the head off three times and all the valves twice. In addition at one point the starter that came with the engine stopped working, nothing at all. Removed it to find the pinion nut loose in the bell housing, no split pin through the shaft!
I have just driven 5 miles and tightened the head down, now to get a good number of miles on the clock before setting off for The Dales in two weeks time for a short break, in the Austin!
Thanks all for your thoughts and ideas, you were right, I would in future if fitting a rebuilt but longtime stored engine, definitely strip the valve gear and probably the ancillaries, for correct fastening, possible dryness and general workmanship.

[Nick Lettington]

Hi Jack.

Great to hear it's sorted. 

When doing the valve cotters, I have always found that a blob of grease inside the cotter and a blob on my finger works really well. The cotter sticks to your fingertip, then it sticks to the valve stem. Put it on at the front and slide it to the left side, then repeat putting the second on the right side. It works surprisingly well.