Valve clearance - 1098cc engine

[TFM150K]

I am convinced that this has been dealt with before but I am half-way through a service and can't find it here - both the Workshop Manual and the Haynes manual ( both of which I am not allowed to mention) give the clearance as 0.012" cold. The w.m. says that the engine has been designed to operate with this clearance and no departure fom it is allowed - the h.m. says that the importance of correct clearances cannot be overstressed as they vitally affect the performance of the motor.
BUT I am sure I have read somewhere (here) that 0.015" is preferable. The engine is bog standard, not converted for lead-free but running on it with no funny additives...and has been for 30000+ miles.
I'll go and get on with the rest of the service pending words of wisdom....

Thinks - if only it were possible to have an alphabetical index ont' forum I would be able to find everything!!!!

[aupickup]

many do exhaust valves at 15 thou

[bmcecosse]

When unleaded fuel was introduced MG/Rover changed the spec to 15 thou all valves. I do suggest 15 thou on the exhausts is a good idea - unleaded runs hotter - the valves are hotter - they expand more. If the gap ever closes up then the seat and valve burn. IT makes not the slightest difference to performance. In fact I run my exhausts at 18 thou - just to be SURE. Run yours as you wish. The important thing is to check and reset every 3000 miles !

[philthehill]

Even before the introduction of unleaded fuel I found that the A series ran better with 0.015" valve gaps for both inlet and exhaust and it never did any harm.

[TFM150K]

Thanks, folks. I'm going to try 15thou all-round to start.

[bmcecosse]

By all means keep 12 thou on the inlets if you wish - but it is simpler to make them all 15 and then no fiddling with different feelers.

[TFM150K]

All done at 15thou and seems to be fine - haven't been far but no loss of power and (being a van with a ladder on top) no more noise as far as I can tell. Agree that inlets at one size and exhausts at another is a bit fiddly - and knowing me I'd get them mixed up anyway!
Thanks folks!

[Davidmbe]

Is that 15 thou metic or 15 thousand of an inch
David

[svenedin]

Is that 15 thou metic or 15 thousand of an inch
David

15 thousandths of an Inch.

Stephen

[oliver90owner]

Is that 15 thou metic or 15 thousand of an inch
David

The SI unit of length is the metre. One thousandth of a metre would be 15mm, would it not? If you are considering 15 micro metres (microns), I very much doubt anyone would be able to set that clearance (approx 0.6 imperial thou).

Morris Minors were made to Imperial design specifications (unless you can supply any obvious metric considerations?).

Most, who use feeler gauges, are unable to set clearances accurately - because of wear on the rocker surfaces. The use of a dial gauge is required for setting accurately, where wear has taken place on the contact surface.

[les]

One thousandth of a metre would be 1mm.

[philthehill]

You can always use one of these for worn rockers:-
https://www.ebay.co.uk/itm/166280103359 ... R6CGs_7YZA

[svenedin]

You can always use one of these for worn rockers:-
https://www.ebay.co.uk/itm/166280103359 ... R6CGs_7YZA

Yes, I use a Clickadjust tool. That particular one is very expensive but it is in a nice wooden box. A good one, even unused (not in a wooden box) can be bought for £30 or less if you hunt around.

I have tried 12 thou all round and 15 thou all round. To my ear 15 thou gives a somewhat noisier top end compared to 12 thou. I noticed absolutely no difference in performance but then I don't push the car at all. When I was a teenager my Morris (the same one I still have) was serviced by a very old fashioned mechanic friend. He liked the engine to run like "a Singer sewing machine" as he said. I have since learned that a very quiet top end is not really a good thing and suggests the valve stem clearances may be too tight.

Stephen

[philthehill]

It may be expensive but it has the correct sockets.
Many of the click adjustment tools do not have the correct socket which is important for proper use.
A suitable socket is Geddre D19 7/16" A/F. 1/2"" drive. The socket has to have the retaining hole for the retaining peg in the right place otherwise the socket will fall off the tool when it is lifted.

[geoberni]

Yes, I use a Clickadjust tool. That particular one is very expensive but it is in a nice wooden box. A good one, even unused (not in a wooden box) can be bought for £30 or less if you hunt around.

I found a pricier one though...
Looks to be unused, or pretty much so, no surface rust.
https://www.ebay.co.uk/itm/273805558264

[oliver90owner]

One thousandth of a metre would be 1mm.

Yes, quite right. Too early in the morning! - I was meaning 0.015m. The tappet clearance would likely be greater than the lift, and not achievable, anyway!?

[olonas]

When I was an apprentice, many moons ago, a fitter asked one of the other apprentices, "How many thous are there in an Inch?"
Reply - "Oh, they're very small, there must be millions."

[win]

20241027_123503.jpg (2.13 MiB) Viewed 531 times

The attachment 20241027_123446.jpg is no longer available

Looks like this may have been a good bargain, I even talked him down from £6, I nearly feel embarrassed.
No box or sockets, not sure what SPQR difference is?
What has it got to do with the Roman Senate.
They always had mixed reviews on usefulness.
Win

[svenedin]

The usefulness is not really about the tool being quicker or easier than using a feeler gauge (although it is). It is about worn rockers. With a worn rocker pad the feeler gauge ends up bridging a worn gap and so it is not accurate. My Clickadjust did not come with a socket but I bought a socket specifically to use with it. I must have been lucky because the socket does not fall off. I think the socket I bought was of German manufacture but I would have to check. Like all tools, you have to learn how to use it properly. I am a fan of the Clickadjust.

Stephen

[philthehill]

There are no major differences between the SPQR tool and the Gunson's tool.
SPQR back in the day made all sorts of bits and pieces and used to be a regular advertiser in the likes of Car and Car Conversions.
Some of the parts they made and advertised in the December 1968 edition of Car and Car Conversions were:-
Radiator muffs, tachometer cowls, throttle quadrants, seat adjusters, Classis Mini remote gear changes, toe eyes, magnetic drain plugs, speed braces, Adjustafit accelerator pedals, engine stabilisers, anti-friction throttle cables, Classic Mini window finger grips and of course the SPQR tappet adjuster tool.
I have the Draper Version (Draper Part No: 3455) of the SPQR tappet adjusting tool. It was supplied with the SPQR 1/2" A/F socket but I had to purchase the 7/16" AF socket separately.
It came with different data sheets. One of the data sheets state that the 'A' Series at 0.012" requires 8 clicks to set the clearance correctly.
The original purchase price was £3.99 (with no VAT back then).