Tappets

[gazsen]

Hi,
Thought I would check my Minors` tappets as I`m sure one sounded a bit noisy. Following the Haynes method rule of 9, it appears that my tappets are set at 0.052" rather than 0.012". I have checked this twice with he same result. Now, I haven`t done this job for many years and am wondering if I am doing something obviously wrong? Would the engine run like this? it does seems to use a lot of petrol. Any advice would be appreciated.
Gaz

[les]

Well it would run and obviously it does if you can hear excessive noise. Provided, for example, number one valve is fully open and number eight is where you take your reading from, and you don’t force the gauge in. Usually the gap gets smaller over time.

[mike1864]

I can't see them all going wrong by exactly the same amount.
Maybe the last mechanic set them all wrong?
Or are you misreading your feeler gauge?
Try a (old!) credit card. At a typical 0.033" thick, this would be really sloppy in a 0.052" gap.

[Peted7202]

You are probably reading a metric (millimetres) gauge.

[gazsen]

The gauge is definitely imperial. Double checked that.
I shall adjust them and see what happens as I don`t appear to be doing anything wrong.

[philthehill]

I would ignore the 0.052" measurement and just set them to 0.012".

[King Kenny]

When adjusting tappets I can not recommend highly enough the SPQR tappet adjuster. Tappets can be adjusted accurately in seconds. The first time I used one i did the job twice as I did not believe how easy it was. The tool also takes into account any pocketing within the tappet that inevitably takes place over time.

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[Bill_qaz]

Just bought and old one, complete in original wooden box
(pre-plastic packaging days)with sockets, instructions etc. Used one many many years ago in workshop

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The Commercial Motor Archive

[Classiccars]

Tappets or valve settins I have seen done online.However I am advised that the exhaust valve clearance is different yo the non exhaust clearances.But if so how do you know which is an exhaust valve or not.And why online didi they set them all the same.Any ideas please.

[simmitc]

The original factory specification was for 12 thou on all valves. Modern thinking is that 15 thou for exhaust allows for more modern fuels, but opinions do vary. IMO either is acceptable, but others may disagree.

If you look at the manifold, you can see which valves are adjacent to the branches from the carb. These are the inlet valves. Valves adjacent to the branches going to the exhaust are the exhaust valves. Many people think that it is easier to look at the manifold rather than trying to memorise a sequence of which valve does what.

[svenedin]

As Simon says, the original setting, 12 thou, is the same for all the valves. When lead was removed from fuel, people recommended that the exhaust valves were set to a larger gap of 15 thou. This larger gap reduces the time the valve stays open which means it closes sooner. The effect of this is in theory that the hot exhaust valve is in contact with the valve seat earlier and this helps it to cool. Overheating of the exhaust valves and damage to the valve seats (valve seat recession) was the main concern with unleaded fuels but lead also acted as a lubricant and reduced the risk of micro welds that can cause the valve stem to stick in valve guide or the valve seat to be damaged by impact with the valve. To make it easier, some people suggest that all of the valve clearances can be set at 15 thou. Then you do not have to worry about which valve is exhaust or inlet. The trouble with this is that the top end of the engine can be a bit noisy with the wider gap and in theory it might reduce power a little.

Stephen

[geoberni]

If you look at the manifold, you can see which valves are adjacent to the branches from the carb. These are the inlet valves. Valves adjacent to the branches going to the exhaust are the exhaust valves. Many people think that it is easier to look at the manifold rather than trying to memorise a sequence of which valve does what.

I agree with simmitc, I just check which one is by which manifold pipe....
But it's basically the one at each end and the two in the middle are Exhaust.

I'm currently running mine with 12 and 15 combination, to see if I notice any difference....

Also a Vote for the SPQR Tool, I brought one recently from eBay and it's much less of a fiddle....

[Classiccars]

Once again thanks for the useful advice.

[Bill_qaz]

My purchase arrived today,not used one for 50 years
Looking forward to giving it a go

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[stuffedpike20]

My purchase arrived today,not used one for 50 years
Looking forward to giving it a go
20250809_132501_1.jpg

Could you show us the full instruction page please Bill. I have just bought one, but with no instructions.

How many clicks give you 12 thou?

Thanks
John

[philthehill]

Just my thoughts but I will share them anyway:-
I have a SPQR rocker clearance adjuster so know the tool but I have to say if you have to use one because the rocker anvil face is worn it is time to consider replacing the rockers. The rocker anvil face is case hardened and the hardening is not very thick. Once the case hardening is breached the rocker anvil face will wear rapidly.
Some use a oil stone to remove the hollow but that is just putting off the inevitable.
The SPQR tool is a get round solution but a better solution is to replace the rockers.

[svenedin]

Just my thoughts but I will share them anyway:-
I have a SPQR rocker clearance adjuster so know the tool but I have to say if you have to use one because the rocker anvil face is worn it is time to consider replacing the rockers. The rocker anvil face is case hardened and the hardening is not very thick. Once the case hardening is breached the rocker anvil face will wear rapidly.
Some use a oil stone to remove the hollow but that is just putting off the inevitable.
The SPQR tool is a get round solution but a better solution is to replace the rockers.

Of course you’re right but my tappets are (recently) new and it is still a very convenient and quick way to adjust the clearances.

Stephen

[Bill_qaz]

My purchase arrived today,not used one for 50 years
Looking forward to giving it a go
20250809_132501_1.jpg

Could you show us the full instruction page please Bill. I have just bought one, but with no instructions.

How many clicks give you 12 thou?

Thanks
John

12thou is 8 clicks 7/16 socket you may need to zoom picture. How to use
https://share.google/kgpBKOh8rZfNN28Ca

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[stuffedpike20]

Thanks Bill.

[stuffedpike20]

I thought I would try my SPQR tappet adjuster today and fell at the first hurdle.

When locating the sdrewdriver and deploying the 'automatic torque loading mechanism' turning the screwdriver just compressed the valve spring a long way and the 'click' did not happen.
Even trying it without the 'click' did not give an accurate setting.
I put the tool to one side and set the clearences with spanner, feelers and screwdriver. Very dissappointed.

Anyone want to buy a SPQR tappet adjuster?