Joined: Dec 2019 Posts: 29 Threads: 11
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Location: The north
Dear all,
New old stock nippy head, fitted with short reach spark plugs (NGK, Champion)...... valves reach and close the plug gap (tappets set at .008", road/trial cam and followers), tried using extra crush washers, though plugs then prove difficult to seal.
Please could you kindly point me in the right direction as to the next course of action?
Thank you all.
Joined: Dec 2019 Posts: 29 Threads: 11
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Location: The north
Thank you John,
Though both the NGK ab-6 and the champion d16 I have are standard spark plugs it seems, and definately similar to the left hand option in your photo.
Joined: Aug 2017 Posts: 1,666 Threads: 46
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Location: Auckland NZ
Car type: 36 Nippy, 31 RM, 38 Special, 24 Works Rep
I have found some after market 9E1 Heads are machined incorrectly, the plug pockets are cut too deeply and cause the problems you describe with high lift cams. If you have a std or low lift trials cam perhaps you may have discovered why it has never been used previously. if the C/R is std for a Nippy/9E1 head the plugs mention will be fine if all else is well.
Black Art Enthusiast
Joined: Aug 2017 Posts: 114 Threads: 8
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Location: NE England
Although a different head, a finned Cambridge for me, I've had the same problem getting protruding plugs (the right hand ones in your picture) not to be closed up by the valves. My solution was to selectively fit the plugs to cylinders such that the earth electrode, on tightening, sits east/west across the engine in the space between the valve heads. Hacksaw a slot in the HT connector of the plug in line with the earth electrode and selectively fit them such that it then sits across the engine and use additional sealing washers to adjust where it goes 'tight' in the thread. You have to mark each plus so they always go back into the same cylinder. Make sure you fit the plugs with the valves in or near the shut position.
I hope that helps, Dave
Joined: Dec 2019 Posts: 29 Threads: 11
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Location: The north
Understood. Thank you all.
