tappet ajustment on 42b

[djbnsp]

i know that they should be set at .020
my question is should they be set hot or cold
one manual says cold the other says hot? if they
need to be set hot, what should i put them at
after assembly

 

[Paul from MI]

Set them at 0.020" cold, they aren't that fussy, few thousandths looser won't hurt. It'll run fine.

 

[Lee B]

In total agreement with Paul's advice, they will talk to you if too loose which I don't care for but that's a personal issue. If you care enough to roll the engine around some you might find maximum clearance at a point close to tappet lift off. This makes them looser than .020 when you set them at TDC fire position religiously, just so you know. This issue is why mine talk to me at standard .020 TDC setting. Base circle takes a dip just before lift off, so I run quiet at .015 and no big deal.

 

[Mike M]

.020" HOT so I if you set them at .022" cold when that long push rod heats up it works out right.
But you also have to make sure the rocker arm faces aren't hammered in as this will throw off your adjustment. Easy to resurface them. Just follow the contour of the original face and touch them up with a fine grinder.

 

[gtx1967jewison]

Lee if you work it hard you may end up with burned valves. The exhaust valve grows a lot when it's hot. Pushrods too. Noise does not mean it's wearing rapidly, my Deere book says to tighten till pushrod has resistance to rotate, then loosen 1/3 turn (2 flats )that method eliminates problems with false readings due to rocker tip wear.

 

[Anonymous-0]

Sounds like your book is for adjusting the valves on a D.

 

[gtx1967jewison]

1/3 turn is the same distance no matter the tractor, as long as threads per inch & rocker ratio are the same or close. It is a B book.