[Healeys] Denis Welch Tappets Again

[Michael Salter]

Speaking as someone who has over the years had 2 bouts of tappet failure in
100 engines I would suggest that you are wise to be cautious.
I can't advise on the tappets that you have fitted but can say the I am now
using sets from A H Spares which are proving to be very satisfactory and
are different from those I have had problems with.
I have, in B.#174, a magnetic oil drain plug and have found that to be a
very good indicator of impending tappet failure. On the last 2 oil changes
there was absolutely no metal on the plug.
My procedure initial start procedure was to firstly remove the inner valve
springs as I have found that they and the additional pressure that they
produce are just not required as my engine exhibits absolutely no sign of
valve bounce right up to the red line.
I use Lucas 20/50 break in oil for the 1st 500 miles.
On first start I held the engine around 1500 RPM for about 20 minutes. (I
have difficulty believing that this is necessary but that's what the
experts recommend so you have to be sure that the cooling system is in good
shape).
I change to VR1 non synthetic 20/50 after 500 odd miles and then change the
oil every 3000 miles.
The engine in B#174 now runs with absolutely NO tappet clatter which is
pretty unusual for a 100.
I recently checked the valve clearances and they were unchanged after 2500
miles, another good indicator that the cam and tappets are holding up well.
I'm sure others have had different experiences but I  would recommend that
you make every effort to avoid a cam/tappet failure because rectification
requires a complete engine strip down.
Good luck.

M
 (Still running perfectly with outer springs only)

On Wed., May 24, 2023, 8:46 a.m. Michael MacLean, <springer.mike51 at gmail.com>
wrote:

> As I get closer to starting my 100 engine I have yet to replace the
> modified Denis Welch tappets like a list member suggested I do.  I got
> nervous, so I ordered a set of NOS tappets from Ahead4Healeys to swap with
> the installed Welch tappets recently.  Now, searching the archives, I  find
> someone had problems with NOS lifters after 6000 miles. Ruined a cam and
> the lifters.  So, what am I supposed to do now?  Should I just buy
> aftermarket tappets?  Are the aftermarket tappets hardened correctly?  Why
> wouldn't the NOS tappets be hardened right?  I don't want to replace the
> cam after I get this thing running.
> Mike MacLean
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