[Healeys] Denis Welch Tappets Again

[Bob Spidell]

Maybe why DWM sells cams and tappets ('followers') as a set? Installed 
them in my--most recent and, hopefully last--BJ8 overhaul and no issues 
after 7K miles or so.

I don't think you can rule out improper break-in as a cause.

Bob


On 5/24/2023 6:42 AM, m.g.sharp--- via Healeys wrote:
>
> Mike, I am really no expert on this, but having had cam/tappet issues 
> with my ’56 BSA motorcycle (same technology as a Healey) in the past I 
> did look into it about 18 years ago, and Mike Salter and I had a long 
> discussion about cams and tappets when we did my BT7 engine a few 
> years ago.  One thing I was told by a bike engine builder I trust is 
> that the hardness of the cam lobes and the tappets should be the 
> same.  If they are mis-matched, rapid wear can occur.  It _may_ (I am 
> speculating) not be so much that the cam or the tappets are not 
> hardened properly, it is just that they are hardened _differently_. 
>   I eventually ordered the motorcycle cam and tappets from the same 
> source with the promise that they were made to work together.  That 
> seemed to work on the bike.  I think buying a cam and tappets from 
> different sources is not the best idea.
>
> With my BT7, we were lucky, as even after over 100.000 miles, the cam 
> had virtually no wear, and only one tappet showed signs of wear, so 
> that was replaced with an good used original one that Mike had.  So my 
> original cam and 11 of the tappets were re-used (with the tappets put 
> back in the same order as they came out).  Only 2000 miles on the 
> engine, so jury is still out on that, but I just checked  the tappet 
> clearances and so far no signs of wear.  I am surprised that 
> Ahead4Healeys actually have NOS tappets.  Are you sure that they are 
> not re-manufactured?  If they are actually NOS, I would be inclined to 
> use them and find a good original cam to use with them (assuming the 
> original one you have is too worn to re-use).  The fact that my 
> original parts were fine after 100,000 miles are a testament to the 
> quality of the original parts.  Mind you, I am only the second owner 
> of the car, and I knew  the first owner well, and we both performed 
> regular maintenance; that is key to longevity.
>
> Also, I don’t know what you are doing with valve springs and rocker 
> gear.  Remember whenever you deviate from stock, there are 
> repercussions.  Higher lift cams, increased spring pressure, etc., all 
> excerpt additional stresses on cam lobes and tappets.
>
> Good luck with it – these are hard decisions when re-building and 
> there is so much mythology about cams and tappets to sift through.  My 
> personal approach is use original parts whenever I can – they work and 
> they last!
>
> Cheers, Mirek
>
> *From:*Healeys <healeys-bounces at autox.team.net> *On Behalf Of *Michael 
> MacLean
> *Sent:* Wednesday, May 24, 2023 8:42 AM
> *To:* Ahealey help <healeys at autox.team.net>
> *Subject:* [Healeys] Denis Welch Tappets Again
>
> 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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