[Healeys] cam failure

[Ed O'Neal]

I trust the engine oil being used had the right concentration of Zinc dialkyldithiophosphate?  Proper concentrations should be 1500 to 1700 ppm.  Current engine oils are at about 500 – 600 ppm.

ed at wadsworthoneal.com<mailto:ed at wadsworthoneal.com>

Edward J. O’Neal, P.E., Pte.
Wadsworth O’Neal Associates, Inc.
6418 Commerce Park Drive
Fort Myers, Florida  33966
phone:  (239) 245-8728
cell:        (239) 410-6174



From: Healeys [mailto:healeys-bounces at autox.team.net] On Behalf Of warthodson at aol.com
Sent: Sunday, March 25, 2018 11:15 AM
To: healeys at autox.team.net
Subject: [Healeys] cam failure

A friend recently had a reground cam fail after a few years of normal use. The engine had been professionally rebuilt. There are several possible explanations, however one unusual thing he discovered is that the wear on the lobes & tappets is only apparent on cylinders 4,5 & 6. The worst visible wear is on the exhaust valve lobe/tappet of Cyl 6. & the least wear is on the exhaust valve lobe/tappet of Cyl 4.
Cyls 1,2 & 3 appear to be in very good condition.

Does this suggest any specific cause for the failure?

He will be having the cam & tappets replaced & will be using a Piper Camshaft, for an Austin Healey 3000, it is Part No. AH3BP270 (Fast Road) and is from a “billet” and not a regrind.

Are the Piper Cams generally considered good quality?

Any comments on this subject would be appreciated.

Gary Hodson
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