Worn PW3 cam

Fullauto

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Anybody know of any worn out PW3 cams? 26,000 miles, Lifters perfect. Jim Comstock's conical valve springs.
 
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After 4000 miles, showing noticeable wear. I believe they tend to be a bit soft.
Mike B
 
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Yes, 1200 miles and two lobes badly worn. Went back to using the standard profile. PW3 Performance wise, no real benefit (3 hp from the bottom end to put 2-3 hp at the top end) apart from a bit more of a 'crack' to the exhaust.
 
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This is bad news .. any of you take the matter up with suppliers ? Soft cams on the 850s where an issue in the 70s, but I understood PW3 was usually chilled cast not of itself a guarrantee against letting new cams run in motors that are idling, but better than the 4S steel cam I have whose lobes can be scratched with a hacksaw. Probably not En40 so should not have been subject to nitriding
 
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Where did you get it from ? Mine is a chilled iron one from Mick Hemmings with his serial number on it. I got it an its lifters secondhand an so have no idea of the mileage but it must be more than yours an it was fine the last time i checked. I just changed the oil an there was next to no metallic particles on the three magnetic drain plugs either.
Cams in general seem to be a never ending issue like wet sumping an many other things but if the start loose the harden outer surface things go bad very quickly.
Is yours just one lobe or more that is affected?
 

yves norton seeley

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Before I was using JS cams, I was using a PW3, never a problem with it till the day, at a drag race, the PW3 broke in two pieces
Yves
 

Fullauto

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Off the shelf at Andover Norton/ I shall be taking this up with them. This is very poor indeed.
 

comnoz

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Got two shot PW3's on the shelf. Definitely wasn't oil. Jim
 

ntst8

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Sounds a bit scary, i fitted one a year or two back so following with interest.
There was an article i think in Roadholder a while back which from memory suggested the Norman White and others all went to the same supplier for PW3's.
 
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The crappy thing with a cam grinding down quick like that is the amount of relatively hard grindings it puts thru everything else.

Glen
 
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Before I was using JS cams, I was using a PW3, never a problem with it till the day, at a drag race, the PW3 broke in two pieces
Yves
There was a piece in Roadholder about precisely this mishap but it did not involve a pw3 .. Les Amery cast doubts on the suitabilty of cast iron as camshaft material.. saying all his are made from EN40.
 

Fast Eddie

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Sadly Ken, you are not alone with this problem. Lots of theories and counter theories out there, good luck navigating your way through that lot!

I prefer hardened steel cams over chilled cast iron, simply because I’ve had lots, mainly in Triumphs, and they do tend to last well... but they’re only as good as the hardening process.

But my real preference is for hard welded steel cams, ala JS or Comnoz Web cam.
 

Fullauto

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Furore on Facebook. Local man in the same boat with his engine built at the same time as mine. Same problem. I think this is shaping up to be a batch issue. Both cams were sourced from the same supplier, about the same time, but there's plenty of reports of PW3 cams lasting forever. My cam is being metalurgically tested so I will await the results.
 

Fast Eddie

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there's plenty of reports of PW3 cams lasting forever.
Theres plenty of reports of premature wear too! And from way outside of your batch Ken.

Why not do a poll on here? Who’s had one last forever, who’s had one fail prematurely.
 

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