Sky65

http://www.compcams.com/information/...s/COMP_225.pdf

SWCDuke

The secret to vintage engine camshaft and valvetrain longevity is:

1. Use an OE cam grind from either GM or a quality aftermarket vendor, especially Tier 1 OEM suppliers like Federal Mogul. Same for the valve springs and rocker arms.

2. Use a motor oil with an API service category rating of CI-4 (READ THE LABEL!), which is HD diesel engine oil, because it has a higher concentration of anti-wear additives like ZDDP than modern spark ignition motor oils (latest API service category SM).

Shell Rotella T is CI-4 as are Chevron Delo and Mobil Delvac, which are the other major national brands.

Duke

00fxd

Now that is a good article.
Thanks.

AmericanPie

What about using a good synthetic, such as Redline or Mobil 1? I believe one advantage of synthetics is that they're supposed to offer superior shear protection compared to dino oils. Or have their formulations been compromised too?

w1ctc

Why is the cam breakin procedure (2k for 15 min or the like) needed for new cams and not for new cars?

SWCDuke

Myth! The only advantages of synthetics are wider viscosity range and higher oxidation resistance, so you can have easier cold starts in subzero weather and extended drain intervals.

If you want to use a synthetic base in a vintage engine, go ahead if you think it's worth something, but make sure it's rated CI-4. If it's only SM don't use it in a vintage engine.

What counts is the ADDITIVE PACKAGE, and CI-4s have a higher concentration of critical additives like ZDDP that vintage engines need more than modern engines.

Duke

JohnZ

GM OEM flat-tappet cams were made in the engine plants, and were heat-treated and Parkerized after machining; the Parkerizing created a thin micro-porous surface that held oil, so no cam break-in was required. Engines ran for less than a minute on the hot-test stand (just long enough to set the timing and check for leaks or loud noises), and the next time they were started was when the car they went in was driven off the Final Line at the car assembly plant.

Current aftermarket flat-tappet cams are NOT Parkerized, so they require the break-in procedure, assembly lubricants, etc.

Most modern cars have roller lifters (on pushrod engines) or roller rockers (on overhead cam engines), so there are no "rubbing" surfaces between the cam and lifters or rockers, so no break-in is required to make those contact surfaces "happy" with each other.

Most modern engine plants don't hot-test at all any more - engines are cold-tested on heavily-instrumented computerized cold-test stands that turn them at low rpm and provide 100 times more diagnostic capability than the old hot-test ever did; the first time the engine is hot-fired is when the car drives off the line.