Back in the day there was 3/4 race and full race. You lined up the dots and were done. If you were a tooth off it was a total catastrophe. Never heard of a cam lobe wiping out.
Today you can buy any grind you want. Advance or retard the damn thing any number of teeth you want but whatever you do don't go by the dots. You might stand a better chance winning the lottery instead of wiping out a lobe on breakin
This is progress?

what is up with companies that can design any cam you want but cannot accurately tell where there own centerline is.

 

Not sure what the purpose of this post is?? There is no mystery about the IC, and the cam companies certainly know where it is at, you just obviously don't understand it all, it can be a tad confusing. Yes, back in the day you "lined up the dots", that does not mean the cam was in the right spot. It was just that nobody checked it. Cam lobes wiping out is not an issue with the cam companies, it is the change in over-the-counter engine oil, IMO.

Yes, this IS progress. My first hot rod was a 440 Charger with 4.10 gears that ran on 102 octane fuel, it ran high 13s. I recently had a very mild 355 running high 13s in a heavy car with a 3.42 gear. A factory 350 Cutlass ran low 15s. Why? Not any expertise on my part. Advancements in technology. Dual pattern cams, multiple angle valve jobs, cylinder finishing techniques, and on and on. Yearn for the "good old days" if you want, not me!

 

Back in the old days 99.9% of the gear head population had no idea how to degree in a cam. Most didnt know a thing about csm timing or even what the eventd were. Isky sold a 5 cycle camshaft and people sucked it up. As long as an engine could burn the hide off a set of polyglass they were happy. The technicality of it didn't exist to 99.9%.

 

Not sure what the purpose of this post is either, other than to spew about things you don't seem to have a grasp of.
The oil was changed due to the zinc and phosphorous reducing the effectiveness and life of catalytic converters.
With the advent of spintrons and other aides valve spring tech has jumped in leeps and bounds.
And Smittys right, people seemed to not check their stuff as much then as they do today. But a pile up of manufacturing tolerances is mostly to blame for having to check cam timing, not because the cam grinders can't get it right.

 

The post is not a slam on Cam companies or installing a cam properly by dialing it in. Seems there should be a middle ground between the ignorance of the 3/4 race days and the dead nuts on of today. Racers want every tenth of a second they can squeeze out of an engine or setup. Nothing wrong with that. But there is a large component of the hobby that is more plug and play. It seems that with today's machining technology a cam manufacturer could offer a cam and timing set combo that would be reasonably close enough. Within 1 degree? I also see enough posts here and elsewhere from the guys who used the additive, lubed the cam, and had high quality oil , checked spring pressure etc. to make me wonder what is up with that?

 

What's up with that is a thing called Zinc dithiophosphate, or ZDDP.

ZDDP is a lubricant additive that was used in decent quantities in motor oil for many years, that reduced friction in shear-force situations, such as between a cam lobe and a lifter.
When catalytic converters were mandated, ZDDP was found to slowly pollute them, reducing their efficiency (and requiring expensive replacement). At the same time, manufacturers migrated from flat-tappet cams to the more expensive, but better, roller lifter cams.
Since the special lubricating qualities of ZDDP were now less needed in most cars, and since it damages catalytic converters (thus increasing pollution), the government has mandated that its content in motor oil be reduced.
This causes no problems at all for most cars, but for people breaking in new flat tappet cams, if can cause big problems, and, as you have observed, it sometimes does, especially in high-lift, high-spring-pressure, high-revving applications, where these forces are the greatest.

Next question?

- Eric

 

Thanks Eric and I get that. But again I frequently see it on this site and on a Mopar site I follow where a guy adds the ZDDP additive and apparently goes through proper build and break in procedures and whoops there goes a lobe. I fortunately did not have the problem with mine. I talked to the engine builder who did the machine work for me about it (he has a very good winning reputation in These parts and is known for attention to detail). His statement was that even with all the careful prep sometimes they fail.

 

I agree, sometimes it just happens.

I would say, though, without any evidence to back it up, that I would bet that a lot of it is caused by steeper ramps and higher lifts than they used to use, brought on by improved technology and also by a desire to offer flat tappet cams that compete with the more expensive roller cams.

- Eric

 

I think you are correct. Remember that the venerable W-30 used a .474" lift, 328 duration cam. Compared to today's grinds, that is not a lot of lift and it has slow ramp rates.