Interesting Rocker Discovery

[ForcedFirebird]

OK, well you are splitting hairs at $120 to NOT ruin a new cam :p

...and good choice on the rockers. We have been beating the crap out of them on the track ad they are holding so far. If one fails, Andrew and I will get reacquainted over the phone lol.

[digger]

make sure you check the sweep pattern with HD as the older ones have issues when you talk very big cam lobes the lobe runs off the rocker pad (OEM no issue) due to the pad seemingly being designed/positioned for reground cams negating the use of o/s eccentrics.

i think this has been rectified though

another option is MM peened and inspected rockers. more $$$ though

[TobyB]

10 years ago, oem and febi had identical void problems.

I broke both, in identical ways.

Resurfacing rockers works, too, if they are in decent shape.

t

[jeffnhiscars]

This is another one of those discussions where every comment needs to include the disclaimer that "your experience may vary". Pros and cons to every option unless you spend big bucks which I've already said I'm not going to do, just for practical reasons.

It's safe to say my OE rockers are not going to break since a)!they just don't seem to break and b) we are talking DD with auto trans (I can't repeat that often enough).

The consensus is the only downside is possible premature wearing of the new cam which I'm prepared to live for a few reasons. One is if my old cam was not past its "best by" date I'd have reused it and I can't believe the new cam won't outlast a used cam regardless of the rockers. Second, I wonder how many people who follow the new cam new rocker policy also replace all their guides, valves and springs (which I did). Third, a worn cam is a worn cam...big deal...you fix it for about what a set of rockers cost. A broken rocker has a very different outcome.

Last thought (for the moment) is whats the extent of the damage when a timing belt breaks and the rocker doesn't ?

[TobyB]

But: if the cam wore out, then the rockers are worn in a mating pattern to the lobes.
Getting a cam to bed to the rockers has become one of the harder things with old
sliding- tappet engines now that the oil's "green" and lacks the sliding friction additives
it had when these engines were new.
Refacing seems like a good compromise- they'll bed, you'll spend $50, and life's good.
Spend for the high- ZDDP break- in oil, too- it's cheap insurance.


Honestly, too, take 10 minutes and check the springs. If they're good, you won't break a rocker.

What I'd do (what I DO do) for a dd,

t

[digger]

new or refurbed pads is a must with a new cam IMO its not worth the risk of damaging the cam, many people do it i'm sure but many people don't change timing belts either.

Also running the cam in is a good idea, i dont think yo need anything special on this spec of engine its basically stock just whatever oil you current use at it should have enough zinc and so forth anyway but make sure you coat the rocker pad and cam faces with moly lube before start up and run it at 2000rpm or so to take some load off the nose of the cam and pads and get some more oil flow happening to the topend.

[jeffnhiscars]

I was not aware that pads could be refurbed so will check around for a shop that does it after i check the rockers for side play on th shafts. Good info

I do use assembly lube and run Mobile 1 15-50'which has lots of zddp. I can always add some more for initial wear in if it matters.

Are you suggesting to run it at 2000 just til the oil circulates or for xx minutes to bed the cam ?

[jeffnhiscars]

Hah...EZPZ

https://m.youtube.com/watch?v=k5CV3pv1Bgo

And this is cool. Anyone know where to get one ?

http://www.google.com/patents/US3566550

[Kershaw]

That doesn't look that hard to make. Put your bench grinder near your vise, 2 long bolts, a couple of washers, and a scrap piece of wood or metal with 2 holes drilled in it, and maybe you got it.

I'd definitely practice on a throwaway one first....

[jeffnhiscars]

You really..REALLY need th face to be square to the bore of the rocker so as simple as this is, it has to be precise or the pad will not sit flush on the cam lobe.

I'll see if my machinist has the jig or else will find someone who does. For the $50 or so this will cost, I'm in

[digger]

call a cam grinder, they should have equipment

[TobyB]

That's who has done mine- Delta Cam, in Tacoma.

And yeah, spend the $13 for the additive-
I've been bitten twice now, and it's just
not worth not doing it. Or use a break-in oil- it's actually
cheaper than the M1.

t

[jeffnhiscars]

We all agree on what the best practice is here and I think it's safe to say very rarely do we all follow those practices completely either cause we discount it, can't afford it or just don't feel like spending the time or money to make it "as new". The real question is what's the cost benefit equation as it relates to real world risk.

1) For those who have had premature wear on a new cam without replacing the rockers what was the driving style (i.e. Track, auto X, DD) and was the engine stock or "performance enhanced" ?

2) if you are supposed to replace your rockers when you replace the cam, why have I never seen anyone say you have to replace the cam when your broken timing belt takes out half your rockers and you replace those ? I mean don't new rockers with an old cam create the same wear inducing mismatch as a new cam with old rockers ? Surely someone has had half their cam lobes vaporize as a result of replacing half their rockers and leaving the old cam. No ??? Hmmmm

just food for thought...and comment.

Note...I pay $23 for a jug of M1. Dyno was $15 last I checked. Not significant

[nando]

the cam isn't supposed to be a wear surface, that's why.

[jeffnhiscars]

the cam isn't supposed to be a wear surface, that's why.

Not sure what you mean. Rockers are hardened all the way through whereas cams are surfaced hardened, yet they both wear out.