Observation and dumb question ohc-6

[patrickth]

I finally got around to working on cars again after a couple of years. I started taking the Pontiac down today. It looks brand new inside more or less. I haven't got the head off yet, but belt has no wear and just tiny scuff marks on cam. Most of the bluing or whatever treatment they use is still on it. What is the nature of the cam followers? They seem almost like a plastic material and very pliant. Do they serve to provide some sort of hydraulic function. Not even signs of oil on them and one was very loose. Like it was just sitting on top. I don't remember dislodging it.

I know Randall has all this info and tried to read a thread of his on Skylark on Buick forum. They have the posts, but pics were not accessible.

[Deaf Bob]

Would need to read his firebird thread.. Skylark's got a 455 Buick in it..

Silver Buick's 1969 Firebird OHC 6 or something like that..

[patrickth]

http://www.v8buick.com/showthread.php?219250-The-Break-Down-of-a-69-Pontiac-OHC-inline-six

[Beagle]

I think DB was talking about here -

http://www.bangshift.com/forum/forum/bangshift/project-cars-update/37480-the-silver-buick-s-1969-firebird-ohc-six-project

It might be easiest to ask in that thread, he'll get notified.

[patrickth]

One and the same, Apparently posted both places, I have read them several times, but pics are now gone. At least the tear down ones anyway. I wanted to see how his cam looked at that stage. Mine looks like it was put together, tried to start and then just buttoned up and put away. No real evidence of it running, especially on the exhaust side.

I didn't ask in that thread because he is far beyond that stage now and I didn't want to interrupt. since he is "on a roll" LOL.

[Beagle]

somewhere around page 33?

The pivot should have the hydraulic bit in it, the cam follower should be steel...

Go ahead and ask, he's a good dude... if the pictures still exist, I'm pretty sure he'll get them for you. Or maybe it's Hyde day instead and he'll tell you to pound sand. Not likely.

[patrickth]

I looked on ebay and cam followers seem to be more substantial than mine.

[Beagle]

those are ebay piics or yours? Those look like they are cast metal and the top part with the clip is the lash adjuster which is most likely hydraulic. Polymers of the sixties wouldn't have lived in that environment...

[patrickth]

No, these are of my engine taken yesterday. I will look again once its daylight. Been a very long time since I messed with anything other than a V*8 and specifically Hydraulic lifters.

[Beagle]

That's the fun of it.. there aren't any "lifters" in the Pontiac, strictly speaking. The lash adjuster isn't a lifter, just something to regulate clearance between the follower and the cam. I'd like to see some more pics of it, but I imagine it is much like a hydraulic lifter, just in a different location.

[patrickth]

I know spring height is critical, but can't remember how they get there and maintain it. I am taking a considerable number of pics. My memory isn't what it used to be for sure. Not positive I am going to use this engine in Impala yet either, may go with a 5.3 LS.

[TheSilverBuick]

What was the question again? Facebook has fubar'd my picture links....again. Playing with the link get's the picture back, but its a pain when they do to go back to every post.

The followers are simple cast iron with a polished top where it rides against the cam. Now sure how they can be pliant as they are case iron... The clips stopped being used at some point, and are just an "assembly" thing, though they do help keep the followers in place if you are less careful about setting the cam housing in place. They apparently are known to break and then you have metal pieces floating around. Never heard of an engine damaged by said floating metal pieces, but you know how that can go.

Oil should be EVERYWHERE if it ran. There are no oil passages on the follower itself, but each cam lobe has a hole that pours oil out, and that is how the follower surface and cam face is oiled. The lash adjuster leaks a tiny bit of oil on its nose, in the follower's cup. The lash adjuster is the hydraulic part of the valvetrain to maintain lash.

I haven't taken any pictures of the followers or cam after I've used them. Both engine's I got had flat lobes on the cams. Then I used a used 1bbl cam and used followers for a couple months. Then I upgraded to a 4bbl cam with new followers but only ran it a few hundred miles before swapping in new high pressure valvesprings. So the cam and the followers looked used, but nothing stood out to me visually. Now its in experimentation phase on longevity with the high spring pressures and using the blue STP bottle as a ZDDP additive. Your followers have definitely been ran on, but how much is hard to quantify.

[TheSilverBuick]

And it's valve stem height that is extra critical. For a standard cam and cam housing (no base circle reductions or cut down cam housings) the install height of the valve tips should be 0.850" above the cam housing seat rail on the head. Though small block chevy valve dimensions are correct for height and the seats can be ground wider for the width, the groove for the retainer would be in the wrong spot. The stem has to be a certain height above the retainer to keep the cam follower from tapping the retainer (which could lead to a dropped valve).

I can add pictures with new links later tonight when I get home.

[patrickth]

There are no followers present, just the clips. I suspected early on something wasn't right. The clips look new and not really clipped on just kind of sitting on top. I appreciate your input and didn't want to put you through the hassle of going back over old posts. Going out to pull head right now.

[TheSilverBuick]

Huh, all your pictures are of the followers.....

These are the followers