Lifter Destruction?

Hi guys,
yes, I know I'm asking too many questions at the moment and not fiddling for myself :-) But here's my next question:

I read somewhere that to set your valves on a 350 SBC you want to screw in the rockerarm nuts til you fell a resistance when turning the pudhrods, then a halfturn more. I did that, but it seems like I overdid a few, it ran OK, but used masses of gas. I guess none of the valves fully closed anymore.
Can that damage the lifters? I've corrected that condition now, but some lifters are depressable by hand (I can push the pushrods into them a bit) but others won't budge. Do I need new lifters?
As always: Thanks in advance!

Hey Mad,

It's not likely that you damaged anything. Hydrualic lifters are designed to adjust to spring loads (preload). Your half turn you mentioned is most often correct according to the lifter manufacturers. What may have happened is that when you did the initial adjustment, the lifters weren't fully "pumped up" with oil, so you may have already had some compression on them, and that extra half turn pushed them in a little too far and kept the valve off the seat. Then, when they filled with oil, you began floating the valves a little. No big deal, you already backed them off so you're good. Best thing to do is back off your rockers until they are tapping a little. Warm up the engine to normal opperating temp. With the engine running, start tightening your rockers until you no longer hear any tapping (or until you can't slip a feeler gauge between the rocker and valve). Then, give it another half turn (this will add about .003 preload). This places the pushrod seat down into the lifter body where it will remain as the lifter gets used to the preload. The only thing to really worry about with new lifters is that you get them spinning on the camshaft lobe. Under normal preload, you should see all of your lifters (pushrods) rotating. If not, start the engine and help them spin by twisting them with your fingers. This prevents the cam lobe or bottom of the lifter from wearing. And don't worry, just get those lifters spinning and they will eventually pump up with oil. The only damage you can really do to a lifter is wear out the bottom (or the cam lobe) or pop out the retaining lock (due to zero preload).

If you're interested, here is a nice article from Crane Cams on your valve train that covers lifter installation...

http://www.cranecams.com/?show=techa...7c4ece208e7e09

Hope this helps...

tjpoc

THX a lot, that page is really interesting, but now I'm conderned about something new. They say:

"... pumping up the lifters by hand before the engine is assembled to fill them with oil may make them seem like solids later..."

That's exactly the problem I'm having. I seem to have pumped the lifters too hard (when applying too much force in torqueing down the rockers), now some of them seem to be stuck and don't allow for preload. A lifter should be depressable by hand, shouldn't it? Can you disassemlbe and reassemble lifters yourself? Or should I get new ones? Or might that problem be solved when the lifters get pumped porperly a few times by the engine? The lifters have no foot wear, they're actually brand new.

I wouldn't think that cranking the rocker would be the equivilant of pumping up the lifter. A lifter is designed to adjust to whatever preload you put on it...as long as you haven't bottemed out the pushrod seat (about .060 travel). When I say bottemed out, I mean at this moment how you've got the rockers adjusted. If you ran it with them bottemed out, but you backed them off, it is HIGHLY unlikely you did any damage. You would have smacked a piston with the valve if that were the case. If the lifters seem "too hard" just shut the engine off, tighten down the rocker a couple of turns and wait about a minute. Can you wobble the rocker? If so, the lifter has leaked down and it is working just fine. Some lifters will leak down quicker than others...that's okay. It's when the engine is running and the oil is being pumped into them is when it really counts. It is possible that a lifter gets stuck, but it just isn't that common.

Give that a try and see what happens. Make sure when you do the test, you are not on any part of the lobe lift as that can seem like you've got a solid lifter because it can cause the oil to be pressed out from the force of the spring and you really are botteming out the seat. Again, this is all common stuff with a hydraulic lifter...I don't think you have anything to worry about.

...but what do they say about opinions?

tj

Here's a critical question. Did you do all of this adjustment by turning the engine to TDC for each cylinder - or did you adjust all of the rockers without rotating the engine?

This may be a stupid question, but I've seen it done. If you don't have the lifters on the base circle of the cam when you adjust the rockers, all hell breaks loose. . . and so can some engine parts.

Hi Henry,
No question is stupid, I've heard of that being done, too, but I did turn the engine; in the right direction of rotation, one cylinder at a time, and TDC on the compression stroke, as it should be. Shouldn't think I did anything wrong in that way.

What I know I did do wrong was:
According to the Haynes manual (I'm not blaming them, though, it was my own fault!) you adjust the rockers by turning the pushrods between your fingers til you feel a resistance, then turn them a halfturn more to seat the rods in the lifters (for preload). But I didn't notice when the resistance started (had the intake on at that time and couldn't watch the lifters), so I turned til they didn't move anymore, and then a halfturn more, I guess that was what opened my valves continuously. But not so far that they banged my pistons. just to let fuel out through the exhaust, cut my power and contaminate the mix in the carb.
And now some of the lifters seem solid, all though I have now backed the rockers off and adjusted it all correctly with the intake off. I guess I'll just have a test drive, as long as it works fine and gives me power and I have proper mileage I guess nothing can be very wrong. Wish me luck!