What do you make of this pic of my lifter? Looks to me like the lifter is not rotating... But why? Is this an indication of a cam going flat? See the wear in the center of the face of the lifter? I've got my own thoughts on all this. I would just like some other opinions... Thanks guys.
T-roy,.. Yes ..the lifter is NOT rotating Only 2 things can cause that wear pattern. The cam was not ground with any taper across the face of the lobe OR the lifter is too tight in the bore.. As OCfab says, the cam is gone.. If you are lucky all you need to do is pull it apart and hone the lifter bores, clean eveyrthing ( hot tank ) and reassambe with new cam and lifters.. Check the bearings and pull the cover on the oil pump and inspect...If this thing is fairly low mileage you should be ok.. I just fixed a 350 for a buddy that had the same problem..The rebuilder used a shot blast cabinet to clean the block and failed to hone the lifter bores..It is back on the road and running good now ( and yes, we pulled the valve covers @ 500 miles to adjust the valves and all 16 pushrods are spinning about 1/4 turn every time the valve opens..) good luck Dave
When you replace the cam ,install it and lifters and turn cam and watch that the lifters rotate. The lifter bores may be off.
You may have also overtightened a rocker. If a hydraulic lifter is bottomed out they sometimes don't spin
Lot's of stuff can go wrong here. I've got a nifty tool from sunnen that trues the lifter bores and that can be the problem. If all was new and all was clean and all was done right in the short block department I have seen weak valve springs cause this>>>>.
It is an oil problem. You need to run Shell Rotella or another diesel formulation oil. Been discussed here before. Do a search.
I just replaced the cam, lifters, valve springs and had the heads rebuilt. Motor probably has @ 250 miles on it since. The cam was broken in on Rotella T30. No extra zinc additive was used, shouldn't have had to add any. I did however coat the cam & lifters deliberately with the comp cam lube. The motor was running fine but while chasing down some oil leaks, I had the pass side valve cover off and noticed the #4 exh rocker arm was not square on the valve tip. I'm using self aligning Comp roller tip rockers and the aligning guides on both sides of the roller tip were flattened which caused the rocker to sit slightly off to the side of the valve tip. I've never had a cam go flat before, but I suspected a flattened cam lobe would dig into the lifter face and really cause the face to have a chewed up rough surface. Is this not always the case? I'm hoping to be able to hone this one lifter bore, replace the lifter and change out the rocker arm... Below is a link to a previous thread I posted after breaking this cam in. I had just got my motor back together after a separate issue of a lifter in a different bore came apart... Damn old cars... http://www.jalopyjournal.com/forum/showthread.php?t=263027&highlight=valvetrain+carnage
Thanks, I know all about the "not enough zinc" in oil issue. There is so much or too much hype to read about this subject on the internet. There are other anti-wear additives that are being used in place of the small amount of zinc that has been taken out. This of course is all in an effort of reducing emissions in the late model diesel engines that have to run the low emission CJ-4 type oils. I don't believe my cam and or lifter issue is because of the oil. The oil wouldn't cause the lifter to not spin in it's bore. Seems like it's more of a mechanical issue... But, I could be wrong.
So the same valve that did that also flattened out the alignment tabs on the rocker? Because lack of lifter spinning shouldn't harm the rocker. Now you gotta do a chicken and egg to figure out which caused which. Or what yet unknown thing caused both. Kind of a head scratcher
im thinking i wouldnt put that back togeather until i solved this..how does that cam lobe look? have you pulled the cam back out to see if its flat? or if the lobe is sharp on the sides? by "sharp on the sides" im relating to the fact that that lifter didnt spin for a while and the lifter had to have wore on the cam lobe. feel the edge of that cam lobe and compare it to another lobe that didnt have this probelm...feel different?
I haven't done anything else yet. The cam is still in the motor. I just went and looked through the bore with a flashlight and felt the cam lobe with my finger. The cam looks and feels smooth. The oil holes in the lifter bore feel like they may have a slight ridge... Maybe that's what is keeping the lifter from spinning. After talking with Don (Racer756) this weekend, I'm going to slightly hone that lifter bore and install a new lifter. Then "break the cam in" again to break in the new lifter. We'll see what happens. It'll either work or it won't. I'll just be out a little more time if replacing the one lifter and rocker arm doesn't work...
Doing that is very risky you could wipe out the whole motor. But to each is own. Make sure you change the oil and filter because you now have lots of little metal shavings in your bearings and oil pimp just trying to help OC.Fab
I have had issues with "tight" lifter bores and have used a "ball-type" hone to clean it up. My last rebuild had a ton of miles on it and there was build up in the bore that the hot tank did not get out. A quick hone took care of it. I have never did it with the engine together but I wouldn't put it past me. Some of the aircraft engines I work on will have the same issues with the lifter not rotating, we replace the lifter without replacing the cam, and go fly. We have never had an issue....just my 2cents.
If you do end up having to change the cam, I have to recommend you go roller. No more flat tappet issues afterwards. Maybe Comp will offer you a good deal on one...it's worth asking about once you get them on the phone. ~Scotch~
I bought a "ball type" hone to do this job. We'll see what happens... Thanks for the positive outlook.
And I have given this some thought... Roller would be bitchin'. Then I'd just have to worry about the rollers comin' apart. Right Don? hahahaa Seriously, a roller set up would really be bitchin' though.
Don't forget the ZDDPlus sold here by an Alliance Vendor. This is an example of what can happen to cam and lifters. If the lifter was stuck in the bore that's one thing but if it's a lifter foot cam lobe wear problem - chalk it up to the new reformulated oils. The lifter has such a small contact area on the cam lobe to get it to rotate, the valve spring pressure can remove metal in a hurry w/o the high pressure lube of ZDDP in the oil. I wiped out several cams before realizing the new reformulated oils were causing the problem.
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