Lifter and cam nightmare

[rcvivian]

I just installed the second cam in my 396 and for the second time it eat one of my hydraulic lifters and colapsed three others...what am I doing wrong? I soaked the lifters in oil when I put in the first cam and lifters, the second time I installed them dry. Both times I pre-adjusted them rocker arms using the method in my Chiltons by following the instructions. The method described had me align the motor at TDC tighten certain valves, then crank the motor and tighten the rest. I tightened them until there was no lash (I did this by spining the pushrod with my fingers. Once I could no longer spin it, I stopped and then turned it another 1/2 turn). After doing this, I put the valve covers back on and ran it for about 10 minutes until I heard the lifters start knocking. I immediately turned the car off, took off the valve covers and found that some of the rocker arms were significantly loose. Having seen this before, I took off the intake and found the 3 colapsed valved, one that had been worn down significantly. I pulled the rest of the valves, and a couple were very hard to remove. I used all new parts.

Any ideas where I've gone wrong? Will the shavings require me to replace any of the lower bearings?

 

[maxrevs85]

Start with #1 at TDC, the rotor should be pointing the #1 plug terminal on the dist, cap and then follow the firing order for each cylinder adjusting only the intake and exhaust for that cylinder. It takes a quarter turn of the crank each time to accomplish this. 1/4 to 1/2 turn of preload in all thats necessary.

Are you running a big cam and are the pushrods the right length?

 

[rcvivian]

Cam and lifter nightmare

The cam has a 280 lift. The only required replacement according to the instructions were the springs. The pushrods are stock. What causes lifters to colapse? What's the proper procedure to pump-up a lifter?

 

[69_coupe]

Are the colapsed lifters, and the destroyed one close to each other? Check that there is oil supply for these lifters, there should come oil up through the push rods.

 

[rcvivian]

Are the colapsed lifters, and the destroyed one close to each other? Check that there is oil supply for these lifters, there should come oil up through the push rods.

They are randomly scatted throughout the engine. It looked as though all were getting oil.

 

[Jack]

I just recently helped a buddy do 396 for his 67 camaro ss resto ... used factory blueprint cam for 396/350HP (about .461"/.479" VL & 214*/218* dur @0.050" LL) ... got new cam & lifters from GM (both apparently by crane). Excellent iron GM oval port heads freshened. New ferrea stock length ss valves, new crane springs & retainers recommended by crane (one step up from a standard "replacement" stock) ... shimmed to 120 lb on seat per cranes recommendation. New OE type stamped rockers w 1.7:1 OE RAR. Good, clean used stock pushrods.

Soaked lifters overnight in 30 weight. Slathered each cam lobe & each lifter face with a moly paste ... same with rockers' balls & valves' tips and dist gear. Set each cylinder separately .... rolled motor through until lifters all the way down (valve closed) ... then tightened rocker until spun pushrod has drag (zero lash) ... then tightened 3/4 turn.

Cranked motor ... timing was off ... stopped motor right away ... bumped dist around ... cranked motor and kept revs varying 2K-3K rpm for 20 minutes of breakin.

After breakin this motor was rigorously put through paces to check for any hint of overheating ... long periods of idle. Motor has total of about 2 hours time ... and about 20 miles ... everything AOK.

You'll need to check to see if any bearing damage ... pull front main bearing cap & a rod cap ... look-see. Suggest you get new cam & 16 new lifters ... liberally lube lifter faces & cam lobes w/ a lube made for breakin ... & set preload one-at-a-time when lifter is on heel of cam.

If I recall, 67 and up is different from 65 & 66 BBC block, cam & cam bearing. When using most available cams (for 67 up) in a early block ... you may have to machine a groove into cam's rear journal. Never been faced with this but understand there'll be lube failure & engine failure if not addressed properly. Dunno what year your 396 block is? ... but if it's a 65 or 66, its cam better have the groove in the rear journal and that cam journal's bearing better have a groove.
JACK:gap

 

[goingballistic]

I'm just finishing my rebuild on my 388. The part you are dealing with appears to be the most troublesome and certainly was for me. It took me about a month to decifer what was real and what wasn't. I haven't fired up the engine yet, going to the dyno in two weeks and yup, I'm worried.

What I found out, for what it's worth.

1) The cam/lifters/rods/valve stems etc HAVE to be prelubed, the more you rotate the more damage you cause to the lifter base and also the lobes so don't crank it around if you can avoid it.
2) There is a procedure for adjusting each rocker that takes exactly two turns of the engine to complete in 45 degree increments ( 8 intake and 8 exhaust) PM me if you need it.
3) The push length is critical, contrary to others opinions, it is the most important part to lifter and cam lobe life. It was time consuming but I went though extensive research in determining ( and talked to several people on this board) about how to determine the right geometry of the push rod/ valve stem relationship, if that is not correct, it will cause problems that will vary from ecessive wear to total failure.
4) Lifter preload, and Jack referred to that in his post, is also critical. Some say 1/2 turn, some say 3/4 turn.... Call the lifter manufacturer, the cam manufacturer, the rocker manufactuer etc and ASK them.....tell them what parts you are using so they understand the combination...they will be more than happy to tell you the right way because they look bad if it doens't work the way they advertise it and they have massive amounts of experience.

In my rebuild, almost everyone I talked to had a similar but different story or approach. I bought a book, read it and spent many hours on the phone with the manufacturers to get it right....................and I'm still worried. If the lifters are collapsing, I can speculate, that they are getting too much pressure from the rods/rockers/lobe or not enough and the rods are "slapping" into the lifter........can you tell if there is any surface damage to the rod end, top/bottom of the lifter, valve stem or cam lobe........that might point in the right direction.

 

[rcvivian]

All,


Thanks for the inputs....I've decided to take it to a pro. I'm heading for Iraq in a couple weeks and can't justify the time required away from the family to fix the problem. Thanks for taking the time.

 

[JohnZ]

If I recall, 67 and up is different from 65 & 66 BBC block, cam & cam bearing. When using most available cams (for 67 up) in a early block ... you may have to machine a groove into cam's rear journal. Never been faced with this but understand there'll be lube failure & engine failure if not addressed properly. Dunno what year your 396 block is? ... but if it's a 65 or 66, its cam better have the groove in the rear journal and that cam journal's bearing better have a groove.
JACK:gap

Jack's on the money - if your cam doesn't have a groove in the rear journal (only needed on '65-'66 BB's), you'll have no oil pressure to the lifter galleries, and the lifters will collapse. If your next cam doesn't have the groove, you can have it machined in - it's centered on the journal, and is 3/16" x 3/16". Many parts houses don't know this, and think all BB cams are the same - they aren't.

 

[rcvivian]

It's a 70 block. Good info to have in the hip pocket.

 

[rponfick]

You stated that you adjusted the lifters by tightening them until "you could not turn them any more". I'm not sure what you mean by that, but you should only tighten them until you feel a slight drag on the pushrod. It's possible that I misunderstood your explaination. If you did indeed tighten them until you could not turn the pushrod, you took all the adjustment out of them. And I am sure that would adversely affect the lifters.

 

[69_coupe]

All,


Thanks for the inputs....I've decided to take it to a pro. I'm heading for Iraq in a couple weeks and can't justify the time required away from the family to fix the problem. Thanks for taking the time.

Have a safe trip to Iraq, I 'm going home from Iraq in two months and looking forward to spend som time in the garage again.

 

[RodsnRides]

Jack and goingballistic are straight up here. Use of moly lube and prelubing with a dummy distributor or oil-galley sealing oil pump primer (Milodon, etc,) is right. Lube is good-you will change oil at 100 miles on the first go, anyway.

Cold adjusting valves, I do it before I install the intake, get intake valve lifter at highest point, tighten exhaust to a slight pushrod drag (roll between fingers) + 1/2 turn, turn engine, do opposite valve-keeping in mind Jack's suggestion of oil soak 24 hours before. When priming, I also turn the key on (if a light) and/or have someone watch the gauge. I also manually turn the engine 90 degrees and spin it again-all up, 4 times-then install the distributor, plugs and fire it up. It works well...I know it's lubed-very important on fresh stuff. BTW, the early Big Block cam issue is right-but if yours is a '70-you're ok there.
You may have lifter bore issues, but my first impression here is lubrication...I'll stay tuned... Good luck.

Rick

 

[brusso]

Unless I missed it somewhere, the only other thing that I would add is after letting let lifters stay submerged in oil for 24 hours, use a pushrod and actuate the lifter plungers.