Ok so I have a 64 impala ss with a rebuilt (long ago) 250HP 327. It has a 300HP cam in it and has ran great for years. I figure it may have 10,000 miles on it tops. Stock rebuild with exception of the cam. As many classic cars, they sit for weeks or months at a time, and before you know it, its been a few years since the last oil change. I had a lifter on #3 start rattling on me about a year ago. I put some mystery oil in the pushrod hole, and in the crackase oil, fired it up and let run till warm and shut off for a few nights in a row, and it cured itself. So I changed the oil and went on my merry way. Last month, starts rattling again (after sitting a few months while I work on another vehicle in driveway that wont move). Ok so lets do the same thing, mystery oil down the pushrod holes and in the oil and run till hot a few nights. After getting warm, loosen the rockers so the lifters can expand if that even happens. Well, no change. Both #1 lifters this time. I was thinking maybe flat cam, so I adjusted to 0 lash (between loose, and cant spin the pushrod) and it runs great, idles smooth, no noise (so I'm thinking cam is OK). So both? I'm thinking I may need to need to put a new cam and lifters in it, however I have read that you can replace lifters only if you break them in like a new cam and lifters. Any insight?
I have put a new lifter on a old cam due to having the guts in one collapse on a engine I tore down to just rebuild so i could check the cam at the same time. I would pull the cam and inspect it because new lifters could just accelerate the lobe going flat.
I know it is more work , but if you want to eliminate any future problems (hopefully) put a new cam , cam bearings, lifters and timing chain in . Check your rocker arms at pushrod contact as well as pushrods for wear, galling etc. Peace of mind is well worth it.
it ran fine, the motor was just a simple rebuild and sell. Last time i talked to the guy with the motor it was still running strong a couple of years later in a old work truck
If the cam is ok, you can run new lifters on it. The cam lobe is harder than the lifter, so “break in” is really wearing the lifter in to match the cam. Sent from my iPad using The H.A.M.B. mobile app
Well when I adjust all of the slack out of the lifters the motor runs great and smooth so the cam I beleive is still ok.
When the lifter is removed, the cam lobe wear can be seen. You'll know a toasted lobe when you see it ...
When you pull the lifters look at the bottoms. If its real noticeable concave the cam is shot. If not install new lifters it will be fine.
Pull the old lifters disassemble and clean before putting back in put the lifter in a can with enough oil to cover the lifter take a push rod and work the plunger in the lifter up and down until it pumps up. If it does you are ok to go.no break in because its back in the same location.
If you can get it out the top. I have seen them wear a little wire edge around the bottom, mushrooming it out enough it wont come out of the hole. Good Luck
That's only if the cam has a flat lobe to wear the lifter like that! Not likely that that will be a problem here as he states that it runs great with it adjusted to zero lash.
When I take the push rod out, theoretically it should pop back up right? I wonder if i could stick an air nozzle down the push rod hole and blow a little air into the lifter to pop it back up, change the oil, run some zinc additive and see if it stays up this time. it actually happened before on another cylinder but I was able to pour some marvel mystery oil down into the lifter and into the oil, fire it up and run to operating temp in the garage and shut it off. After about 3 nights of this it freed itself.
I replaced the lifters in my sbc without replacing the cam and within 15 minutes it wiped my cam. I won't do that again.
I agree with ''Sunbeam''. If the lifter looks good /no wear, pull out the retainer clip, dismantle and clean the internal piston and bore, with fine wet and dry.. , lightly lube and reassemble (don't fill it up, it will pump up as soon as oil pressure comes up).. Oil puts a coating/varnish on the inside, and with the car sitting a while, causes the inner piston to stick down.. You will probably have to tap the lifter on a block of wood to shock out the inner piston..
have you actually adjusted the rockers for the hydraulic cam. you can do it cold or hot. I do it with the engine running, backing off till the tappet rattles, then tighten till the rattle stops, then a 1/2 turn tighter in 2 of 1/4 turn motions, do this to all 16, can be messy without a cut up rocker cover.
Yes I have adjusted the rockers, the motor has been running great since rebuild in 2004. As all classics, when you have more than one to choose from, sometimes they sit in the garage, especially when another project is disabled in the driveway. I don't have a mechanical oil pressure gauge, but I have an oil pressure light that works, so Im getting something. Guess I could hook up a gauge and see where I'm at before I go through all the hassle of replacing individual parts when I need something bigger.
Well, you seem to know the root cause. So after getting it fixed, perhaps regardless of miles driven, just change the oil and filter once a year. If it has been sitting a lot during that year, just before the oil change add some Marvel Mystery and run it around some. You didn't mention the oil you use, but I assume it has the right additives for older flat taper cams. Or you use an additive.
^^^This.^^^ If the lobes and lifter bottoms look good, why spend money replacing things and go through a cam break-in procedure? The cam and lifters that were put into the engine in 2004 are likely better material than what is available today. Pull 'em out, pop 'em apart and clean them. Keep the plungers and lifter bodies matched, and also place the lifters back into the bore from which they were removed.
Thought I would report back. After the car sitting for about a month with both lifters cranked down to zero lash, I decided to loosen them up and start the car. Well as i loosened them, the lifter expanded and they both freed up. However when I started it up after that, a different one was collapsed! So I ran till hot then shut off and let sit. thought Id try again and it pumped up. So I got it nice and hot with the marvel in it, then changed the oil and filter. I used 10w40 Valvoline synthetic blend with some zinc additive and a bottle of Lucas oil stabilizer. The thing now will be to drive it more and change the oil at least once a year.
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