'55 264: Very loud SNAP.......SNAP......SNAP...when cranking after sitting long term.

[TexasJohn55]

Help me out here. My 55 sits for weeks or months at a time. It has always had random lifter noise on startup and then quiets down. I decided to look at overhead, noticed strainer bowl also empty. Removed valve covers and all spark plugs to inspect. Felt of rockers initially and there were a few that I could push down against lifter spring appx 1/8 inch from bleeding off while sitting. Cranked engine to fill and prime fuel system, slow to prime. Cooled starter awhile and hit it again, very loud snap....snap....snap....snap while cranking. Let off starter and felt of fuel pump body while cranking, could not feel knock. Watched rockers while cranking, didn't notice any valves sticking but didn't crank very long. Noise seemed to be occurring once every 2 revolutions but can't be sure, might be once every rev. My first instinct was fuel pump lever hanging up and slapping back on the cam, secondly was a valve sticking. Engine is absolutely clean inside, looks like it was overhauled but has very few miles on it. I bought it in 2004? Next time I hit the starter, no noise at all. Primed fuel bowl. Pulled dist cap and turned engine back and forth with socket on damper bolt, very little hesitation at rotor when reversed direction of crank so timing chain set looks good. Put cap on, plugs in and fired it up. The usual lifter noise, but quieted down after a couple minutes. Most pushtubes spinning, 2 or 3 very slow, 30 degrees at a time. I may have some cam wear or maybe not. All rockers look to have normal lift without actually measuring, top end is oiling good but not spurting over to tips when idling. Put valve covers on. Disconnect dist vacuum and booster vacuum lines, hooked up vacuum guage, idling on almost 17" Hg with very little quiver of less than 1/4 " Hg. RPM not checked, but seems about right, possibly a little high but does not engage transmission harshly in low and reverse. Hooked up timing light, I had forgotten where I set it. It is idling with the damper mark off-scale appx 1" advanced before the timing tab. I had advanced it initially because I could not get it to take off without stumbling and dieing. I had gone into the 2 bbl carb and misc, finally cranked up the timing and it almost drives normal, seems to pull OK but I have not been on the Interstate. Some history: once or twice after sitting awhile, it had an irregular cylinder "roll thru" while cranking, would miss on startup and clear up to non detectable when running. I don't remember if it was a "skip thru" like no compression or whether it slowed down thru one cylinder while cranking as if exhaust valve did not open. but it always straightened itself out. I did use some Marvel in the crankcase to free up lifters but I think they just have too much clearance and leak off under valve spring pressure. I know this is a long post but I wanted to get out as much info initally to eliminate too much guessing and questions about history of engine. HAS ANYONE HEARD THIS KIND OF NOISE? TexasJohn

Edited May 24, 2013 by TexasJohn55
chronology (see edit history)

[Guest NikeAjax]

John, could this be leaky valve lifters? A buddy of mine told me about this happening: they drain partially and need to refill, this happens when some cars sit for a bit... just a though?

Jaybird

[Guest NikeAjax]

Oh, gosh--silly me... yeah, I had this same problem... went away after I dropped in some new hydro-valve lifters...

Jaybird

[TexasJohn55]

Guys, I'm talking loud SNAP! I know what lifter noise is and this ain't it. John

[Guest 54fins]

sounds like lifters, given they clear up after running. Pretty common, generally goes away after running. I would replace the cam and lifters together if you go that way. Why? metallurgy- new stuff and NOS stuff doesn't always play together. I got a cam and lifters for $260, I would only do them as a matched set. New lifters will flatten an old cam. I have seen them click but snaps sound scary. Another idea that might not set well. Use the 20 wt oil that your shop manual recommends. It moves quicker into the lifters and into the valve train. The common idea is thicker is better- not true, oil has to move around to do it's job. But 60 year old lifters may very well be tired. I get real nervous if there are any metallic sounds, nailheads are not real forgiving with valve issues. Metalic sounds always seem to end badly....

did have a broken starter once, check that out too.

[JohnD1956]

Could be spark leakage at the coil. Had the same thing in my GS till I saw it happen one day. But if I read your initial post correctly, you did not have this till you pulled all the plugs and cranked the engine. Of course, this is not the issue if you disconnected the positive side of the coil before cranking the engine.

[NTX5467]

Respectfully, I've not heard of a lifter "snapping" noise. Clicking and such, but not "snap". The first thing which came to mind was the possibility of a plug wire or two "snapping" as the particular cylinder fired. On a cold engine, the loss of fire-power to the plug might not be noticeable, with the suspected lower actual cylinder pressure at peak compression, but when the engine warms up and the plug "cleans up" more, it's firing resistance can go down and everything smoooths out nicely.

A while back, I was at a friend's warehouse/shop as they were setting the valves on his '67 Chevelle SS396. The car already had an MSD ignition box, which needed the adapter posts for the point-ignition's ignition coil. With the coil lead removed, they bumper the starter to get the valves on the appropriate part of the cam lobe to adjust the valve clearance. As this was progressing, as the engine was turned by the starter, a bump at a time, we heard a lous "snap", but didn't know where it was coming from. With more attention to the repeating noise, but only ONCE every so often, I finally discovered the source . . . as the starter was being turned, a spark was jumping from the inner terminal of the ignition coil's tower to each of the posts on the adapter posts for the MSD ignition. There were four posts and it would spark to EACH of them, in sequence. That meant, basically, it was shooting a spark about 4", at the most! Not randomly, but to each one of the four posts. Such a deal! We would have never suspect THAT would happen, until we saw it with our own eyes, as the engine was cranked by the starter (this time, as if the engine was being started).

My suggestion would be, before cranking the engine after it has been inactive, carefully remove each of the spark plugs and check their condition. Clean them of any residual "stuff" (possibly with brake clean spray?), dress the center and ground electrode (for good measure), set the plug gap to specs, then carefully re-attach the wire to the plugs after their re-installation. If the "snap" is diminished in magnitude, then a check of the plug wires and boots, plus the leads going to and from the ignition coil might be in order.

Regarding the lifter noise upon start-up, what type/viscosity of motor oil is being used? Please advise. Just curious . . .

Just some thoughts,

NTX5467

[NTX5467]

What about a flex plate issue? Broken, but not broken in-two?

More thoughts,

NTX5467

[Guest NikeAjax]

Gosh, how loud: hand-clap, heavy-duty-staple gun, cap-gun, .22-CB, .45/70 (sorry I just couldn't resist that last one!)

[TexasJohn55]

54Fins: Not replacing cam or lifters, runs too well, I will put up with a little ticky ticky on cold startup. I think 10w30 works equally well. JohnD: Definitely had spark jumping like mad, like a soda straw in bicycle spokes. NTX5467: I pulled plugs first and all were normal color, light tan. I pulled them primarily to unload starter and prime fuel system faster as well as build oil pressure and watch rockers. Cheap version of prelubing or priming. Secondarily to inspect plugs. Flexplate and starter are non issues. The odd thing is that it didn't SNAP everytime I cranked it while priming up. It had stopped doing it at all by the time I got fuel in the glass bowl. I don't recall if it ever did it before on normal startup. Could be that the higher cranking speed without plugs contributed to it showing up. Thing is, it either snapped or it didn't. Volume? maybe loud hand clap with cast iron in both hands, hard to describe. No, I can't record and post the noise. Not like a 45-70 but my neighbors could have heard it if they were outside.Imagine for a moment you could reach inside your engine, get your hand on the fuel pump lever, pulll it back all the way on the return spring then let it go and snap against the cam. That was my first impression and I know that the pump was dry but I can't imagine what that has to do with it. I would expect a broken pump return spring to make a different noise and certainly not that loud. TexasJohn

Edited May 24, 2013 by TexasJohn55 (see edit history)

[MrEarl]

Sounds like valves sticking and push rods bending from where I'm sitting................ very scary.

[TexasJohn55]

MrEarl, maybe, I kinda looked for that after she started up, didn't see any wobbling too bad, and she runs good with no loud lifter noise even with covers off. From where you are sitting, nah it's not THAT loud. John

[TexasJohn55]

I'm thinking that if one did stick, completely unloaded the pushtube and piston kissed it, it would make a loud snap when it slammed back on seat. You know, it may not even bend the pushtube, or is it pushrod? John

[55 SURVIVOR]

John;after it sits,pull the valve covers,wiggle the rockers for play,maybe lifter collapsing.when cranking the piston may be just kissing A valve(not closing all the way,or hanging up) Is the noise on A side or center internal Mark

[buick5563]

Also, if the valve covers are still off, check to see if the rocker assemblies are fully bolted down. I know that is an unlikely scenario as they wouldn't normally loosen, but if they weren't fully seated when assembled, it is conceivable that whenever the pushrods nearest the end of the assembly comes up, it could physically push up the rockers enough to make it snap back on the downstroke. Yeah. I'm reaching.

John, you seem to "feel" that it is the fuel pump. I put a lot of weight on gut feelings. Pull the pump and check it. At least make sure those attaching bolts are tight.

[bhambulldog]

What about a flex plate issue? Broken, but not broken in-two?

More thoughts,

NTX5467

I'm thinking something on that end of the engine...

Sent from my BlackBerry 9370 using Tapatalk

[TexasJohn55]

Mark, I did precisely that but it is not clear in my first post. I need to rearrange chronology of statement " I felt of rockers initially". Mike, I did check holdown bolts, all tight. The noise seemed deep but I only have good hearing in one ear. After more thought, it may have been valve sticking at full stroke, pushrod left loose, cam lobe retracted, piston came up and kissed valve causing it to snap back on seat and at the same time slamming the lifter back down on cam lobe. That could create the kind of noise I heard. Keep them ideas coming. John

[TexasJohn55]

James, engine was spinning free with plugs out, no load or bounce. It didn't seem to be a "tinny" noise, sounded solid. When it stopped, it did not do it on startup. John

[old-tank]

John, if it does it again, start removing things like the fan belt, fuel pump. In the meantime, in case it is sticky valves squirt some Risolone around the valve stems, let it sit overnight, start it and pour some MMO into carb and add some to gas. After that a 200 mile trip with fresh oil and gas is recommended. Sounds like it runs too good to be serious and it is my understanding that nailheads are not interference engines...no damage from a rebuild where the timing chain was installed like a chebby.

Willie

[TexasJohn55]

Willie, 10-4 thanks, John

[Guest 54fins]

I'm inclined to think sticky valves. The piston will slap the valve and it does make nice noise. But it won't do it for long! it hits at an angle, bending the shaft and making the valve stick even more. Once it slaps on a nailhead you are living on borrowed time. I would pull the heads and I suspect you will see some valve marks on the piston. If that is the case, you are lucky as a valve job is relatively cheap. When the valve goes through the piston, you have a boat anchor or a 3K overhaul. Last, I assume you changed the oil. My boat anchor ran like a top, so well that I put off changing the oil. I think scap iron is $200 a ton now, so I probably got $50 for it

[buick man]

Here is a link to a primer on the care and feeding of your hydraulic lifters. Grab a cold one first then kick back and read. Good luck on the outcome !

http://forums.aaca.org/f162/how-do-series-learn-how-we-322149.html

... oh I would also after you have removed the carb/intake, valley cover, valve covers and sparky plugs turn the motor by hand and watch the valley area and distributor area that runs off the rear of the cam. Also never add oil to a dry lifter as they will fluid lock and then breakage of parts occur. They must be able to pump themselves up. If they drain after sitting and are dry that is because crap is set into the inside of the lifter bore and the spring is no longer effective and they leak down to nothing or if plugged up they will not travel and force the pushrod and bend it and/or snap off at the rocker arm. That would positively make a snap crackle n pop sound for sure. Just some thoughts.

Edited May 26, 2013 by buick man (see edit history)

[TexasJohn55]

Thank you buick man, that is a VERY GOOD article! I once went thru 2 sets of used lifters building a 283 for my father in law in the 70's. Started first by culling those that showed wear or flatness on the scrubbing end, tore them down and cleaned them up. The main criteria I used to identify usable ones was to set them upright submerged in a can of diesel fuel, set it in a drill press, used a suitable plunger chucked up, with drill not running, used press to pump the lifter thereby filling it with diesel fuel. After it pumped up, I would put moderate pressure on the lifter and see if it wanted to bleed off. After doing several I determined a standard to judge by. A good one bleeds very slow if any. Yes you do need to "deflate" them before installing. I overhauled that engine and the lifters worked great and quiet.............Now if you find that strange, GM, in their instructions for cam and lifter replacement on the 379ci / 6.2L diesel directs you to fill the lifters in precisely that manner and install them, with specific instructions to bleed them down a little at a time with the rockers during assembly. I put a cam and lifters in mine in '86 so I don't remember all the details but I had no problems following the book method. BTW, they are roller/hydraulic. Thanks again. TexasJohn

Edited May 26, 2013 by TexasJohn55 (see edit history)

[Aaron65]

Maybe you should try running a bottle of Rislone through it...

[60FlatTop]

A snap in the rear of the engine, huh. Since it is a holiday weekend and there is time to do little extra "dumb" things, I would take just a little dab of lube; light grease, cam lube, something like that and put it on the distributor cam. Those points could be banging closed and making a hell of a racket. Only happened to me once, but you never know.

Bernie

[TexasJohn55]

Bernie, I could have used that advice 30 years ago when I twisted my Pontiac 350 to about 4500 showing off. Just as it peaked rpm it shut down like I turned the key off. I found the rubbing block knocked plumb off the points from banging the lobes. Oh yeah, the noise ain't in the rear. TJ55

[TexasJohn55]

UPDATE: The '55 has been running nicely and quiet since running around town a little and cranking once in awhile. I'm not going to chase problems that go away when driven on a regular basis. It appears that no damage was done from the horrid snapping noise after sitting 6 months. New inspection sticker this week, first time since '03. Sure felt good to drive it around. Next project, shocks, feels like the rear need some fluid and front need replacing, and on and on..........

[NTX5467]

THANKS for that update!

NTX5467