To begin with, I've done a search and found lots of stuff that kind of skirts around this issue, but nothing that specifically helps. Here's the deal; I've got this '47 Mercury with a 59AB flathead. (At least that's what it says on the heads.) It has very noisy lifters or valves. I'm pretty sure it's making oil pressure. The gauge doesn't work but the filter canister is full and when I loosened the inlet line with the engine running, we got oil! I haven't pulled the intake off yet so I don't know if there are adjustable lifters in there or not. I've also had people tell me, "It's a flathead, they're supposed to make noise. Just drive it and forget it." But that just doesn't seem right to me. I made a short 18 second video so you can hear it for yourselves. The picture is dark but since the audio is what I want you to hear, I wasn't worried about video quality. Just take a listen: http://www.youtube.com/watch?v=za3xRAjT8wU So, what have I got here? What's the best course of action? If I don't have adjustable lifters, how do I quiet this thing down? How much damage is being done if it runs like this? Should I just dump in twelve cans of STP and forget about it? Thanks in advance for any advice.
It's definitely clanking. Do you know if it has an aftermarket cam or if someone ground the heal of the stock version? You may need adjustable lifters -Lee Atomic Radio www.atomicpinup.com
Holy crap dude - that's a ton of racket. I would get that manifold off pronto and see what going on. Either a cam gone bad or a screwed up set of Johnson's would be my guess. Never heard one with that much noise.
Its not right! Put an oil pressure guage on it, as long as it has some pressure when hot. If it doesn't have adjustable lifters, only adjustment is to grind valve stems.
Most likely adjustables whose screws have loosened, or prhaps cheap import adjustables of the sort that wear catastrophically immediately. Stock mushroom valves rarely wear much over life of engine.
Flatheads are NOT supposed to make mechanical noise. Its one of the most quite engines you can have. Anyway remove the manifold and take a peak, for stuck valve/vales or other valve related problem. Dont worry about the oil gauage, they did not get standard until 1935 if i remember right .
You might be looking at worn camshaft, or no-one has done a valve job on it for a long time. Best to figure on a bad cam, and going to adjustables. As long as you are going to have to open it up, take a look at the cam anyway, you might as well figure on upgrading the valve gear. traderjack
Oh you're just full of good news, aren't you? Actually I appreciate the answers from everybody. That's about what I thought you guys would say. It will probably be a week or two before I'll have a chance to pull the manifold and look in there and see what's going on. Thanks.
One more thing; Believe it or not, in spite of the noise, the thing runs real well. It has enough power to get around nicely and pulls up the hill we live on just fine. It's just real noisy. Oh well.
It sounds too even and consistent to be a rod or piston - like every cylinder is doing it. Better look inside
Maybe you mentioned it and I didn't see it, but.... Have you had it long? Just buy it? Did it always sound like this? Just get worse? Slowly get worse? How long have you driven it this way? ? Pete
Does it get quieter as it heats up or stay the same? If it was too much valve lash, it should still get quieter as things warm up and expand. Best bet has already been put forward, pull the intake. Flatman
Just bought it three weeks ago. It has sounded like this since we bought it, no worse, no better. Have only driven it locally, and never over about 40 mph.
It could be related to the fuel pump push rod that rides on the rear of the cam. It slides up and down inside if the housing of the oil filler tube at the rear of the intake. If it’s badly worn it can slap around and make quite a racket.
The only real way to find out whats going on is to pull the manifold. Once in there, you can measure valve clearances and determine the problem. A word of caution. Once you pull that manifold off you will likely look in there and say "holy shit". Those valleys in the flatheads can really get nasty with years of gunk and crud. If it is excesive valve clearance and it does NOT have adjustables from a previous rebuild you may have a cam problem as those valve mushrooms rarely wear enough to clatter badly. Either way, you may be only looking at a valve job. Like has been said. You've got to look in there and see whats going on.
I agree with Flat Ernie, get someone to hold the tail pipe shut, while you search for a leak. A leak in the manifolds often sound like a mechanical problem. Try this first, and hopefully your problem is solved.
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