450 SE, Rod Knock or exhaust leak?

[haromaster87]

 Hey guys,

I'm kinda scared right now and hopin someone can give me some assistance here. The other evening I started my '74 450 SE and heard a noticeable ticking noise with the windows down, with the windows up, it's not as noticeable, but still there. I didn't think too much of it, sounded like a manifold exhaust leak.

Drove the car around, drove fine, no worries. So today I put it up on some ramps to investigate and I couldn't find any obvious cracks or anything in the manifold. The only place I think it could be leaking is either where it bolts onto the head, or where the manifold joins the mid pipe.

When I run the car and listen above the engine, the noise is obviously coming from the lower part of the engine bay on the passenger side. When I get under the car, it sounds like it's kinda coming from the manifold/midpipe joint. But as the mind will do tricks, it kinda sounds like its coming from the block.

I didn't have a stethoscope on hand, but I had some in ear headphones, and when the wire is pulled tight, these can act as a mock stethoscope. So I listened to the valve cover and didn't hear anything out of the normal. And I did the best I could to put it on the block on the bottom and I didn't hear an apparent amplification of the sound.

The sound is a very uniform tick tick tick tick, type nosie. It increases with engine speed, and after a certain engine speed, it's hard to notice anymore. I suppose I don't know what info I'm looking for here, but can someone give me some idea of what I might be looking at here? I searched and didn't even see anything about anyone ever having a rod knock, but that doesn't mean anything. lol Thanks for any help.

-Tony

[WGB]

?Exhaust manifold leak,
?Leak in the manifold to pipe joint.
?Exhaust leak.
?Noisy valve lifter

If the oil pressure is OK (particularly hot on the idle)  it is unlikely to be anything serious in the mechanicals.

It might pay to remove the LH cam cover and check the plastic connectors to the oil feeder lines are not damaged  if you want to be sure.

If you have a d-jet you also have manually adjustable cam followers instead of hydraulic ones. It was always said avout those that you worried more about those when you couldn't hear them in case the gaps were too tight.

Bill