What is this engine noise?

[Timothy B.]

Re: What is this engine noise?

Dick,

Is the silicone called ultra copper or something else? The stuff I have is ultra copper and the package say's 700* temp.

[Dick W.]

Re: What is this engine noise?

Dick,

Is the silicone called ultra copper or something else? The stuff I have is ultra copper and the package say's 700* temp.

Ultra Copper. I used it on my dually exhaust headers and had no problems. I am sure the exhaust temp greatly exceeded what Patrick would ever see. Most of the time truck and trailer weighted about 24,000+. A lot of hills to climb around here.

[Patrick H.]

Re: What is this engine noise?

Something with the heat riser?

Actually, I think that the heat riser may be part of the cause.
It appears that the new imported heat riser doesn't open when it's supposed to. As a result I suspect that there has been excessive heat at the right side manifold - likely causing the previous crack as well as the new leak.
Now I'll be on the search for a good heat riser.

Patrick

[Terry M.]

Re: What is this engine noise?

I am just sort of thinking out loud here. Do you know if the intake manifold heat cross-over passages are restricted or blocked? That could exacerbate a malfunctioning or marginally functioning heat riser valve.

[Bill C.]

Re: What is this engine noise?

patrick,


look for a old box GM NOS - only way to go.

Trust me -- been there once with my 72' ....

Bill

[Joe L.]

Re: What is this engine noise?

I am just sort of thinking out loud here. Do you know if the intake manifold heat cross-over passages are restricted or blocked? That could exacerbate a malfunctioning or marginally functioning heat riser valve.

Terry and Patrick------



Yes, if there is a blocked crossover passage and a stuck closed heat riser valve, that will cause big problems.

[Patrick H.]

Re: What is this engine noise?

They were fine a couple hundred miles ago when I had the intake off the car.

Tonight I wired the heat riser open as a test. We will see what happens.
However, a heat riser that doesn't open (and it hasn't in the past few weeks of testing) would probably cause 40 year old manifolds to crack or warp.
This is especially true when you think of the 3+ hours each way he drives from here to his home north of Chicago.

Patrick

[Terry M.]

Re: What is this engine noise?

Patrick,
I was not just thinking of carboned passages, but the little stainless steel plates used int he intake manifold gaskets to block, or partially block (some have a hole int he plate) the passage.

[Patrick H.]

Re: What is this engine noise?

Patrick,
I was not just thinking of carboned passages, but the little stainless steel plates used int he intake manifold gaskets to block, or partially block (some have a hole int he plate) the passage.

No crossover blockoff plates installed on this engine.

[Jack P.]

Re: What is this engine noise?

Hi Pat,

It might be the valve cover being hit by the nut on the rocker arms. After my rebuild, I could hear a ticking noise... turned out the thin gasket on the valve covers allowed the new nuts to touch the cover. I put on the thicker gasket and ticking went away.

Check the inside of valve cover to see if there is a mark from the nut......the old nuts were more rounded then the new ones...

jack

[Monte M.]

Re: What is this engine noise?

I know you have had a ton of advice and are leaning tward the exhaust being un-true. The length of hose usually works great, that one of the first posters suggested. You put one end to your ear and the other near the noise. It will get louder as it gets closer to the problem. Try it.
Years ago I had a 69 with the same problem. I ended up going as far as taking of the fan off the engine to keep the noise and commotion down while I was working trying to figure out what was wrong. It makes a huge difference.
If you are going to true the exhaust manifold again, it is best to have it as warm as you can while you are doing it. Metal has a memory and wants to return to its original working condition / shape.
If this does not work, Dick had a great idea with using the Ultra Copper. I tried everything on an old boat I used to own with an Olds in it. The constant changes in Lakes and water temps made it impossible to keep thing from exhaust leaks. I finally broke down and used two thin gaskets on one end and a single thick gasket on the other two ports with a little Ultra Copper in the middle one. It lasted years and years until I overheated the engine due to the oil cooler failing.
Best of luck.

[Patrick H.]

Re: What is this engine noise?

Thanks guys.

It was the manifold-to-head junction:

https://www.forums.ncrs.org/showthread.php?93240-What-is-this-engine-noise&p=607382#post607382

And, I think I might know why:

https://www.forums.ncrs.org/showthread.php?93240-What-is-this-engine-noise&p=607492#post607492

Now I'm looking for a high quality heat riser for the car.

Patrick