Summershandy

Exhaust manifold gasket bubbling oil?

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A new find just came up. I was letting my '54 - 8 cylinder warm up and smoke started coming from the front at the manifold. I could see something bubbling from the gasket and I guess it was burning off on the manifold. The gasket is new with very little hours on it. There are no air leaks and the bolts are as tight as I can get them. I've ran the engine before and haven't had this issue. Don't remember spilling anything there. Should I keep running it in hopes of a burn off? The old gasket was blown apart in a few places and I think I remember this was one of them. I have an arrow where the leak is and the gaskets.

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I have the same issue with a recent rebuild on my 53 l8. I am thinking that a rich running carb and a non working heat riser may be my problem. Raw gasoline saturating a new gasket and eventually has to boil off. My intake runners were wet when I removed the manifolds. I have recently repaired the heat riser and have not started it yet. Waiting for new gaskets.   I will post results as soon as possible.     John

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Mine has no exhaust leak and starts when the engine is at operating temp. The straightness of my manifold has been questioned. The heat riser came up late last night so I'm double checking today. I had checked it way back and it moved freely but never bothered to spray it. Something else came to mind overnight. I had been troubleshooting a no start and did a dry/wet compression test. Also probably got unburnt fuel in the system when I didn't know better trying to start it. I was advised to change the oil. That stupid oil can of mine likes to drip a lot. I wonder when I was squirting the cylinders if I got a drop of heavy weight oil right on top the gasket? It would have a couple days to absorb into the gasket and maybe burn off? Reason I think is this issue wasn't there before my tests. 

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Hmm...my heat riser moves freely. Engine got to 180 degrees but it didn't move. Spring was still tight. Manifold started smoking and I held the valve in the open position and made no difference. Can anyone confirm that when the engine is cold the heat riser valve should be in the closed position by the force of the spring like in the picture? That would mean my valve would slowly turn counterclockwise until open with engine warm....which it did not. Can't tell what's open or what's closed. Maybe I should wire it in the opposite position and see if things change.

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It looks to me as if your heat riser is open by position of the weight. Look at the slot on the shaft on the spring side and compare to attached photos. These are my recent repairs. If your weight has not spun on shaft, it is open as shown. Trial with torch on my repair has confirmed open and closing properly.    I see you are missing a stud on exhaust. As for the oil bubbling, make sure the stud is not leaking from water jacket. I had that happen also.

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Thanks for the pics John! One's like those are priceless. Sorry it took a while, I was drooling over your engine. The way yours looks to me the weight rolls forward to open. Like 12 to 10 o'clock. Mine rolls backwards like 12 to 2 o'clock. Make sense? I'll play with it again and try a heat test. I was surprised when the only stud came out of the block and leaked coolant. That was new to me. I don't think it's leaking as my burn off is a good 10" away. 

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Well I put a heat gun to the heat riser and it didn't really move. It was easier to turn however. I unhooked the spring and let the riser fall. Made no difference at start up and when I moved it open and closed I could feel the exhaust against it making me think it's in the proper closed position. However, the manifold still leaked and I discovered another exhaust leak. It matches the blown out gasket on the left side of the picture. I've been told that these inline manifolds like to warp and to remove it and put a straight edge on it. If it's out to get it machined. I'm thinking this is what happened to the previous owner and he eventually blew them out. The heat riser isn't on the top of the list right now. Thanks and good luck with yours!

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I removed my manifold and you can tell by the imprints in the gasket where the seal was tight and where it was leaking. No straight edge required. Guess it's machining time.

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Did you have the intake/exhaust apart? 4 bolts . 2 reasons why I ask.    If you or PO had them apart, it is possible they get misaligned, and this can cause uneven indents on new gaskets as you are seeing. It's a balancing act kinda to get both pieces to seal. I installed new gaskets at both points. Just snug up intake/ exhaust halves(4 bolts,2 short ones ,2 long ones) then install manifold to block (10 nuts) Tighten to specs, then tighten the other 4 bolts. You may not actually need any machine work done.   Carb removed makes this easier too!!!  Also you will be able to see if your heat riser at this point to verify if it's working properly.    If you saw my pictures, I meant to tell you that the one with the weight rolled clockwise was in the 'hot' open position.   Hope this helps some.    John

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Forgot to tell you, your picture of the weight, shows your heat riser flapper in the hot, open position.   Look at my pictures again and make sure your spring is on the right direction.  They can be put on backwards !   John

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We think alike! I was looking at those 4 bolts and thinking there could be a little play there. It doesn't look like they've ever been removed. I can see that my intake manifold is uneven with the exhaust manifold making the exhaust part not quite sealing. Good guess. As for the heat riser, I too questioned if the spring was put on backwards. Don't shun me but I applied Permatex Copper sealant on the leaky joints. All I'm trying to do at the moment, before the snow starts to fly up here in Canada is to get the car to my mechanic to OK the frame/structure before I start pumping money into it, then I can get it in the garage and start at 'er.  I'm good but a self taught/back yard/youtube mechanic! If all is good it will become my new project. Thanks for the help John!

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