those are the ones that I ran across . we annealed them with a torch ( have to a oxy with a rosebud tip ) the old timers showed me how to do it . you soot them up with the carbon , then use the flame to burn the soot off and let them sit in a draft free area .
Well I have a pretty good straight edge I guess, one of those big steel carpenter L deals. I use it to make sure the relief is correct on guitars. I sort of checked the manifold the last time But I don't know what I'm doin'. I'll call around and check and see if there's anybody left. One thing. A tick under load would be the manifold itself right? The connection at the exhaust tube to manifold might be a little sketchy, I sealed that up as well as possible. I figure it would sound different. I'll see if I can't find evidence of the leak. Some suggest stuffing a rag in the exhaust and they are easier to find, that seems like that would be a two man job to work best.
not hot enough also the soot burning off tells you its temp . it takes around 650-700 degrees . a tempique marker possibly be used but to get the heat even s the trick .
I use a few feet of heater hose as a stethoscope to pinpoint sounds like that. The heat shield looks like the style they had on some of the Dodge LA engines around 1970, it's embossed sheet steel. When a bolt gets loose, it burns the gasket area. And they are not real good for multiple uses, either. But yeah, listen for the sound, you should be able to figure out right where it's coming from
Obviously (as above) sum ting wong. Manifold is not flat soo take the thing and get it surfaced. I use copper gaskets on my flathead motor projects...just sayin!
I think squirrel nailed it: Yes, Chevrolet did use locking tabs: Get REAL exhaust manifold bolts and the locking tabs shown above and be done with this issue. Of course, this is my opinion...
I just looked at the OP's original picture enlarged --> I was looking at the thumbnail size at first. --> that is a Y-block, correct? I thought we were talking about SBC ram horns. So, nevermind... I still I think you need to get better bolts and lock washers.
That heat shield has a crush rib around the ports, and that rib provided the seal and It looks new. Your used shields were probably pre crushed to fit the other engine and manifolds. It is a giant gasket that is a heat shield too. Used heat shield is a used gasket.
"Drug store bolts",,, Are they stretching? " crack the ears",,, Are the ears not setting flat? There is an air gap on some ears? You can see the ears move when tightening? That means something isn't flat.
Just means the bolts aren't anything special. All I meant by that is that I torqued them to spec hot and cold. Didn't want to gorilla torque 'em down trying to stop the leak and end up breaking something.
A little high in the center is OK the ends will pull down low in the center they won't pull down I assume no problem with the other style manifolds?
I guess that pretty much rules out the head side. I'd try the Yale muffler cement I've used it on FEs that I could no keep from leaking and it worked Just apply it to the gasket like any sealer and let it cure. If you get it at Napa don't let them give you the stuff from Walker.
Does your used heat shields have that raised crush rib around the ports and bolts? If they are used thet were crushed to fit the original engine and manifold mateing surfaces. Sorry it's not too clear I Cropped your photo
Yep, and I wondered about that. Figured maybe they would seal well enough if careful. Maybe not. I don't think anybody repops those shields either, like to use them. I'll try a few things and see what happens. Lots of good ideas to here! Much appreciated.
They're pretty proud of that stuff! My NAPA had one tube left, $19.90 + tax. Thanks for the part #, the other stuff pops up in a search. It's 1 lb tube so should be good to go for a while.
Before I had my ram horns coated, I trued the gasket surface by gluing a strip of 80 grit sandpaper (longer than the manifold ) onto a large piece of plate glass. By rubbing it back and forth you will easily see the high and low spots. Keep sanding till the surfaces are completely trued. It actually sands pretty quick.
I knew I forgot something at NAPA today. A big enough piece of sandpaper! 80 grit you say? That's pretty stout stuff.
So if gaskets are going to be used with the flatted heat shield- there ought to be a gasket on each side of heat shield. Head-gasket-heat shield-gasket-manifold.
Well since the heat shield is supposed to pull double duty and be the gasket- but it cant, won't or isn't ,,, right? Where would the use of a single gasket go??? Between the head and heat shield allowing the heat shield to manifold go without ??? Or should the single gasket go between the manifold and heat shield allowing the head to heat shield go without ??? That's my point- Which of the scenarios sounds less leak prone? Use of one gasket allowing the other surface to be without Any gasket? Or the use of a gasket sandwich utilizing 1 gasket on either side of the heat shield. Clearly using new heat shields that can still seal is the best option. If using gaskets Id guess it is much more leak prone for any one side of the shield to be with out a gasket, more than a gasket on either side which also sounds like a trip to leak city
I have used the top cast iron surface of my table saw and big sheets of sandpaper to true flat surfaces that are warped. Works great on large cast items.
Try the stuff you got from Napa use your heat shields apply it to both sides. The stuff truly sets up like cement filling up imperfections. I used it on a tractor manifold that had a place that was eroded and it stopped the leak.
That's the plan. Have some tree trimming to do this week sometime, not sure when exactly using truck to take away to the "yard waste site" with the old gal so it's gonna have to wait a bit. It needs to cure 24 hours or so right?