Lee, one "trick" I've used on manifolds, to provide a somewhat more durable coating than paint, is to spray graphite lube on a rag, then wipe to an even dark-gray/black color. The solvent dries, leaving the graphite in a thin coat on the manifold. The manifold should be given a wire brush cleanup to remove loose rust, before applying, of course. The graphite will last pretty well, and is easy to reapply when it wears thin.
The graphite spray works very much like the "stove polish" my Dad got at the local hardware store when I was a kid, which was a liquid mix of carbon black, wax and solvent. My job was to wipe it on our woodstoves to bring back a dull-black shine to the cast iron. As it dried, it left a waxy black finish on the stove, and I had black finger nails for a few days. Stove polish is still available, and although I've never tried it on manifolds, it might work pretty well, too. [Edit: LugNutz beat me to this one, while I was typing...].
Lee & Swami, As for the heat-riser spring pre-tension, yes, the spring gets 1/2 turn from unhooked position to set it correctly (ref, bottom right column p. 6-19 of the '54 Chevy Shop Manual [chevy.oldcarmanualproject.com]), set cold as Dad said. The Shop Manual also recommends a mix of "kerosene and a small mount of baking soda" to loosen stuck shafts. I had forgotten that one. Might be worth a try.
If it isn't clear by now, you really need to free the heat riser valve as a priority. If stuck in the heat-on position you will burn valves pretty soon. IF stuck in the heat off position it will take forever to warm up and run well.
Heat the exhaust manifold with a torch being careful not to overheat it, then tap the shaft of the riser valve left and right rather than trying to twist it. Once overheated by a stuck closed heat riser, the exhaust manifolds tent to warp and cause exhaust leaks. Sometimes they crack. You're on the right track to have it refaced but do the exhaust manifold separately from the intake. Be very careful removing the bolts that connect the two manifolds together. They tend to crystalize and weaken to the point where they will snap off and then an easy-out will become your best friend or worst enemy depending on how it goes.
On old trick for stopping exhaust leaks on warped manifolds was to retard the timing and get it good and hot then snug down the retaining bolts for all you're worth. Doesn't always work though but usually worth a try.
When reassembling, leave the bolts that hold the manifolds together loose till last. Tighten the manifold-to-head bolts first then the manifold-halves bolts at the end.
I had my Exhaust manifold Powder coated. They (my shop) only does this "Silver" on Exhaust.(High Heat) Its two years old and still looks good. The intake was powder coated gloss black. Both still look great two years later, over 1,000 miles on engine. Todd
I just installed my manifolds and had a similar experience to Schaffer’s1950. When I bolted the intake/exhaust manifolds together I noticed the the intake and exhaust ports were not on the same plane, so I loosened them and checked with a straightedge to see It there was enough slack to get them aligned and there was. When I installed them, I tightened both the manifold port bolts and bolts that attach the two manifolds together at the same time so they would basically self align. Seemed to do the trick but I won’t really know until I start the engine.
PS: Lugnuts, I love the Stove Polish idea and I’m running out to the local Ace to pick some up! [LINK] [acehardware.com]
Last edited by Phak1; Sat Nov 14 2020 02:51 PM.
1952 Chevrolet 3100 Project Journals ‘59 235 & hydraulic lifters “Three on the Tree” & 4:11 torque tube 12v w/ Alternator
One other thought. Evan (Coilover) posted this some months ago. The discussion was about Remflex gaskets (which I will not endorse for a couple of reasons). Evan mentioned he used high temp rtv sealer...you can read/see here: https://tinyurl.com/yxnsycdb
I've been meaning to try Evan's method, but I don't think either of my manifolds is leaking.
I got the manifold off with no problems; it even separated easily. Still working on freeing up the heat valve, but I did find that my thermo spring is broken. I also see that the valve has a bend on one side (see attached photo); is this normal?