1960s 1969 472 Reinstallation Questions

[R Simone]

It's time for engine reinstallation after several months at the rebuilder, and while I took LOTS of pics there's of course a few things I just didn't consider or missed and am not seeing in the manual after digging a bit and I have a few questions:

1. Heat Riser - Although the engine ran great before it was torn apart the Heat riser was stuck closed. Seems unlikely that it would run so good but..? There's no way it's operating correctly and looks like someone literally put a nail in it. There are new ones online for ~$150, but this car will likely never see the cold much or at all. Sounds like a lot of people eliminate the valve, but I'm not seeing any pics - should I open it and then spot weld, cut the butterfly out, or?

2. Emissions Crossover Tube was pulled out by the rebuilder and not re-installed.  It doesn't look like it, but do they have any O-ring or gasket on each side where it enters the head?

3. Vacuum Switch - unfortunately I don't have a pic of how it was plumbed when we tore it apart so they may have had stuff bypassed anyway, but I can tell at least one port was broken during the rebuild. I'd rather have a good one and be prepared if I'm able/plug lines off if needed.  The only thing I'm seeing is used on Ebay - anyone know a part number or source for a new one?

["Cadillac Kid" Greg Surfas 15364]

1. Open and either tye it or as you suggested spot weld the valve open.
2.There are a couple of (I think they are asbestos) gaskets in the overhaul gasket set.
3.Unless you are going to go back stone stock you can eliminate the thermal vacuum valve by hooking the distributor vacuum advance directly to the manifold vacuum port on the carb. NOS might be unavailable but a good used valve should work if you are going to go back stock
Greg Surfas

[TJ Hopland]

On that crossover pipe the adapter bit where the hose connects is a check valve.  Flow is from the hose side but should block any flow from the head.  This valve failing is what makes a mess of the system not only keeping it from functioning properly but eventually the exhaust backflow kills the bearings in the pump which breaks the belt so you are left with no water pump or alternator.  Those valves should still be available they were somewhat universal and used through the 90's by most makes.

The first bit to fail after a failed check valve is the dirverter valve.  Those I don't think were ever made by aftermarket and GM hasn't made them for 30+ years now so they can be really hard to find.  When those fail at a minimum you get little backfires in the exhaust.  If you are really unlucky you can get a major backfire and blow your muffler apart.

The dirverter valves job is to either send the air to the heads which is the usual state. Under certain circumstances like when you lift off the throttle a vacuum signal diverts the air from the heads to out that little muffler dodad that is part of the valve assembly.  It has to do this because when you lift off the throttle the mixture momentary goes really rich which makes the exhaust really rich so if there is extra air being injected there it will basically explode. When the mixture is correct that extra air just lets the mostly burnt mixture finish burning as its leaving the heads. 

And not related to any of this in any way it seems I heard that there is an American coin that fits perfectly in those holes in the head.  While its apart you could see which size that is just in case you ever need a place on the car to store a couple coins.  If the dirveter valve was set to divert to its exhaust port everything would look stock and no one would know where those coins were.        

[R Simone]

1. Heat Riser: I ended up ordering a re-production. It wasn't cheap, but I got looking closer at the end of mine and it had a teensy crack that made me nervous. I'd rather pay a little extra and never had to take that part off again.

2. Emissions Crossover Tube - No gaskets leftover in the rebuild kit and I'm not seeing info on these anywhere other than people plugging them. I'll have to keep digging, but any guidance appreciated

3. Vacuum Switch - Found a nice one on eBay very reasonable that's headed my way.

[Chopper1942]

The car will run much better during warm up with a working heat riser. Go to a GM  dealer, ebay, or Amazon and get a can of GM Rust Penetrant and Inhibitor part #88862628. This used to be called Heat Trap Lube. Perodically you want to spray it on each end of the heat valve shaft and move it up and down. It has graphite in it to lube the shaft and not burn off like an oil.

["Cadillac Kid" Greg Surfas 15364]

Richard. PM me your address and I'm sure I can find a couple of cross over o rings to send you.
Greg Surfas

[R Simone]

The car will run much better during warm up with a working heat riser. Go to a GM  dealer, ebay, or Amazon and get a can of GM Rust Penetrant and Inhibitor part #88862628. This used to be called Heat Trap Lube. Perodically you want to spray it on each end of the heat valve shaft and move it up and down. It has graphite in it to lube the shaft and not burn off like an oil.

Ordered - I'll be sure to keep the new one lubed up, Thanks!

[R Simone]

Richard. PM me your address and I'm sure I can find a couple of cross over o rings to send you.
Greg Surfas

Much appreciated Greg I PM'd you - Are these gaskets, or High Temp O-rings I could just source locally?

Thanks,

["Cadillac Kid" Greg Surfas 15364]

They are actually a sort of sleeve that fits around the ends of the tube. I found a couple and will send them to yo
Greg Surfas

[TJ Hopland]

Its pretty sad that the gasket companies just start leaving stuff out of the sets when they quit making them.  I guess thats slightly better than them just quitting making the whole set but its still frustrating. 

["Cadillac Kid" Greg Surfas 15364]

FWIW I have NEVER found a complete gasket set without both the two sized o rings for the oil pick-uptube nor the AIR/cylinder head sleeves (packed in a separate bag in the set). Typically they just get thrown away along with the stock umbrella valve seals . I of course don't throw away anything, so I have about a dozed sets of valve seals and small oil pick up tube o rings. LOL
Greg Surfas