Eric's.64.Superwildcat Posted February 10 Share Posted February 10 I completed my winter project of removing, cleaning and painting my '64 intake manifold. I'm now ready to reinstall. I have cleaned the original metal gaskets and I'll be reusing them as they are in good shape. Should I apply silicone gasket sealer as part of the process? I reviewed the chassis manual but it makes no mention of intake manifold removal and replacement procedures. Thanks in advance. Link to comment Share on other sites More sharing options...
BulldogDriver Posted February 10 Share Posted February 10 You might want to rethink the use of those intake gaskets. Look at Matt’s Tech articles as to why using block offs for the carb heat ports is a good thing. http://centervilleautorepair.com/ Ray Link to comment Share on other sites More sharing options...
1965rivgs Posted February 10 Share Posted February 10 Get new gaskets, don't reuse the old. No need for a sealer, they install dry Be sure to install them correctly, it's easy to install them backward. When installed properly the gasket openings will appear correctly centered relative to the ports. Don't install block off gaskets on a dual quad manifold. The heat passage in a dual quad manifold is not drilled through to the exhaust crossover passage so there is no direct contact of exhaust gas with the base of the carb or heat shield. Your dual quad car will be a real cold blooded pooch if the manifold doesn't warm up quickly. Tom Mooney 1 Link to comment Share on other sites More sharing options...
60FlatTop Posted February 10 Share Posted February 10 14 minutes ago, 1965rivgs said: et new gaskets, don't reuse the old. I will never try to reuse Nailhead intake manifold gaskets again, no matter how good they look. Rock Auto had a close out on them and I bought 3 sets. And be sure to take something like an 8 oz. ball peen hammer and tap all over that Welch plug on the bottom side testing for weakness or just replace it. Ditto on the heat passage. Psychrometrically speaking you will be about 20% lean on a 40 degree morning. Link to comment Share on other sites More sharing options...
gungeey Posted February 10 Share Posted February 10 On steel gaskets the points aim towards the lifter valley. I use 4 long bolts with the heads cut off as guide pins so the gasket doesn't shift when installing the intake manifold 2 Link to comment Share on other sites More sharing options...
XframeFX Posted February 10 Share Posted February 10 4 hours ago, Eric's.64.Superwildcat said: I have cleaned the original metal gaskets and I'll be reusing them as they are in good shape. I never entertained the possibility of using steel intake gaskets, a new set of course. They appear to be unobtainum anyway. Endless chasing of vacuum leaks, I prefer composite gaskets with those exhaust block-offs left off. This is for a single 4BBL. However, steel shim head gaskets would've been nice! Link to comment Share on other sites More sharing options...
BulldogDriver Posted February 10 Share Posted February 10 http://centervilleautorepair.com/ Should have them. Ray Link to comment Share on other sites More sharing options...
NTX5467 Posted February 10 Share Posted February 10 Blocking the exhaust heat crossover via the intake manifold gaskets can work well in warmer climates, as to cold starts, but in even a temperate climate much less a "northern" climate (north of Oklahoma), it can make things work better on those cold starts in the colder times of the year. Especially with a divorced choke! Newer electric choke carburetor, less problem. Location, location, location . . . NTX5467 Link to comment Share on other sites More sharing options...
Eric's.64.Superwildcat Posted February 11 Author Share Posted February 11 Thanks to everyone that responded. I ordered new gaskets. I went with the composite gasket which I'll install without any silicone gasket maker. Link to comment Share on other sites More sharing options...
carbking Posted February 11 Share Posted February 11 Late to this thread, and seems the OP has it figured out. In the FWIW category, some 30 years ago, I listened to the internet and blocked the heat passages on a Pontiac. Took awhile to finish the engine (lots of folks wanted carbs rebuilt ) . When I finally got it together, and started driving it, was quite disgusted with performance in town for the first 30 MINUTES! It stalled at every stop sign or light, even with the ambient above 80 degrees. It did start fairly easily. Changing the carburetor to one with a MANUAL choke was easier than changing the intake; and it solved the problem. And no, I WOULD NEVER BLOCK THE CROSSOVER ON A STREET DRIVEN VEHICLE AGAIN! Jon 3 1 Link to comment Share on other sites More sharing options...
NTX5467 Posted February 11 Share Posted February 11 I suspect that many people who used to block the heat crossover did it as "that's what the drag racers/hot rodders did" for more power. In a situation where a cold intake manifold MIGHT mean a more-dense air/fuel charge got to the cylinders. Not worrying about any cold-start drivability issues which might happen in the winder or colder times of the year. Some engines/carburetor/intake manifold combinations tolerated these things better than others. When I got the 355 built for my '77 Camaro LT, to replace the 305 it came with, at that time, the trickest thing was the then-new Corvette factory aluminum heads which came on their tuned-port motors. I knew they had no exhaust crossover cast into them, but I was not very concerned as I already had an aluminum intake on it. When it was finally installed, it was DIFFERENT to drive until enough heat migrated into the intake manifold. whether from the cyl heads or the warm oil hitting the underside of the manifold. More "cold natured" than previously, although the heat riser had been deactivated. I tweaked the electric choke and fast idle speed screw a bit and it was a bit better. Lesson learned! Cast iron intakes take much longer to heat up. Do NOT block the exhaust crossover with a divorced choke thermostat, as the choke will stay closed well past the engine needing it! Prior to about 10 years ago, "winter temps" had their times of the year. Years after that have been different, with many more temperature swings from cold to warm, by observation. Just some thoughts, observations, and experiences, NTX5467 1 Link to comment Share on other sites More sharing options...
RivNut Posted February 11 Share Posted February 11 I’ve heard that you block the cross-over on the intake just where the gasket sits, letting hot exhaust get into the intake but not letting it cross over. The carburetor will warm up but the corrosive gasses won’t touch it Link to comment Share on other sites More sharing options...
XframeFX Posted February 11 Share Posted February 11 8 hours ago, carbking said: I WOULD NEVER BLOCK THE CROSSOVER ON A STREET DRIVEN VEHICLE AGAIN! Ditto Link to comment Share on other sites More sharing options...
carbking Posted February 11 Share Posted February 11 (edited) Started working on cars in 1959. The blocked cross-over was one of the top 3 of dumbest mistakes I have made in that time working on my own cars. Thinking about it, it would be number 3. Jon Edited February 11 by carbking (see edit history) 1 2 1 Link to comment Share on other sites More sharing options...
Frank DuVal Posted February 15 Share Posted February 15 And one and two are??? Not suitable for publication?🤣 Link to comment Share on other sites More sharing options...
NTX5467 Posted February 15 Share Posted February 15 I suspect that one reason this subject is a bit controversial is that LOCATION of the people who do it never is mentioned. Just "Do it, it worked for me". Others do it as a "high performance" modification, not later admitting how poor the car runs when cold in cold weather. Usually blaming it on the gas or similar, not the modification. Many times, they did it because somebody in a car magazine said they did it. Again, not taking into consideration where that car lived! NTX5467 Link to comment Share on other sites More sharing options...
RivNut Posted February 15 Share Posted February 15 For me it would not be a matter of where I lived but when I would drive the car. The KC Metro has highs that approach, and sometimes exceed, 100° and lows that sometimes will go below 0°. I’ll just drive the car when it’s nice. 🫨 I can see myself threading the holes at the top of the intake and screwing in some plugs that could be removed later. Link to comment Share on other sites More sharing options...
carbking Posted February 15 Share Posted February 15 (edited) 6 hours ago, Frank DuVal said: And one and two are??? Not suitable for publication?🤣 Frank - number 1 was putting an electric choke on my wife's car (a 1970 with automatic transmission) because I didn't (at least I thought I didn't) have time to fix the heat source for the hot air choke. Number 2 was thinking I was a smart enough enthusiast to modify a Pontiac TransAm with a 301 to run as well as a 1969 Toyota Corona 4 cylinder! Both are long stories. Both were lessons. The short versions: (1) My wife informed me she didn't like walking home! (2) Before modifications the Toyota could spot the TransAm 1st and 2nd gears; after a complete engine overhaul and a factory turbo was added to the 301, the Toyota could still spot the TransAm 1st gear. Jon Edited February 15 by carbking (see edit history) 1 1 Link to comment Share on other sites More sharing options...
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