85lebaront2 Posted November 10, 2019 Share Posted November 10, 2019 You should back it off so it is no longer stopping the throttle from fully closing, basically with the main stop screw backed out, loosen the fast idle until the cam will move with no drag, then make sure the main idle stop is still not touching. OK, this is good to know! Thank you sir! So the throttle plates stop just by closing in the barrels then? The reason I started looking so closely at the fast idle cam is that it is nice and loose and moving freely until I back the idle speed screw all the way out. With the idle speed screw all the way out, there is a little drag on the fast idle cam stop screw. It looks like it could be loosened just a little bit. And, on the intake gaskets. Do you guys put a little RTV around the coolant ports or install them dry? I put a very thin film, you do not want to block the weep channel around the water passage, this lets any leakage go out rather than down inside the engine. Link to comment Share on other sites More sharing options...
Gary Lewis Posted November 10, 2019 Share Posted November 10, 2019 You should back it off so it is no longer stopping the throttle from fully closing, basically with the main stop screw backed out, loosen the fast idle until the cam will move with no drag, then make sure the main idle stop is still not touching. OK, this is good to know! Thank you sir! So the throttle plates stop just by closing in the barrels then? The reason I started looking so closely at the fast idle cam is that it is nice and loose and moving freely until I back the idle speed screw all the way out. With the idle speed screw all the way out, there is a little drag on the fast idle cam stop screw. It looks like it could be loosened just a little bit. And, on the intake gaskets. Do you guys put a little RTV around the coolant ports or install them dry? I put RTV around the coolant ports. I agree with Bill's approach of using studs to position the intake. And the RTV on the end walls. But, I'll add that it is possible to put the intake on at an angle, and it won't always line itself up just by torquing the bolts. So do your best to get it on level. Link to comment Share on other sites More sharing options...
85lebaront2 Posted November 10, 2019 Share Posted November 10, 2019 I put RTV around the coolant ports. I agree with Bill's approach of using studs to position the intake. And the RTV on the end walls. But, I'll add that it is possible to put the intake on at an angle, and it won't always line itself up just by torquing the bolts. So do your best to get it on level. That's part of the reason for the RTV, if you let it cure partially, it will stay in place as you snug the manifold. I usually take all the bolts down finger tight, then slowly alternately work on the center and checking the ends to be sure it is even as it seats. Once it is evenly seated, then start torquing in sequence. Link to comment Share on other sites More sharing options...
Gary Lewis Posted November 10, 2019 Share Posted November 10, 2019 That's part of the reason for the RTV, if you let it cure partially, it will stay in place as you snug the manifold. I usually take all the bolts down finger tight, then slowly alternately work on the center and checking the ends to be sure it is even as it seats. Once it is evenly seated, then start torquing in sequence. If I'm using RTV on the end walls, and I always do any more, I religiously clean the block and the intake, apply the RTV, and then set the intake down level and run all of the bolts in finger tight. Then I snug them up in the torque pattern, but don't torque them down, and let it sit over night so the RTV cures. The next day I torque it down. Otherwise I'm afraid I'll squish the RTV out. Link to comment Share on other sites More sharing options...
Rembrant Posted November 10, 2019 Author Share Posted November 10, 2019 If I'm using RTV on the end walls, and I always do any more, I religiously clean the block and the intake, apply the RTV, and then set the intake down level and run all of the bolts in finger tight. Then I snug them up in the torque pattern, but don't torque them down, and let it sit over night so the RTV cures. The next day I torque it down. Otherwise I'm afraid I'll squish the RTV out. Thanks for all the tips gentlemen! I have never been so happy to find a bad gasket!! I was beginning to feel like I had a more serious mechanical problem. Hoping to get the intake pulled today and have a look inside. Do you think that the gasket has been out of place since it was installed? The leak either started later on, or started out small and got worse over time? Link to comment Share on other sites More sharing options...
Gary Lewis Posted November 10, 2019 Share Posted November 10, 2019 Thanks for all the tips gentlemen! I have never been so happy to find a bad gasket!! I was beginning to feel like I had a more serious mechanical problem. Hoping to get the intake pulled today and have a look inside. Do you think that the gasket has been out of place since it was installed? The leak either started later on, or started out small and got worse over time? I can't see the gasket moving once the intake is torqued down against it. And if it were exhaust I'd say it got worse over time. But I can't see how an intake gasket got worse. The air going in wouldn't have been all that hot nor corrosive, so I think it had to have been there from Day 1. It is such a small leak in the overall scheme of things that it wouldn't make much difference in dyno runs at WOT. But it sure will at idle. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted November 10, 2019 Share Posted November 10, 2019 Thanks for all the tips gentlemen! I have never been so happy to find a bad gasket!! I was beginning to feel like I had a more serious mechanical problem. Hoping to get the intake pulled today and have a look inside. Do you think that the gasket has been out of place since it was installed? The leak either started later on, or started out small and got worse over time? Cory, so glad to hear you've come to the root of the problem! With your new carb tuning prowess I'm sure that you'll have it running like a top once that gasket is replaced. 👍 Link to comment Share on other sites More sharing options...
Rembrant Posted November 11, 2019 Author Share Posted November 11, 2019 I can't see the gasket moving once the intake is torqued down against it. Gary, Again you are correct sir. Upon closer inspection after disassembly, the intake gasket was out of place (and probably broken) from the day it was installed. See pics below. I'm not sure if this had anything to do with the issue, the but the gaskets were installed backwards...the side of the gaskets that said "Head Side" were facing the intake. I can't see what that matters though, except the gasket stuck like glue to the cylinder head, and not at all to the intake. The other interesting thing is that the gasket is actually broken...and they're actually both broken. The gaskets have a metal core, and I can't even see how that happened...it's broken at the top of cylinder #3, and also on top of cylinder #6. You can't tear them...I tried. They're thin sheet metal in the middle(core). The only thing I can see is that maybe the gaskets were not sitting correctly when the intake was set into place, and as it was torqued down, it bent the gaskets and broke them? I don't know. Is this what I get for having a shop that builds a lot of BBC's work on my SBF?>..lol. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted November 11, 2019 Share Posted November 11, 2019 I can't see the gasket moving once the intake is torqued down against it. Gary, Again you are correct sir. Upon closer inspection after disassembly, the intake gasket was out of place (and probably broken) from the day it was installed. See pics below. I'm not sure if this had anything to do with the issue, the but the gaskets were installed backwards...the side of the gaskets that said "Head Side" were facing the intake. I can't see what that matters though, except the gasket stuck like glue to the cylinder head, and not at all to the intake. The other interesting thing is that the gasket is actually broken...and they're actually both broken. The gaskets have a metal core, and I can't even see how that happened...it's broken at the top of cylinder #3, and also on top of cylinder #6. You can't tear them...I tried. They're thin sheet metal in the middle(core). The only thing I can see is that maybe the gaskets were not sitting correctly when the intake was set into place, and as it was torqued down, it bent the gaskets and broke them? I don't know. Is this what I get for having a shop that builds a lot of BBC's work on my SBF?>..lol. It'd be interesting to throw a precision straight edge across the head and manifold faces and see if they are truly flat. Link to comment Share on other sites More sharing options...
Gary Lewis Posted November 11, 2019 Share Posted November 11, 2019 I can't see the gasket moving once the intake is torqued down against it. Gary, Again you are correct sir. Upon closer inspection after disassembly, the intake gasket was out of place (and probably broken) from the day it was installed. See pics below. I'm not sure if this had anything to do with the issue, the but the gaskets were installed backwards...the side of the gaskets that said "Head Side" were facing the intake. I can't see what that matters though, except the gasket stuck like glue to the cylinder head, and not at all to the intake. The other interesting thing is that the gasket is actually broken...and they're actually both broken. The gaskets have a metal core, and I can't even see how that happened...it's broken at the top of cylinder #3, and also on top of cylinder #6. You can't tear them...I tried. They're thin sheet metal in the middle(core). The only thing I can see is that maybe the gaskets were not sitting correctly when the intake was set into place, and as it was torqued down, it bent the gaskets and broke them? I don't know. Is this what I get for having a shop that builds a lot of BBC's work on my SBF?>..lol. Hard to believe they did such a poor job of the intake install. Breaking the gaskets is hard to do, but I'd guess that they put studs through in the center to hold the gasket and align the manifold, and then they had to press hard to get it down on the ends. And since it was sandwiched between the head and the intake the gasket couldn't fold over so tore. And then to put them on backwards as well. Even lowly Chevys should be treated better than that! Link to comment Share on other sites More sharing options...
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