viven44 Posted September 2 Author Share Posted September 2 This is about where your VCV should be switching the advance to full manifold vacuum. But you say you're lacking power... Or is it forward motivation? Jim, noise goes up. (I think) I have less power. No bogs, hesitation, or problems keeping up with the modern traffic..... I don't know if the VCV for a 460 is setup that way to switch between ported to manifold when hot (Even though it makes a lot of sense!!!). The only switch on the stock VCV is from manifold vac VREST to manifold vac no VREST when hot. Link to comment Share on other sites More sharing options...
mat in tn Posted September 2 Share Posted September 2 Yes, we will have experts up here. Bring it on! Seriously though, have y'all considered the noise the cooling fan makes? If there's a perceived difference between hot and cold then maybe the noise the fan makes when hot is clouding the perception? depending on which fan assembly you have and which fan clutch. that can be a noticeable change when the fan engages. it can sound very loud especially if the truck is quiet. do you have a tach and if not, can you rig one into the cab for the drive as a test. to be able to see whether the rpm's are surging higher will be very helpful. even though the c6 is fully on the multiplication of the torque converter it is still one of the best and most durable automatics out there. if it only had an od then it's all I would use. but od is why I build so many aod's. I recently rebuilt my c6 in my f250 with 351m. it failed on me towing another truck on a trailer. all bands and clutches looked as good as new and i only found a couple seals that were hardened from being a 1981.it turns out that the vacuum modulator had been leaking and that's where the fluid went and caused the slipping. I filled it back up and drove the rest of the way home but pulled it out of caution and rebuilt it. moral of the story is that even after that, it had not actually failed. it may have carried on for many years but at least now I have peace of mind. and a new vacuum modulator! Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted September 2 Share Posted September 2 depending on which fan assembly you have and which fan clutch. that can be a noticeable change when the fan engages. it can sound very loud especially if the truck is quiet. do you have a tach and if not, can you rig one into the cab for the drive as a test. to be able to see whether the rpm's are surging higher will be very helpful. even though the c6 is fully on the multiplication of the torque converter it is still one of the best and most durable automatics out there. if it only had an od then it's all I would use. but od is why I build so many aod's. I recently rebuilt my c6 in my f250 with 351m. it failed on me towing another truck on a trailer. all bands and clutches looked as good as new and i only found a couple seals that were hardened from being a 1981.it turns out that the vacuum modulator had been leaking and that's where the fluid went and caused the slipping. I filled it back up and drove the rest of the way home but pulled it out of caution and rebuilt it. moral of the story is that even after that, it had not actually failed. it may have carried on for many years but at least now I have peace of mind. and a new vacuum modulator! I know that when my clutch fails the dang fan sounds like an aeroplane labouring for takeoff! Link to comment Share on other sites More sharing options...
mat in tn Posted September 2 Share Posted September 2 I know that when my clutch fails the dang fan sounds like an aeroplane labouring for takeoff! I have not seen many fail locked but that would be a loud load. most that I have seen fail. fail to engage. one even was so loose that I did the unthinkable. I stopped it with my hand and said, "you need a new one of these". not suggesting this by any means. so, all you kids out there, don't try this at home!! yes i have all of my fingers:nabble_head-rotfl-57x22_orig: Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted September 2 Share Posted September 2 I have not seen many fail locked but that would be a loud load. most that I have seen fail. fail to engage. one even was so loose that I did the unthinkable. I stopped it with my hand and said, "you need a new one of these". not suggesting this by any means. so, all you kids out there, don't try this at home!! yes i have all of my fingers:nabble_head-rotfl-57x22_orig: I can stop my fan cold any time. Hot, I wouldn't dare! Link to comment Share on other sites More sharing options...
viven44 Posted September 2 Author Share Posted September 2 I can stop my fan cold any time. Hot, I wouldn't dare! Hi all, I just ran across something that I can only rationalize and close as a honest beginner mistake The Motorcraft thick gasket that is stock for the Holley 4180 interferes with the opening of the Edelbrock secondaries and to some extent the primaries as well. So my secondaries only opened potentially when enough vacuum suction occasionally opened it from time to time. As soon as I realized it my heart started racing..... I think at the very beginning Gary asked me if the secondaries were opening and I guess now I know what that truly meant. I was only going off the feel while driving and I could tell when they kicked in... Physically confirming in-situ with a camera is paramount (now I understand!!). Getting up and over to see the secondaries on the dentside is physically impossible as your resting area is the radiator. Today I used my camera and could see the interference. I installed the base gasket without a divider that came with my Edelbrock and I am officially burning rubber now!! The acceleration is smooth and I think I have unlocked about 30% more power on the Bronco. Next up is Big Blue 2WD which was already very peppy in my view... Big Blue 2WD still has the original Motorcraft gasket and has been running this way for a while I have no idea what this is going to do to - operating temps - fuel efficiency Should I also use an Edelbrock gasket like the one below that is a heat insulator and also has a divider ? Why is a divider needed ? I am using the stock 460 EGR plate/stock intake manifold. https://www.oreillyauto.com/detail/c/edelbrock/edelbrock-carburetor-heat-insulator/edb0/9266 Here is a rough illustration/overlay of the gasket types that show the difference. The one with 4 holes is the stock Holley 4180 460 gasket. The one with the divider is the Edelbrock 9266 gasket. I hope it fits the EGR plate. Link to comment Share on other sites More sharing options...
viven44 Posted September 2 Author Share Posted September 2 depending on which fan assembly you have and which fan clutch. that can be a noticeable change when the fan engages. it can sound very loud especially if the truck is quiet. do you have a tach and if not, can you rig one into the cab for the drive as a test. to be able to see whether the rpm's are surging higher will be very helpful. even though the c6 is fully on the multiplication of the torque converter it is still one of the best and most durable automatics out there. if it only had an od then it's all I would use. but od is why I build so many aod's. I recently rebuilt my c6 in my f250 with 351m. it failed on me towing another truck on a trailer. all bands and clutches looked as good as new and i only found a couple seals that were hardened from being a 1981.it turns out that the vacuum modulator had been leaking and that's where the fluid went and caused the slipping. I filled it back up and drove the rest of the way home but pulled it out of caution and rebuilt it. moral of the story is that even after that, it had not actually failed. it may have carried on for many years but at least now I have peace of mind. and a new vacuum modulator! I have a tach installed and there is no RPM surge(indicative of slipping....?) Link to comment Share on other sites More sharing options...
85lebaront2 Posted September 3 Share Posted September 3 depending on which fan assembly you have and which fan clutch. that can be a noticeable change when the fan engages. it can sound very loud especially if the truck is quiet. do you have a tach and if not, can you rig one into the cab for the drive as a test. to be able to see whether the rpm's are surging higher will be very helpful. even though the c6 is fully on the multiplication of the torque converter it is still one of the best and most durable automatics out there. if it only had an od then it's all I would use. but od is why I build so many aod's. I recently rebuilt my c6 in my f250 with 351m. it failed on me towing another truck on a trailer. all bands and clutches looked as good as new and i only found a couple seals that were hardened from being a 1981.it turns out that the vacuum modulator had been leaking and that's where the fluid went and caused the slipping. I filled it back up and drove the rest of the way home but pulled it out of caution and rebuilt it. moral of the story is that even after that, it had not actually failed. it may have carried on for many years but at least now I have peace of mind. and a new vacuum modulator! Mat, on Darth, hot weather towing our 30 ft, 10 K loaded 5th wheel in traffic (SE of DC on US301/MD5) going past all the shopping areas and stop lights, pulling away from a stop, the fan sounded like one of NASA Langley's wind tunnels till about 45 mph at which point the air flow through the radiator was adequate for it to start to uncouple. I had to replace the original fan clutch and the replacement never worked as well. Gary had posted some cooling system PNs, and in looking them over I found the Ford PN and was able to cross it over to a different number than what Autozone sold me. I haven't installed it yet as I need to determine why I am getting coolant #1 and possibly #2 from a lower radiator hose blowing off. Link to comment Share on other sites More sharing options...
mat in tn Posted September 3 Share Posted September 3 I have a tach installed and there is no RPM surge(indicative of slipping....?) well, you have discovered a lot. and diagnosis is that the cause is the cause whether it's a failing part or a simple operator/installer error. often it's a matter of look at the last thing touched. Link to comment Share on other sites More sharing options...
viven44 Posted September 3 Author Share Posted September 3 well, you have discovered a lot. and diagnosis is that the cause is the cause whether it's a failing part or a simple operator/installer error. often it's a matter of look at the last thing touched. Yes I agree... In this case unfortunately it was a build throw together with parts from 2 trucks. The last thing touched was just about everything (Transmission, engine, intake). I didn't have the experience to investigate this from the get-go. Well if I had stuck with the stock 4180, this would have been a non-issue... but I have just always trusted Edelbrocks. I didn't also think to investigate Big Blue 2WD's situation as I have been plenty happy just putting around town with the primaries. I had fortunately not subjected the truck yet to a major tow or anything of that sort. Link to comment Share on other sites More sharing options...
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