throw1932 Posted June 28, 2020 Report Share Posted June 28, 2020 it has new gaskets and the spacer is intact. will try with RTV tomorrow when I get a chance. if that doesn't help I'll order new gaskets. Quote Link to comment
datzenmike Posted June 28, 2020 Report Share Posted June 28, 2020 I see the hole now. I'm guessing here... but perhaps this is a 'weep hole' just like on the underside of the water pumps. If the pump diaphragm was to begin leaking it would come out here rather that down the pump arm and into the timing cover and into the oil pan. I would guess you could also plug it with RTV. 2 Quote Link to comment
FatDatSun Posted October 31, 2020 Report Share Posted October 31, 2020 Any update on how that rtv is holding up? Issues or happy cruising, I now have encounter this issue now, but only after installing the weber 32.36, yes after a year I finally ordered it for 20 dollars less. And also threw a cherry bomb muffler on it... it doesn't sound throaty but the weber sucktion sound is much better than a exhaust. But, lmk about this rtv diy please. Quote Link to comment
AlexDeLarge Posted October 31, 2020 Report Share Posted October 31, 2020 Did mine back in May and is still holding up. I put new gaskets and spacer on mine as well. Quote Link to comment
FatDatSun Posted November 4, 2020 Report Share Posted November 4, 2020 Weep hole was plugged for two days now, I dont see nothing wrong atm. Quote Link to comment
throw1932 Posted November 13, 2020 Report Share Posted November 13, 2020 disassembled my Ampco pump a few minutes ago, expecting a damaged diaphragm, but it is in wonderful condition. it would appear my failure point is the lower body seal. very clear that there has been oil in this vacuum bowl for a while, where it shouldn't be, and has been coating the pass side of my engine bay in oil through the weep hole for the last few years, only recently beginning to absolutely pour oil out of the weep hole. long shot but anyone have a PN on hand for item #10 lower body seal so I can begin my hunt? per 1974 FSM Quote Link to comment
AlexDeLarge Posted November 14, 2020 Report Share Posted November 14, 2020 17 hours ago, throw1932 said: disassembled my Ampco pump a few minutes ago, expecting a damaged diaphragm, but it is in wonderful condition. it would appear my failure point is the lower body seal. very clear that there has been oil in this vacuum bowl for a while, where it shouldn't be, and has been coating the pass side of my engine bay in oil through the weep hole for the last few years, only recently beginning to absolutely pour oil out of the weep hole. long shot but anyone have a PN on hand for item #10 lower body seal so I can begin my hunt? per 1974 FSM Can't see your first three pictures. Quote Link to comment
FatDatSun Posted November 14, 2020 Report Share Posted November 14, 2020 My old original one went bad, got one from oriellys, didn't put the spacer in and made the weep hole leak. So since its lifetime warranty, I got another one. There are two that the 620 ask for. The older looking style one works better because of that arm that goes in is less of a bend. The newer style always makes that weep hole leak. I've tried 4 total. Remember the spacer, running without it guarantee that the pumps weep hole will "weep". JUST my experience. Quote Link to comment
AlexDeLarge Posted November 14, 2020 Report Share Posted November 14, 2020 I don't know dude, you are probably not going to find that and will have to improvise with some sort of o ring or something. Do you have the original seal to use to compare against or is it rotted away? Quote Link to comment
throw1932 Posted November 15, 2020 Report Share Posted November 15, 2020 the original seal is in a million pieces, unfortunately. I was thinking of trying an oring but im not sure how I would secure it in the pump. i guess I could plug the weep hole but that isn't really the right thing to do as it is there for when the diaphragm fails so you don't let gasoline dilute the oil and smoke your bearings. i have a handful of Carter pumps (they're absolute garbage), im going to disassemble one and see what it looks like it has for a seal Quote Link to comment
AlexDeLarge Posted November 15, 2020 Report Share Posted November 15, 2020 (edited) Sounds like a plan, when you find something that works let us know. I have the same pump and would appreciate the info in case I run into the same problem down the road....Also, I see you only have posted a few times, could you post up some pictures of your '74 620? I'd like to see it😎 Edited November 15, 2020 by AlexDeLarge mo info Quote Link to comment
throw1932 Posted January 12, 2021 Report Share Posted January 12, 2021 been a little while, but I found a resolution. I had a spare Carter fuel pump and disassembled it to see how it was sealed, and found a totally different seal. rather than being pressed into the lower body where the pivot point is, it sits above that and is held in by the diaphragm spring. much much simpler. I took that seal off of the new pump, and it went right into my original pump. I have yet to test it as my truck is in winter storage, but I need to get over to it and fix a vacuum leak at somepoint anyways, so I will update once I try it. I see no reason it will not work though, it is totally sealed off. posting a few pictures of the fuel pump and my truck right now 1 Quote Link to comment
throw1932 Posted January 12, 2021 Report Share Posted January 12, 2021 seal on the carter pump with diaphragm and spring removed new spring and seal on my old diaphragm seal itself and retainer ring 1 Quote Link to comment
throw1932 Posted January 12, 2021 Report Share Posted January 12, 2021 I have looked briefly for a part number for the seal, but have had no luck. the diaphragm out of the Carter unit is the same as the Ampco unit. basically, you could buy a Carter pump, and swap all the internals into the old Ampco body. somewhat tedious, but looks a lot better. the Carter pumps aren't that expensive either Quote Link to comment
throw1932 Posted January 12, 2021 Report Share Posted January 12, 2021 some background: I saw a 620 years ago when I was a child, and instantly wanted one. as I grew older and my knowledge on them grew, I decided my "dream" truck was a mustard yellow, '74 (for L18), original paint truck. when i was 13, i started at working at a local classic car dealership. through them i could ship cars pretty cheap, so while in highschool, I always had my eyes online looking for a California truck, but they were always rusty and obliterated dashes. then one day, after I graduated highschool, I return to work after lunch break, and this little truck is sitting in the parking lot. quick inspection tells me it is mostly original paint, rust free, and an early truck. I find the owner, and he tells me he wants to sell. sold! the tailgate has been repaired and painted as they backed into something when it was completely down. also pushed up the passenger side tail light and tweaked the quarter, but they are fine. has extra padding underneath two seat covers that the original owners made specifically for the seat. the padding and first cover were installed when they bought the truck, and the second cover was installed later. the original seat is untorn, and in beautiful shape. the only flaw on the interior is a small hole in the carpet. here is where it gets interesting: it was bought new a few towns over from where I grew up, and lived in my neighboring town its whole life, practically down the street from me. it has never left the state of Maine. the couple that owned it since new bought it to use as a little work truck, basically a cleaning cart as during the summer they ran cottages in a local tourist town, and would clean them every day. once tourist season was over, it was parked in its garage and they left for Florida where they live primarily. truck was dealership maintained its whole life, and only had OEM parts on it. the coil, shocks, even oil filter were stamped OEM Datsun/Nissan. I have since done an engine rebuild as the headgasket blew, and had bad rings as the PCV was completely clogged inside the block. it was originally auto, and I swapped in a ZX five speed while I was doing the engine. during my five speed swap, I sourced all the correct parts, including original pedal pads that have the same level of wear as the original auto brake pedal, gives it that more natural look. under the dash is completely untouched, totally stunning. i did lower the thing three inches, but that is it. I always planned on having multiple 620s, but never realized my first truck would not only be truly my dream truck, but one with a phenomenal story. sorry for the length of post lol, but story is too good not to tell. 3 Quote Link to comment
AlexDeLarge Posted January 12, 2021 Report Share Posted January 12, 2021 Sweet truck....glad I asked to see pictures 😎 1 Quote Link to comment
throw1932 Posted March 17, 2021 Report Share Posted March 17, 2021 hopefully going to get to my truck sooner than later. earlier last week I stopped by and retorqued the head, got a decent turn on each bolt, so hopefully the headgasket stops leaking oil. the carb had a vacuum leak between the top hat and main body, could see on the gasket where it wasn't crushed when I took it apart. I used some Permatex fuel resistant sealant with the gasket, should work well. also had a massive vacuum leak at the base of the carb, and again can see were the gasket between the bottom of the carb and spacer did not seal on one side. going to use the sealant again and then test for vac leak, hopefully that fixes the wicked high idle and overheating issues. also need to adjust valves, and put the original fuel pump back on to see if the seal works. I will update once I have a good verdict on the seal. hopefully it works, I cannot stand the look of that garbage Carter pump. 1 Quote Link to comment
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