Farmgirl458 Posted March 10, 2016 Report Share Posted March 10, 2016 I have a 1979 Datsun 620 4 speed that my grandma handed down to me. It sat for 12 years and with a few minor adjustments and a new master cylinder in the clutch it started up and has been drivable since. However when you switch gears or push on the gas you can hear the muffler rattling. It sounds as if the catalytic converter is busted on the inside. It drives me nuts when I'm driving because you can't hear yourself think. I know a thing or two about cars but this is puzzling me. I thought maybe the muffler was just loose so i for under it and tightened it but it didn't make any difference. I'm not sure what else to do. I'm restoring the inside right now so i can't start it because i pulled out the whole dash. I want to make it look decent again and can't wait to drive it but I'm seriously going to go insane if i have to hear this noise anymore lol! Any input would be helpful! Thank you Quote Link to comment
datzenmike Posted March 10, 2016 Report Share Posted March 10, 2016 Safely... climb under and grab the pipe when it's cold. Give it a good shake. Locate where it's hitting the frame, the cross member, the differential or the transmission. 1 Quote Link to comment
orangie Posted March 10, 2016 Report Share Posted March 10, 2016 I didn't think 620's went that far back. 1 Quote Link to comment
datzenmike Posted March 10, 2016 Report Share Posted March 10, 2016 Goes back from the engine and over the axle past the rear bumper. Quote Link to comment
5t341tH Posted March 10, 2016 Report Share Posted March 10, 2016 he meant year wise. op states its a 1969 Quote Link to comment
hobospyder Posted March 10, 2016 Report Share Posted March 10, 2016 vehicle list says 79, possibly a typo? Quote Link to comment
Farmgirl458 Posted March 10, 2016 Author Report Share Posted March 10, 2016 Omg my phone changed it. It's a 1979! Sorry for the confusion Quote Link to comment
Farmgirl458 Posted March 10, 2016 Author Report Share Posted March 10, 2016 It was hitting the frame when i first heard it. My dad got under it and put like a u shaped bolt onto it and tightened it up but it still made the noise and when we shook it it didn't move anymore. This is what led me to believe it could be something to do with the catalytic converter. I know absolutely nothing about mufflers. My brother owns a muffler shop but he is in Missouri! Quote Link to comment
flatcat19 Posted March 10, 2016 Report Share Posted March 10, 2016 Just beat the heck out of the exhaust until you can duplicate your concern. 1 Quote Link to comment
datzenmike Posted March 10, 2016 Report Share Posted March 10, 2016 Only California models got a catalytic converter under the driver. Otherwise just a muffler under the bed. If a baffle has rotted away inside it could block flow. Usually it's just hitting something from vibration. Make sure. Quote Link to comment
DanielC Posted March 10, 2016 Report Share Posted March 10, 2016 Exactly when does the muffler rattle? The muffler on my 521 rattles when climbing a very steep hill, when accelerating hard in first and second, but I put a two inch exhaust system in the same space that the stock 1 1/4 pipe was. Does it rattle in neutral? When revving the engine? Does turning right or left affect the rattle? Or like my Datsun, only when in a lower gear. Maybe this thread might give you some in site on why your muffler rattles. http://community.ratsun.net/topic/61167-how-i-replaced-a-521-exhaust-system/?hl=exhaust 1 Quote Link to comment
banzai510(hainz) Posted March 10, 2016 Report Share Posted March 10, 2016 why would you pull the dash apart? wait till brother come back. Minor issue on muffler. Quote Link to comment
DaBlist Posted March 10, 2016 Report Share Posted March 10, 2016 when you switch gears or push on the gas you can hear the muffler rattling. Ratsun Quote Link to comment
Farmgirl458 Posted March 10, 2016 Author Report Share Posted March 10, 2016 I pulled the dash out because as i stated before I'm fixing the inside now that i have it running. When my Grandma passed away i decided making it look decent again would be nice. The floor is rusted out and has holes all over from the rust eating it away. The dash was cracked and brittle so i put foam in the cracks and covered it with material. I bought all new wiring because while it was sitting for 12 years rats literally chewed through all the wires. I welded new metal sheets onto the floor after taking the grinder to the rust and pouring acid on it to kill the rust. I didn't want anything to get on the new dash or wires while I redid the floors. If i knew how to post pictures i would show you exactly why i took the dash out! Quote Link to comment
bilzbobaggins Posted March 10, 2016 Report Share Posted March 10, 2016 http://community.ratsun.net/topic/54932-photobucket-ratsun/ how to post pictures using photobucket. They have to be pictures hosted by another site. There is no uploading photos to ratsun. 1 Quote Link to comment
Farmgirl458 Posted March 10, 2016 Author Report Share Posted March 10, 2016 The muffler rattles only when I'm driving. Anywhere between 1st and 4th gear! It also does it when you rev it up as well. But turning doesn't effect it Thank you for the link. It could just be because it's old. who knows lol i guess as long as it runs. I just want to get everything fixed up on it to make it in tip top shape Exactly when does the muffler rattle? The muffler on my 521 rattles when climbing a very steep hill, when accelerating hard in first and second, but I put a two inch exhaust system in the same space that the stock 1 1/4 pipe was. Does it rattle in neutral? When revving the engine? Does turning right or left affect the rattle? Or like my Datsun, only when in a lower gear. Maybe this thread might give you some in site on why your muffler rattles. http://community.ratsun.net/topic/61167-how-i-replaced-a-521-exhaust-system/?hl=exhaust Quote Link to comment
Draker Posted March 10, 2016 Report Share Posted March 10, 2016 My 510 has a rattle... something is loose inside the resonator. Get under there and start shaking. or.. lift the rear off the ground, fire it up (when you have it back together) and shift through the gears. It might not make the noise since no load on the engine.. but maybe worth a shot. 1 Quote Link to comment
Farmgirl458 Posted March 10, 2016 Author Report Share Posted March 10, 2016 The hole where the drain plug was when i had popped it out part of the floor came with it. FYI I'm not a welder but the piece that's welded on is where i covered a huge hole and well it got the job done lol Quote Link to comment
Farmgirl458 Posted March 10, 2016 Author Report Share Posted March 10, 2016 Before i took the plug out Quote Link to comment
Farmgirl458 Posted March 10, 2016 Author Report Share Posted March 10, 2016 The outter dash before Quote Link to comment
Farmgirl458 Posted March 10, 2016 Author Report Share Posted March 10, 2016 After Quote Link to comment
Farmgirl458 Posted March 10, 2016 Author Report Share Posted March 10, 2016 The material i put over the broken plastic dash Quote Link to comment
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