RED-Z06 2,221 #1 Posted January 19, 2022 Since the rebuild with new rod, piston, rings, with the crank and bore both within tolerance...it still rattles at idle. Ive put 6 gallons through it since and it seems fine, but under a load it rattles, and at idle it rattles. I pushed it hard...riding the brake in 3rd gear to load it up, sounded like hell..but nothing happened except now the brakes work really well. Oil is still clear..and i have an electric fuel pump now..i really like that. 1 Share this post Link to post Share on other sites
WHX?? 48,828 #2 Posted January 19, 2022 Sounds like valve clatter fellas? I know some guys like to set the valve lash a little tighter to avoid valve clatter but not sure if that's what it is. Balance gears in or out? 1 Share this post Link to post Share on other sites
RED-Z06 2,221 #3 Posted January 20, 2022 10 minutes ago, WHX?? said: Sounds like valve clatter fellas? I know some guys like to set the valve lash a little tighter to avoid valve clatter but not sure if that's what it is. Balance gears in or out? Gears in, engine has 158 hours on it. Valves both within spec, in fact both Valves are near the minimum spec. There was alot of lash in the mesh of the balance gears 1 Share this post Link to post Share on other sites
Jeff-C175 7,202 #4 Posted January 20, 2022 That's a somewhat different kinda rattle than my K301 has. Yours is VERY regular, and consistent. Hard to describe mine... when it's rattling it sorta like 'comes and goes', like something is 'floating around' in there. That's why I keep going back to camshaft end play. Yeah, at this point if'n I were you, I'd just run it until it does something bad... IF it ever even does something bad. I onceuponatime had an old MGA that had a piston slap, and it was loud. Well... pretty loud... and I put about 50K on that thing and it never got louder or blew up. Hopefully your engine will do the same, run for ever'n'ever. 1 1 Share this post Link to post Share on other sites
RED-Z06 2,221 #5 Posted January 20, 2022 7 minutes ago, Jeff-C175 said: That's a somewhat different kinda rattle than my K301 has. Yours is VERY regular, and consistent. Hard to describe mine... when it's rattling it sorta like 'comes and goes', like something is 'floating around' in there. That's why I keep going back to camshaft end play. Yeah, at this point if'n I were you, I'd just run it until it does something bad... IF it ever even does something bad. I onceuponatime had an old MGA that had a piston slap, and it was loud. Well... pretty loud... and I put about 50K on that thing and it never got louder or blew up. Hopefully your engine will do the same, run for ever'n'ever. If i find a bit more rpm...it will come and go. Honestly right before this video it just randomly and suddenly decided to idle right after about 4hrs...like it just started running rich and it let me turn the low speed screw out about 3/4 turn and turn the low in 1.5 turns and the Hi in 1/2 turn...not sure what happened but its running nice now. 1 Share this post Link to post Share on other sites
Snoopy11 5,714 #6 Posted January 20, 2022 (edited) I'll be a horses pa-toot if that doesn't sound like the rod to me. Are you POSITIVE that you tightened the cap to spec? Don Edited January 20, 2022 by Snoopy11 3 Share this post Link to post Share on other sites
AMC RULES 37,130 #7 Posted January 20, 2022 Comes to mind. 1 2 Share this post Link to post Share on other sites
Snoopy11 5,714 #8 Posted January 20, 2022 Just now, AMC RULES said: Comes to mind. Yes sir. I second that. Even if there isn't any oil coming out of the breather... it sounds like it is only a matter of time... If there IS any oil coming out of the breather, coupled with a knocking sound... LOOKOUT... I certainly would not run with that sound... Don 2 Share this post Link to post Share on other sites
Snoopy11 5,714 #9 Posted January 20, 2022 By the way, that is not a rattle, that is a knock. Don 1 1 Share this post Link to post Share on other sites
AMC RULES 37,130 #10 Posted January 20, 2022 (edited) From hell! Edited January 20, 2022 by AMC RULES 2 Share this post Link to post Share on other sites
Snoopy11 5,714 #11 Posted January 20, 2022 2 minutes ago, AMC RULES said: MONEY Craig... Just... MONEY... Don 1 Share this post Link to post Share on other sites
Snoopy11 5,714 #12 Posted January 20, 2022 I think... in this case, @RED-Z06 you can disregard my signature... Don Share this post Link to post Share on other sites
Achto 27,601 #13 Posted January 20, 2022 17 minutes ago, RED-Z06 said: Honestly right before this video it just randomly and suddenly decided to idle right after about 4hrs Things are breaking in and running free. Most often I find my self turning the idle down after a few hours of run time. 2 Share this post Link to post Share on other sites
Wheelhorse#1 1,667 #15 Posted January 20, 2022 (edited) Yep sounds like this one. Edited January 20, 2022 by Wheelhorse#1 2 Share this post Link to post Share on other sites
WHX?? 48,828 #16 Posted January 20, 2022 40 minutes ago, RED-Z06 said: Gears in Thers yer first mistake .... who was it guys that just ripped a rebuild back down to ditch them to find a bad bearing? I couldn't hear the knock but will take it from younger ears. Yer a Madge.... 2 Share this post Link to post Share on other sites
lynnmor 7,307 #17 Posted January 20, 2022 Wrist pin maybe? Try turning the engine back and forth at different degrees of rotation and feel for looseness and noise. 2 Share this post Link to post Share on other sites
RED-Z06 2,221 #18 Posted January 20, 2022 16 minutes ago, lynnmor said: Wrist pin maybe? Try turning the engine back and forth at different degrees of rotation and feel for looseness and noise. Nothing, and on shut down...nothing out of the ordinary, it goes away a few hundred rpm above low idle 1 Share this post Link to post Share on other sites
RED-Z06 2,221 #19 Posted January 20, 2022 36 minutes ago, Snoopy11 said: Yes sir. I second that. Even if there isn't any oil coming out of the breather... it sounds like it is only a matter of time... If there IS any oil coming out of the breather, coupled with a knocking sound... LOOKOUT... I certainly would not run with that sound... Don Breather's dry, plug clean, no oil use at all...heck i pushed dirt with it for an hour today screaming 3600...never thought twice about it. Sounds angry loaded up but..so far its just the sound. 2 Share this post Link to post Share on other sites
RED-Z06 2,221 #20 Posted January 20, 2022 45 minutes ago, Snoopy11 said: I'll be a horses pa-toot if that doesn't sound like the rod to me. Are you POSITIVE that you tightened the cap to spec? Don Called for 285 in/lb and i took it to 24 ft/lbs, the sound was evident immediately upon starting..and there was no movement in the rod while it was apart. 1 Share this post Link to post Share on other sites
WHX?? 48,828 #21 Posted January 20, 2022 Runner like ya stole her then ... gets any worse tho I would pull it apart again. 1 Share this post Link to post Share on other sites
RED-Z06 2,221 #22 Posted January 20, 2022 Im keeping an eye out for another Magnum..12 thru 16 locally. 1 Share this post Link to post Share on other sites
Snoopy11 5,714 #23 Posted January 20, 2022 Let me say it this way... I wouldn't run that engine with that sound... period... Don 1 Share this post Link to post Share on other sites
RED-Z06 2,221 #24 Posted January 20, 2022 17 minutes ago, Snoopy11 said: Let me say it this way... I wouldn't run that engine with that sound... period... Don Well...she's gonna get a couple more hours of break-in tomorrow. Im not even worried about it, msybe the video makes it seem worse...in person it sounds more like loose sheet metal rattling. 1 Share this post Link to post Share on other sites
kpinnc 12,083 #25 Posted January 20, 2022 (edited) 4 hours ago, WHX?? said: Thers yer first mistake .... who was it guys that just ripped a rebuild back down to ditch them to find a bad bearing? Not a rebuild, but I went back recently in one to find almost gone gear bearings. Trying to motivate myself to do the Bronco now. Almost killed my back, so I'm struggling to convince myself. Edited January 20, 2022 by kpinnc 1 1 Share this post Link to post Share on other sites
