That's what I get for being a hot rod. I let her shift at 6,000 and now I can hear a rapping noise. ou: It's most noticeable around 1,500 RPM, and seems to come and go as I gently push the throttle up just a little and then back off. But coasting, you really don't hear it. (at light load it's loudest) If I listen at the right side of the engine while doing this out of gear, the sound is most pronounced at the right front, #1, cylinder. I doubt it's a rocker arm. b/c it's pretty quiet at idle. son of a b*tch.........I killed a Nailhead! :af: :rant: :ball:
Bummer.... I am kinda curious to know if there's some sort of "special" Buick punishment for doing such a thing? Does the 3 strikes and yer out rule apply?
Welp, I just confirmed it's definitely cyl #3. If I kill the spark going to that cylinder, the noise goes away. When I restore the spark, the noise instantly returns. Son of a b*tch! :af:
Maybe you'll get lucky, and find that it's a rod bearing or a wrist pin. From my foggy memory cells, it seems that the noise you described could be attributed to either of those. I'm hoping for the best.ray: ray:
yeah you probably spun a rod bearing. but as long as you have it out you might as well hone and re-ring it. If your looking for cheap labor, call me :TU:
I've only got 19,000 miles on this engine. I'm hoping rod bearing too, b/c I was never happy with my MB clearance anyway (.0035") thanks to the machine shop who ground my crank. Rods were .002. If it's a cracked piston, I'll be going forged this time. I've literally beaten the SNOT out of my old Nails and never had something like this happen before. I think it's a piston whacking the head, but it's strange that it doesn't do it at idle. I only tested it at 1,500 - 2,000 rpm, and that's where the noise seems loudest. Now I'm afraid to even run it, these 425's are getting scarce. :blast:
sounds more like a main to me, what is the oil pressure like??? no, I would not run it either ,Joe. Run a compression test and see what that cyl has. If the piston is busted it should show with that test.
Joe, I'd start by draining some oil and take a good look at it...if it looks like metallic paint, then you've wasted a bearing. If that's okay, pull the #3 spark plug and see it anything (like a chuck of piston) has been hitting it. Then pull the valve cover and see if all the valves will return to their fully closed position as the engine is turned by hand....if not, suspect a bent valve. Once upon a time, I was driving to Pa from the '81 Car Craft Nats in Indy. It was the first major trip I took in my fresh Nailhead. At a fuel stop, The nail was knocking badly. Thought for sure I wasted the bearings. Turned out it was only loose torque converter bolts. What a relief!! Hope you can save itray:
Yes-unhappy bearing should show up with reduced (often not all that much reduced, but noticeable at hot idle anyway) oil pressure-if so, don't run it anymore. I usually see broken skirts on OE type nail pistons.. often with no other damage-hoping that's what you have.
Welp.......the cylinder making the noise has 125 PSI of compression. Unless it's a wrist pin, I'm also starting to think rod bearing. Like I even feel like doing this job. This sucks........4 weeks left of cruising season and now I blow up my ride! :af:
Sorry to hear this Joe, but why did you take it to 6K in the 1st. place???? The good news is you weren't happy with the 1st. rebuild, now you get to do it properly. Bring it to a shop that knows the ole "Nails" & you can build it with the thought that maybe, just maybe, when you want to up the performance you can add my "Rockers". Bad news is it costs $$$$ which many of us don't have much of. But, more good news is now you can also go through the trans. again to put in the wavy plates. Good luck.
To tell you the truth? I had her in low 2, instead of all the way in drive. All I remember is whacking it to the floor, and hearing her race up and waiting for a second gear that was just not coming. I didn't have my eye on the tach, (factory tach, even worse) but judging by the feel it wouldn't surprise me if she revved over 6,000 before she finally shifted. Felt like it could have even been 6,500. :shock: You know, the engine is screaming and the car stops accelerating? ou: I never bothered testing what my full throttle shift points are in low 2 because I never use that gear. She likes to shift at 5,200 in Drive. You would think it wouldn't matter, low 2 should be the same. :af: I always thought that it would take more than this to spin a bearing, but I guess I was wrong. Son of a b*tch! :rant:
2 main reasons for killing rod bearings are RPM and detonation...If you spun it that high I'd check valve springs as well.
I intend to yank it out today. I'm praying ray: it's just a spun rod bearing. If I need to do a complete rebuild, maybe I'll just do up a 455 this time. Did I just say that? uzzled: I feel like such an idiot....... :blast:
Joe, Don't beat yourself up! Find the problem and fix it and no, we didn't hear you say ANYTHING about a 455! LOL! If it is a piston, you might get lucky, Dan Lapham has had a couple of Nail's that broke the skirt off of the piston with no damage to the bore. You could do a piston with the engine in place if needed, but a spun bearing means the engine comes out and all the way down. Back in the day when 231's were loosing rod bearings, we had to clean and replace everything! At high RPM's oil pressure can force the by pass valve open and all that metal that is being ground off of the bearing and crankshaft can find its way deep into the oil passages. We even went as far as replacing cams and lifters after having a couple V-6's tick after a new crank, connecting rod and bearings. I'll personally take a cracked or broken piston any day over a spun bearing! And to answer Tom as to what you were doing with a Nail at 6000 RPM: Havin' FUN!:3gears: Good Luck on the repair! (NO 455's allowed!) Tim:bglasses:
