nitroguy
Full Access Member
Howdy all! It's been a bit since I've posted, but every now and again I still lurk. PIcked up a couple more idi's, sold a few. I'm sitting at 3 currently, and that seems to be a good mix. 
. I tell ya, these things are a disease.
I've been banging my head on this one, figured I'd ask the hive-mind. Not a big deal, but one of those mind-keeps-chewing-on-it-when-you-finally-rest kinda things. Or at stoplights. Definitely at stoplights.
It knocks.
Video link at idle so you can hear it.
Not a ting, not a thunk, not whoosh, not a whunk. A knock.
Some history - this is the engine I built up (albeit cheaply - dangit). Pulled the engine (I did have an experienced builder help guide me through it), had heads inspected and valves and seats cleaned up to spec. New Bearings, rings, honed the cylinders, etc.
For those reading attempting to build an engine: don't, DON'T, think your sealing surfaces are *good enough* on your front and rear mains. I've got a driveway stain viewable from space that reminds me daily of my poor decision making skills.
Got it reassembled, and it knocks. Sent in my CDD 110 pump to get it recert'd, and they did. Sent in my injectors (stage 1's) to get recalibrated, and they did.
Still have to check timing, (dang hole is clogged and won't clean out, gotta tear it down to clean in there to time it properly), but the knock seems to chase me, no matter the timing.
Check out the video to hear what I hear when sitting. It persists through the rpm's, though loudest at idle. It does, every now and again, fade out for a half-second or so when cruising on flat ground, usually when I back out of the throttle. But barely repeatable.
I did, (again - I'm dumb), bend a pushrod when I reassembled the engine the second time to replace leaky rubber valve cover seals with the better cork ones. The bolt on the rocker came loose, pushrod jumped out of the rocker cup, and kapowyee. I haven't gotten to check compression, but the noise was there before and after that uh, "incident.".
Current theories:
*Either a bent pushrod or collaps(ing) lifter. (I "inspected" and reused pushrods and lifters on rebuild. I wonder if I missed something.
*Leaky exhaust (I don't think it's this, it seems pretty sealed up, but it's a possibility)
*Fuel knock (this is why I had injectors and pump re-checked, but it's still a possibility I suppose)
*Worse
So, here I sit, in the airport, waiting my flight. I'm going to sign off now, and let you all think about it while I go back to sleep. If you have any suggestions, I'm all ears! Can't wait to see what we come up with when I wake up.
. I tell ya, these things are a disease. I've been banging my head on this one, figured I'd ask the hive-mind. Not a big deal, but one of those mind-keeps-chewing-on-it-when-you-finally-rest kinda things. Or at stoplights. Definitely at stoplights.
It knocks.
Video link at idle so you can hear it.
Not a ting, not a thunk, not whoosh, not a whunk. A knock.
Some history - this is the engine I built up (albeit cheaply - dangit). Pulled the engine (I did have an experienced builder help guide me through it), had heads inspected and valves and seats cleaned up to spec. New Bearings, rings, honed the cylinders, etc.
For those reading attempting to build an engine: don't, DON'T, think your sealing surfaces are *good enough* on your front and rear mains. I've got a driveway stain viewable from space that reminds me daily of my poor decision making skills.
Got it reassembled, and it knocks. Sent in my CDD 110 pump to get it recert'd, and they did. Sent in my injectors (stage 1's) to get recalibrated, and they did.
Still have to check timing, (dang hole is clogged and won't clean out, gotta tear it down to clean in there to time it properly), but the knock seems to chase me, no matter the timing.
Check out the video to hear what I hear when sitting. It persists through the rpm's, though loudest at idle. It does, every now and again, fade out for a half-second or so when cruising on flat ground, usually when I back out of the throttle. But barely repeatable.
I did, (again - I'm dumb), bend a pushrod when I reassembled the engine the second time to replace leaky rubber valve cover seals with the better cork ones. The bolt on the rocker came loose, pushrod jumped out of the rocker cup, and kapowyee. I haven't gotten to check compression, but the noise was there before and after that uh, "incident.".
Current theories:
*Either a bent pushrod or collaps(ing) lifter. (I "inspected" and reused pushrods and lifters on rebuild. I wonder if I missed something.
*Leaky exhaust (I don't think it's this, it seems pretty sealed up, but it's a possibility)
*Fuel knock (this is why I had injectors and pump re-checked, but it's still a possibility I suppose)
*Worse
So, here I sit, in the airport, waiting my flight. I'm going to sign off now, and let you all think about it while I go back to sleep. If you have any suggestions, I'm all ears! Can't wait to see what we come up with when I wake up.
