Not sure if I am just hearing things or what,but since the motor was freshened this spring I have put about 400 miles on it and today while driving down the highway between 2500_2800 rpm I thought I could hear a knocking noise from the engine. I pulled over and stood next to the motor and a ran it up to 2700 and couldn't hear anything. When I took off back down the highway I could hear it again at cruising rpm,I am not real sure what to think right now. Any suggestions would be helpful
could be anything. Frozen U-joint.... Look for rust around caps. Hows your engine oil look. You runnin the right weight? hows the filter. I had a fram collapse and wipe a crank.... If it isn't doin it while still but doin it rollin, look at whats movin whien your rollin.....
thanks I will have to get under it and check it out, the u joints are new and I did just change the oil about 50 miles ago and used a wix filter. I will look around the drive line a little more
Thanks for the ideas. I will slide under it tomorrow and start from the converter and work my way back
Good call! Had a friend call me with same problem last week. I told him to check converter bolts or flexplate, and he found one bolt missing, and two loose!
A few years ago, we went to the NSRA meet in Bakersfield. On the last day, his Rod developed a knock so he trailered the car home. His son looked underneath and saw the bell housing was slightly separated from the engine. Tighten the bell housing bolts, problem solved. He had installed a new crate motor and was afraid it was bad.
The motor was built a couple years ago but only had about 1000 miles on it so we put new rings and bearings in it
The bearings looked good the engine had some blow by they tried to run synthetic oil from the beginning we did a leak down test and pulled it apart and had it re honed
Correct size bearings I assume, did you at least plastic gauge it? Grumpy says the most HP he found on a engine combo that work was to tear it down and hone it and it made more HP if that makes sense.
Yes sir, I'll bet its something simple like this. Those converter bolts have a habit of being loose or plain forgotten. I hope the motor itself is fine and its a simple fix like this and you're off & running.
I haven't solved my knock problem yet but here is where I am at, I have tried taking some timing out and went to a higher octane fuel and I thought it had quieted down but it really has not. If I rev the engine in neutral to 2500-3000 and hold it there and lightly accelerate or let off I can hear it randomly knock,when driving at cruise speed I can hear it and when its decelerating like going down a hill it knocks. when I hook up the vacuum advance it seems worse, I went from 36 degrees of timing to 32 and changed the curve so it wasn't all in till 3500 and didn't seem to make any difference.starting to wonder about something like piston or piston pin maby?
Wrist pins sometimes give you a double-knock, one of those things you have to learn by hearing a lot of sick motors. A header gasket leak can fool the ear as well, look for one of those. Try to isolate it to one cylinder by taking off 1 plug wire at a time and see if it goes away or is diminished. Bob
It sounds like it is coming from towards the back of the motor but definitely a knock from top side of motor Posted using the Full Custom H.A.M.B. App!
well I found the problem, I borrowed a bore scope and was able to see part of the top piston ring on the #4 cylinder! looks like I will be tearing apart and try and figure out what went wrong
well I got a good laugh today I pulled the engine out and started tearing it down got the heads off and all the pistons look fine!! my buddy that had the scope are still trying to figure out what we saw, we both looked at the top of the piston with the scope for several minuets and thought it was clear the top of the piston was broke. After scratching my head and laughing I put everything away for the day and figure I will dig into the bottom end tomorrow and try to figure out the cause of the knock