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1G What is this sound? tapping

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tsiawd90

Supporting Member
101
22
Nov 16, 2017
Houston, Texas
Alright I finally get the car running and I am hearing this sound. I am not sure what it is. It does it right when I give it throttle then goes away. I bought a used motor that had been sat up for a while. I'm planning to pull the valve cover off tomorrow and look inside.

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Sounds more severe than lifter going bad, which would tend to tick most during idle, and quite as the oil pressure builds with revs. Ignition knock, as motomattx mentioned, can be diagnosed by adding better fuel or octane booster, should get a little better, and then you would know to track down the cause. I’m afraid it might be rod knock, as was also suggested. The sound is more like it, and it can start to show up under only certain load/rpm conditions owing to how all the various bearing clearances add up with the forces and inertia of all the moving mass. Sort of a harmonic situation. Rod knock will likely get worse quickly, as it implies way too much clearance in a bearing, which will rapidly wear.
 
Hate to say it but I agree about the early signs of rod knock.....and hope it isn't!
 
Pull one plug wire at a time while its running and then rev it like you did and see if it goes away with any single wire unplugged, if it does its rod knock/wrist pin clearance issues and it will tell you which cylinder is the problem cylinder.
 
Pull one plug wire at a time while its running and then rev it like you did and see if it goes away with any single wire unplugged, if it does its rod knock/wrist pin clearance issues and it will tell you which cylinder is the problem cylinder.

I will try this.

I do think it could be a ignition timing issue. I was not sure how to adjust the cas. I got it installed correctly but did not follow all the steps to adjust it. I was just reading how ro adjust it with a timing light. I will do this as well as the check for rod knock.

If its rod knock I'm putting this thing up for awhile. I dont think i am mentally able to process that.
 
I've heard that noise before but can't put my finger on it. Check the turbo???
I have heard something like it before but it was an automatic car. Pulled the motor for rod knock and found 2 broken webs on the flexplate.
 
Just dont do what my neighbor did with his truck. He bought it for cheap and it started to... lets say shake violently. They were driving it over to my dads friends shop and half way there, BOOM. It left a trail of oil and water all the way to the shop.

I should try to find some of my old bearings to show in my build update just to show why you should go and check things out when you buy a used engine. There is already a picture of what was wrong with my block. Needless to say, they were basically copper and the thrust bearing had chunks out of it and some chunks were in the bottom of the pan as well as part of the oil pickup screen being clogged. Good thing the crank was still good.

I had lifter tick but it has went away on its own, probably because I cleaned everything with my rebuild.

Your tapping/ticking sounds mechanical to me though.
 
I have heard something like it before but it was an automatic car. Pulled the motor for rod knock and found 2 broken webs on the flexplate.

Now I remember. The flex plate bolts were loose on my jeep.
 
It really sounded like it was in the head. The sound only comes right when I give it gas and only if I bump the gas then sound goes away.

If I slowly give it gas it doesnt make any sound.

I held it at about 2k rpm for 3 or 4 minutes with no unuasual sound. I was hoping holding some oil pressure on it would pump up the lifter if that was the issue.

Would rod knock get worse with higher rpm?

I havent listened to it from the bottom yet.

I'll check under the valve cover today and if I dont see anything I will really start digging in on Monday.
 
It's hard to try and diagnose stuff like this over the interwebs unless it's a real common issue. You're just going to have to use your senses on this one, ears and touch. Check the baffle on the valve cover when you take it off??? I've listened to you video about 20 times. To me, it sounds like something is barely loose. Good luck man and I hope it's not rod knock.
 
Issue was a broken injector clip. Car is now running nicely. Just need to bleed the clutch and it will be finally ready to drive under it's own power.
 
That’s super news. How did you diagnose it?
I was very happy that ended up being the issue. I was getting really close to dropping the pan.

I was suspecting a fuel or spark problem because I could tell that the engine was not firing properly. I wasn't sure if the knock was related. I first check to make sure the rods were tight by pulling spark plugs rotating to the down stroke and pushing down on them. All rods were tight so that lead me to think it was not internals causing issue. Also this motor was super clean so I dont think it could have been run enough to cause major bearing failure.

I was going to clean the injectors and fuel rail because of how long the car had sat and just to rule out a clogged or damaged injector. When i went to disconnect the injector I noticed that the wire had broke in the connector. I replaced the connector and it fired right up and is running perfectly. I'm going to replace the rest of the connectors when I install my upgrade injectors .
 
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