4.3 knocking...

[Nuts]

ITS NOT THE ROD OR MAIN BEARINGS!!!! But there is a loud knock coming for my 4.3. The motor is a 97 or 98, is there anything thats known for hammering on these?

[yellowjacket]

is it knocking the same in neutral as in gear with a load?

[Redriverranger]

If it's an auto, maybe loose torque converter bolts, or cracked flywheel.

[sarge]

that is what mine is doing beed that way for over a year , I'll second Casey's diagnosis , I'm going to dig in to mine while it's under the knife and see what it is . Load doesn't change mine knock.

[Nuts]

Load doesn't change it, and all the convertor bolts are tight and the fly wheel is good. I know this because i just put the motor in... Its kind of a high pitched knock, and I'm starting to think the crank is hitting the windage tray in the oil pan.

[Redriverranger]

I had a 4.0 ford knock like hell for about 10 minutes once when I first installed it. I wouldn't have given you two cents for it and was about to yank it back out of the truck. Then I thought what the hell, what have I got to lose and revved the hell out of it. It got quieter. I pushed it a little more and it finally got very quiet and was an extremely good motor for about 4 years. I know this is probably the exception to the norm, but I feel that the engine had some power steering fluid or tranny fluid that ran down in the intake, as it was sitting at a junkyard under a shelf with other engines above it that created a hot spot, or detonation point when I started it, hence the knock. That is the only way I can explain what may have caused it as it truly ended up a great engine.

[Redriverranger]

My bro-in law just had an LT1 knocking and it was the crank hitting a small indentation in the oil pan.

[Nuts]

My bro-in law just had an LT1 knocking and it was the crank hitting a small indentation in the oil pan.

I'm gonna pull the pan off this week an check. This thing sounds like 2 kitchen pots banging together lol

[carwash]

Definitely a clearance issue... pull the pan and you will see your problem im sure.

[sarge]

I'm laughing at this post now !

Nuts , you ever find out what was knocking ?

I sure did :cool: on mine ! rod bearing took a crap

[Nuts]

Yep, crank smacking the pan. But I also found out that motor liked mixing water and oil so I pulled it and found a good motor to replace it.


I still have those 2 blocks if you want them lol