superchomper2003

iTrader: (1)

Well completed a 5.3 and 4l60e swap into my 86 c10 and everything went pretty smooth until I hit about the first 120 mile mark and the 60e rear planets go out so I get a performance tranny build with a 2800 stall. Get it back and great love the way it drives but every since I first started this engine after I put it in this truck it has had a slight tapping noise, I figured ahh it just needs a rocker adjusted or its just the normal piston slap on these engines and nothing to worry about. But now about 20 miles after tranny swap it has gotten much louder and sounds like something really bad is happening. I pulled the valve covers and all is adjusted correctly so its deff internal engine. Its really weird sounding because while it almost always makes the noise sometimes its almost unoticable (you have to pay close attention to hear it) but then some times its super loud sounding like a someone is hammering under my hood. I cant really hear it when driving because the exhaust drowns it out but I can deff hear it at idle and when reving in park. I dunno if its a rod, cam bearing, or just piston slap at the extreme (i think this is it but if so its really really bad). Regardless Im pretty sure it needs a rebuild. What are all you guys thoughts on this. I had exhausted my budget on the build and then with the new tranny Im way over budget! But I have to fix it because it was built to be my daily driver and with me and the wife sharing just her car its really hard! So I want to do a quality rebuild but on as tight of a budget as possible. (Rebuild stuff is so expensive for the LS line!) I have a 4.8 engine that currently needs a rebuild. I know its the same block as a 5.3 so i could just rebuild it into a 5.3. Basically the 4.8 only had like 40k on it and was in great shape but after coming out of a wrecked truck someone let it sit awhile with water in 1 cyl and rusted it up some (isnt that bad and could deff be bored out). So what do you guys think rebuild the 4.8 into a 5.3 (would have to buy 5.3 crank and rods and pistons. Or what if I bored it out to accept the ls1 pistons and left the 4.8 bottom end. What would that make the engine size? What do you guys think about this idea? What about the weight difference of the ls1 pistons over the 5.3 or 4.8 pistons, would I have to use the ls1 crank and rods or could I get the 5.3 or 4.8 crank rebalanced (no idea what that would cost). Im just thinking because I deff want to do it the cheapest way and still have it be right but im going to have to get it bored and pistons anyway so would it really cost more to do the ls1 pistons? And I cant use any parts from my current 5.3 because Im just gonna have to keep driving it and pray it holds up till I can get this one built and I dont know whats good inside it with the knocking noise. Also need some good cam choices but don't want to spend a ton on expensive valve train parts. Let me know what you guys think about everything. Thanks and sorry so long just wanted to include everything!

TXSZ66AVLANCHE

iTrader: (7)

Sounds like a chewed up lifter and camshaft lobe.

superchomper2003

iTrader: (1)

I thought it might be something like that except that I pulled the valve covers and there was no slack in any of the rockers. Could this be the case? And if so could a cam and a set of lifters fix my problem? Thanks

MikeGyver

iTrader: (5)

Lifter travel can easily hide the clearance from cam damage with the engine off. It can also be very intermittent, just exactly as you described, when the engine is running.

superchomper2003

iTrader: (1)

Wow I would hope that this is all the problem is. How would I know? Do I have to pull the heads and take the lifters out to look? Again the truck is running great other than the noise. Its weird because the first couple of seconds after I start it on a really cold morning it sound like someone is banking under the hood with a hammer and then it basically goes completely quite and I cant hear anything for several minutes untill it starts warming up. But after it warms up the noise comes back (not nearly as loud as it was the first couple of seconds though) but the intensity changes but the noise never goes away after warmed up. I will post a video in just a bit of a cold start from this morning. Then later I will try to get a warm running vid.

superchomper2003

iTrader: (1)

Here is the cold start vid from this morning. You can hear how it is really load for just a sec then going away untill it completely warms up. I will get a vid of that after I get off from work tonight.

http://www.youtube.com/watch?v=HGu4j5nt-Bs

Suburbazine

That sounded just like a lifter loose in the lifter tray. It will turn sideways occasionally and make a really loud clacking sound.

And when one turns sideways it tears the lobe off the cam and the roller off the lifter.

superchomper2003

iTrader: (1)

Thanks, would that cause the lifter bore in the block any damage? And why would it be really loud the first few seconds then quite untill the truck was warmed up? Would I need to pull the heads to confirm this?

Suburbazine

I haven't seen one cause the lifter bore damage from just getting turned sideways- usually it damages the bore when the lifter and cam get degraded to the point where the cam tears the lifter apart (and I've only seen it happen once). The bore will also get torn up if the engine is run out of oil or metal particles from the cam/lifter get inside and grind it.

superchomper2003

iTrader: (1)

Wow after I took the vid yesterday morning I drove it all the way to work and then I drove it back on that night and it never made a sound. A few hours later I had to go back uptown to take my wife something and by the time I got home it was doing it pretty badly so I got a vid of it warmed up knocking for you guys. The vid is terrible because it is at night but you can clearly hear the sound. It sounds terrible! What ya think?


5.3 knock.MOV - YouTube