I've got this intermitten noise coming from the bottom end of my engine and need a little help. I replaced my rod bearings a few months ago but didn't use the plastigage to measure the clearence. I got a good deal on a full gasket set which included new rod bearings and rings. Is it possible the new rod bearings are just too sloppy or am I looking at new crank bearings? My company gave me a little Christmas enima <img src="/forums/images/graemlins/zombie.gif" alt="" /> in the way of moving my lab to Michigan so I have the time to fix any problems, but want to watch the funds. Jobs are a bit sparce in these parts so so want to be carefull what I have to replace.

The bearings you recieved may not be the same bore as what is on the crank. Did the noise start right after the bearing install? Have you owned the engine for its entire life? If not someone may have had the crank and rod journals turned which would require an oversized bearing. This is why plastigauge is a must.

If you are sure it is the lower end, I would think about taking the pan off and inspecting the bearings.

I only replaced the rod bearings, not the crank bearings, with stock bearings. I would really like to rule out the rod bearings. I rthink the noise was coming on gradually and now it's pretty loud after the truck has warmed up. I've owned the truck since it's birth. I heard about this plasigage in FSM, they suggest checking the bearings with this stuff.

Have you tried pulling spark plug wires from each cylinder one at a time while the engine is running to narrow it down to one cylinder? When the noise stops you have found your problem cylinder.

Make sure you put the first wire back on before going to the second and so on.

Can ya give some more background as to why you replaced the rod bearings in the first place? Wondering why there was such a good deal on full gasket set, rings and rod bearings....recall what brands were on the boxes?

Start the truck up, make sure its secured in place and climb underneath it...if the exhuast amplifies the noise and it sounds like a metal thingy hitting another metal thingy kinda hard then good chance (more like definate) slop in one of the connecting rods large end. Were you positive to torque down the rod caps...easy to get distracted ya know...all it takes is a buttered up big breasted honey in a skimpy bathing suit, kids playing and screaming- or a nekkid woman going by walking her dog and thats that...engine is destined for problems. <img src="/forums/images/graemlins/smile.gif" alt="" />

Cheap tool that is a must when diagnosing noises is a Mechanics Stethescope. Cost about $4 at Harbor Freight and will will help you pinpoint the source of all kinds of noises. Just dont be letting the end hit anything when them doodads are in your ears.....hurts like a sumabitz!

~Darin <img src="/forums/images/graemlins/baby.gif" alt="" />

Man I need to move to Port Orchard...all we have is old people who let their dog poop in your yard. <img src="/forums/images/graemlins/rodent.gif" alt="" />

No, I didn't try the spark plug thing but I will in a minute. I'll get back to you.

I replaced the rod bearings not only because they came with the kit, but since I had to replace the rings and I knew they were right there anyway, I went for it. I did take my time and replace the rings and bearings one at a time. Every thing is torqued to spec. I'm not sure if I still have the boxes from the rings and bearings but I do have the box for the gasket set, I'll let you know what brand it is, I never heard of them before but that doesn't mean anything. It was far more complete than the set Fel-pro makes and am real impressed with the quality.

O.K., pulled the spark plugs one at a time and unfortunately didn't find any noticable difference in the sound. what this thing sounds like is exactly what valves sound like when they need adjustment. Darin, I don't have the boxes for either the rings or the bearings and what was left over from the gasket set I put into the Fel-Pro box. The enw kit was placed on a piece of cardboard and covered with plastic, no box so I must have threw out the package. I don't tend to keep old shizzit sitting around too long.

If it sounds like valves, it could be top end. Does it get louder when you pull the oil fill cap? Other than the noise, how does it run?