JFROG

ok so far i changed all exhaust gaskets. ran tranny fluid in the oil, drained with car jacked up on pass side to try to help get any sediments get out. ran a bit with new oil and filter with more 1/2 quart tranny fluid then put synth oil in. there is still tapping on the passenger side, can hear from under the car/ wheel well. very hard to hear in the engine compartment. tapping starts when engine warms up but after it sits. for about an hour, when i start the engine it will tap for about 2-3 seconds stop then start again when warmed up. could this be header noise/tapping? i do have edelbrock headers and i hear they are not really good quality. should my next step be to drop the oil pan? not really looking forward to that. the oil pressure will sit about 45-60 when engine cool and then when warm will drop to about 15 at idle and raise back up when givin gas. heard this is normal. runs pretty good otherwise. just have sort of perfectionist attitude when it comes to a running engine. any help will be appreciated.

84z28350

sounds like it could be lifters or maybe just improperly lashed...

tawd

Try using a dowel rod (broom handle or something similar) and hold one end up to your ear, and the other end up to each valve cover. Then try to lay under the car and hold it up to the oil pan. Which was louder, one of the valve covers, or the oilpan?

If it was your valve covers, Try popping off the valve covers and give each rocker arm stud nut 1/2 turn clockwise. Put the valve covers back on and see if there is still a problem.

If the oilpan was the loudest, you probably have a bearing letting loose. I wouldnt start it anymore and hope no bearings have "spun" yet. Take off the oilpan and one at a time - take off the rod bearing caps. Make sure the bearings are still in their alignment grooves. Replace each bearing with a new bearing of the same size. Look on the back of the bearing, it will say if it is STD(standard) .010/.020 etc... Get some emery cloth and try to polish the crank journals the best you can. Put it all back together and do the normal breakin procedure.. 2000-2200RPM for 15 minutes. See if its still ticking. If it is, its probably a worn wrist pin. Have to tear the pan back off, and the heads to fix that...

PS If a bearing has SPUN (no longer in its alignment grooves) there is no point in putting in new bearings. The crank/rod will need to visit a machine shop.

JFROG

i had already adjusted the rockers, if a bearing why does it tap for a few seconds at startup after sitting for a while? sort of like oil starvation is what i was thinking. if it is the bearings would it be best to just get a 350 long block use everything else ( change to 350 injectors) rather than spend money on the 305? nothing but problems since i got the car.

joe350

In my experience, lifter problems either happen all the time, or when the lifter is being starved of oil (usually at startup or if you have really low oil level). I've never had bearing problems but the previous poster has the right idea. Find out where the tapping is coming from. I once had tapping caused by my cooling fan hitting the radiator. Only happened every once in a while. Often times fuel injectors tap. My opinion though, if its not very audible from the engine bay then its probably not a lifter.

tawd

Well, When you start getting worn bearings you will hear a slight knock when you first start up your car after not running for a while. All of the oil has returned to the pan, and there isnt enough oil to take up the clearance between the rod journal and the bearing. As soon as oil pressure builds, it will quit knocking. When your bearings get REAL bad, It will knock like that when its first started up, and the knocking will then return when its at running temperature because the oil has gotten warm and thinned out. Its no longer thiick enough to satisfy the bearing clearance on the rod/mains. So, the only way to fix that is to reduce the amount of clearance between the bearings/journals. The bearing is designed to do the wearing, unless a bearing "spins". As long as there are no spun bearings, the engine should be fine with a new set.

A 350 is ALWAYS a better choice over a 305. If you are planning on just buying a new longblock, go with a 350...

JFROG

got any pics of how bearing will look of spun? cant find my repair manual. also if any one has the torque specs. do i need to get to the bottom of the rod (move the piston up) or just pull off the bearing caps?

JFROG

update: found bent pushrod on #4 replaced the pushrod and rocker assembly. adjusted the rocker while the engine was running and it now has no tapping. the only thing now is to replace the crappy flowmaster single exhaust.

Nixon1

Bent pushrod....eep...probably over-rev damage

Glad ya found it, yeah I can see that making a noise

Sort of like when I broke a pushrod in half...yeah that made a real funny noise.