I posted a thread in the 302 section and I'm not getting just a whole lot of information. seems to be more people over here so i thought i'd throw this out.

cold start up, at idle she's quiet. when i touch the gas to go *in gear* she's tapping. the noise is load dependent and affected by rpm and temperature. when the engine gets warm after about 10 or 15 mins of in town going home driving it gets much much much quieter. after a 30/45 min hwy session she sounds like her nice old self.

i've done and checked a few things. first was my belts becuz they were so loud they might have been masking the noise some. pulled the valve covers, checked for any slack while hand turning the engine. cldn't feel any and dad still hadn't heard the noise cuz she was hot off the hwy. nxt morning we checked again cold for slack, cldn't feel any and fired her up w/ the covers off, in gear on the brakes and gas and it sounds like it's coming from the back passenger side in 3 or 4. still can't feel any slack in anything in that area or anywhere else for that matter. all of them are oiling good. so we went to put in an aux oil pressure guage to get a better idea of what's going on and wasted a day and a half when dad twisted off this aluminum extender inside the block. fun fun! oil pressure at cold is around 50, at warm it's about 35. ran out of time so we put it back together including new exhaust manifold gaskets as a wishful thinking kind of deal and i pulled my 85 out of it's 6 year hibernation and gave her a workup as a backup. threw a quart of marvel oil in it to replace what was lost with the covers off and crossing my fingers that'll help, took her about 30 miles and when i got to the first stop the oil pressure dropped just as close to 0 as she cld go w/o pegging out. that was the first time she'd been truly hwy hot since i started. after two days of city driving and another 30 mile trip home finally a week later, the tapping seems more constant, more all the time, and not as sharp or loud when she's stone cold. i could have been missing the all the time becuz of the noisy belts though.

my questions:

what could the tapping be?

could the thinness of the marvel be affecting the oil pressure that much?

what else can i listen and watch for that might give me indication one way or another on the real problem? *i've had several suggestions*

is the size difference on the internal diameter of the busted aluminum extender *narrow* vs the replacement southern engineered looks like a plumber pipe stuff *wider* gonna affect the oil pressure reading?

does anyone have a cigarette i can have???????

all suggestions are appreciated!!!!!!!!!!

 

It's more than likely exhaust pop.

Once the metal of the head and exhaust manifold heat up it goes away.

Next time take a piece of garden hose and with one end at your ear ...take the other end and search exhaust - head joints or up against the valve cover.

This will magnify the noise a help determine what the problem is.


Quit Smoking all together you ....and don't ask for any

 

changed the manifold gaskets already last week. the PO had them on backwards but the sound didn't go away when i did that. does that mean the manifold may be cracked or something?

i cld go into my list of suggestions, the worst of which means buy a block somewhere and take it to a machine shop like a core and buy one that's already rebuilt and do a swap so i can tear into this one and figure out what the hell and still have something to drive. the 85 hasn't been driven since the wreck until this past week and the alignment's off and there's a squeak on it that makes me think something else was damaged in the wreck so i'm not all about just trusting it blindly either.

wld a cracked exhaust manifold just suddenly make itself apparent? wouldn't it have that pffft kinda softness to the knocking? do you know anywhere that does free exhaust leak checks cuz i wldn't have a clue what to look for.

i have a pair of those stethascopes that i borrowed from my uncle, but i'm afraid i wldn't know what i was hearing if i do hear it.

 

Next time you take the valve cover off check the rocker arms for looseness.

also, when cold ...start run the engine and check for oil on ALL the rocker arms.

Maybe a lifter or 2 are getting pieces of debris in them and blocking oil delivery ?

Stethoscopes are a good thing.

Make sure you dress up in your nurse's outfit as well

 

The Marvel is a good cleaner, but don't run it more than 100 miles or so, it evaporates and will leave your oil level low. If you don't have that many miles on it, run it til 100, then change the oil and filter with your regular oil, but substitute one quart for Lucas Oil Stabilizer. If you normally use synthetic oil, Lucas does make a synthetic version.

How many miles do you have on the engine? I imagine is a lifter ticking that is causing the noise.

I wouldn't jump into a rebuild for just a little lifter tick... but it may be worth starting to gather up parts for a 347 build, that will wake the old truck up.

 

i guess i shud have been more clear. i was checking the rocker arms for slack with the valve covers off and hand turning the engine to check each one. i cldn't find any slack in any of them. i was running the marvel to clean it in case it's a stuck gunked up lifter. there's no debris in the oil that i can see on the dipstick or coming up through the engine or any of the four times we had the oil filter off replacing that hunk and aluminum my dad broke. i didn't know the marvel wld evaporate out though. we had it running warm with the covers off saturday last week and cldn't hear it but sunday morning running when she was cold and the covers off we could hear it under load and i cld see each one of them was oiling about the same. dad didn't break that extender until after i'd already put the covers back on.

and this noise just showed up all of a sudden sounding awful. i'm not sure i hadn't heard it before right before i got my last oil change but not anymore after that. it's been steadily oozing from the oil pan and covers for a while and i have to add a quart every so often. i don't pretend i've kept up with it as well as i shud have though because there's been a time or two i've caught it two quarts low instead of one and i know that's not good for it. i try to catch it about one quart low so i'm not trying to keep open quarts laying around in my toolbox leaking all over the place. when i heard that racket monday before last i checked it and it was low and i added two quarts but that's only happened this makes twice this year where i've let it get that bad and it's always right before i'm fixin to get the oil changed cuz i keep thinking oh i'll get it changed and then don't.

so here's me showing my ignorance for the day, 347 build?

 

so you checked each and every rocker arm for extra clearance when the rocker arm was slackened off the valve ?

This would be done with about 3 different positions of the cam,

 

my guess from what you said is it is a lifter makeing the noise. the stock fist 302 i had in my 86 had a lifter tap and the 302 i replaced it with has one, im pretty sure 302s came stock with lifter taps.

 

There is no point in checking the rocker arms, they aren't adjustable. They can be shimmed, but this is something a machinist has to do.

A 347 is a potent stroker version of a 302.

 

No..they aren't but the push rod to rocker maybe worn out causing the extra click clack ?

I don't what she has done with engine or how many miles on it.

 

i haven't done anything with it. i've had it 6 years and the PO said his brother or some such body rebuilt it 6000 before i bought it. don't know who or what that guy is or what kind of job he may have done on it. i'm not sure exactly how many miles i've put on it becuz the odom is wrong (oversized tires) and the speedo cable was busted for over a year but she's showing around 40000 that i've put on her in that time so i'm guessing closer to 50000 actually that i've put on her. started mostly hwy miles when i got it and now it's a combination.

yes dad spun the engine around by hand until i cld check each one for slack. i knew the engine wasn't adjustable or whatever.. if there's slack you have to buy longer or shorter pushrods. i did read that in the manual before i started on this but does that not let you find slack?? if the lifter's stuck then the marvel shud be cleaning it but if it's just retarded then i'd need to replace it but i don't know how to tell if it's a lifter or exhaust leak or rod bearing etc. i've been given some maybe's but not any way to really figure out what it is except for the checking the rockers for slack which i cldn't find any but that doesn't mean i wasn't doing something wrong. i haven't had any noise up until about 2 weeks ago now at this point. it just started as far as i can tell.

i haven't done any work to this engine except had a waterpump abt a year ago which was an ordeal cuz i had to take it in three times to get it right, a radiator, and a transmission rebuild 5 years ago. i don't know that any of that affects anything. she's been a good solid engine up until this noise that makes me think she's gonna blow up. i keep apologizing to her... *shaking my head*

i appreciate all the help guys. if there's any tricks you know that give it away what it is. i'm gonna try to listen to it tonight when i get off with that stethoscope not that i'd recognize a noise if i heard it. just see what i hear and come back here and bug y'all some more.

 

Normally a stuck or plugged lifter will not yield any oil to the rocker.
That is usually the first clue.

Replacing a pushrod and rocker arm will usually solve the problem.

THe one problem in T/S'ing is lifter tick and exhaust pop sound the same

 

t/sing?? sorry for my ignorance...

 

day later and it comes to me.. troubleshooting... ok now that my blond moment has passed.

the marvel hasn't helped at all so i'm guessing that it's not a stuck lifter becuz if it were the marvel should be helping it and it's not.

now it's developed an almost squeak like higher pitch tone to the knocking at dead cold start up. there's still the sharpness to the knocking sound but there's an undertone to it that's a higher pitch than the knock. it seems to have the same span as the knock, doesn't seem to be coming before it or lasting longer than the knock.

does that add any guesses to the pile of what in blue blazes it might be?

 

Stupid question, but does your oil dipstick read full? Recently I had developed this gawd awfull exhaust leak while going down the road, it kept getting worse and worse. I stopped to check the engine out, it was making a taping noise near the back of the motor. I shut the truck off, and check all of my fluids. The dipstick read about 1 1/2-2 quarts below full, I figured it was good enough because it showed on the dipstick. (the engine leaks like a seive) I started the truck back up and used the heater hose trick to listen to the motor. I shut it off again, and contemplated life. The motor has a pretty bad rod knock, I had just done an oil change with 2 QT lucas oil stabalizer,(thick stuff) and 3 QT of 30W oil. Figuring it would not hurt any, I added 2 quarts of oil, low and behold the noise went away.