[74chevyflat]

i have a 1980 mustang with a 200 l6. it has 110,000 miles on it. everything works ac, cooling, heating, brakes, carb, fuel pump. OK here the thing every since i got it it seems to have a knock under light acceleration during cruising and gets louder with more rpms. on cold startup i have a knock and then it goes away. i was thinking it was timing so i checked it and it was set right 14*. Additional info may be that the engine has never had anything done to it. no reseal no rebuild nothing. i recently changed the valve cover gasket to fix a leak and i noticed allot of gunk on everything!!! i mean this is the nastiest engine i have ever seen. well not as messy as a 267 chevy out of a malibu. it literrally has 1/4 inch of gunk.. could it be that the oil pickup tube is clocked? or the oil pan is so filled with sludge that it wont pickup oil till it creates a valley in the settled sludge?.

I am only asking for some info cuz i cant adjust the valves. i dont like this design i am a chevy guy. I wish i had the money to buy the clifford adjustable rocker arms.
But anywho this weekend im gonna drop the oil pan clean it change the oil pump, pull the head get it reworked clean the surfaces check for straightness. the usual and if there are galleys clocked in the block ill try to use some ether and shove a bristle brush down inthem and see if theyll clean up? does this sound like a remedy??

[eloc431962]

Does it knock all the time? Or if it does it just when it's cold first start like you say? If it does it when you first start the engine (cold) or after it sits awhile after driving it i would be willing to say it is the oil pump slow to pick up the oil. Could be clogged or just worn . If it had that much build up under the valve cover you can only imagine what's in the pan and the pick up tube. JMO


Cole

[74chevyflat]

ok it does it on startup, and while cruising at light throttle

[a1supersport]

Knocking or pinging? Just wanted to make sure. Sometimes when I put gas in my car (always premium 92), the car starts pinging shortly after filling up (from almost empty). If it's pinging...bad/old/low-octane gas maybe?

But that gunk is a bad thing. I've seen that on many commercial vehicles that we pulled SBC's out of. Lack of maintenance of the previous owner(s) was to blame.

[74chevyflat]

sounds like valves slapping shut like as if they were hit by a large 2 lb. hammer sometimes sounds as if u were to beat the pushrod against the camshaft
the sound comes from the driver side of the engine

[74chevyflat]

on cold start sounds kinda like a rod knocking

[eloc431962]

I really think it's struggling to pick the oil up and get it circulating through out the engine. Had one do the same thing and have seen countless others also.JMO But someone else might have a better explanation.


Cole

[74chevyflat]

how about i go with an old saying and put it to funtion." Take it apart clean it put it back together." it'll definitely work then. and in the meantime lap the valves new seals. clean up on the combustion chamber and runners. hopefully i can polish them up a bit.

[techinspector1]

Originally Posted by 74chevyflat

on cold start sounds kinda like a rod knocking

It probably is. A high miles motor that has not been properly maintained could easily have excessive bearing clearances. My old 300 six did the same thing before I tore into it for a rebuild. If you're gonna pull the pan anyway, get some rod and main bearings and change them out. No big deal, just loosen the main cap bolts enough to drop the crank down a hair. Tap the edge of the bearings with a popsicle stick to rotate 'em out. Go back together with a standard oil pump, not a high volume or high pressure.

[matt167]

there an extremely easy engine to work on/ rebuild.. don't worry to much about the gunk under the valve cover. those engines are quite common to get build up there.. also keep in mind that those shaft rockers will knock if they get worn enough... if you rebuild, Melling makes replacement oil pumps.. most any auto parts store can get them

[scrot]

If the oil pan is all gunked up, I'd like to see some pics please.

[eloc431962]

Originally Posted by scrot

If the oil pan is all gunked up, I'd like to see some pics please.

Hummmm!!!!! you haven't ever seen build up in the bottom of a oil pan before?


Cole

[74chevyflat]

ok i just bought an m-65B replacement pump,
got standard size rod bearings.
i cant locate the main bearings. The parts store doesn't have them in stock and they dont "work" with them they said. I was wondering could it be ok if i just change the rod bearings?

I have a question about later on. is it possible ot change the camshaft bearing while the motor is in the car. when i get home this afternoon i`m gonna break into the engine and get to work.

and about the pickup tube. they also didn't have it. i`m gonna get some ether from work and clean the old one with a dental pick and cylinder brushes.

I will take some pictures of the bearings when i get them out, because i really think that one of them has been spun. The knocking is getting louder every time i crank it up and drive it.ON cold startup light throttle, oh and it stas quiet on deceleration and going uphill, i think the transmission not having overdrive and driving to work at 2500 rpms for about 35 mins doesn't help at all.

[matt167]

if it really is knocking and your still driving it.. it's going to need some machine work..

as far as main bearings.. any 'good' auto parts store can get them.. or you could get them at www.classicinlines.com.. as for the pickup tube. you gotta reuse the old 1 as I don't belive anyone is making them anymore

[74chevyflat]

it doesn't knock constantly. Does anyone know the torque specs on the oil pump bolts? i have the Haynes manual and it doesn't state the oil pump bolt torque specs. Gonna tear into the engine here in a lil bit once i get the torque specs on hand. ,: so i don`t get the computer greasy lol.