engine knock

[ryanwitski]

i drive my car from Youngstown to canton (40 miles) and i get a really nasty knock after about 35 miles. the next day I'll turn it on and it's quiet again. My oil is over due but then it's kinda expensive to put new max life in it. My oil pressure is a little low after a while but not below 25lbs. also i have a 3.42 rear and cruise at 3000-3500 rpm. anyone know what is wrong? thanks!

 

[Chevyman85]

Is it a knock or a lifter tap? If its valve train noise it wouldn't hurt to do an oil change. I'd opt for that first. If its knocking or missing I'd try running higher octain fuel. This time of year the winter blend fuels are out and they dont run as well in some vehicles. Just a couple of tips.

 

[SBCregal]

5 litres of oil and a filter costs a lot less than a motor rebuild

 

[thebaron]

maybe change the oil pump anyhow and check out the bearing/rods during the change over...

 

[ryanwitski]

the oil pressure is fine though. It has cheap oil in it. It's the first time I did not use max life. It's a knock in the number 7 cylinder. I'll change the oil and it will probably go away forever. It always runs much quieter with new oil.

 

[Chevyman85]

5 litres of oil and a filter costs a lot less than a motor rebuild

Enough said!

 

[pontiacgp]

if your getting a knock after you drive it for awhile it might be a carbon knock.....get some good water and pour it down the carb with the engine running to clean steam clean....you can also pour some transmission fluid down the carb to clean the upper part of the engine.....and before you do an oil change running the ehgine with a quart of transmission fluid in the oil will clean the lower part of the engine......I have also heard a cracked flex plate sound like a bearing knock......but if you sure it's #7 that's knocking take the plug wire off and if it quietens then it is probably the rod bearing thats knocking...I had a 305 that spun the rod bearing on #7 but I havn't heard if it's a common problem...good luck

 

[ryanwitski]

I'm just going to have to put in that stuff to clean it before changing the oil and put in new oil. There is no option rather than that, it needs it! I wanted to try that royal purple since i'm 5 miles from the main Summit racing in Tallmage OH. Probably just use max life again though!

 

[RedHotRegal]

I think my flexplate is cracked and causing my horriffic knock. Everyone else thinks its the motor, but I think its the flexplate or the converter. How much water/transmission fluid is acceptable? Just wondering. thats good to know.

 

[pontiacgp]

red...theres no limit to how much water you pour into the carb and if you pour too fast it'll stall the engine......it's stream cleans the pistons and valves....for the transmission fluid you can use as much as you want but you don't need more than 1/2 litre or quart and do it in an area where the neighbours won't kill ya...the amount of white smoke out of the exhaust will cover the area pretty quick....for the tanny fluid added to the oil use a whole litre/quart and run the car to get it up to operating temp and let it idle for about 10 minutes.....then dump the oil and put some good stuff.....