Confusing knocking problem..New engine..Please help..

latham83 · May 18, 2004

Ok...turned the timing back to 12...and fuel pressure is at stock setting...Found out that it is def. not detonation that i hear...This is not good at all..kinda of depressing...See if you can help me with this before i take it anywhere...Its like a knocking..sounds like something is slapping the bottom of the oil pan almost...but maybe its not doing that..im just giving a sound..it is coming from that general area...bottom towards the back it seems like...Now ppl say ok..it can be a bearing...but heres the confusing part...the car runs great until it gets very hot...I have a 180* thermo. in there..and it will stop at like 190 or so...and steady there as long as im driving and moving..Once again..i have zero knocking then...THE ONLY TIME AT ALL that the knocking starts..is when the guage reaches about 205-210? which it probably shouldnt do? Usually the last couple times i had the car out for a very long drive..beat it up alittle even..came to stops and it was fine..then if i would let it sit in a parking lot for alittle bit , it would hit the 205-210 point and there came the knocking. It goes faster when you hit the gas. BUT..once it cools down alittle..like if u open the hood..it fades away!??! i swear everything im saying is true...it only comes when it gets to that temperature..i dont understand and neither does my dad...With a 180 in there, it should not hit that 210 point should it? I had an idea tho.. What if i thro in a 160* thermo. So it keeps it from getting to that 205 point..do you think that might work? I mean i dont know how bad of a thing that is going on tho? ask around or please get back to me asap if u have an idea because im lost..and i dont wanna pay anyone just yet if i can fix it...

Js5ohLX · May 18, 2004

what does your oil pressure do when it heats up? Sounds like it's running hot due to friction, then knocking, sounds like you need a crank kit.

Mike86Stang · May 18, 2004

What wieght oil are you using? Might try a heavier oil

latham83 · May 18, 2004

hmm im not sure what the oil pressure does..it usually steadys at about 50...it MIGHT drop alittle bit once its getting really hot..like 25-30? a crank kit?! eveythings brand new! thats bullshiit if this block if messed up. its a dss racing 306 short block.
im running 10w-30.....u think if i go thicker and maybe add some lucas oil stabalizer it will delete the knocking? what about it overheating tho..where does that come into play? if theres a 180 in there it should not heat up to 205-210 am i right? should i try a 160.

BYRDPE · May 18, 2004

latham83 said:
hmm im not sure what the oil pressure does..it usually steadys at about 50...it MIGHT drop alittle bit once its getting really hot..like 25-30? a crank kit?! eveythings brand new! thats bullshiit if this block if messed up. its a dss racing 306 short block.
im running 10w-30.....u think if i go thicker and maybe add some lucas oil stabalizer it will delete the knocking? what about it overheating tho..where does that come into play? if theres a 180 in there it should not heat up to 205-210 am i right? should i try a 160.

195/108/160 is just the temp that the thermo opens.

latham83 · May 18, 2004

well yea..exactly...it i put a 160 in there..maybe it will not hit the 205-210 temp. point and i will not have knocking anymore? make sense ? i dunno...im just pissed...

bjmellon · May 18, 2004

When you say you returned it to the stock setting, what was it before?? Have you tried to fatten it up at all?? I'm wondering if this is due to a lean coondition. Is the EGR working?? It sounds to me that it is spark knock....the chambers are heating up causing the detonation. Do you have the correct spark plugs in there, try taking them out and reading them. Look for discolered insulator's, or what look's like " a rough suface on the electrode.

bjmellon · May 18, 2004

It could also be a fan clutch problem!!

hllon4whls · May 18, 2004

try to get the cooling problem squared away first. The lower temp stat should only help if the old one is sticking. Do you have good water flow through the rad with the stat open? What sort of fan are you running?

latham83 · May 18, 2004

i dunno bout a spark knock tho..i had the timing at 16* and the fuel pressure at like 45 without vaccum...still knocked when it was really hot....
it looks like im being told to do the 20-50 oil by most ppl..see if thats the problem..

latham83 · May 18, 2004

its a flex fan..belt driven...worked awesome on my stock block....never went past 190*
man i dont know what 2 do...a 160 thermo will give me drivability issues? thast what i was told...

hllon4whls · May 19, 2004

I've heard the same.

Did you replace the WP on this new motor? If you did, did you get the right rotation pump? It just doesnt seem that it should get that hot!

bjmellon · May 19, 2004

Changing oil weight is a band-aid!!!!!!!! You need to fix the problem! A thermostat is designed to keep the engine hot (above a certain temp). Lets say a vehicle is running hot, say 240*, if you were to put a 100* thermostat in it would still be running at 240*, unless the t-stat was sticking, thats a diff story. If a cooling system were able to keep the temps down below the t-stat temp, then changing to a lower temp t-stat would allow the engine to be regulated at that temp.
The thermostat was designed to: a)heat the engine faster by not allowing any coolant to circulate through the radiator. b) keep the engine above a specific temp (its rated temp) in order to allow the engine to operate at its peak efficiency. In other words, if you were to remove your t-stat (thats definitely working corectly), and run your engine it would still reach a high temp. I have a very strong feeling that you either have a fan problem, water pump issue, or a sticking t-stat. Best chance being a fan problem (backwards, not broken, no shroud.....

Js5ohLX · May 19, 2004

"Its like a knocking..sounds like something is slapping the bottom of the oil pan almost...but maybe its not doing that..im just giving a sound..it is coming from that general area...bottom towards the back it seems like"

Sorry, but spark knock is more of a rattle, that sounds like a rod. If your cooling system is ok, I'm still gonna say you have a lower end issue. Maybe you had a bad build or if you have old or reman rods, one was slightly out of round, happened to my buddie on his. If you have a rod knock, it will make that engine heat up substantially. If it's over heating while your driving it (down the road) , and your not beating it, I don't think a fan would be a problem either. Technically after about 25 mph your fan is useless.

bjmellon · May 20, 2004

"the car runs great until it gets very hot...I have a 180* thermo. in there..and it will stop at like 190 or so...and steady there as long as im driving and moving..Once again..i have zero knocking then"........"Usually the last couple times i had the car out for a very long drive..beat it up alittle even..came to stops and it was fine..then if i would let it sit in a parking lot for alittle bit , it would hit the 205-210 point and there came the knocking."

The engine is not getting hot while he is driving, this is why I feel as though it is a fan problem... It could also be due to a flow problem like a bad w/p impeller, when he is driving he's at higher r's giving more flow, at idle he has less... maybe too much less..

Js5ohlx, I saw in your profile that you are a tech, well, so am I. You should know that there are multiple different types of detonation, timing= ping or rattle sound, lean= ping or tap sound, hot comustion chamber faces causing the a/f mixture to fire randomly btdc sounds like a knock (listen to a diesel and tell me it doesn't sound like it's knocking). Knowing the different noises of an engine allows me to isolate a certain system for quick, accurate diagnosis.
One way to test for a internal engine noise is to disable the cylinders (pulling plug wires, disabling the injectors). If the noise stops or changes, you can isolate it to that specific cyl.

Confusing knocking problem..New engine..Please help..

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