Here is a question for yall!!!

[79Chevypickup]

What does it mean when my engine knocks at high rpm?
1979 Chevy 350ci

Need a better description than that?
Just ask...

Thanks to all!!

[old Rusty C10]

knock like a bearing knock??
bad oil pump?? jammed oil galleries?
are ya sure it aint like preignition??

[79Chevypickup]

I am afraid I dont have any answers to those questions...
For real...

I dont know,
It kinda sounds like..... uh.....

Well its knocks kinda with the sound of the engine
when its at high rpm, like when its fixing to shift or
when I am on the freeway trying to go the same speed
you know what I mean?

[MylilBowTie]

It would help with a better description. What all are you running like carb, ingniton, timming and things like that.

About the best I can guess is that is pinging at a high rpm. But there are a couple different reasons as to why it would be doing it.

[79Chevypickup]

I have a 350ci engine
with a edelbrock carb 1406 650cfm
also have an edelbrock rpm intake
is this the info you guys are looking for?

[MylilBowTie]

that helps a little. Do you have HEI? When was the last time it was tuned up? What is your timing set at? Things like that help narrow things down. How many miles are on the engine?

[79Chevypickup]

I have no clue how many miles are on the engine....
Timing has never been set... except by me and my brother-in-laws guessing due to the fact that my timing cover has no timing tab gauge thing....
HEI? bro, I dont even know what it stands for.... sorry....

[CRRoy71]

HEI = High Energy Ignition I believe. It will have the coil in the top of the cap.

[79Chevypickup]

Then I am gonna have to go with no.....
Cause recently I changed out the cap and rotor....
and ignition chip thing

[85 K5]

Originally posted by ChevyGuyBC
sorry it sounds like you know nothing, take it to a mechanic, seriously

Even though I agree with the suggestion I can't think this is how we want to portray our friendliness on this board.......

[Prerunner1982]

i dont think he is trying to be unfriendly. but without a better description or actually hearing it... its hard to diagnose. like someone saying help my truck doesnt start... and thats all they say and they want us to tell them whats wrong. i am by no means saying anyone on here is stupid.... but without all the info its hard to tell...... a knock... could be alot of things.. rod...valve... piston slap..

[Tom]

If its a high RPM only knocking noise my bet is a bearing is going out. It could be MANY MANY other things though so unless he can start going over them one by one its a lost cause.

[1FaastC10]

Originally posted by ChevyGuyBC
exactly, it sounds like he really knows very limited things about how an engine works and the internals of a engine. i myself know quite a bit and before i waste any more of my time on here, just take it to a shop who knows what they are doing. do not wanna mess with a knocking engine

sit back, relax, and keep quiet junior. the guy is asking for help, and that's what we do here is help each other. if i remember correctly, you said that you are 16-18 in another post. 99% of guys your age dont know half of the things they think they do. i was there one time too. just a dumb question for you what is the dynamic compression ratio of your truck?


anywho, back on topic. i had what i thought was spark knock, so i tinkered around with timing, and plugs/gaps. what i found i had were shot valve springs. replaced them, and not only did the "knocking" go away, but the power felt like i added an extra 2 cylinders to the engine.

[swervin ervin]

Yes, I agree, take it easy on not wanting to waste your time. If you don't won't to waste time, find another hobby.

We are here to help and get help. That's the whole concept of forums like this. We try to learn and teach where we can. We also try to help others not waste money by giving it to mechanics when they don't have to.

But, with very limited knowledge, and a big risk of destroying your engine, I would see if I could find someone you know, who knows what sounds are, to listen to it. We can guess at what it might be, but that's what it would be, a guess. Noises are real hard to diagnois without hearing them. If you can find someone, ask them all kinds of questions. If they are good at what the know, they will be able to explain what it is they are saying. Be careful of folks who pull answers out of their butt.

Mike

[79Chevypickup]

I just wanna say thank you to all the people that acctually tried to help me....

And to the rest.....

Whatever...

I haven't been at this site not to long, but I do participate...
I have always tried to help when I could, and never knocked anyone for not knowing something I did... But thats just me...

I thought this site was great, had nothing but people who wanted to help others and give inputs and b.s. about there trucks

I guess there always has to be a few bad apples....

Thanks anyway!!

[stan79chevy]

was it knocking befor you changed the cap and rotor? How high rpm does it start knocking

[swervin ervin]

79Chevypickup,

don't let the childish behavor of others get to you. We are a great group and will not tolerate others being rude to anyone. There's no use in it. If they don't won't to waste there time with a question someone has, just pass it up and go on to the next question they feel like messing with.


ChevyGuy,

I think Jeremy was wanting to know what dynamic compression means, not what you think yours is. The 9:1 you are talking about is your static compression ratio.

Here's is the difference, from the designer of the DCR calculator his self.

DCR is just the same as static compression ratio except it is measured from a different piston location in the cylinder. SCR is measured from bottom dead center (the piston at the bottom of the stroke) to the top of the stroke and compared to the combustion chamber. DCR is measured from where the piston is when the intake valve closes to the top of the stroke compared to the combustion chamber. With DCR the piston will be some distance up the cylinder so it will always be less than the SCR.


Now, let's all play nice. No use in being rude.

[1FaastC10]

Originally posted by ChevyGuyBC
i was never being rude and if i was indeed rude im sorry. It just sounds like your engine has a major rotating asembly problem.

2 things are apparent here. you're a young punk who thinks he knows it all, and you have no manners. read your first post in this thread, if that doesnt strike you as rude, you need to have your eyes examined.

just because there is a "knock" doesnt mean that there's lower end engine failure. every time you hear a noise, you need to investigate before throwing parts at it, just as 79ChevyPikcup was trying to do. check everything possible, fuel, timing, head gaskets (by compression/leakdown tests), valvetrain. then, if none of that can fix it, THEN pull the engine. saves alot of money that way. but mommy and daddy are probably still footing the bill for your ride anyways, so what do you care?

[swervin ervin]

Dang Jeremy, don't hold back now. Just come out and say what you feel.

Cut him a little slack. He said he was sorry if he sounded rude.

Now why don't we just move on to the next question and let this die out before everyone thinks you and I are two mean old bastards or worse.

Let's get back to playing nice or I'm taking my ball and going home. :p

[Russell]

Woah woah woah, chill out guys, this isn't a contest of who knows most... Throwing insults around is like throwing a can of ether onto a gasoline fire, it gets things hot very fast, and isn't needed...

If you must bicker, there is a neat thing called a Private Messaging system, or possibly IRC or whatever your chat client of choice is

[1FaastC10]

Originally posted by swervin ervin
Now why don't we just move on to the next question and let this die out before everyone thinks you and I are two mean old bastards or worse.

i may be mean, and i may be a bastard, but i am NOT old!

[swervin ervin]

Well, not sure on the bastard or mean part for my self either. I like to think I'm not either one. But I do know about the old. I'm older than dirt.

But I'm still good looking as all get out. :p

[TwinTurbo]

Wow, this is turning pretty ugly

chevyGuyBC, that's your static CR, not your dynamic CR you're talking about

On to help this here lad.

Could be numerous things so let's check the easy stuff first.

Go get a TDC locating tool and mark your balancer for TDC, then find a buddy with a timing light, preferrably one that can be dialed in and check the timing.

If it's not the timing, pull the plugs and tell us what they look like, all 8 of them

Now you go and look if you have an exhaust leak or maybe a loose torque converter bolt.

If you're thinking it's a rod knock, pull the plugwires with the engine running 1 at a time, the one that has a bad bearing will be pretty easy to recognise as the knocking sound will be a lot less with that cylinder not firing

Marck

[LOHRTBT]

Mike!! Your good looking?? ACK!! Damn My head still hurts from the last pic you posted#!! !haheehehahahaha

[Russell]

Haha, thats gotta hurt!