Engine Knock (Me too!) - Team Camaro Tech
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post #1 of 70 (permalink) Old Sep 12th, 12, 11:08 AM Thread Starter
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Engine Knock (Me too!)

Man, the more I read this forum the more I like it!

I did not want to hijack the other thread, so I posted this one. I just noticed my engine knocking too. Its the first time I've noticed it. The previous owner did mention that I may need to adjust the valves due to the new cam having been broken in.

I have no idea how to do this. I see that several of you mentioned the "lash", I do not know what that is either (forgive me!).

Now, I did just have to jump start the car, could a weak spark (due to dead battery) cause knock? Typically I'd say it was poor/low-grade fuel. The knock seemed less pronounced (almost non-existant) after I drove the car for a bit; performance was not diminished.

Should I try octane booster to see if its poor gasoline? I use 93 octane.
I've also been advised that a valve oil additive may assist. Though, this engine has been re-built and has less than 2k miles on it.

I am determined to get some time to work on it this weekend (still have some e-brake and pedal adjustment advice to use!). Thank you all!!!

'67 Camaro
350 V-8 bored .030 over
Edelbrock Intake Manifold &
600CFM Carburator
MSD Ignition, Crane Cam
World Heads, Hooker Headers
3" Flowmaster dual exhuast
Aluminum drive shaft
Muncie 4-speed Transmission
Posi-rear end with 3-leaf rear springs
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post #2 of 70 (permalink) Old Sep 12th, 12, 12:09 PM
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Re: Engine Knock (Me too!)

So there is a lot of different kinds of engine noise you could be hearing and too many loosely used terms or words used to discribe what you are hearing.

Valves, lifters and rockers make a ticking noise if too loose that can be heard coming from the valve covers.

You could be hearing a "rod knock" but it would be coming from much deeper in the center of the engine.

You could have an exhaust leak, it's typically a popping sound accompanied by an air spurting sound on top of the popping.

There is also pinging, knocking and detonation which isn't usually heard at idle, it will actually sound like marbles rattling in a coffee can or something metalic and tinny being dragged.

Hopefully that will help you figure out what you are hearing. As for "lash" think about lashing something down with a rope, "you lashed the boat up to the dock". Basically you have a lifter sitting on top of a cam lobe, then a pushrod on top of the lifter and a rocker arm on top of that. You adjust the nut on the rocker to lash everything in place. When you hear "zero lash" that means all the pieces touch but there is no force other than the parts weight and gravity pushing the pieces together. Preload is putting additional force on the parts, this is used when the lifters are hydraulic. With a solid lifter cam you will hear of the lash being set at .020" or something like that. That is a the opposite of preload and can be measured with a feeler gauge.

...Dennis

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post #3 of 70 (permalink) Old Sep 12th, 12, 12:30 PM
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Re: Engine Knock (Me too!)

earlier I had horrendous pinging and it turned out to be a blown head gasket.
do a compression test before going any further.
If its not that use a higher grade fuel.


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post #4 of 70 (permalink) Old Sep 12th, 12, 01:38 PM
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Re: Engine Knock (Me too!)

Quote:
Originally Posted by VengefulTick View Post
The knock seemed less pronounced (almost non-existant) after I drove the car for a bit; performance was not diminished.
What kind of pistons did they use on the rebuild? If you use a forged piston with a centered pin you will usually get a knock till the engine warms up and the piston expands.

Jerry G.

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post #5 of 70 (permalink) Old Sep 12th, 12, 02:43 PM
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Re: Engine Knock (Me too!)

invest in a mechanics stethoscope... they are rather cheaper than one would expect..

Since it seems u havnt been around engines much...follow Dennis descriptions above...but from my experiance a person can confuse a tap tick etc but a deep "knock" is usually that.
Knocks tend to be deep in the engine...collapsed piston skirt, stuff like that.
Saying that, go thru all the easy cheap stuff 1st....
A oil and filter change with correct oil weight.
Check compressions, and when plugs are out, read those...eg a blown head gasket will give 1 very new looking plug...any cyclinder out of the 10% variation of the rest.

A tappet is not a knock..it is definately a tap or tick.....aexhust manifold leak can be a tick, same as a HT jumping a spark...the latter one can hear on the radio.

My Spelling is not incorrect...it is creative

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post #6 of 70 (permalink) Old Sep 13th, 12, 07:04 AM Thread Starter
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Re: Engine Knock (Me too!)

Jerry,

I'm not sure honestly, the rebuild was done within the last 2k miles, though, before my ownership (I've had the car about two weeks).

Steptoe,

Unfortunately, I haven't been around engines as much as I wouldn've liked. As mechanically inclined as I may be, there are some things I don't know. The last time I worked on a carburated engine was on my '87 Charger rebuilding its carburetor...back

I've added the stethescope to my list of items to get this weekend. I plan on crackin' the valve covers open to at least take a peek. I'll pull the plugs too then and look. I can't wait for Saturday...I'm eager to get this fixed/diagnosed!

Thank you all!

'67 Camaro
350 V-8 bored .030 over
Edelbrock Intake Manifold &
600CFM Carburator
MSD Ignition, Crane Cam
World Heads, Hooker Headers
3" Flowmaster dual exhuast
Aluminum drive shaft
Muncie 4-speed Transmission
Posi-rear end with 3-leaf rear springs
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post #7 of 70 (permalink) Old Sep 13th, 12, 07:40 AM
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Re: Engine Knock (Me too!)

All good advice here.

What you will be trying to do is isolate where the noise is coming from, and exactly what type of noise it is. Think of it like one of those AAMCO commercials (if they air where you are) where the people are making all kinds of funny noises, and the AAMCO expert knows exactly what it is just by the noise.

A lifter makes a different noise than a slapping piston, an exhaust leak sounds different than a bent pushrod, and so on.

I would not advise a novice to try and set/change valve (actually rocker arm or pushrod) settings without a whole lot of direction. If you end up tightening something that didn't need it, you can apply too much force to the cam and round off a lobe. If that is what it turns out to be, we can direct you to appropriate procedures (providing you can tell us what kind of cam and valvetrain you have: roller cam, solid or hydraulic lifters, OE type stamped steel rocker arms vs adjustable and/or roller tipped, etc). If possibly having to "adjust the valves" after some cam wear was mentioned, then you probably have something other than a traditional hydraulic lifter "flat tappet" cam; when set up correctly after assembly and checked after break in, those are normally a set and forget style of cam and valvetrain.

One thing I did not see in the advice above is trying to isolate a cylinder if indeed it is an engine noise. Once you have it up to temp, or whenever the noise is occurring, you can disconnect spark plug leads one at a time to see if the noise is only associated with one cylinder.

Make sure you check simple things, like making sure none of the spark plug boots have burned through because of contact with the header. I mention this because I chased a noise and a miss all over on my 68, despite all my so called "knowledge" and working on engines since before I was a teen. I returned two "defective" Edelbrock QuadraJets (boy, do I wish I had those carbs now), and did a bunch of other things before, going to remove the plugs and check condition, I found one of the MSD plug boots had burned through on #1 or #2. I was so smart, I knew the issue was carb or timing/distributor related... until I found such a simple thing.

And always mark things like the plug wires (and distributor cap, if you remove that end too), because we have seen too many guys try to diagnose something like a small noise and come back that now their car won't run at all, because they put something back together incorrectly. I've done it, probably most folks here have some similar "boy am I dumb" moment. You'll have yours too. Just try to minimize...

Eric
69 'vert project big block/TKO 600 RR
68 'vert driver RS clone -- gone!
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post #8 of 70 (permalink) Old Sep 13th, 12, 07:56 AM Thread Starter
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Re: Engine Knock (Me too!)

Just heard back from the previous owner, he said that the lifters need adjusting as the break-in period for the new cam is over. He gave me some instructions as to how to accomplish this as well. This will be my first step and I'll let you guys know how it goes!

'67 Camaro
350 V-8 bored .030 over
Edelbrock Intake Manifold &
600CFM Carburator
MSD Ignition, Crane Cam
World Heads, Hooker Headers
3" Flowmaster dual exhuast
Aluminum drive shaft
Muncie 4-speed Transmission
Posi-rear end with 3-leaf rear springs
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post #9 of 70 (permalink) Old Sep 14th, 12, 07:03 AM Thread Starter
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Re: Engine Knock (Me too!)

Ok...so...the valve adjustment....yeah...that didn't turn out so well. LoL.

After crackin' open the valve covers I did discover that a litte more than half of the rods were loose (I guess the mechanic's term for this is "lash").

Combining the advice from the previous owner and an instructional video I found, I did the valve adjustment (it has Roller Rockers). I must have done something a bit off. It started fine, but it didn't have that same rhythmic pur. The "knock" I was talking about seemed a bit less pronounced, but was still there some. It was late, and I felt a bit defeated so I pulled the car back in the garage and parked it for the night.

When looking at the engine from the front of the car, I started at the furtherst back valve/rod on the passenger side. I first loosened the alen-bolt in the center, then I tightened the main bolt slowly until there was no more lash in the rod. Afterwhich, I gave the main bold one full turn and tightened the alen-bolt fully. I repeated this for every valve. I ran into a bit of frustration as it seemed that some of the rods I had already adjusted would gain some lash when I adjusted those after it.

Most of what I saw online showed the engine on a brace/engine lift when they did the adjustment. I'm doing this on a working engine that is in the car. Is that a no-go?

Is there something I did wrong? Something I failed to do?

My goal was to eliminate the lash (and hopefully the knock) and drive it in to work today; many of the people I work with wish to see it and maybe go for a ride.

'67 Camaro
350 V-8 bored .030 over
Edelbrock Intake Manifold &
600CFM Carburator
MSD Ignition, Crane Cam
World Heads, Hooker Headers
3" Flowmaster dual exhuast
Aluminum drive shaft
Muncie 4-speed Transmission
Posi-rear end with 3-leaf rear springs
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post #10 of 70 (permalink) Old Sep 14th, 12, 08:02 AM Thread Starter
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Re: Engine Knock (Me too!)

Quote:
Originally Posted by Eric Kammerer View Post
All good advice here.

What you will be trying to do is isolate where the noise is coming from, and exactly what type of noise it is. Think of it like one of those AAMCO commercials (if they air where you are) where the people are making all kinds of funny noises, and the AAMCO expert knows exactly what it is just by the noise.

A lifter makes a different noise than a slapping piston, an exhaust leak sounds different than a bent pushrod, and so on.

I would not advise a novice to try and set/change valve (actually rocker arm or pushrod) settings without a whole lot of direction. If you end up tightening something that didn't need it, you can apply too much force to the cam and round off a lobe. If that is what it turns out to be, we can direct you to appropriate procedures (providing you can tell us what kind of cam and valvetrain you have: roller cam, solid or hydraulic lifters, OE type stamped steel rocker arms vs adjustable and/or roller tipped, etc). If possibly having to "adjust the valves" after some cam wear was mentioned, then you probably have something other than a traditional hydraulic lifter "flat tappet" cam; when set up correctly after assembly and checked after break in, those are normally a set and forget style of cam and valvetrain.

One thing I did not see in the advice above is trying to isolate a cylinder if indeed it is an engine noise. Once you have it up to temp, or whenever the noise is occurring, you can disconnect spark plug leads one at a time to see if the noise is only associated with one cylinder.

Make sure you check simple things, like making sure none of the spark plug boots have burned through because of contact with the header. I mention this because I chased a noise and a miss all over on my 68, despite all my so called "knowledge" and working on engines since before I was a teen. I returned two "defective" Edelbrock QuadraJets (boy, do I wish I had those carbs now), and did a bunch of other things before, going to remove the plugs and check condition, I found one of the MSD plug boots had burned through on #1 or #2. I was so smart, I knew the issue was carb or timing/distributor related... until I found such a simple thing.

And always mark things like the plug wires (and distributor cap, if you remove that end too), because we have seen too many guys try to diagnose something like a small noise and come back that now their car won't run at all, because they put something back together incorrectly. I've done it, probably most folks here have some similar "boy am I dumb" moment. You'll have yours too. Just try to minimize...
Eric! Man do I wish I would have seen your post first! I don't know how I missed it. My first plan was to do just that...the small simple things that I can definately do on my own. Valve oil, plug wires, new plugs, octain booster, etc. I would have if not for the advice of the previous owner. He does almost all of his own restoration work and so, being impressed with the work he had done, I thought his advice rock solid.

Unfortunately for me I already messed with the valves and while I did find some loose rods, I'm afraid I may have just given myself a bigger headache than I had already. =/

I appears I've dug myself a pretty deep hole...my only hope is that one of you can throw me a rope as I don't have the means to tow this thing anywhere. =(

'67 Camaro
350 V-8 bored .030 over
Edelbrock Intake Manifold &
600CFM Carburator
MSD Ignition, Crane Cam
World Heads, Hooker Headers
3" Flowmaster dual exhuast
Aluminum drive shaft
Muncie 4-speed Transmission
Posi-rear end with 3-leaf rear springs
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post #11 of 70 (permalink) Old Sep 14th, 12, 08:51 AM Thread Starter
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Re: Engine Knock (Me too!)

Just found this too...

http://www.montecarloss.com/communit...&Number=702654

Looks like I did mess up?

'67 Camaro
350 V-8 bored .030 over
Edelbrock Intake Manifold &
600CFM Carburator
MSD Ignition, Crane Cam
World Heads, Hooker Headers
3" Flowmaster dual exhuast
Aluminum drive shaft
Muncie 4-speed Transmission
Posi-rear end with 3-leaf rear springs
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post #12 of 70 (permalink) Old Sep 14th, 12, 09:48 AM
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Re: Engine Knock (Me too!)

I don't know where the idea comes from but you don't need to adjust hydraulic lifters after a break in period. With hydraulic you set them and forget them! I can understand re-adjusting them if you suspect something is wrong but that's totally different.

Now as for how you adjusted your rockers (aka; adjusted the lifters or adjusted the valves) one turn past zero lash is probably too much pre-load. Original factory installed or over the counter replacement cams use one full turn of pre-load but most aftermarket cams today recomend 1/2 turn of pre-load.

There are many ways to adjust hydraulic lifters. Here is the least complicated way I know of. It requires you find #1 TDC: rotate the engine and watch the number 1 intake valve (second from the front on the drivers side). You want the TDC that happens right AFTER the intake valve has opened and closed. Once you have #1 TDC then it's this simple. This works because 3/4 of the cam lobe is base circle. If you have a solid lift cam don't use this method...

Quote:
Adjust the #1 exhaust valve
Adjust the #1 intake valve

Adjust the #3 exhaust valve

Adjust the #5 intake valve

Adjust the #7 intake valve

Adjust the #2 intake valve

Adjust the #4 exhaust valve

Adjust the #8 exhaust valve

Now rotate the engine 360 degrees. The mark on the balancer should be back at the TDC mark. Keep in mind that this is not the TDC where #1 would be firing! It's where #6 would fire.

Adjust the #3 intake valve

Adjust the #5 exhaust valve

Adjust the #7 exhaust valve

Adjust the #2 exhaust valve

Adjust the #4 intake valve

Adjust the #6 exhaust valve
Adjust the #6 intake valve

Adjust the #8 intake valve

You are now done.
With roller rockers and poly locks, make sure you tighten the set screw when holding the adjustment nut with a wrench so you don't change the adjustment. Once the set screw is tight you can lock things down by turning both the screw and the nut against each other, if you do this right neither should really move but the added torque will keep them from back off.

How did you determin zero lash? Often you hear spin the pushrod with your fingers but I prefer the bounce or jiggle the pushrod up and down until all the lash is gone. Then use the cam manufactures recomended amount of pre-load... It could be as little as 1/4 turn or as much as 1 full turn.

Get your valves adjusted properly and then start over with all the simple stuff. Try to identify the noise, an arking spark plug wire is not going to sound like a lifter or an exhaust leak... Don't be afraid to get a second opinion, find a shop locally and take the car there and ask the shop owner to have a listen and give you an opinion. Most will be glad to take a look (listen) and make a recomendation.

...Dennis

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post #13 of 70 (permalink) Old Sep 14th, 12, 11:27 AM Thread Starter
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Re: Engine Knock (Me too!)

Thank you Dennis. I'm really upset about this...I've been kickin' myself in the *** all day.

I appreciate you taking the time to post those instructions. They look similar to the ones I found on that site.

I'm thinking about giving it one last try...before paying for it to get towed to a shop and then paying for it to get fixed. IDK...at the same time I don't want to try one more time only to shave a lobe.

I think the key will be looking up the pre-load for the cam. It's a Crane cam, the model I think I have at home. We'll see...

'67 Camaro
350 V-8 bored .030 over
Edelbrock Intake Manifold &
600CFM Carburator
MSD Ignition, Crane Cam
World Heads, Hooker Headers
3" Flowmaster dual exhuast
Aluminum drive shaft
Muncie 4-speed Transmission
Posi-rear end with 3-leaf rear springs
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post #14 of 70 (permalink) Old Sep 14th, 12, 11:48 AM
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Re: Engine Knock (Me too!)

Quote:
Originally Posted by VengefulTick View Post
Thank you Dennis. I'm really upset about this...I've been kickin' myself in the *** all day.

I appreciate you taking the time to post those instructions. They look similar to the ones I found on that site.

I'm thinking about giving it one last try...before paying for it to get towed to a shop and then paying for it to get fixed. IDK...at the same time I don't want to try one more time only to shave a lobe.

I think the key will be looking up the pre-load for the cam. It's a Crane cam, the model I think I have at home. We'll see...
Cranes published installation instructions are here.
http://www.cranecams.com/uploads/instructions/214e_.pdf

I'll cut to the chase, they recommend 1/2-1 turn. Don't quit now! This is just a learning curve. Do it again until you are certain it's right. Then the next time you can do it just for fun.

'67 rs - ordered new by my Grandfather
327 L30, K-K, Deluxe int, tach & gauges, 12 bolt posi, 4 speed.

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post #15 of 70 (permalink) Old Sep 14th, 12, 11:57 AM Thread Starter
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Re: Engine Knock (Me too!)

Thanks Melrose! I actually liked doing it...its just the worry of messin' up my cam that has me so anxious. Thank you very much for looking up those instructions for me!

'67 Camaro
350 V-8 bored .030 over
Edelbrock Intake Manifold &
600CFM Carburator
MSD Ignition, Crane Cam
World Heads, Hooker Headers
3" Flowmaster dual exhuast
Aluminum drive shaft
Muncie 4-speed Transmission
Posi-rear end with 3-leaf rear springs
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