Loud engine noises

[Winter911]

Hello,

I just did a valve adjustment on my 911 and I have QUADRUPLED checked all the valves, intake and exhaust. I went with the backside method using 3 different set of feeler gauges. 0025 as a go and a .003 no go. All the valves checked out good.

Engine is making a little more noise than before and I’m not entirely sure why.

My car is a 1972 911 but the engine 2.4 MFI was made early 73.

Does this sound like the famous chain tensioners issue? How much of a nightmare are they to replace?
There was a tiny bit of play on each rocker arm when I was adjusting the valves.

The sound is not a heavy knock (thank goodness)

Any ideas would be greatly appreciated

Here is a link to the video.

https://youtube.com/shorts/h82T4q1Sj8s?feature=share

[s5uewf]

my Mac may not be playing the sounds loud enough, but all I hear is what I believe to be some valve tap and normal engine sounds. I am not hearing anything metallic beyond those ... is it the tapping noise that is worrying you? Maybe valves were to tight before and so now they seem louder than they should?

[OSC911]

Originally Posted by s5uewf

my Mac may not be playing the sounds loud enough, but all I hear is what I believe to be some valve tap and normal engine sounds. I am not hearing anything metallic beyond those ... is it the tapping noise that is worrying you? Maybe valves were to tight before and so now they seem louder than they should?

Same thing here, sound pretty normal to me also

[Winter911]

Originally Posted by s5uewf

my Mac may not be playing the sounds loud enough, but all I hear is what I believe to be some valve tap and normal engine sounds. I am not hearing anything metallic beyond those ... is it the tapping noise that is worrying you? Maybe valves were to tight before and so now they seem louder than they should?

Yes the loud tapping sound on the right side of the engine.
Tight valves might’ve been what’s going on here. I just want to make sure these noises are normal for an early 911. I should mention I noticed a slight puff of blue smoke on start up.

[stownsen914]

.0025” is a little tight, no? Is my memory going?

[proporsche]

all i hear is loose valve adjustment....

ivan

[acme911]

Originally Posted by proporsche

all i hear is loose valve adjustment....

ivan

Agreed

[EC900]

x2 agree, sounds loose. Is this your first valve adjustment or have you had success on the last adjustment ?
Btw, How’s the oil level?

[Winter911]

Originally Posted by EC900

x2 agree, sounds loose. Is this your first valve adjustment or have you had success on the last adjustment ?
Btw, How’s the oil level?

This is my first time doing a valve adjustment but I was extremely careful with everything I was doing. I quadrupled checked all the valves with go and no go feeler gauges.

Oil level is in the middle between the max and low marks on the dip stick

[Solamar]

I've been adjusting valves since my first car, bug, 30+ years ago, many cars and motorcycles since.

Somehow I screwed up my last valve adjustment on my 911 and it sounded just like yours. Took the covers off, started from scratch, and found my mistake. It happens.

Why the backside method? I've never used it, but the traditional method has served me well.

[icarp]

For some, this way of adjusting valves, has been a god send . The 911 is not an easy
valve adjustment by any means. The more you do it , the better you get . The back side is not
the easy way either .
So I suggest this method for you .

SnapGap - A Review

[ahh911]

It might sound silly, but I don't know..

What makes the tick sound when the valve adjustments are loose and why?

Phil

[Winter911]

Originally Posted by icarp

For some, this way of adjusting valves, has been a god send . The 911 is not an easy
valve adjustment by any means. The more you do it , the better you get . The back side is not
the easy way either .
So I suggest this method for you .

SnapGap - A Review

I’ve heard many good things about snapgap and I think I’ve finally gave in. Gonna order a set tonight. Do you still have to set each cylinder to top dead center when installing the collar nut on each adjustment screw?

[icarp]

The sound of the valve ticking is much like clapping your hands .
Start with your hands 1/2" apart, then clap them , now separate them by 12-18"
now clap. The clapping sound is much louder with your hands further apart .
The interesting thing with a valve adjustment is that .001"-.0015" loose will make a difference in sound
I hope this helps
Ian

PS , The best way to set the valves is to start on #1 cyl @ tdc then use the pulley to follow the firing order .
The pulley has a notch every 120* that corresponds to the firing order .
Leave the car in fourth gear and nudge it forward to each mark if the car is on the ground .
If the car is in the air then use a wrench on the crank or the alt pulley

[ahh911]

Originally Posted by icarp

The sound of the valve ticking is much like clapping your hands .
Start with your hands 1/2" apart, then clap them , now separate them by 12-18"
now clap. The clapping sound is much louder with your hands further apart .
The interesting thing with a valve adjustment is that .001"-.002" will make a difference in sound
I hope this helps
Ian

Thanks, Does cam profile play as well in the large increase in valve train noise? If the roll off on the cam was smoother then the sound wouldn't increase as dramatically between two relatively small changes in valve lash setting? I was wondering if the point at which the valve is free of the rocker vs the slope of the cam makes a difference.

Phil

[911SauCy]

+1 on simply going back and rechecking your gaps. Motor sounds normal, adjustment sounds a little lose.

Small puff of smoke on start-up is 100000% normal.

IMO, you have nothing out of the ordinary to be concerned about here

[proporsche]

winter..i do it like this for almost 40 years...it is not really hard even with the feeler..
https://www.youtube.com/watch?v=O_ypBn_u7g8

[PFNog]

This may be a dumb question but I’ll ask anyway— Is “a little loose” a bad thing? Will it increase wear, cause damage or noticeably reduced performance? Just curious which is safest side to err on.

[911SauCy]

Originally Posted by PFNog

This may be a dumb question but I’ll ask anyway— Is “a little loose” a bad thing? Will it increase wear, cause damage or noticeably reduced performance? Just curious which is safest side to err on.

I'm on engine builder but I'd imagine there is added potential for uneven or advanced wearing on the surfaces, and less "performance" given the valve travel isn't optimal given additional gap. Also, the added clacky noise as per the video in this thread.

Safer to be a hair lose, but ideal is exact spec.

[PFNog]

Thanks for the info. that’s helpful. Also, does the gap get tighter or looser as the engine wears? In other words will an engine that has a proper adjustment, but is not adjusted again for 30k miles tend to have loose or tight valves? Or does that depend on the wear of components and vary by engine? Just curious.