Odd engine vibrations and noise...water pump?
Thread Starter
Racer
Joined: Oct 2008
Posts: 276
Likes: 5
From: Aptos, CA
Odd engine vibrations and noise...water pump?
Help me solve this puzzle.
My '69 has developed some odd vibrations, here are her symptoms.
-At idle a slight abnormal vibe is felt. Just enough to feel wrong.
-The vibration is paired with a noise coming from the engine bay at a frequency less than that of the engine idle rpm.
-The noise AND vibe remain constant regardless of the clutch being engaged or disengaged while the manual trans shifter is in neutral.
-When I blip the throttle the vibe gets VERY pronounced at 1500 rpm, but then smooths out above 1500 rpm. Again, clutch position creates no change in this test.
-There is slight play in the water pump pulley.
Could a failing water pump shaft bearing cause a significant vibration like this?
I had a failing pump on my Chevy Blazer a year ago, but I can't remember what the symptoms were like (other than leaking at the weep hole and noise).
Since the clutch doesn't seem to change the sound I think I can rule out everything from the flywheel back. But I hope this isn't an internal failure waiting to happen.
Any ideas? Water pump? Engine mount? Worse?
I appreciate your time and knowledge in helping me out.
-Brad
My '69 has developed some odd vibrations, here are her symptoms.
-At idle a slight abnormal vibe is felt. Just enough to feel wrong.
-The vibration is paired with a noise coming from the engine bay at a frequency less than that of the engine idle rpm.
-The noise AND vibe remain constant regardless of the clutch being engaged or disengaged while the manual trans shifter is in neutral.
-When I blip the throttle the vibe gets VERY pronounced at 1500 rpm, but then smooths out above 1500 rpm. Again, clutch position creates no change in this test.
-There is slight play in the water pump pulley.
Could a failing water pump shaft bearing cause a significant vibration like this?
I had a failing pump on my Chevy Blazer a year ago, but I can't remember what the symptoms were like (other than leaking at the weep hole and noise).
Since the clutch doesn't seem to change the sound I think I can rule out everything from the flywheel back. But I hope this isn't an internal failure waiting to happen.
Any ideas? Water pump? Engine mount? Worse?
I appreciate your time and knowledge in helping me out.
-Brad
Race Director
Joined: Sep 2002
Posts: 10,362
Likes: 5
From: San Diego - Deep Within The State of CONFUSION!
One of the very first things I would check would be the harmonic balancer under the water pump. They are well known to cause shakes when the rubber between the pieces fails and the balancer slips.
Check it & see if the timing marks are correct. If they appear well out of bounds then perhaps it has slipped.
Thread Starter
Racer
Joined: Oct 2008
Posts: 276
Likes: 5
From: Aptos, CA
Not that I think it's the pump, but you shouldn't even be able to wiggle the fan attached to the water pump at all, right?
Mine wiggles back and forth a bit, but no green coolant on the driveway.
Mine wiggles back and forth a bit, but no green coolant on the driveway.
Drifting
Joined: Dec 2007
Posts: 1,634
Likes: 1
From: aurora
Todd
Thread Starter
Racer
Joined: Oct 2008
Posts: 276
Likes: 5
From: Aptos, CA
I'll try taking the belts off and running the engine for a short time without them on to notice any changes in the vibrations.
Also, this vibration feels mechanical so I doubt it's related to a leaking header. But I have been wrong before.
Thanks for the help thus far!
Also, this vibration feels mechanical so I doubt it's related to a leaking header. But I have been wrong before.
Thanks for the help thus far!
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Le Mans Master
Joined: Oct 2000
Posts: 8,897
Likes: 1,357
From: Santa Ana CA
I'll try taking the belts off and running the engine for a short time without them on to notice any changes in the vibrations.
Also, this vibration feels mechanical so I doubt it's related to a leaking header. But I have been wrong before.
Thanks for the help thus far!
Also, this vibration feels mechanical so I doubt it's related to a leaking header. But I have been wrong before.
Thanks for the help thus far!
On their Rambler engine (that had been running fine) they noted that it sounded like someone had a ball peen hammer and was beating the heck out of the innards.
They got all kinds of experts and no one knew what to make of it. One of the experts noted it was a leaking header.
Seems that the header bolt was too long and bottomed out. The editor, who has done beaucoup engine builds, noted this was the first time he ever heard a header leak sound this violent.
Thread Starter
Racer
Joined: Oct 2008
Posts: 276
Likes: 5
From: Aptos, CA
I had a leaky header last year about this time and replaced it, so I'm familiar with the sound.
But that doesn't explain the vibration. Hopefully I can figure it out soon when I get some free time.
But that doesn't explain the vibration. Hopefully I can figure it out soon when I get some free time.
Instructor
Joined: Mar 2010
Posts: 111
Likes: 0
From: lafayette indiana
i agree with everyone check bal,headers,take belts off to rule out water pump and as.u would havet to run engine a while to case prob. if that dont help u need to look back at clutch/flywheel ***.
Thread Starter
Racer
Joined: Oct 2008
Posts: 276
Likes: 5
From: Aptos, CA
Alright...quick update
Checked timing and it looks fine. 8 deg BTDC like it has always been.
Didn't have time to loosen and remove the accesory belts but
Alternator and power steering pulleys look fine.
Water pump pulley has a slight wobble. When engine is off I can grab a fan blade and wobble the fan a little bit.
Next to remove the belts and give it a shot.
Checked timing and it looks fine. 8 deg BTDC like it has always been.
Didn't have time to loosen and remove the accesory belts but
Alternator and power steering pulleys look fine.
Water pump pulley has a slight wobble. When engine is off I can grab a fan blade and wobble the fan a little bit.
Next to remove the belts and give it a shot.
Thread Starter
Racer
Joined: Oct 2008
Posts: 276
Likes: 5
From: Aptos, CA
Oh yeah, quick question.
At idle should the timing mark on the balancer ever jump around a little bit?
Mine sits at 8 deg BTDC, but every few seconds the mark will do a small jump, is that normal?
At idle should the timing mark on the balancer ever jump around a little bit?
Mine sits at 8 deg BTDC, but every few seconds the mark will do a small jump, is that normal?
Le Mans Master
Joined: Oct 2000
Posts: 8,897
Likes: 1,357
From: Santa Ana CA
Le Mans Master
Joined: Oct 2000
Posts: 8,897
Likes: 1,357
From: Santa Ana CA
You need to pull the distributor and check the play in the bottom gear on the shaft. I believe that Lars has a paper on this.
Instructor
Joined: Mar 2010
Posts: 111
Likes: 0
From: lafayette indiana
if this is org. dis. in car and your having the timming jump around u should think about upgrading to a new one keep the old one so u can say u haveit for resale but dont wast your time on shimming and rebuilding a new msd is 10 times better than anything chevy ever made in 69
Thread Starter
Racer
Joined: Oct 2008
Posts: 276
Likes: 5
From: Aptos, CA
Not sure if it's original, but it does have a Mallory electronic conversion kit on it so it's definitely not completely stock.
So let me get this straight, you WANT slop in the distributor shaft? You don't want it bottomed out on the oil pump drive shaft?
So let me get this straight, you WANT slop in the distributor shaft? You don't want it bottomed out on the oil pump drive shaft?