C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

Engine whine

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Old Mar 30, 2017 | 12:23 AM
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Default Engine whine

It's kind of there at idle, but most obvious when backing off throttle. It's a 93 and has had heads/cams replaced. I've replaced the WP, the timing set and all front seals, no leaks as of yet.

So when backing off the gas a little bit, horrible whine coming from it. PS Pump and oil are topped up, pretty sure the tranny is too but it doesn't sound like its coming from there anyway, more like the front cover. Start simple? take the belt off? and see if gone? Or does this sound nothing like belt?

It is an aftermarket timing set specific for the year of optispark drive, made by Lunati. Unsure if this has anything to do with it but i replaced all sprockets and chains. http://www.lunatipower.com/Product.aspx?id=914&gid=222 When the timing set was installed (Properly...) it had a slight amount of slack in it, but i think thats normal.

Attached a cruddy video of it. Also got a bit of valvetrain noise on the left bank so going to pull valve covers
Attached Files
File Type: mov
IMG_1486.MOV (1.90 MB, 40 views)

Last edited by Hive; Mar 30, 2017 at 01:09 AM.
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Old Mar 30, 2017 | 12:47 AM
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Belt has been pulled and there's still a whine, it seems to be coming from the water pump area, or from inside the front cover. It takes a few seconds for the whine to start when the cars started.

As for the water pump, i'm not too sure how legit it is.

https://www.am-autoparts.com/product...-34945987.html

That's it essentially. Still have the old pump so could always swap it. Another possibility (completely ignoring things like "serious engine failure" right now ) could it be the new front seals? i did the main front seal, opti and water pump seals. The optispark... has that dowel that connects it to the timing gear, is there any specific orentitation or can it go in any way?

Same with the WP - it has that coupler, i faced the marked end towards the engine. The water pump was tight going in, felt like some interference as you couldnt get the pump seated to the gasket surfaces without torqing bolts on, if that makes any sense. Possibly that has misaligned something?

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Old Mar 30, 2017 | 02:04 AM
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More to come: Took the rocker covers off and no noise from the valvetrain or any coming from inside the lifte valley, i can see all the roller lifters are in properly and not spun out of the dogbone. Did catch a sneaky exhaust leak from the manifold but that was just a loose bolt. Still there.

I am thinking more and more water pump, 2 of the front bolts were finger loose right out of the box. When i went to install it by hand, the pump itself wouldnt mate with the block cooling ports and had a gap between pump and block. (by about 3mm including gasket) the dowel is in with the mark towards the block end. Only after torquing the bolts in could i get it to align and mate the surfaces with the gasket. Seems really dodgy but thought nothing of it at the time... there's a lesson to be learnt here im sure of it :P

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Old Mar 30, 2017 | 04:23 PM
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I seriously doubt that whine is connected in any way with anything under the valve covers.
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Old Mar 30, 2017 | 05:24 PM
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Interesting, spoke with the AM auto parts guys to see if anyone else using this pump has whine with engine whine, they didn't ask any questions but refunded right away when I mentioned the whine.... known issue?

will pull pump on weekend and throw old OEM back in

Last edited by Hive; Mar 30, 2017 at 05:27 PM.
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Old Mar 30, 2017 | 06:24 PM
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Originally Posted by RICHARD TILL
I seriously doubt that whine is connected in any way with anything under the valve covers.
Me neither, my whine comes from the wife located in the passenger seat
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Old Mar 30, 2017 | 07:17 PM
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Originally Posted by billschroeder5842
Me neither, my whine comes from the wife located in the passenger seat
My condolences
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Old Apr 1, 2017 | 10:19 PM
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>>>When i went to install it by hand, the pump itself wouldnt mate with the block cooling ports and had a gap between pump and block. (by about 3mm including gasket)<<<

Did you remove the 6 bolts on the face of the water pump to align the drive ? or just try to eyeball it on ?

later, tiny

Last edited by 1800Wing; Apr 1, 2017 at 11:09 PM.
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Old Apr 1, 2017 | 11:51 PM
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Originally Posted by 1800Wing
>>>When i went to install it by hand, the pump itself wouldnt mate with the block cooling ports and had a gap between pump and block. (by about 3mm including gasket)<<<

Did you remove the 6 bolts on the face of the water pump to align the drive ? or just try to eyeball it on ?

later, tiny
Yup, removed the bolts on the pump face and spun till it mated, but even with the shaft mated,the pump itself wouldnt seat to the block with a 3mm gap.

An update, i ran it without the water pump for 5-10 seconds and reproduced the rev range no whine sound, just high idle initially, didnt want to run it too long without coolant.

When i installed the original OEM water pump, the whine was back but VERY different, sounded much less worrying.

Since i have a new timing chain and new cam sprocket + crank sprocket, could it just be the new cam sprocket gear wearing/mating to the old/original water pump drive gear?

Should i even care about this whine sound?

Last edited by Hive; Apr 1, 2017 at 11:55 PM.
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Old Apr 2, 2017 | 05:21 PM
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Originally Posted by Hive
Yup, removed the bolts on the pump face and spun till it mated, but even with the shaft mated,the pump itself wouldnt seat to the block with a 3mm gap.

An update, i ran it without the water pump for 5-10 seconds and reproduced the rev range no whine sound, just high idle initially, didnt want to run it too long without coolant.

When i installed the original OEM water pump, the whine was back but VERY different, sounded much less worrying.

Since i have a new timing chain and new cam sprocket + crank sprocket, could it just be the new cam sprocket gear wearing/mating to the old/original water pump drive gear?

Should i even care about this whine sound?
I'm more concerned with that big gap you had between the block and the pump, I suspect if we can fiquire that out ,your whine will disappear. Is your new water pump a remanufactured GM or a "new" pump from an aftermarket manufacturer ? Just a guess since I haven't seen the car but I'd sure be looking at the alignment pins on the block and the matching holes on the pump.

I had a slight mis-alignment on mine due to old adhesive on the pins and some paint ( yes I painted my water pump to match the car ) in the holes that held the pump off the block like you describe.
Once I finished cleaning the block and chased the alignment holes it plopped right on there without interference.

later, tiny

Last edited by 1800Wing; Apr 2, 2017 at 05:22 PM.
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Old Apr 2, 2017 | 07:45 PM
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Originally Posted by 1800Wing
I'm more concerned with that big gap you had between the block and the pump, I suspect if we can fiquire that out ,your whine will disappear. Is your new water pump a remanufactured GM or a "new" pump from an aftermarket manufacturer ? Just a guess since I haven't seen the car but I'd sure be looking at the alignment pins on the block and the matching holes on the pump.

I had a slight mis-alignment on mine due to old adhesive on the pins and some paint ( yes I painted my water pump to match the car ) in the holes that held the pump off the block like you describe.
Once I finished cleaning the block and chased the alignment holes it plopped right on there without interference.

later, tiny
i'm probably not explaining properly, the pump i bought was an aftermarket reproduction, like cheap. we are talking $70 form am-autoparts for a "new" pump, i can guarantee its not OEM. This pump when installed had that 3mm gap, but after torquring down the gap closed and it sealed.

I took that pump out, made sure all pins were clean, and put the original pump in (old OEM one), this just "snapped in" and mated to the block with no force, i.e. perfect fit. Still a little whine but much less. I know the WP drive is gear driven so maybe this crappy pump damaged the bearing or something from the poor alignment or manufacturing faults. The way the gap was, it seems as though the design was wrong for this engine, it just felt like threading a hotdog through a keyhole installing it.

This aftermarket pump was interfering with the optispark mounting tabs/bolts by the looks of the scrapes/marks on the aluminium pump.

Last edited by Hive; Apr 2, 2017 at 07:50 PM.
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Old Apr 2, 2017 | 09:42 PM
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Well, if it's running we'll know sooner or later if the bearing is boogered up.
I quit using the aftermarket stuff years ago unless there is absolutely no other way. I hate doing something twice.

later, tiny
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Old Apr 2, 2017 | 10:23 PM
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How about the cam itself?

Do many people run into this after a cam swap to afermarket?

It is a comp cams grind LE2 cam (Lloyd 218/224 spec)

Reading this... hmmm sounds identical no?

ls1tech.com/forums/generation-iii-internal-engine/458841-whining-noise-after-cam-change-1.html

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Old Apr 3, 2017 | 06:45 AM
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Huh, may have just found it. Broken EVAP hose. Much quieter now, i imagine some noise is expected form timing chains anyway?
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Old Apr 5, 2017 | 05:51 AM
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Originally Posted by Hive
Huh, may have just found it. Broken EVAP hose. Much quieter now, i imagine some noise is expected form timing chains anyway?
Did you use straight cut gears or beveled ? The factory ones would have been beveled.

later, tiny
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