ENGINE - ZR-1 Net Registry Forums

AUTO DOCTOR PLUS · 04-25-2007

I HAVE A 90 WITH 38,000 , I HAVE A MOTOR NOISE AT REV. WHEN LETTING OFF THROTTLE, SOUNDS LIKE BEARING NOISE?? OIL PRESSURE IS VERY GOOD, NOISE IS LOUDER IN MORNING, ANY IDEAS???/ HATE TO TEAR DOWN AND NOT FIND A PROBLEM, KEVIN

jonszr1 · 04-25-2007

does the car make noise in neutral with the clutch out / you could be losing the flywheel?

AUTO DOCTOR PLUS · 04-25-2007

WE CHECKED THE FLYWHEEL IT IS OK, REV AND BACK OFF, IT WILL MAKE NOISE MOST OF THE TIME, WHEN PULLING OUT MAKES NOISE UNDER LOAD, KEVIN

A26B · 04-25-2007

You should try to locate the noise, front, rt side, left side, center, deep, etc and use a rod (wood dowel rod abt 2' long) placed on the engine and to your ear. Is the noise rpm frequency, no particular frequency, multiples of rpm frequency? Describe the noise; rattle, knock (heavy or light), tinny, etc.

Check all the pullys & belt to see if it's a bearing (tensioner, AC clutch, PS pmp, water pmp) or pully. A timing light works pretty good.

Very difficult to analyze like this.

Kevin · 04-25-2007

where in pa are you from

AUTO DOCTOR PLUS · 04-26-2007

I AM IN ALTOONA PA.

Sgreg · 04-26-2007

I had one of these weird noises under the car and almost tore the Z apart trying to find it only to discover it was a loose exhaust heat shield which really showed itself at 15-1800 RPM. Not saying this is what your problem is but sometimes little things can be the worst and lead to spending big money needlessly.

A26B · 04-26-2007

I'm wondering about the catalytic convertor(s). Wasn't it the 90 model without the screen and catalyst could get back into the exhaust header? Point is, it could be in the catalytic convertor, hence the reason to try & isolate where it's coming from and the frequency.

Loose heat shields, as stated above, have ocurred several times, driving the owners nuts to find the source.

AUTO DOCTOR PLUS · 04-27-2007

THANKS FOR THE POSTS, I WILL CHECK AND POST WHAT I FIND OUT, KEVIN

Kevin · 04-27-2007

I've been trying to think of anyone around the area that you could take the car to and I can't think of anyone. Sorry

04-25-2007	#1
AUTO DOCTOR PLUS Join Date: Apr 2007 Location: PA. Posts: 4	ENGINE I HAVE A 90 WITH 38,000 , I HAVE A MOTOR NOISE AT REV. WHEN LETTING OFF THROTTLE, SOUNDS LIKE BEARING NOISE?? OIL PRESSURE IS VERY GOOD, NOISE IS LOUDER IN MORNING, ANY IDEAS???/ HATE TO TEAR DOWN AND NOT FIND A PROBLEM, KEVIN

04-25-2007	#2
jonszr1 Join Date: Sep 2006 Location: lone pine and mammoth lakes Posts: 1,407	Re: ENGINE does the car make noise in neutral with the clutch out / you could be losing the flywheel?

04-25-2007	#3
AUTO DOCTOR PLUS Join Date: Apr 2007 Location: PA. Posts: 4	Re: ENGINE WE CHECKED THE FLYWHEEL IT IS OK, REV AND BACK OFF, IT WILL MAKE NOISE MOST OF THE TIME, WHEN PULLING OUT MAKES NOISE UNDER LOAD, KEVIN

04-25-2007	#4
A26B Join Date: Dec 2003 Location: Arcadia,OK Posts: 3,394	Re: ENGINE You should try to locate the noise, front, rt side, left side, center, deep, etc and use a rod (wood dowel rod abt 2' long) placed on the engine and to your ear. Is the noise rpm frequency, no particular frequency, multiples of rpm frequency? Describe the noise; rattle, knock (heavy or light), tinny, etc. Check all the pullys & belt to see if it's a bearing (tensioner, AC clutch, PS pmp, water pmp) or pully. A timing light works pretty good. Very difficult to analyze like this. __________________ Jerry Downey JERRYS LT5 GASKETS & PARTS http://www.jerrysgaskets.com 1994 *ZR-1*, Black/Black, Lingenfelter Aerobody, 416cu in, 3.91 gears, coil-over susp, Brembo brakes, etc. 2016 Black-Red, 3LT-Z51 Auto 8-speed.

04-25-2007	#5
Kevin Join Date: Jun 2005 Location: pittsburgh Posts: 4,632	Re: ENGINE where in pa are you from __________________ It's not the car, it's the people - Doug Johnson 90 r/r "KEYS ON" nick named "T.L.B"

04-26-2007	#6
AUTO DOCTOR PLUS Join Date: Apr 2007 Location: PA. Posts: 4	Re: ENGINE I AM IN ALTOONA PA.

04-26-2007	#7
Sgreg Join Date: Aug 2006 Location: Texas Posts: 518	Re: ENGINE I had one of these weird noises under the car and almost tore the Z apart trying to find it only to discover it was a loose exhaust heat shield which really showed itself at 15-1800 RPM. Not saying this is what your problem is but sometimes little things can be the worst and lead to spending big money needlessly. __________________ 1991 ZR-1, Black, Black, # 541

04-26-2007	#8
A26B Join Date: Dec 2003 Location: Arcadia,OK Posts: 3,394	Re: ENGINE I'm wondering about the catalytic convertor(s). Wasn't it the 90 model without the screen and catalyst could get back into the exhaust header? Point is, it could be in the catalytic convertor, hence the reason to try & isolate where it's coming from and the frequency. Loose heat shields, as stated above, have ocurred several times, driving the owners nuts to find the source. __________________ Jerry Downey JERRYS LT5 GASKETS & PARTS http://www.jerrysgaskets.com 1994 *ZR-1*, Black/Black, Lingenfelter Aerobody, 416cu in, 3.91 gears, coil-over susp, Brembo brakes, etc. 2016 Black-Red, 3LT-Z51 Auto 8-speed.

04-27-2007	#9
AUTO DOCTOR PLUS Join Date: Apr 2007 Location: PA. Posts: 4	Re: ENGINE THANKS FOR THE POSTS, I WILL CHECK AND POST WHAT I FIND OUT, KEVIN

04-27-2007	#10
Kevin Join Date: Jun 2005 Location: pittsburgh Posts: 4,632	Re: ENGINE I've been trying to think of anyone around the area that you could take the car to and I can't think of anyone. Sorry __________________ It's not the car, it's the people - Doug Johnson 90 r/r "KEYS ON" nick named "T.L.B"