Engine knock - ZR-1 Net Registry Forums

Perry Mitchell · 10-23-2023

I have been doing research on this subject, but have not come up with anything definitive. This motor came from a wrecked 91 ZR1 with only 17,000 miles on the odometer. It has been transplanted into my 67 Camaro that has been an ongoing project since 2010. I?ve been able to start it for the last several years but have yet been able to take it on the road. It starts, idles, and revs well. However, it has this very annoying Knock that I am worried about. To me, it sounds like a rod knock. All my research says it is probably the dual mass clutch fly wheel assembly but this motor is connected to a 700 R4 transmission. Does the camshaft chain assembly make that kind of noise? Any and all help will be appreciated. Thank you.

I tried downloading a video so you could hear it but I guess I don?t know how.

XfireZ51 · 10-23-2023

How has the motor been modded if at all? If its stock and has the stock calibration, knock shouldn?t be much of an issue.

bob@tradeshowconsulting.c · 10-23-2023

could be piston slap, or lifter as well .. Mark Haibeck would be a good contact to troubleshoot

Perry Mitchell · 10-23-2023

Thank you for your replies. Internally, the motor is stock. It does have the secondary delete modification, and long tube headers. Mark has provided calibrations for those.

grahambehan · 10-23-2023

If you have a 700 r4 trans, you do not have a dual mass flywheel, just a flex plate, unless someone did something very creative. The chain tensioner makes more of a "clatter" and is normally present for a few seconds after start up, normally. A video or just audio would help.
The lt5 is a relatively noisey engine tho.
Graham

Perry Mitchell · 10-23-2023

Thank you Graham. Yes, the original flywheel, clutch and transmission have been removed and replaced with a flex plate and 700 R4 transmission. I?ve tried several times to download a video with audio, but had no luck. It says the attachment is down loading and to please wait but then eventually just goes away. Am I doing something wrong? Any help with this as I would like for you to hear the knock.

grahambehan · 10-23-2023

Its probably too large a file. If you recordwd it on a cell phone sendbit as a text to 260-701-8860.
Graham

10-23-2023	#1
Perry Mitchell Join Date: Nov 2018 Location: Washington Posts: 98	Engine knock I have been doing research on this subject, but have not come up with anything definitive. This motor came from a wrecked 91 ZR1 with only 17,000 miles on the odometer. It has been transplanted into my 67 Camaro that has been an ongoing project since 2010. I?ve been able to start it for the last several years but have yet been able to take it on the road. It starts, idles, and revs well. However, it has this very annoying Knock that I am worried about. To me, it sounds like a rod knock. All my research says it is probably the dual mass clutch fly wheel assembly but this motor is connected to a 700 R4 transmission. Does the camshaft chain assembly make that kind of noise? Any and all help will be appreciated. Thank you. I tried downloading a video so you could hear it but I guess I don?t know how.

10-23-2023	#2
XfireZ51 Join Date: May 2007 Location: Chicagoland, IL Posts: 9,704	Re: Engine knock How has the motor been modded if at all? If its stock and has the stock calibration, knock shouldn?t be much of an issue. __________________ [SIGPIC][/SIGPIC]Former Membership Chairman Former ZR-1 Registry - BOD 1972 Corvette 4speed base Coupe SOLD long time ago 1984 Corvette Z-51/4+3 SOLD 1992 Corvette ZR-1 Aqua/Gray #474 SOLD 1992 Corvette ZR-1 Black Rose/Cognac #458 2014 Honda VFR Interceptor DX

10-23-2023	#3
bob@tradeshowconsulting.c Join Date: May 2022 Location: Georgia Posts: 82	Re: Engine knock could be piston slap, or lifter as well .. Mark Haibeck would be a good contact to troubleshoot

10-23-2023	#4
Perry Mitchell Join Date: Nov 2018 Location: Washington Posts: 98	Re: Engine knock Thank you for your replies. Internally, the motor is stock. It does have the secondary delete modification, and long tube headers. Mark has provided calibrations for those.

10-23-2023	#5
grahambehan Join Date: Feb 2013 Location: New Concord Kentucky Posts: 181	Re: Engine knock If you have a 700 r4 trans, you do not have a dual mass flywheel, just a flex plate, unless someone did something very creative. The chain tensioner makes more of a "clatter" and is normally present for a few seconds after start up, normally. A video or just audio would help. The lt5 is a relatively noisey engine tho. Graham

10-23-2023	#6
Perry Mitchell Join Date: Nov 2018 Location: Washington Posts: 98	Re: Engine knock Thank you Graham. Yes, the original flywheel, clutch and transmission have been removed and replaced with a flex plate and 700 R4 transmission. I?ve tried several times to download a video with audio, but had no luck. It says the attachment is down loading and to please wait but then eventually just goes away. Am I doing something wrong? Any help with this as I would like for you to hear the knock.

10-23-2023	#7
grahambehan Join Date: Feb 2013 Location: New Concord Kentucky Posts: 181	Re: Engine knock Its probably too large a file. If you recordwd it on a cell phone sendbit as a text to 260-701-8860. Graham