Think I spun a bearing - rebuild time. Need advise. - Page 2 - ZR-1 Net Registry Forums

EvanZR1 · 03-10-2018

Quote:

Originally Posted by We Gone

I assume you have checked the oil for coolant? yes I would think a head gasket could cause the knock as a coolant will not compress. I say this because I had a 90 that had a few very bad injectors and was putting a lot of gas in the cylinder/s and a very bad knock.

Now that you mention it, I remember the same thing happening on my previous 91. Had an injector stick open and I remember it making a very similar knock. Changed the injector and the car ran great again.

Demps · 03-10-2018

As an easy diagnosis at this point: pull plenum & check injector housing to head security & plenum too. There's a water passage there. Possibly that or injector stuck open.
Ted

32valvesftw · 03-11-2018

If it was a stuck injector would there be a noticeable fuel smell out of the exhaust?

jss06c6 · 03-12-2018

Pull your plugs and put a borescope in the cylinders and take a look. Check your plugs to see which cylinder(s) are causing the issue. Blown head gasket would show it's ugly head immediately upon startup and would have been there when you parked it in my opinion. I would say spend some time doing some good diagnostics before you tear into it..

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Mr Blue · 03-13-2018

There are other options. If you have indeed spun a bearing, Pete had a high mileage short block for sale@ $1350. He also could upgrade it to a closed deck 391 CID for $6995. That would be a great upgrade. For that matter, he may be able to do the same for your short block. Offset grind the crank and use small journal rods would get you to 400 CID.

lfalzarano · 03-13-2018

A failing dual mass flywheel will make a similar knock. Put it on a lift and use a stethoscope to isolate the noise while it is running. I blew my flywheel once and it sounded like the motor.

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03-10-2018	#12
Demps Join Date: Jan 2006 Location: Niceville Posts: 997	Re: Think I spun a bearing - rebuild time. Need advise. As an easy diagnosis at this point: pull plenum & check injector housing to head security & plenum too. There's a water passage there. Possibly that or injector stuck open. Ted

03-11-2018	#13
32valvesftw Join Date: Jun 2015 Location: Texas Posts: 530	Re: Think I spun a bearing - rebuild time. Need advise. If it was a stuck injector would there be a noticeable fuel smell out of the exhaust?

03-12-2018	#14
jss06c6 Join Date: Aug 2015 Location: Magnolia, Texas Posts: 884	Re: Low coolant, white smoke, knock. Need advise. Pull your plugs and put a borescope in the cylinders and take a look. Check your plugs to see which cylinder(s) are causing the issue. Blown head gasket would show it's ugly head immediately upon startup and would have been there when you parked it in my opinion. I would say spend some time doing some good diagnostics before you tear into it.. Sent from my XT1585 using ZR-1 Net Registry mobile app

03-13-2018	#15
Mr Blue Join Date: Feb 2013 Location: Tallmadge OH Posts: 116	Re: Think I spun a bearing - rebuild time. Need advise. There are other options. If you have indeed spun a bearing, Pete had a high mileage short block for sale@ $1350. He also could upgrade it to a closed deck 391 CID for $6995. That would be a great upgrade. For that matter, he may be able to do the same for your short block. Offset grind the crank and use small journal rods would get you to 400 CID.

03-13-2018	#16
lfalzarano Join Date: Feb 2011 Location: Clayton, North Carolina Posts: 1,133	Re: Low coolant, white smoke, knock. Need advise. A failing dual mass flywheel will make a similar knock. Put it on a lift and use a stethoscope to isolate the noise while it is running. I blew my flywheel once and it sounded like the motor. Sent from my iPhone using ZR-1 Net Registry __________________ Lou[COLOR="Red"][B][SIZE="4"][/SIZE][/B][/COLOR]