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Old 09-04-2017   #1
XfireZ51
 
Join Date: May 2007
Location: Chicagoland, IL
Posts: 9,686
Default Re: So I had a bit of blowby...

So a bit of an update. A couple of "while you're theres".
Replacing clutch disc and rod bearings. In the course of diagnosing the the cracked compression ring, Pete removed the rod end. He found the top portion of the bearing to be worn to the copper while the bottom end appeared to be fine. No issues w the rod journals. He surmises that this may have happened at engine initial startup. The motor came out of the 92 Aqua ZR and was a service replacement to the original motor. Pete suspects that since the service motors may have sat for some time, the top portion of the rod bearing had drained of oil, and startup of the motor without proper pre-oiling may have caused the wear.
Also, I am replacing the stock LT1 clutch disc I have been using. I have suspected that possibly the clutch could be slipping at top end after having done a series of mods that should have resulted in an increase of trap speed. Instead the trap has remained relatively flat and really isn't indicative of the power the motor is making. The disc we have removed shows signs of wear and is pretty thin. Replacing it w Centerforce sprung hub which has more "meat" to it. As you can see in the attached pics, the CF disc utilizes more of the area in the center to increase friction surface and several others like the way it works with their Fidanza FW.

Last edited by XfireZ51; 03-08-2024 at 02:10 PM.
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Old 09-04-2017   #2
RichS
 
Join Date: Nov 2013
Location: Wilkes-Barre, PA
Posts: 148
Default Re: So I had a bit of blowby...

I ran a Centerforce clutch in the GS before swapping to a auto. Drove like stock, pulled 1.5x 60's with it.
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Old 09-04-2017   #3
GOLDCYLON
 
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Location: Peoria, AZ
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Default Re: So I had a bit of blowby...

Quote:
Originally Posted by XfireZ51 View Post
So a bit of an update. A couple of "while you're theres".
Replacing clutch disc and rod bearings. In the course of diagnosing the the cracked compression ring, Pete removed the rod end. He found the top portion of the bearing to be worn to the copper while the bottom end appeared to be fine. No issues w the rod journals. He surmises that this may have happened at engine initial startup. The motor came out of the 92 Aqua ZR and was a service replacement to the original motor. Pete suspects that since the service motors may have sat for some time, the top portion of the rod bearing had drained of oil, and startup of the motor without proper pre-oiling may have caused the wear.
Also, I am replacing the stock LT1 clutch disc I have been using. I have suspected that possibly the clutch could be slipping at top end after having done a series of mods that should have resulted in an increase of trap speed. Instead the trap has remained relatively flat and really isn't indicative of the power the motor is making. The disc we have removed shows signs of wear and is pretty thin. Replacing it w Centerforce sprung hub which has more "meat" to it. As you can see in the attached pics, the CF disc utilizes more of the area in the center to increase friction surface and several others like the way it works with their Fidanza FW.
Is that the Camaro clutch disc Dom ?
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91 WHITE/BLACK #2014. 380 P&P&PCed,Ported Heads, Jeal Long tubes, Corsa Exhaust/FIKSE FM-5s /LED TLs, LED Headlights, Front Wilwood 6 piston narrowlite calipers and rear Wilwood caliper street shop mod,CNCed Coolant Pipes,TPI Cvr,Filter cover,Stainless Bolts, DRM/DOM PROM /ZFDOC mod build #102,DRLs,BMAD with stainless Debris Screen,Coplan Air Blaster, Pioneer APP Radio 4,Brey-Krause HB,Sub Bar,Fire extinguisher seat mount,DRM Coilovers,LEDs everywhere,Compass mirror (orange),V1 DIC hidden display, Homelink sun visor, Carbon Fiber top x3 and APSIS Carbon Fiber interior, APSIS CF Steering Wheel/NAPA Leather, Banski trailing arms, Guldstrand front suspension,urethane bushings from Prothane (total suspension) ZFDoc drive shaft safety loop, raptor shift light (orange),AO engineering louver front plate, Console seat cushion, 96CE seats with black custom Sheepskins, ss billet catch can,Viper remote entry/alarm,Cragar Rear Louvers,LED side louver lights, Dewitts Radiator with SPAL fans and a Woods 160 T-Stat

90 RED/BLACK #2794. 4L60e Automatic Stage V by RPM Transmission, TCI Dedicated TCM, OBX Stainless Headers, Corsa Exhaust, SAN Secondaries and Haibeck PROM, Exotic Muscle Coil overs, LED Interior Lights, LED Tail Lights, LED Headlights, 94 Sport seats with black custom Sheepskins , Cragar rear louvers, GS Front calipers, Banski Trailing arms, APSIS Carbon Fiber steering wheel, Front and Rear Baer Eradispeeds, DRLs, Guldstrand front suspension,urethane bushings from Prothane (total suspension), Dewitt's Raditor with Dual SPAL fans and a Haibeck 170 T-Stat

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Old 09-04-2017   #4
XfireZ51
 
Join Date: May 2007
Location: Chicagoland, IL
Posts: 9,686
Default Re: So I had a bit of blowby...

Quote:
Originally Posted by GOLDCYLON View Post
Is that the Camaro clutch disc Dom ?
The one I am replacing is a stock OEM LT1 clutch disc. So will be using the Centerforce. With 345s in back, I probably could use the clamping force.
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Old 09-07-2017   #5
XfireZ51
 
Join Date: May 2007
Location: Chicagoland, IL
Posts: 9,686
Default Re: So I had a bit of blowby...

Below is a view of the top compression ring from #7. Also, motor is starting to go back together. Before Pete started, we discussed cc'ing the heads just to make sure we had all uniform chambers. Pete verified that they were uniform
40cc chambers. We did this on the suggestion of Marc H. Wanted to check if there was some other explanation for compression being overall somewhat lower on the driver's v passenger side banks. However, the FSM states compression should not vary greater than 15% from low to high cylinders. We're ok there (210 v 245). And FSM states that high end of adequate compression is 200psi. So we are over that by a significant number.

Last edited by XfireZ51; 03-08-2024 at 02:10 PM.
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Old 09-08-2017   #6
WARP TEN
 
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Join Date: Apr 2007
Location: Lake Bluff, IL
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Default Re: So I had a bit of blowby...

Quote:
Originally Posted by XfireZ51 View Post
Below is a view of the top compression ring from #7. Also, motor is starting to go back together. Before Pete started, we discussed cc'ing the heads just to make sure we had all uniform chambers. Pete verified that they were uniform
40cc chambers. We did this on the suggestion of Marc H. Wanted to check if there was some other explanation for compression being overall somewhat lower on the driver's v passenger side banks. However, the FSM states compression should not vary greater than 15% from low to high cylinders. We're ok there (210 v 245). And FSM states that high end of adequate compression is 200psi. So we are over that by a significant number.


Did the little pieces of the ring stay in the groove or did you have to go fishing in the oil for them?--Bob
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Old 09-08-2017   #7
XfireZ51
 
Join Date: May 2007
Location: Chicagoland, IL
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Default Re: So I had a bit of blowby...

Quote:
Originally Posted by WARP TEN View Post
Did the little pieces of the ring stay in the groove or did you have to go fishing in the oil for them?--Bob
Bob,

Fortunately, the ring pieces all stayed within the ring groove. No damage was done to the cylinder bore. U can still see the xhatch pattern on the Nikasil.
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