09-29-2020, 01:47 PM | #1 |
Drives: 2018 Camaro SS 1LE Join Date: Jul 2018
Location: Stuttgart, Germany
Posts: 829
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Rear Main Seal Leak
I had a fair amount of oil leakage from the rear main seal area on a recent long WOT run of a stock LT1 engine with LT4 blower.
I cleaned it up and planned for a replacement of the seal - awaiting parts. In the mean time, I've gotten no further oil leaks although admittedly I've only done short WOT bursts (300 miles). I had already replaced the front main seal with an LS3 seal and understand the rear main seal is the next weak point if one's crankcase is over-pressurized for various reasons. My question is, does the rear main seal 'roll' when failed and simply continues to leak under normal operation or is it possible it just passes oil/pressure when under duress and returns to normal? The oil was coming from the lower bellhousing breather holes as well as the side access covers...all appeared internal to the bellhousing... I suppose wishful thinking... Thanks.
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09-29-2020, 02:55 PM | #2 |
Drives: 2022 Lt1 A10 Join Date: Nov 2015
Location: clark, mo
Posts: 8,873
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How much boost are your running?
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2022 Lt1 6.2 A10, Maggie 2300, THPSI Port Inj/10 rib, Rotofab, E, Nickey, SCOL, Griptech, RC Bandits, Hoosiers/MT 9.80@142.96 1.44 60ft, 6.34@112 707/669 RWHP/TRQ. 16SS Maggie 2650 9.41@147 1.35 60ft, 5.99@119. 16 C7 A8 10.90@128 Bolt on stuff
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09-29-2020, 03:02 PM | #3 |
2018 Camaro 1ss M6
Drives: 2018 Camaro 1SS M6/ LT4 SC Join Date: Mar 2018
Location: Connecticut
Posts: 92
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catch can?
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2018 Camaro 1SS M6 Lt4 SC, LT4 Fuel, JMS Voltage Regualtor 592hp 610ft lbs
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09-29-2020, 03:40 PM | #4 |
Drives: 2015 C7 Z06 M7 Join Date: Dec 2012
Location: So-Cal
Posts: 665
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Replace the seal and get the tune fixed - it's knocking.
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09-29-2020, 08:16 PM | #5 |
Drives: 2022 Lt1 A10 Join Date: Nov 2015
Location: clark, mo
Posts: 8,873
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Yes it is, me and Mike have been there on my Camaro just me pushing him to make more boost and power. Plus I didn't get the crank case vented as I was supposed to do. It will break some ring lands at some point. Been there also.
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2022 Lt1 6.2 A10, Maggie 2300, THPSI Port Inj/10 rib, Rotofab, E, Nickey, SCOL, Griptech, RC Bandits, Hoosiers/MT 9.80@142.96 1.44 60ft, 6.34@112 707/669 RWHP/TRQ. 16SS Maggie 2650 9.41@147 1.35 60ft, 5.99@119. 16 C7 A8 10.90@128 Bolt on stuff
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09-30-2020, 12:06 PM | #6 |
Drives: 2018 Camaro SS 1LE Join Date: Jul 2018
Location: Stuttgart, Germany
Posts: 829
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Appreciate the posts folks...
laynlo15: I recall reading your ring land failure failed your RMS (excessive crankcase pressure). How much oil did it puke and was it constant? Thanks.
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09-30-2020, 12:18 PM | #7 |
Drives: 2022 Lt1 A10 Join Date: Nov 2015
Location: clark, mo
Posts: 8,873
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Enough to oil the track down and try catching the car on fire it was smoking so bad. I also had a belly pan or diaper because we were running a lot of boost and it saved my ass from probably crashing the car. I was on an 1/8 mile pass when it happened and I checked to see where the other guy was and couldn't see the tree on the starting line so I got over against the wall but still put some oil down. The pass before was a 1/4 pass as I was running two classes that day, if that would have happened at 142 mph I'd been screwed. I'd guess a 1/2 pint was in the belly pan, maybe a little more. Yes I had two ring lands break, number 1 and 8. Sucked.
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2022 Lt1 6.2 A10, Maggie 2300, THPSI Port Inj/10 rib, Rotofab, E, Nickey, SCOL, Griptech, RC Bandits, Hoosiers/MT 9.80@142.96 1.44 60ft, 6.34@112 707/669 RWHP/TRQ. 16SS Maggie 2650 9.41@147 1.35 60ft, 5.99@119. 16 C7 A8 10.90@128 Bolt on stuff
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09-30-2020, 03:58 PM | #8 |
Drives: 2017 Camaro 2SS A8 Join Date: Aug 2018
Location: Petersham MA
Posts: 5,125
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Mike, care to elaborate? How do you know it’s knocking from an oil leak?
OP: if you can add a Mighty Mouse Wild catch can, I would definitely recommend it.
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2017 Chevy Camaro 2SS A8 Whipple 3.0, Mast Black Label heads, Fore triple in-tank pumps, 112mm TB, LPE +52% injectors, LPE BB HPFP, 15” conversion 1059 WHP/944 WTQ, 9.48@150
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10-02-2020, 12:47 PM | #9 | |
Drives: 2015 C7 Z06 M7 Join Date: Dec 2012
Location: So-Cal
Posts: 665
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Quote:
Adding additional crankcase ventilation will help to prevent the seal problem, but if it's caused by detonation, it's a nice warning sign that something isn't quite right. I personally feel the factory GM oil separator on the Camaro does a great job. If I'm running more than a "pump gas" boost level (6-7 psi), I'd upgrade the hose that runs from the separator to the the throttle body to a larger diameter (one I use is 1/2" or 5/8"). Sorry Tim, you'll probably have to replace the seal, haven't seen one fix itself yet...
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10-02-2020, 02:37 PM | #10 | |
Drives: 2017 Camaro 2SS A8 Join Date: Aug 2018
Location: Petersham MA
Posts: 5,125
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Quote:
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2017 Chevy Camaro 2SS A8 Whipple 3.0, Mast Black Label heads, Fore triple in-tank pumps, 112mm TB, LPE +52% injectors, LPE BB HPFP, 15” conversion 1059 WHP/944 WTQ, 9.48@150
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10-04-2020, 02:19 AM | #11 |
Drives: 2018 Camaro SS 1LE Join Date: Jul 2018
Location: Stuttgart, Germany
Posts: 829
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toohighpsi: Agreed, very interesting information. The leak began on a track visit when I wasn't logging, but previous logs had shown very little knock thanks to careful tuning. Its evident that I've got a combination that the German 98 octane fuel does not fully support when used with gusto.
Dumb question, but can the RMS be replaced without pulling the oil pan? Rear engine cover? It appears one might be able to pry just the RMS out and tap a new one in. I've got limited experience with LS/LT engines and since there doesn't seem to be a published book on the subject. My trans jack arrived...still awaiting remaining parts. Comment: I did a good clean up, added a METCO breather with check valve to the valve cover, and then exercised the car on the autobahn...very minimal oil residue was found on inspection. But it does need to be replaced - no question. Thanks.
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