Excessive Crank Case Pressure - Need some Help
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From: Earth
Excessive Crank Case Pressure - Need some Help Alright guys. I rarely venture into the internal engine area so I'm a newbie regarding the internal workings of our LS1's. I need your help.
I've recently been spraying a 100 shot (wet) of nitrous. My oil dipstick pops up about an inch or so after every run. No oil is spraying onto the hood though. I sure it's probably excessive crankcase pressure from the juice and I'm getting blow by. I won't spray until I can solve the problem.
How do I approach the problem? I've been told to check the PCV first then do a leakdown test. I'd like to avoid a leakdown test if possible.
Where exactly is the PCV? Plugs into the front of the intake manifold doesn't it? <img border="0" title="" alt="[Embarrassed]" src="gr_emb.gif" /> Geez, I told you I was a rookie. All mods are in my sig.
Help!
Dan
I've recently been spraying a 100 shot (wet) of nitrous. My oil dipstick pops up about an inch or so after every run. No oil is spraying onto the hood though. I sure it's probably excessive crankcase pressure from the juice and I'm getting blow by. I won't spray until I can solve the problem.
How do I approach the problem? I've been told to check the PCV first then do a leakdown test. I'd like to avoid a leakdown test if possible.
Where exactly is the PCV? Plugs into the front of the intake manifold doesn't it? <img border="0" title="" alt="[Embarrassed]" src="gr_emb.gif" /> Geez, I told you I was a rookie. All mods are in my sig.
Help!
Dan
Re: Excessive Crank Case Pressure - Need some Help Assuming there isn't a problem with your PCV setup you are probably going to have to re-ring the motor if you want it to hold that cylinder pressure. It's like a cycle. Your rings are bad so you get blowby which causes more pressure which causes the rings to get worse.
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From: Earth
Re: Excessive Crank Case Pressure - Need some Help Is some blow by expected with nitrous or do I have a hurt motor? Can you guys take me through a step-by-step diagnosis process. Is it a forgone conclusion that I have bad rings/ringlands?
Re: Excessive Crank Case Pressure - Need some Help I'd say a little bit is normal. If you are getting enough to blow the dipstick tube out it's signifigant. You could install a custom electric vaccum pump to pull more vaccum than the pcv does on it's own.
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Re: Excessive Crank Case Pressure - Need some Help i havent seen a clogged pcv in a long time, you should have a ring seal problem with out NOS if thats the problem. Ultra high cylinder pressure from nitrous should promote ring seal if rings are functioning ok. Additional rpm from extra mph may be causing crank pressure to build up and blow out dip stick. i personally run a vent on my oil dipstick tube to vent lower crankcase pressure since i do not own a LS6 motor with its additional crankcase ventilation. Just some food for thought here. <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />
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Re: Excessive Crank Case Pressure - Need some Help Replace the pcv or even run the pcv into a catchcan and see if it still does it... I can't see a 100 shot killing the motor. LS1's in general seem to generate a lot of crankcase pressure both Tony and I both had a lot of crankcase pressure with our strokers and I can tell you that my rings were perfect when we pulled the motor at Xmas.
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From: Earth
Re: Excessive Crank Case Pressure - Need some Help My LS1 still has a stock bottom end and internals. I only have minor bolt-ons and the NX kit. It has 45,000 miles on it. I've made about 50 or so passes. Other than that, I've babied her to a point of obsession. Even with this problem, oil consumption is minimal.
Edit: I don't seem to have a ring seal problem when running N/A. I burn about 1/2 quart per 3,000-4,000 miles. I use Mobil 1 sythetic 10w30 FWIW.
<small>[ April 04, 2003, 06:35 PM: Message edited by: unit213 ]</small>
Edit: I don't seem to have a ring seal problem when running N/A. I burn about 1/2 quart per 3,000-4,000 miles. I use Mobil 1 sythetic 10w30 FWIW.
<small>[ April 04, 2003, 06:35 PM: Message edited by: unit213 ]</small>
Re: Excessive Crank Case Pressure - Need some Help </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by unit213:
<strong> Alright guys. I rarely venture into the internal engine area so I'm a newbie regarding the internal workings of our LS1's. I need your help.
I've recently been spraying a 100 shot (wet) of nitrous. My oil dipstick pops up about an inch or so after every run. No oil is spraying onto the hood though. I sure it's probably excessive crankcase pressure from the juice and I'm getting blow by. I won't spray until I can solve the problem.
How do I approach the problem? I've been told to check the PCV first then do a leakdown test. I'd like to avoid a leakdown test if possible.
Where exactly is the PCV? Plugs into the front of the intake manifold doesn't it? <img border="0" title="" alt="[Embarrassed]" src="gr_emb.gif" /> Geez, I told you I was a rookie. All mods are in my sig.
Help!
Dan </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">I just sent ya' a private message.
<strong> Alright guys. I rarely venture into the internal engine area so I'm a newbie regarding the internal workings of our LS1's. I need your help.
I've recently been spraying a 100 shot (wet) of nitrous. My oil dipstick pops up about an inch or so after every run. No oil is spraying onto the hood though. I sure it's probably excessive crankcase pressure from the juice and I'm getting blow by. I won't spray until I can solve the problem.
How do I approach the problem? I've been told to check the PCV first then do a leakdown test. I'd like to avoid a leakdown test if possible.
Where exactly is the PCV? Plugs into the front of the intake manifold doesn't it? <img border="0" title="" alt="[Embarrassed]" src="gr_emb.gif" /> Geez, I told you I was a rookie. All mods are in my sig.
Help!
Dan </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">I just sent ya' a private message.
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From: Earth
Re: Excessive Crank Case Pressure - Need some Help Ok, I just ordered a new PCV valve from SDPC (pat on the back for using a sponsor <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" /> ). I'll try that then comes the leakdown test.
Just as a side note, I'm getting rid of the car early in June. I can't let it go with a problem and have clear conscience though.
Just as a side note, I'm getting rid of the car early in June. I can't let it go with a problem and have clear conscience though.
Re: Excessive Crank Case Pressure - Need some Help From personal experience I still think it is blowby from the extra cylinder pressure. With your low oil consumption I think the motor will be fine NA. Just take the gas off until you sell it.
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From: Earth
Re: Excessive Crank Case Pressure - Need some Help That's probably what I'll do. I haven't even made one N20 pass at the track. I was hoping to resolve the issue and have some fun this spring.
Re: Excessive Crank Case Pressure - Need some Help </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by 4mulaJoe:
<strong> From personal experience I still think it is blowby from the extra cylinder pressure. With your low oil consumption I think the motor will be fine NA. Just take the gas off until you sell it. </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">I had zero oil consumption on mine, but I was getting 80% on the leakdown test. I think the compression rings are shot, not the oil rings.
<strong> From personal experience I still think it is blowby from the extra cylinder pressure. With your low oil consumption I think the motor will be fine NA. Just take the gas off until you sell it. </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">I had zero oil consumption on mine, but I was getting 80% on the leakdown test. I think the compression rings are shot, not the oil rings.
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From: Earth
Re: Excessive Crank Case Pressure - Need some Help I probably did a dumb thing today, but in the true spirit of drag racing I threw caution to the wind. I made about 6 N20 passes today at the track. She ran like a champ. I popped the hood and checked the oil after each run. I was expecting to see oil blown all over the place. Nope, nothing. The dipstick didn't even pop up once. I pulled the intake off and look inside the manifold. I didn't see any oil build up. I also swiped a shop towel (blue paper towel) on the backside of the TB blade. No oil there either. I have a new PCV valve on the way and a leakdown/compression test in the works. I don't doubt any of you guys, but I seriously doubt I have a ring problem. I've never done anything to hurt the motor. I don't know. We'll see. I'll definitely keep this post going to keep let you guys know the result.
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From: chicago
Re: Excessive Crank Case Pressure - Need some Help I never had my dip stick blow out but my engine had oval cyl. bores and they replace the engine because of this problem. detonation will upset the ring seating it could have been lean or if you used the n2o and were not at wot at first hit. excessive blow by will be the only thing that could cause the dip stick to pop up like you are disscribing If you are throwing caution to the wind an dare going to run it anyway I would duct tape the dip stick to avoid a mess. good luck
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From: Earth
Re: Excessive Crank Case Pressure - Need some Help Hey guys- I think I may have eliminated the problem. I still don't know the root cause. I'll chalk it up to blow by from crankcase pressure. After my 1/4 mile runs at the track I would decelerate in 3rd gear from 117mph. I think the high rpm deceleration was the culprit. Now after I cross the finish line I'm dumping it into OD (A4) and the motor seems to like that much better.
Hopefully that'll help someone if this problem occurs again.
Hopefully that'll help someone if this problem occurs again.
