I've had my LT1 built w/ the hotcam kit, LT4 intake, and all the other goodies inj. etc...well after about 3000 miles for some reason it started smoking out of the right bank, the guy that built it took the hose off going to my throttle body and it was soaked in oil along with my egr vavle. He thought it was building too much pressure and pushing it through there b/c it blowed my oil dipstick out of the block going down the road. BUT we found that it has blowed an oil ring.

My question is..after we fix the bottom end and replace the rings...will it still build that much pressure making me have to vent the crank case or is it bldg. pressure b/c of the blowed ring???

Thanks ahead of time guys.

 

I've seen that with older SBC's when people tried to run without a pcv valve or a crank case evac set-up. They were getting bad blow by and shooting the dipstick out of the tube. Hooke up pcv or do an evac kit to the header collectors and problem was solved.

 

If you have the rings sealed well, and everything else in the crankcase is healthy, there is no reason why the stock PCV system, with the vent line from the TB to the valve cover should not work correctly. I have the stock system intact, spraying a 300-shot, and the dipstick has never "blowed" out of the engine, nor have I ever found oil in the hose or the top of the throttle body.

 

that's what I was wondering, I have the pcv hooked up and the tube running from the TB to the valve cover. Do you guys think that it was building excessive pressure after the ring blew??? b/c like i said i had no problems what so ever bldg. pressure and no oil in lines until it started smokiing which is when the ring blew. The guy that built the engine seems to think that it is bldg. pressure b/c of the blowed ring?? does that make sense to you all?

 

A bad ring allows the combustion gasses to bypass the ring, and enter the crankcase. With enough blowby, you will exceed the capacity of the PCV system to vent the crankcase, and pressure will build up.

Did you fix the "blowed" ring or didn't you?

 

Jeez, injuneer your killing me with the "blowed" thing

fix of tenses and viola!

Your "blown" ring was first and caused the dipstick to be "blown" out also.. provided you fix it and have good compression afterward you should be fine..

I hope whoever built your engine (if you paid them a lot) are giving you a break on the price to fix it.

 

No I haven't fixed the blowed ring, my car has been parked for 3 months due to it and not having the funds b/c of a newborn to fix it. Hope to get it done by spring.

But I was just seeing if the blowby was caused by the broken ring and when it's fixed the blowby will be fixed b/c I didn't want to have to vent the crank with some aftermarket pump and all.

But i'm concerned as to why a ring let go anyways sense the bottom end was never touched and if it did let go, why and looks like it will only happen again if i just fix the bottom end and not fix the initial problem that caused the ring to blow, I thought it might be b/c of compression to start with.

 

You are probably better off just doing a budget rebuild on the bottom end.. if the LT4 kit is the max the car will ever see a stock refresh is fine..

If the rest of the stuff is only 3k old just clean it off and put it all back on.

Feel for you with the newborn. Took me two years to get my current rebuild done what with job, wife, three kids..

 

Personally, I believe the LT engine factory (OEM) PCV system "is not" adequate on most performance LT rebuilds (even without ring problems).

On my engine I removed the fresh air inlet tube on the passenger’s side valve cover and added crankcase breathers on each valve cover. I had hot oily gases pushing back up the fresh air tube into the TB at high RPMs (a very common problem with LTs). Also, I left the PCV valve and vacuum line installed to ensure ventilation at low RPMs.

WD

 

Same setup I'm running except I have a catch can inline with the pcv valve since thats another source of oil into the intake.

 

Thats what I was wondering is if i needed an updated vent system when i rebuild the bottom end. Because something had to cause that ring to blow other than wear i would assume b/c the car only has 60,000 orig. miles on it and it blew 3000 after the build, so something had to change after I had the car built to cause that ring to go don't you think?

So is breathers sufficent or do i need to purchase a catch can system for 3-400 dollars?

Btw the engine will not see any more build besides the bottom end which i'm going to punch it .30 over and put mahle pistons and goodies in it instead of stock and prolly will be forged.

But yes after that its done b/c it takes alot of money for a newborn as most of you know

 

You may want to do a compression leak-down test on each cylinder, prior to a complete tear-down just based on a “blind assumption" you have a ring problem.

WD

 

Are you saying you blame the lack of a breather for your ring failure? If so, I think you are on the wrong track.

 

not at all, i'm saying that maybe too much compression caused the ring to blow, that's why i'm asking these questions to you guys because I have no idea, but I know a lack of a breather would not cause it to blow a ring but too much compression would and nowhere for that compression to go, right?

 

Do you know for a "fact" you have bad compression ring/s in your engine? Some people run 14-1 compression in their race engines without any ring problems.

WD