Nothing is obvious, How many top engine builders include them on race and performance rebuilds? How many competitive circle track engines don't have 2 breathers on them? How many times have you dyno'd an engine with and without and compared the dyno findings?

I have every oil change sampled by Amalie Oil, and it comes back with a clean bill of health everytime, there is no mention of "acid" contamination or dillution in the report.

I don't want stating facts be confused with fighting. Back to the original question, try it you can't hurt anything by trying something. Don't be fooled by thinking it is only water vapor exiting the pcv valve, it is part of your vehicles emission system, not a performance enhancing item.

 

I have used the pcv and stock LT1 crankcase evac system with a FI 383. I always had dirty oil and oil in the intake manifold. Most oil resulted under high load. I then did a full external vac pump system (winter of 07 - vp103 pump). Sealed the engine and regulated to 1/3 atm vac. Result... The oil is alot cleaner, better ring seal and increased cylinder pressure which was alot of unexpected fun. It was not an easy modification since I had to move the rad forward, and, design pump mount inside a 97 engine bay with FI (not alot of extra space in there). Alot of pressure is generated inside the crankcase from the rotation assembly. You need some type of system to vent the positive pressure. The e-vac kits are good, but, are only effective under high exhaust fluid flow.

 

Interesting................another IMPORTANT aspect of this discussion that I never heard tested before.......................Sounds pretty convincing to me...............

 

How long you leave the oil in the motor?

One race night on the circle track with breathwers is WAY different than even a week of daily driving.

 

I raced and drove my car off and on from the end of May to end of July. Granted it is not my daily driver but it gets out at least 3 days a week and driven around. I also drive my car to the track, race it, then drive it home.

I use full synthetic oil (greatly cuts down on crankcase contamination) and I run a quality filter.

When I park my car for the winter, I change the oil, prime the system and leave it.

 

How does synthetic oil cut down on crankcase contamination???

Now if you had said synthetic copes with crankcase contamination better you might have had a point, but that is not what you said.

 

dino oil breaks down easier and has un-uniform size particulants during the combustion process these smaller particles break down and can become air borne contaminants. Synth oil does not break down as easy. Thats why you cannot use synthetic oils if you would ever use recycled oil in oil burning furnaces or mixing it with diesel fuel in a diesel engine, it doesn't like it trust me I know.

I'm not an expert on oil, its properties or anything else for that manner. I have been lucky enough to be affiliated with a great race engine building facility for the last 20 some years. We done testing for several oil companies and oil additive companies over the years for our research and sometimes for thiers. I can tell you which oils work best when mixed with nitro (dry sump sprint car application) and which oil additives are snake oil and do nothing. We currently have 2 NASCAR 358" yATES engines running a computer controlled cell for 24 hours a day for MAJOR oil company testing a new oil for thier race teams. I'm just trying to relate my experiences with you and not trying to offend.

 

The thread has drifted far away from the purpose of the original poster's question. He isn't driving a dedicated race car.... looks like a daily driver, with well done heads, cam etc. Highly specialized racing engines need highly specialized crankcase evacuation components. Putting a vacuum pump on a race motor makes a lot of sense. Putting one on a street driven car certainly would provide a better crankcase evacuation system, but would be over-kill. As Brahm showed, the exhaust driven crankcase evacuation systems have been the low-cost solution to crankcase evacuation for many years. But they are not practical on an EFI setup with cats and O2 sensor feedback. Totally deleting the PCV system on a daily driver, without replacing it with something better is counter productive. I can understand the concern with putting oil in the intake manifold - that's the easiest way to reduce the effective octane rating of your fuel, and get into detonation problems. But at least with the LT1, and a correctly assembled engine, I've had no problems with oil getting into the intake via the PCV system. 8 years of operation, and the hose and the chamber in the top of the throttle body are dry as a bone.

 

Yes I'm gonig to have to retract my previous statement.. I put my car to the test this weekend...and failed.. I drove 400 miles from Mammoth to San Diego....it took 9 hours due to complications with the car. Me and 2 of my buddies spent all yesterday trying to figure out what is wrong.. and one of the things we decided couldn't be good for the setup, and caused problems was the way I had the evac system setup.. Now I'm not saying these won't work if you do it right.. but mine was setup wrong, and I really should have thought twice as now it's pretty clear as to why it was a bad idea..

Basically the way I had it setup in my old motor (with no thought of 02 sensors) was I put the evac bungs in my header collectors, which in it's self is fine, but when I went to put my o2 sensors I didn't think of what problems I might have by having the evac ahead of the o2 sensor in the exhaust system. So my o2 sensors are in the exhaust behind the evac.. I believe I should have reversed it.. I can't be 100% sure that it is causing problems for me or not...but I can't see how it can help. I ended up just capping one of them off, and will cap the second one off today.. alot went wrong with the car and I'm trying to elemnate any potential problems 1 at a time.

 

put the evac tubes after the mufflers. make sure to check the valve operation of the evac system if you had issues with it, they can go bad. We've done a few 632" engines that did the entire Power Tour with no issues.

 

One shop I talked to about this said just about every LT1 they seen with just a breather on and no PVC system developed oil leaks. dont know how true that is but just a thought.

 

Doesn't just about every LT1 develop oil leaks regardless of the configuration of the PCV system?