Big m blowby at valve cover breather

[rhoward7]

I recently purchased a 555 dart big m engine with dart 335 pro 1 cnc aluminum heads. The engine dynoed at 750 horse at the flywheel. This is a pump gas engine. After only a few times getting on it oil seeps from the k&n valve cover breathers eventually leaking down onto the headers. My engine builder has never really given me a straight answer as to whether or not I need some sort of scavenging system to better ventilate the crankcase. I was considering adding either a k&n #62-1400 or #62-1210. where would you connect to on the block? would I have to tap the intake? This is a street car. What about rear main leaks? Have replaced once after only 1000 miles.

[lun40119]

Sounds to me that you still don't have the rings seated properly. Did you break it in with synthetic oil? About the rear main, that is odd.

[rhoward7]

The engine was supposedly broke in properly before dyno. with synthetic. I ran Mobil ! for the first 800 miles, I have switched to Red Line and now have 1000 miles. I asked my engine guy if I needed to break it in fior 500 miles, he said no its broke in and ready to go. I guess from what I am hearing from you, typically dart big blocks dont have oil coming out the valve cover breathers under heavy load? You thinking the engine was not broke in correctly? Engine was race prepped, line bored, everything. Do i need to put rings in it? Thanks for your input

[want-a-be]

Just a quick question about your valve covers. Under the breather inside the valve cover,...is there some kind of baffling system there? I have seen engines with enough oil pressure to shoot oil right up and out of the breather much like your talking about.

Are you running any kind of crank case ventelation? Even a pvc valve to the base of the carb, " which I don't like, " would be better then nothing. Corvettes came out with a nice lil' electric vacuum pump that alot of guys around here have been running with very good luck. I would look into that before before tearing the engine back down. Try the pcv first,... if it helps the problem you can look into other options. It's the cheapest test.

Don

[lun40119]

Don, when we broke in my new JUNK :D, we spent the first 30 or so minutes loading, and unloading, up and down, with the 20/50VR1. I don't have baffled VC's and this thing even at 8000 doesn't even put a haze on the VC. I am running a PCV though.

[want-a-be]

Well,...he did say the engine was broke in on synthetic oil.

The pcv should keep this problem in check for you Jake.

Don

[lun40119]

I was always told not to break engines in with syn oil. Perhaps some of the machine shop guys could chime in on whether it is ok or not. I know some of the oem's do it, but do they prep differently than private machine shops.

[CNC BLOCKS]

I was always told not to break engines in with syn oil. Perhaps some of the machine shop guys could chime in on whether it is ok or not. I know some of the oem's do it, but do they prep differently than private machine shops.

There are differeng grades of synthetic oils out there and maybe the cheaper ones you can do this (not sure) but its not reccomended at our shop to break an engine on syn. oil.

[want-a-be]

There are differeng grades of synthetic oils out there and maybe the cheaper ones you can do this (not sure) but its not reccomended at our shop to break an engine on syn. oil.

I never have, nor recommend, breaking in new engines on synthetic oils. But Jake, the break in you guys did on the 502 sounds like what I recomend to new engines after they are installed.

Don

[lun40119]

Both my turd, and Jims 502 were broke in the same way on the same dyno. He has joined here, his name is camrat68 I think, I am sure he will chime in soon. Both with 20w50VR1. Only things is, when we made our first pull with mine the pressure went to the moon Alice!!!!!!

[camrat68]

I really have nothing to add as far as chiming in, Jake. :o

After loading the engine to seat the rings, the only oil I had on my valve covers came from checking lash. The breather was dry and like Jake, I'm also running a PCV. VR1 20w50 gave me 75psi@3500rpm and 82psi@6200rpm on the fourth pull in under five minutes resulting in some pretty high oil temps of course.;)
Jim

[lun40119]

DYNO...........Dart headed fuel injected 502. I think we need to start a thread with some dyno vids of a 502. I like dyno videos........

[Awesome Bill]

Plain & simple, your finished honed block changed sizes when put back together, or the finish hone was to rough for the rings and they are now sharp as razors. Syn or Min oils have absolutely no affect on the rings sealing. The oil rings keep the oil to its minimum and that is their job. You could of had et temps way to hot and it baked the oil in the beginning but that still should of allowed the rings to seat. If they are just plazma moly, they give up @ 700 °'s or so and start to loose radial tension. But radial tension is also given a boost by the end gap and the pressurizing of the rings. Stainless or tool steel of well over 1000°. Here is your rule of thumb. There should be no oil coming out of the crankcase. This also means your crankshaft is beating the crap out of the oil and it is turning into and oil plume and will be everywhere, even out your breathers. LEAK the engine @ TDC and 2" down the bore, if the reading differs, the torque plate was not correct. The bore changed from honing to assembled engine.

If you want to take a look @ and engine @ 7000rpm with no evac @ all and has proper ring seal, go to my web here http://awesomeengines.biz/bbc-489ci-awesome-xxtra-pro-bracket-race-engine/ this engine has no "blow by" ALL of my engines even the blown ones do the same thing. I could run my engines with no evac or breahters and would only get minor oil splash from rocker arms only. PCV valves don't work for any engine that has blow by and a large cam. A vacuum pump will control this but you have serious hp loss if the compression is going by the rings and pressurizing the crank case. PCV valves? what the hect is that? These are just plazma molly rings we use for up to 1000hp. Even with a 200 shot of NOS, this engine controls its cylinder pressure. Cylinder pressure is what is causing the pressure pushing out of your engine!

I use the same lube, same torque wrench and same man from honing to assembly and the bores are within .0002 from bottom to top and the ring finish is flawless on every engine I do. Even stockers get the exact same treatment. I use the engines bolts or studs with gaskets being used when torque plate honing. This assures the same bore when it it put together. Can't beat a perfect hone and a killer valve job. This is where the base HP is made.

[want-a-be]

Plain & simple, your finished honed block changed sizes when put back together, or the finish hone was to rough for the rings and they are now sharp as razors.

I use the same lube, same torque wrench and same man from honing to assembly and the bores are within .0002 from bottom to top and the ring finish is flawless on every engine I do. Even stockers get the exact same treatment. I use the engines bolts or studs with gaskets being used when torque plate honing. This assures the same bore when it is put together. Can't beat a perfect hone and a killer valve job. This is where the base HP is made.


AAAMen Brotha!!!! Nothing truer then what Bill is saying here.

Don

[rbrduck71]

i hope this is on the subject enough, i would like to install some kinda crankcase evac on my car, valve cover to header collector, good/bad idea? i have tall cast aluminum dart valvecovers, i would like to plumb it like the car that Doug Christensen has in the racers gallery, front or rear of valvecover

THANKS!!!

rubberduck

[rbrduck71]

AWSOME BBC, THATSA KILLER PRICE FOR THAT 489, DONT SEE HOW YOU CAN MAKE MONEY SELLING IT AT THAT PRICE

http://awesomeengines.biz/bbc-489ci-...t-race-engine/

damn i wish california was closer to you


rubberduck

[Awesome Bill]

that is shipped to you so when do you want it. Customer change his mind and advised me to sell it. Your right, if I did work like this it would hurt. I do get deposits! That is why is it so reasonable.

You can run evac off your header with the one way valve and its worth some real power. Still blow by is blow by, you just try to control it.

[rbrduck71]

i dont know how to order parts for valve cover/ or what to call them

i learned alot in this post about blowby, and it is what it is

thanks

rubberduck

[Awesome Bill]

Get a Moroso 3 Vane Vacuum Pump complete system and install that. The header evac is only for drag racing with open exhaust. It is a little pricey $850 but really worth 10hp and not a drop of an oil leak anywhere! MOROSO