Posted this on the new members/faq thread but figured it's more fitting here. Sorry for the double post.

Hello all,This may seem like a dumb question but here goes nothing. There are tons of long forums regarding crankcase Pressure and the good ol' dipstick popping out issue.I've gone through most of the threads and I understand a broken or damaged ringland can cause the dipstick issue, but what I don't understand is if it's normal on a high output built motor?Essentially, the Evo 8 I'm looking at is on a precision 6466, built motor, and the owner has the dipstick spring installed. Car makes about 700hp on E85 and has the STM vented catch can with AN lines(the cylinder one by intake manifold not the box on trans).Should I be concerned about the dipstick spring being present and being a bandaid for a deeper issue or is the spring a normal thing on a high output scenario?Some forums mentioned the dipstick will pop out regardless of how good the crankcase venting is with high boost, is that accurate?Just trying to learn about this convoluted topic as much as I can, as the sight of the spring and catch can seemingly filling quickly concerned me.Thanks in advance.

 

Pretty normal for a built 4G63 to have a reasonable amount of blowby.
I wouldn't be overly concerned about the dipstick clamp, it certainly saves cleaning up oil from the engine bay and underneath the car.
Extra power, larger piston to wall clearance and ring gaps will all increase blowby.
Factory ring gaps are between 10-14 thou. Most aftermarket pistons recommend between 18-24 thou.

The blowby total flow increase causes the head to not drain effectively. This is because the blowby is going up the oil drains. So it suspends or restricts the oil drain function. This is why Mitsubishi put those "walls" around two of the drains, to promote breathing while the head has liquid oil in it.

When there is lots of oil in the head, they will block off the ports for the crankcase to vent. The block crankcase pressure will go up, while the head pressure will remain low. This will then pop out the dipstick as it's the next link in the chain. Personally I installed thicker O-Rings on the handle, that stopped it popping out as it's very snug in there now.

 

I had 2 builds in 1 year, and both (<500hp)do not have CC pressure/oil catch issues. no spring on the dipstick. before that my similar buschur 2.0 had blowby/oil catch issue right off the bat
I'm sure its only a matter of time before i get some so I left my vented oil catch/return setup installed. i would have used the spring also if it was still there

 

I removed my spring on my buschur 2.3 when I built my crankcase venting setup and I had no issues with my dipstick. If you have enough surface area to vent the flow the gases will not be able to push up on the dipstick. Fluid dynamics 101.

 

What is your crankcase venting setup?

 

On my car (which is now sold and gone) I had machined a 20mm hole in the valve-cover to add a breather port with a 14mm ID hose. I tig put a catch can under my intake on the drivers side just near the headlight. I tig welded the appropriate nipples onto my intake so that it pulled the crankcase vapors back into the intake system sorta like stock.

I took some photos but I can't find a final build photo right now. Here is some stuff I found of when I was putting it together. I made all of my brackets from 1/8" aluminum with my tig welder, and then I powdercoated it flat back myself.
The other catch can (which you can see in the pictures) was right by the factory pcv valve on the passenger side.












Here is a link to a thread I made back in 2021 when I was fumbling around trying to figure out how I wanted to do it:
https://www.evolutionm.net/forums/ev...se-system.html

I vividly remember the day I made the post on April 27th 2021 (with the JEGS screenshot of my browser). I was home in WNY visiting my Dad. We did brakes together and it was the last time I ever saw him because he died later that year.

 

you can just buy a cheap catch can with 19mm barbs. breather ports should be enlarged of course. I added a barb at the bottom of this so it returns oil to the motor


https://www.ebay.com/itm/385424333682?itmmeta=01HXS7BD296BMBQXHCYPVGWG3Z&ha sh=item59bd149b72:g:zscAAOSwe~dj77nQ&itmprp=enc%3A AQAJAAAA4OU1OZym%2BTv6cUTULB3vQ%2BsahyCxDb1ldW1wIm FyIVZUTP1F0N0CDCOuzdTfFT0hrbCbiTLlWas4g9KkyyF0%2FW 3Z3W6WWGAVEPUiGAl0hdzVl7nDcihAgZ9fnpePBPZOjYXBzBwV 2rXyCxmA11JIl%2B%2BTtd1HJM5jkgF9UZSZqAAZjeeV0UMtxv 6hlD%2F4yCIpY5r35LdBJh%2BtrJXxTaHkMzQyC%2BnujmbVRx 5wKVwxsZ6qaAMMAiqnZoPFhtU5sSY9hResZUk3DjOCCjER%2FS YXimmua13RcxMHaiLVAh8Eqb9a%7Ctkp%3ABk9SR6DRrafuYw

https://www.amazon.com/Heinmo-Polished-Aluminum-Reservoir-Canister/dp/B07D49LLHM