Rear BS delete only and PCV idea

[edged1g]

I may have a huge part out coming

You won't part it! It's an addiction! JK...good luck man.

 

[1qkfwd]

Oil drainback will be impeded by any pressure, even atmospheric. For proper windage and drainage a crankcase must be under vacuum. Otherwise the oil wont drain properly no matter how many drains you add.

The oil drain holes in the head provide plenty of area for the vacuum to draw on the entire crankcase. Take a V8 for example which has two, small drains around 1/2-9/16". Using a standard PCV system we can draw 2-4 in/Hg vacuum. Add a vacuum pump and we can easily draw 10-12 in/Hg. The 4G has more drains and they're larger diameter so to say they're insufficient to pull enough vacuum on the crankcase is not an accurate statement.

If you cannot draw at least a couple inches of vacuum on an engine using a conventional PCV system then there is a problem. I'd be looking for cracked or leaking PCV lines and fittings. Additionally, any gasket or seal on the engine that is leaking will allow air to flow in and reduce vacuum. The rear main seal, oil pan and valve cover are the most common areas for this to happen.

I completely 100% agree that we would need full vacuum for the best crankcase setup. But in all reality how many hoods have you popped and seen a good crankcase setup that uses vacuum on? You see some stock, some of the stupid little filters, majority just run bigger lines off the valve cover. We would need a good baffled and sealed box that could hook to the block somehow and then a good vacuum source. Not all of us run intakes with filters (FF turbos and ram air style that produce pre compressor pressure) so getting vacuum is a little more difficult

As a machine shop I'm sure you could agree that the early 4g engines in comparison to the evo style 4g engine really do suffer from the amount of oil drain backs. Two on the early 4g engines weren't really designed as drain backs as much as they were designed to allow crankcase ventilation to leave the block through the head. up and out the valve cover baffling.

Since crankcase pressure will take the path of least restriction, if a vacuum setup is not available or cant be adapted you do the next best thing. So getting the pressure out of the block so it doesn't have to really have to fight its way up through the head past the oil trying to go down is ideal. So in turn you can modify the spot in the head that's made to block oil from going down and now you have two good sized drains back to the pan.

 

[LandSpeed-DSM]

Edit: What he^ said

If keeping oil in the sump/out of the head and excessive crankcase pressure weren't issues (particularly at high rpm).. why do so many programs find a need for products like the Kiggly HLA or taller oil pump gears?

I do have a -12 from one of my intake pipes to pull some vacuum on my catch can. But that doesn't work if I run my headlight scoop, where it sees positive pressure at speed. Plumbing in a one-way valve would essentially make it the same as a passive vent anyways.

Venting pressure from the case and valve cover even without a pump is beneficial. Let it take a path other than the oil returns. A vacuum pump is a great idea, certainly, but in the mean time this will work just fine without. And in my setup, there's already a bung on the can waiting for when I reach that part off my to do list.

 

[JacksonAuto]

HLA regulators and the like are to prevent lifter pump-up at high RPM.

But like I said earlier, and perhaps I didn't properly articulate my point, the oil drains in all of the 4G engines are more than sufficient to allow efficient oil drainage back to the sump. Positive pressure in the crankcase will impede this flow. If you've got an engine in which the oil isn't draining back properly then I would be willing to bet good money that you've got excessive crankcase pressure. It doesn't matter if you've got one small drain port or a hundred giant ones- excess pressure will stop the oil from draining properly and it will build up in the cylinder head.

And please don't misunderstand; I mentioned using a vacuum pump scenario as an explanation/examle of why I find the oil drains in the 4G to be sufficient. Please don't take that out of context and think that I am suggesting the use of a vacuum pump on a 4G63.

 

[LandSpeed-DSM]

Not quite. The explicit purpose of Kiggly's HLA is keeping excess volume in the pan instead of dumping from a relief port at the HLA, all the way up in the head.

Which it does well.

But, Re: Crankcase venting.. it sounds like we're in agreement.

 

[boost97gst]

Well, off topic and ill be starting a thread in a more populated area but the machinist that was known and proven to be good around here is retiring. Im at a standstill til i get a good machinist. Heading to newbie section as the regional st louis area section is deader than a doornail.

 

[JacksonAuto]

Well, off topic and ill be starting a thread in a more populated area but the machinist that was known and proven to be good around here is retiring. Im at a standstill til i get a good machinist. Heading to newbie section as the regional st louis area section is deader than a doornail.

FedEx will carry a block from you to me at a reasonable rate

 

[MIdsm]

I would prefer the back or top of the rear BS hump for a vent, as long as there is enough room to work on/remove the starter. The crank sprays oil as it spins, but the oil leaves mostly in a tangential direction clockwise when looking at the front of the engine. The top of the rear BS hump would be in a location to receive a bit less oil then the top of the front hump. Also, I have thought about using the front bs shaft hole in the front cover as a vent. The plus is that it's a large opening but a minus is that it's at the front of the engine (front cover). The baffle would be hard to implement. The timing belt cover would have to be modified and I'm paranoid about stuff getting in the cover. Also, if there is an oil leak into the cover the timing belt may be compromised. Also, the accessory belts would be in the mix as well. A belt change may require the fitting to be disconnected and then reconnected. I'm getting old and forgetful and would probably drive off with the vent hose disconnected.

I believe in KISS principle. Help the end user minimize the chance of making a mistake.

The BS check bolt location would be great for measuring the crankcase pressure(dipstick tube would be another).

I ramble too much.

 

[edged1g]

I would prefer the back or top of the rear BS hump for a vent, as long as there is enough room to work on/remove the starter. The crank sprays oil as it spins, but the oil leaves mostly in a tangential direction clockwise when looking at the front of the engine. The top of the rear BS hump would be in a location to receive a bit less oil then the top of the front hump. Also, I have thought about using the front bs shaft hole in the front cover as a vent. The plus is that it's a large opening but a minus is that it's at the front of the engine (front cover). The baffle would be hard to implement. The timing belt cover would have to be modified and I'm paranoid about stuff getting in the cover. Also, if there is an oil leak into the cover the timing belt may be compromised. Also, the accessory belts would be in the mix as well. A belt change may require the fitting to be disconnected and then reconnected. I'm getting old and forgetful and would probably drive off with the vent hose disconnected.

I believe in KISS principle. Help the end user minimize the chance of making a mistake.

The BS check bolt location would be great for measuring the crankcase pressure(dipstick tube would be another).

I ramble too much.

STM has this as an option, although I am not sure how many people are running it, if any. I agree with you though as far as complexity. I am an overkill person and would not be happy without being 100% sure my timing belt area was safe from things getting in and leaks.

The balance shaft inspection hole is the easiest to implement with the block in the car, without machining, and without welding. A lot of the other options can't be done without at least dropping the pan to clean up the metal shavings from drilling/tapping. Fittings that thread into the hole are readily available.

 

[boost97gst]

FedEx will carry a block from you to me at a reasonable rate

It may come down to that. Might send ya the head as well. I'll call you if i dont get any local leads in the next week. We can talk specifics.
Thanks though!

 

[1qkfwd]

For the most part we are on the same page

But like I said earlier, and perhaps I didn't properly articulate my point, the oil drains in all of the 4G engines are more than sufficient to allow efficient oil drainage back to the sump. Positive pressure in the crankcase will impede this flow. If you've got an engine in which the oil isn't draining back properly then I would be willing to bet good money that you've got excessive crankcase pressure. It doesn't matter if you've got one small drain port or a hundred giant ones- excess pressure will stop the oil from draining properly and it will build up in the cylinder head.

I cant 100% agree with this. Mitsubishi sees it differently to. I mean they did go ahead and add all those extra oil drain backs in the head and block. That's gotta tell you something.

 

[JacksonAuto]

I cant 100% agree with this. .

You're still missing my point. The statement was made earlier that there aren't enough drain holes to allow enough air to be drawn through to create a vacuum in the crankcase. My point is that there are plenty of holes with enough area allow the air to flow out, and I compared it to a V8 which has two small drain holes.

My other point is that you can have a hundred drains, but if there is positive pressure in the CC then that alone will impede oil drain back. The bottom line is there MUST be vacuum in the crankcase.

And one of the reasons for the amount of holes Mitsubishi engineered into the head/block isn't necessarily for volume but also for location. There are many places cast into the head which don't allow oil to flow from end to end which would cause a back up of oil. So extra drains were added.

 

[edged1g]

So for everyone reading this and thinking about doing it, how would you plumb it with a catch can? My thoughts were running a valve cover and catch can like shown here. One of the inlets of the catch can would run to the block breather. The two vents on the valve cover would then "T" together and enter the other inlet of the catch can. The outlet of the can would then run to the turbo inlet.

Thoughts?

 

[boost97gst]

Ehh you could still keep the pcv and a check valve in line. Just one line going from the block and one from the VC to the catch can then out to the inlet pipe. I think that should be sufficient but if you wanted to pretty it up and delete the pcv i guess your way would work. I still want some vac on my CC so im sticking with my kynar/pcv combo running to the IM like normal, just adding in a catch can and the block hose basically.

Off topic: man o man.... mother f'r. Dropped my block off and head for inspection today. This guy i just happened to find, no luck in finding a local machinist that knows the 4g63. But hes been building engines since 1974 sooooo i think i can trust him. I told him about this idea and how i may want him to tap an extra hole down near the rear BS. I then had to explain why. Not a good sign and made me second guess him. He then continues on about how the oil drains are plenty and i should never worry about cc gases. I said, well, you sawed off prick, this is a turbo motor that will be making over 600hp, blow by is inherent, and it WILL impede flow back to the pan!! If only a small amount. I want to vent from down low to stop this from potentially being a problem(Looks nice too). He wasnt having it. Man, what a contentious little guy he was. I dont care, ill tell him to tap a spot regardless. There is too much knowledge on this forum and it just MAKES SENSE. hahaha just thought id rant, same rant is in my build thread but this pertains to this particular "mod".

 

[LandSpeed-DSM]

Did he know beforehand this will be seeing boost? Or anything else about it's intended application? He needs to set your Piston-to-Wall, Quench, Ring gap , bearing clearances, etc to meet your needs.

If he hasn't asked and made note of any of this it's time to grab your sh!t and walk away!

 

[boost97gst]

Agreed, I did tell him the engine hes looking at was making most likely over 500hp. Its turbo and may see upwards of 40psi. He seemed confident, but i sure as hell wasnt! If he says any more wacky shit im gonna go knockin on another shop's door. We'll see after i get my results on the block. I trust any machinist that experienced will be able to tell me why my #2 cylinder is jacked. Probably gonna be visible as soon as the piston comes out. Thats his guess and mine too: compression ring.

 

[boost97gst]

I updated my build thread(not really too much of a "build" yet). Anyway, i did that god damn leakdown probably 10 times to make sure and everytime i hear it coming through the CC. Come to find out great news today: Turns out it WAS the valves. In particular 1 intake valve on the cylinder in question that had 90psi and 35% leakdown. Just baffled but i believe the guy, he says its he could see it clearly. So now i just gotta find someone to do the valve job properly this time and ill be up n running....... in 6 months ! Just got another IRS letter today, these guys smell blood. I pay so so much in taxes yet its never enough. Was gonna write a check for a new car thursday, looks like the Lincoln is gonna get some more work mileage for a few more months!

 

[keltalon]

I understand wanting to ventilate the pressure, but how do you plan to pull a vacuum on the crankcase? A passive system of just venting to atmosphere is not a good idea.

Here is how I have mine setup. I ran a 1/2 npt 3/4 barb to intercept the factory vent port from the block and the same on the balance shaft inspection hole. The only difference is on the balance shaft inspection hole I tubed the fitting to enter the block about 2 inches this mimmick the factory pcv valve installed in the valve cover and it keeps oil from entering the catch can and there is no need for any type of baffling. I create vacuum via the turbo inlet pipe via a mishimoto sealed catch can and the 6266 does a nice job pulling the vapors out of the block . This way I have a nice clean look on the valve cover side and adequate vents on the bottom. The main reason i did this is to keep the crank pressure from hindering my turbo oil drain flow back to the pan and my oil drain flow from the head back to the pan.

 

[keltalon]

Pictures

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[edged1g]

Here is how I have mine setup. I ran a 1/2 npt 3/4 barb to intercept the factory vent port from the block and the same on the balance shaft inspection hole. The only difference is on the balance shaft inspection hole I tubed the fitting to enter the block about 2 inches this mimmick the factory pcv valve installed in the valve cover and it keeps oil from entering the catch can and there is no need for any type of baffling. I create vacuum via the turbo inlet pipe via a mishimoto sealed catch can and the 6266 does a nice job pulling the vapors out of the block . This way I have a nice clean look on the valve cover side and adequate vents on the bottom. The main reason i did this is to keep the crank pressure from hindering my turbo oil drain flow back to the pan and my oil drain flow from the head back to the pan.

With this setup, did you remove the factory PCV and the vent on the VC and block them? Any pics of the VC?

 

[keltalon]

With this setup, did you remove the factory PCV and the vent on the VC and block them? Any pics of the VC?

Valve cover is stock unmodified. I have the two valve cover holes going to a second breather catch can my thinking is a source of fresh air under boost as bottom end vacuums. When I finish my transmission I am going to log valve cover pressure to see just how much vacuum is being created.

 

[ceedawg]

Valve cover is stock unmodified. I have the two valve cover holes going to a second breather catch can my thinking is a source of fresh air under boost as bottom end vacuums. When I finish my transmission I am going to log valve cover pressure to see just how much vacuum is being created.

Great stuff man. Since it will be a challenge for me to get to that area of the block since the motor is in the car I think I will just get the vented dipstick holder we discussed ,run a -6 line from the -6an fitting it comes with and place it to my other catchcan which is vented. I think your way is the preferred way to go though especially since you have the block out. Nice how you have the top plug going to the vent that leads to the head.

 

[keltalon]

Here is what you want. The factory pcv effect. I would like to make a correction don't use the Bs inspection bolt hole it sits to close to the roof of the area cast for the balance shaft and will allow oil to enter the tube. It's important that the tube be suspended in mid air to capture only crank case vapors not oil. Here's a picture of mine.

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[ceedawg]

Here is what you want. The factory pcv effect. I would like to make a correction don't use the Bs inspection bolt hole it sits to close to the roof of the area cast for the balance shaft and will allow oil to enter the tube. It's important that the tube be suspended in mid air to capture only crank case vapors not oil. Here's a picture of mine.

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I see you have the raceshaft in there too kels