Utoh, I might have done a bad thing... (1 Viewer)

[amaurer]

I made a catch can for my BJ42's breather, which would give me a drop or two of oil as it cooled. I used a cheapie catch can from ebay, however, and I noted (but ignored) the fact that the ports were much smaller than the breather (ID of the ports was maybe 1/8", compared tot he 3/4" or so breather).

Since I had no puffing from the tube I figured it'd be OK, however I went out this morning after a good drive and find that I had a huge oil slick under the car. It looks like I got oil coming from just about everywhere, rear main seal, side cover, pressure sender, the works!! I'm down almost a full quart.

Did I do this by restricting the breather??

 

[MOTERRA]

you might have over pressurized the oil breather line and blew the seals out....i don't know anything about bj42's, just have heard of this happening on small block chevy when the breather is obstructed or blocked. hope i'm wrong but the look of that stain ain't good...good luck amaurer

 

[cruiser_guy]

Yep, I think you're on the right track. Lack of crankcase ventilation blew out the seals! OUCH!

I've often thought about something there to catch the oil drops but I think I'll stop thinking about that

 

[amaurer]

... s***.

So what to do, and what to check?

My plan will be to remove the catch can, degrease the engine, and go for another test drive to see what happens. I have a hope that, rather than seals being "blown out" the increase pressure just made them weep/leak... is that reasonable or am I definitely screwed?

What seals do I need to be thinking about? Crankshaft seals, pan, side cover, and...?

 

[cruiser_guy]

My plan will be to remove the catch can, degrease the engine, and go for another test drive to see what happens. I have a hope that, rather than seals being "blown out" the increase pressure just made them weep/leak... is that reasonable or am I definitely screwed?

What seals do I need to be thinking about? Crankshaft seals, pan, side cover, and...?

I'd do the test drive first WITHOUT the catch pan. Make SURE your low oil cutout is working and you have your cell and AAA card with you. Plan on a drive long enough to get the engine totally up to temperature, maybe a few hill climbs as well.

If the seals are gone I'd to the rear main and front cover as a minimum with the rear main being the real pain since the tranny needs to come out for that. The side cover often leaks and just needs the bolts GENTLY tightened.

 

[lostmarbles]

...My plan will be to remove the catch can, degrease the engine, and go for another test drive to see what happens. I have a hope that, rather than seals being "blown out" the increase pressure just made them weep/leak... is that reasonable or am I definitely screwed?..................

Well that's exactly the course of action I'd take Amaurer. (And I don't think your optimistic outlook is beyond the realms of possibility.)

Good luck.

 

[amaurer]

Ok, i *might* have dodged a bullet.

I degreased everything, ditched my catch can, and went for a little drive. It looks like nothing is leaking, although the bottom of the bell housing is probably going to stay moist for a while since I can't get in there to clean everything out (clutch works fine, even oily, it seems). I'm cautiously optimistic.

As far as the breather, with the can off it does seem to "puff" a bit; guess I have more blow-by than I thought. I can sorta see why such a small oriface caused pressure buildup.

I did a quick redesign of my catch can, and I think I actually like it better this way!

Picture 1 is the $15.00 ebay special I started with.

Picture 2 and 3 is the modifications I made today; I turned the entire top of the can off with the lathe and installed a hose clamp through the side of the can.

Picture 4 and 5 is the can installed. The sight glass is visible through the wheel well and the clamp holds it onto the breather. I could stuff some steel wool in there, but I don't think I'll need it; my oil drips happen when the engine cools, not as its running. Note that the whole top of the can stays "open", so no pressure issues.

 

[amaurer]

more

 

[lostmarbles]

Amaurer.

I can't see how your catch-can is supported. Is it supported off your engine somehow? (My engine has some nearby mounting holes in the casting?)

If your catch-can is supported simply by the breather pipe (via the hoseclip), then I believe the bracket on the breather will break in superquick time. And I say this because my bracket broke long ago (simply from vibration) without any extra weight hanging off it. (I have a beefier home-made bracket now.)

All this raises the question of - Is it worth the trouble? (I'd tend to ditch the catch-can and look at "doing the rings" if the engine is blowing enough oil from your breather to stain your driveway/garage.)

 

[gettocruiser]

60 year old heavy diesel mechanic told me to plumb crank-case vent in to air intake, i guess up stream from the air filter or filter will get soaked in oil. requires installing a fitting of some sort.
plumbing cc vent into air intake creates a negative preassure inside the engine and will stop your oil leaks. unless you have other serious troubles...
make sure there is no oil trap or your situation will repeat itself. maybe cut off breather line straight off the cover and run hose up to the air intake so oil will run back into the engine.
i haven't tried it as i want to monitor my blow-by and i wouldn't suggest it if i didn't completely trust the guy who told me this.
let me know if you try this, good luck.
eric

 

[87 HJ60]

Just curious, what's the purpose of this catch can? Also does my 2H have a catch can and where would it be located?

 

[MOTERRA]

I'd recycle a tin can and use that...like a grease trap on a bbq...leave the labels on for that campbells soup tin look...

seriously thou I have heard of what ghetto cruiser is talking about. many vehicles have a pcv valve that vents oil and gases into the throttle body/carb. at the base.....my dd chevy has this setup.

x2..... is it worth the trouble?

 

[Dougal]

My plan will be to remove the catch can, degrease the engine, and go for another test drive to see what happens. I have a hope that, rather than seals being "blown out" the increase pressure just made them weep/leak... is that reasonable or am I definitely screwed?

You should be fine.
The seals will leak/weep when the pressure gets too high. I've been there myself on other engines.
Sorting out the breather (in my case a slightly pinched hose) stopped the leaks.

 

[american psycho]

Reoute to Air Intake

My 3B was rigged to run the vent into the air intake after the air filter (see photo). I seem to recall seeing a photo of a later 3B or perhaps a 13BT where this was standard.

 

[amaurer]

looks like everything turned out just fine, i burned up and down the highway for about 40 miles in the last two days and not a drip to be seen.

marbles, yeah the can is just hanging on the breather. its pretty light and the tube bracket is in good shape... ill keep an eye on it, thanks for the tip.

my blowby really doesn't seem that bad, i think my original set up was just wayy too restricted. toyota put a 3/4" pipe on there for a reason, i shouldn't second guess them. all of this effort is really just to eliminate the single drop per week that i'd find on my garage floor; no big deal, but then, i hate seeing fluids on the ground, pet peeve I guess.

 

[ohrly?]

lmao, im glad it works

 

[lostmarbles]

Just curious, what's the purpose of this catch can?.........

Just to prevent oil mess/drips. (And Amaurer's one is equipped with a sightglass so he can see at a glance how much oil has accumulated.....With a drain plug to drain the accumulated oil too.)

.....Also does my 2H have a catch can and where would it be located?.....

I doubt Toyota would have fitted one to your engine (but having said that, I'm not familiar with the 2H). I believe catchcans are almost all "after-market fitment".

As I understand it - Older engines had breathers for crankcase venting and things like "worn compression rings" or "turboing an engine that wasn't originally designed for a turbo" tend to cause excessive blowby (excessive combustion gases entering the crankcase)with additional entrained oil droplets/mist that exit the engine via this breather.

And I think the stricter emission standards applying to modern engines meant that crankcase venting via a breather tube (direct to the atmosphere) became taboo. So the manufacturers then went to routing the blowby back into the air intake.

This raises an interesting point - One has to be careful with a diesel because it can run "out of control" by using its own engine oil as fuel. For instance - I would think a rollover that causes engine oil to flow in significant quantities into the air intake via a blowby tube could cause this????

 

[Dougal]

I doubt Toyota would have fitted one to your engine (but having said that, I'm not familiar with the 2H). I believe catchcans are almost all "after-market fitment".

Catch cans that need manually emptied are aftermarket only. But catch cans which drain back to the sump have been used by several. Isuzu's 4BD1T has them factory fitted.

But in most engines an air/oil seperator is built into the breather or rocker cover so no external one is needed.
The reason for Isuzu fitting one to the turbo motor is the mist created by the piston squirters.

I've had an engine worn enough to run on it's own oil. But to get that worn it'd lost enough compression that it had to be run hard (EGT's over 600C) to burn it's own oil.
When the throttle was let off it'd run on for about 10 seconds before slowing down and returning to diesel fueled speed.

Healthy diesels, yeah they'll run on oil just fine.

 

[amaurer]

so, if I plumb the breather into the intake, are we thinking run-away is a risk, or no?

Dougal, I couldn't gues your opinion, you said you it took a really worn engine, but then said a healthy diesel would do it too??

 

[Dougal]

so, if I plumb the breather into the intake, are we thinking run-away is a risk, or no?

Dougal, I couldn't gues your opinion, you said you it took a real worn engine, but then said a healthy diesel would do it too??

Sorry that wasn't very clear.
The experience I has was with a worn engine, which didn't have enough compression to run on oil.
If a healthy engine had something like a valve guide go, it could be possible to still have enough compression to run on it's own oil while the valve is rooted enough to let in enough oil for it to run.

I guess that's still not that clear.

But you'll be fine with a breather routed to the intake.