[Camaro1973]

Well, without going into too much detail I have an oil leak on my now 2nd motor.

I’ll sum it up:

Last October , had a new build done. New shortblock, 377 by LME and the works. Well it lasted 800 miles or so, I cracked Cyl 6. Was other issues with it but that did the block in.

In that time we were troubleshooting the rebuilt trans which was a mess and that rebuilt trans was a scrapped and a new rebuilt trans was put in.

So the car stayed at the shop, LME warranteed the motor and I got a new short block and CSP was great and took care of installing.

Now I’ve got the car back and 400 miles later it’s leaking oil which appears to be from the rear main seal. (Not 100% need to get back under it and trace the uv dye tomorrow.)

It’s not a bad leak and I noticed it more when it’s shut off and sitting, it’s collecting bit barely if at all dripping.

When we were on the first motor we pushed the front seal out. The MM wild can just didn’t seem like it was enough with only 1 an10 vent from
The valve cover. So they redid the ventilation system and ran 2x an 10 from each valve cover and turned the mm can into a breather. No vacuum. I then added my elite engineering can and connected that the normal way under the blower dirty side and vacuum off brake booster.

Fast forward to now that’s how the system is still setup.

My build:
LME 377 fully built , maggy 2650, too high psi plates, port injection w/Holley, fore triple in tank pump and the normal bolt ons.

We are running an 80mm pulley which makes around 18psi. I run pretty much only ethanol 65%. Pump gas tune is very conservative and is only 17 degrees on 93. (25 on ethanol)

I just can’t wrap my head around if it is indeed the rms .. how. (Again)

So far everyone I’ve spoke too says the ventilation is adequate. No issue with front seal, dipstick doesn’t pop out. Remove the oil cap when running I have vacuum. I just don’t know how or why it would need more venting.

It’s very hard to tell, because as you know oil leaks are deceiving. But it collects at the bottom rear of the pan, I also see it by the starter. But I was also able to see it tonight from the top of motor with the uv light down to where the dipstick tube goes.

Tomorrow I’m putting it back on ramps and will trace the uv dye.

This thing ran a 4.8s 60-130 spinning in 3rd.

If anyone has any suggestions please chime in, because it looks like they are gonna have to pull the trans again. Unless by some miracle it’s something else leaking and running down.

[Camaro1973]

Here’s the setup.

You can see the elite can bolted to the roto fab housing.

[george]

I wonder it may be from the engine/tran seal

[laynlo15]

If it was the trans seal the fluid would be red. I've never run a catch can, just larger hoses from the VCs to the GM crank case ventilation system. They are 5/8", I also 5/8" to the RotoFab elbow. On my 16ss I failed to run the larger hoses till it was too late and didn't have enough crank case ventilation, also running too much boost and finally broke a couple pistons ring lands and pushed the rear seal out. I run as much hose as possible as you can see running to the THPSI VCs on the drivers side from the GM Vent system.

[KingLT1]

you might try a metco valve cover breather with check valve and see if the leak goes away.

[Camaro1973]

Originally Posted by KingLT1

you might try a metco valve cover breather with check valve and see if the leak goes away.

I ordered that yesterday. My valve covers have 2 vent spots on each cover. (Dsx covers) both front most vents are being used by the vented can.

I’m going to put the breather on the drivers side rear vent. Only place it will fit.

I just can’t see how it would need more venting since it’s already being vented on both covers into the can.

[Camaro1973]

Originally Posted by laynlo15

If it was the trans seal the fluid would be red. I've never run a catch can, just larger hoses from the VCs to the GM crank case ventilation system. They are 5/8", I also 5/8" to the RotoFab elbow. On my 16ss I failed to run the larger hoses till it was too late and didn't have enough crank case ventilation, also running too much boost and finally broke a couple pistons ring lands and pushed the rear seal out. I run as much hose as possible as you can see running to the THPSI VCs on the drivers side from the GM Vent system.
Attachment 1131147

Attachment 1131148

Attachment 1131149

How is the larger hoses adding ventilation though? Isn’t the stock box just a closed system? The center port is for clean metered air and on either side it just pulls air through the case via top of covers.

My box both ports on either side of the clean air port are capped.

[RobZL1]

I'd say you're pulling air from the mightymouse into the crankcase, it's just not metered anymore (assuming the check function of the MM was removed). Then you are filtering the dirty side with the E2X. Under boost, those lines to the MM should be evacuating any pressure build up. I'm not an expert on pcv, but I think you've got it covered. I wouldn't think pressure build would be cause of a leak, since you have addressed the pressure build.

[RobZL1]

Originally Posted by laynlo15

If it was the trans seal the fluid would be red. I've never run a catch can, just larger hoses from the VCs to the GM crank case ventilation system. They are 5/8", I also 5/8" to the RotoFab elbow.

Are those simply straight hose couplers in the 5/8 lines? (as opposed to inline check valves or something)

[Camaro1973]

Originally Posted by RobZL1

I'd say you're pulling air from the mightymouse into the crankcase, it's just not metered anymore (assuming the check function of the MM was removed). Then you are filtering the dirty side with the E2X. Under boost, those lines to the MM should be evacuating any pressure build up. I'm not an expert on pcv, but I think you've got it covered. I wouldn't think pressure build would be cause of a leak, since you have addressed the pressure build.

Yes the mm can only vents, there’s no flap.

However, I just found this when borascoping via top with uv light.

I don’t know if there is 2 leaks but this would explain why I see it on passenger side running down near the starter and then to the bottom.

I can’t tell but doesn’t even look like the oring is seated ?

[RobZL1]

Assuming that's the dipstick housing, at least you should be able to check it out fairly easily...relatively speaking.

[Camaro1973]

It looks like it’s leaking from the dipstick tube 100%. I guess from being pulled out so many times maybe the oring(s) are worn. Now how to get it out and back in with headers on ?

Any tricks?

[Camaro1973]

Originally Posted by RobZL1

Assuming that's the dipstick housing, at least you should be able to check it out fairly easily...relatively speaking.

Correct it’s leaking from the base of the dipstick tube.

[RobZL1]

DUDE!!! I'm glad that's all it is. You've have enough bad juju with this car. You're due for a win, my man.