File this under "if you want something done right, do it yourself..."

My new 383 with about 300 miles on it has a pretty bad oil leak coming from up high; after thoroughly investigating it, it appears that it is coming from the back of the intake (the distributor is dry as a bone, though I will triple-check once I start taking stuff out of the way). Not sure if it was a bad gasket or if my engine builder just didn't do something correctly.

Anyway, the HSR intake calls for Felpro #1205 gaskets, just wondering if this is what I should use or if there is something better? Would rather spend more money now & not have to do this again anytime soon.

Second question...even though the motor is newly rebuilt & doesn't have many miles on it, wondering if there is anything else I should do/check while taking the intake off? Thanks.

 

One thing came to mind while reading your post ;

... If it turns out that your oil leak is that the seal at the rear "China Wall" has been either sucked in or blown out of it's proper place , you'd best be checking the entire PCV system for proper airflow . I have seen several instances of a blocked/clogged/or just not plumbed right PCV cause this seal to fail . Now , of course there could be another simpler cause like the oil pressure sending unit that is back there or maybe the distributor's O ring , but like you say till you get a direct look at it we're just going over ideas .

 

This is interesting. I recently replaced my PCV valve (side note: I went from the stock one that my car called for to one for a 1990 Corvette with a 350, thinking it would be better). It is plumbed directly to the port in the bottom of the upper intake, as far as I can tell, it's working fine.

However, a couple of points...(1) the PCV valve I had in there was brand new and only had a few miles on it (but quite a few hours). When I took it off to replace, I found that it had quite a bit of oil in it. And (2) in the other valve cover, I have a breather cap and as I was looking for the oil leak, I noticed that there was a small amount of smoke - or what looked like smoke - coming out of the breather cap. Not sure if that is normal?

Any advice on how to check & make sure the PCV system is working? If the PCV did cause the oil leak, I imagine that even after fixing that I'm still going to have to replace the blown out (or sucked in) gasket, right?

 

Have to remember that with a 383 you have the same extra cubes being displaced below the pistons ( in the pan ) that you do above.
If your crankcase breathing is less than perfect ,then the added pumping volume will find somewhere ( weakest point ) to come out.
Blowing dipsticks out is common on strokers

 

Before you pull everything apart , confirm that you haven't blown any oil pressure sensors ( common ) located at the rear oil gallery port located there

 

To answer your gasket question, just stick with the fel-pro 1205 like they recommend. The only differences in other ones will be the size of the cutouts for the ports. Fel-pro makes a good gasket, no need to look elsewhere. Good luck with this oil problem.

 

The 'breather' is a source of air to replace what the pcv system removes from the crankcase. If the pcv system is functioning properly, there should be nothing coming out of the breather, only going in.

 

When you take the new gasket set out of the box, grasp the rubber seals for the china walls firmly in your dominant hand and toss them in the trash. Use black RTV on that area with a good gob on the end tabs of the intake gaskets.

 

My brother said the same thing about seals for the china walls. Sounds like a good plan.

I double-checked yesterday, if you get a mirror to the back of the engine you watch the oil seep out from the intake. Also with the mirror, I checked the oil pressure sender & the distributor, both look completely dry. So, unfortunately I'm going to have to take off the intake.

Going back to my PCV...how do I check it for proper operation? As far as I can tell, the valve is opening and closing, the hose is fine and there are no vacuum leaks. Not sure what else to test or how else to test to make sure it's operating correctly (which doesn't sound like it, based on the smoke coming out of the breather cap).

 

No sir, the OEMs DO NOT have a breather because of emissions regulations. the valve covers are sealed.

The PCV (positive crankcase ventilation) system simply takes the crank case vapors and burn it with the air fuel mixture. via a hose that feed the vapors back into the intake tract.


Pre 1967 cars made in USA had breather caps which VENTED the crankcase vapors to the atmosphere. THE PCV system introduced in 1967 replaced this practice.

the air in the crankcase is provided by the intake air, in the form of blow-by thru the rings.

If you run a PCV valve you DO NOT need a breather valve and it is most likely keeping the PCV system from doing it's job correctly.

Remove the breather cap and install the oil cap, to seal the drivers's side valve cover.

My 383 used the OEM PCV valve and hose from my 305 (it's the same check valve as the 350 it makes no difference) connected to the PCV vacuum port on a Holley projection TBI unit.

I used stock Chevy valve cover, the driver's side had the oil cap only & NO breather.

The smoke you see from your breather cap is condensation / oil vapors escaping to atmosphere, so the breather cap is doing it's job, but you also have PCV valve. So it's counter productive.

 

Guess I'm wrong then. I've only ever seen pcv systems on v engines that suck air thru one valve cover via the pcv valve, and have it made up via fresh air from another source - either a seperate breather or a hose to the air cleaner. That's how I've got mine hooked up, and don't get any fumes emanating from the breather - unless I block off the pcv valve.

 

the stock air filter housing has a solid pipe that connects to the valve cover opposite the PCV valve and is usually have a fiber fabric filter at the air filter housing..

so yes this tube serves as a breather because it will draw fresh air from the filter housing and also vent some fumes that will be sucked into the intake.
and burned. the point is this is a "sealed system" & crankcase vapors are burned by the engine.


Looking at my old 383 photos.. I am mistaken, I did have a breather cap on the opposite side. along with an oil fill cap, because I had an open element air filter.

Some open element filter brands do come with provisions to connect the valve cover to the housing base with a tube, like OEM. Those filter bases will actually have "knock outs " in the sheet metal to install the grommet and tube.

Sorry for rambling I was mistaken.

 

My new engine has a vacuum pump, this is a sealed system with a catch can to collect crank case vapors.

By creating negative crankcase pressure this promotes better ring sealing and increases HP.

 

Dry fit the intake with the paper gasket in place and take note of the gap between the intake and the block. You have an aftermarket intake and I'm assuming aftermarket heads which could give you more or less gap. For small gaps, I use a single solid bead slightly taller then the gap. For larger gaps, I use a welding style, stack of dimes bead as its easier to keep the height of it consistent as you go across the top of the block. Don't really care for any of the black rtv's, a little runny and messy. Use Right Stuff if you never plan on ever removing the intake again, permatex ultra grey if you're thinking you might change your combo within the next year or so.