Oil in injector housing?

[zr1don]

Just pulled my injector housings, when I lifted them off the head there was what seemed like a lot of oil that came from the area where the pvc breather tubes come from. When I lifted them off enough oil drained out that there was oil over most of the rear half of the head - i/h mating surface. Is this normal? If not, what do I need to do to correct it.

[Paul Workman]

The LT5 does use a bit of oil that way. Several have fashioned an oil catch can to collect the oil before routing the vapor back to the plenum. You can see such an arrangement in this photo of =Jeff='s LT5.



A local speed shop (Winner's Circle) has an assortment of cans in various shapes. I'll be checking that out as part of a winter project.

I'll keep y'all posted.

P.

[A26B]

The entire crankcase ventilation goes through the injector housings. Over time, two things happen, (1) oil accumulates in the inj housings and (2) the inj housing bolts frequently work loose, allowing oil to seep along the gasket interface.

Install new inj hang gaskets on clean (with brake cleaner) dry surfaces. Clean the bolts and the tapped holes in the heads with brake cleaner to remove oil. Reinstall with Loctite 242 (blue) or comparable med strength product.

[Aurora40]

Are you saying it was in the intake ports? Or just in the housing? As Jerry mentioned, the pcv system flows through the housing so there will definitely be oil in it.

[A26B]

I've been thinking a bit.......

Does the head side of the injector housing look like this? A


or this? B



and, does the cylinder head look like this?C



or this? D



A Injector housings can be used with C or D heads,
but
B injector housings can only be used with D heads.

With parts being swapped around, it wouldn't be out of the question for later style injector housings with open crankcase ports (no "washer" type baffles) to end up on 1990 cylinder heads with the large crankcase vent holes. its OK to have small baffle holes in the heads AND in the injector housings, but for both to be unrestricted would put a lot of oil into the injector housings and subsequently the PCV system.

[QB93Z]

Good analysis Jerry. Thanks for posting the pictures. We will need to come up with a compatibility chart because I have heard several conversations about what the interchange of heads, IH's and plenums.

Jim

[zr1don]

My engine is a 91 and both i/h and heads look like B and D in Jerry's photos. There was no signs the oil entered the intake passageways, it appeared to come out of the i/h pvc areas. I am having problems passing CA's smog test, high NOx and lean burn indicated from the tests. One of the possible causes is malfunctioning pvc system. I'm thinking the pvc system may not be able to cope with the amount of oil coming through the system. Possible solution, catch cans?

[A26B]

Good on the B & D match. Just making sure.

Is this the engine that is in the 90 you put RC injectors in last year?

I don't think the catch can is the solution to your emissions problem, but others may be able to address the emissions/catch can situation from experience.

Have you checked the PCV valve hoses, lower & upper to be sure they are not leaking vacuum?

[zr1don]

Thanks for the info, Jerry!!!

This is the engine I put new RC injectors in several years ago, 2007 I think. I have checked both the upper and lower pvc hoses (they are new silicone hoses w/stainless clamps sealing the ends and the pvc valves).

Anyone want to share opinions on passing CA smog?

[-=Jeff=-]

Originally Posted by A26B

I've been thinking a bit.......

Does the head side of the injector housing look like this? A


or this? B



and, does the cylinder head look like this?C



or this? D



A Injector housings can be used with C or D heads,
but
B injector housings can only be used with D heads.

With parts being swapped around, it wouldn't be out of the question for later style injector housings with open crankcase ports (no "washer" type baffles) to end up on 1990 cylinder heads with the large crankcase vent holes. its OK to have small baffle holes in the heads AND in the injector housings, but for both to be unrestricted would put a lot of oil into the injector housings and subsequently the PCV system.

So B and C means you get a large amount of oil in the PCV system? In theory or was it tested on a Motor while it was being developed?

how much oil would you say that would be over engine running time (or miles).

What was the reason for the small holes to switch from the IH to the Head?

Would I also have to assume that the excessive oil would be seen out the exhaust as well?

Just curious and trying to understand it..