Injector housing oil leak - ZR-1 Net Registry Forums

secondchance · 01-27-2020

Pooling of oil between the passenger side head and injector housing has been driving me nuts for some time. More like forever!
Last week searching through Net Registry forum, I ran across an old thread (I think 2013?) discussing variations on heads and IH depending on early vs. later design and started to understand the subject a bit.
So, last Saturday, once again, off with the plenum followed by passenger side injector housing.

https://www.flickr.com/photos/158930...posted-public/
https://www.flickr.com/photos/158930...posted-public/
As suspected, "jug handle" cast into the head between #2 and #4 cylinder has no vent hole and dead ends resulting in oil pooling. This results in eventual seepage through the gasket.
Solution,I reasoned, was to plug the hole and eliminated oil pooling.
I ordered a Dorman 555-018 (1" engine plug) but it turned out to be a shade too big.

I called Phil (WAZOO Master) and after a quick discussion ran over to his house. Phil took a look and machines a aluminum plug on his milling machine, a dab of Loctite 641 (I think), and taps it into place.
https://www.flickr.com/photos/158930...posted-public/
https://www.flickr.com/photos/158930...posted-public/

https://www.flickr.com/photos/158930...posted-public/
After the surgery, out of curiosity, we check for flatness and wouldn't you know it? Offending area obviously is bowing out in the middle. No wonder i couldn't get it to seal!
Injector housing was reinstalled Saturday afternoon, drove into work this morning and am happy to report - no more oil leakage between the IH and the head!

secondchance · 01-27-2020

One more thing. It may be I ended up with early version with injector housing when I had it powder coated. There seems to be variations on injector housings from 90 to 95. I am saying this because when I was at Dempsey's, I recall looking at R. Kreigh's injector housing from 95 ZR-1 and particular PCV port on his IH I believe was blocked off.

XfireZ51 · 01-27-2020

I’m not sure I’d want to block off the crankcase vents. Of course there is the issue, as Marc has described, of a mismatch between cylinder head and IH vents.
But I recently went through a similar exercise. My solution was to use Permatex #2 to seal off the vents from leaking oil into the #2 and #4 cylinder head ports.
This is similar to how I also seal off the coolant ports at the front of each head preventing coolant from seeping into cylinders as well.
Frankly, it would be great if a groove could be machined in the head and IH for use of an O-ring.

secondchance · 01-27-2020

Quote:

Originally Posted by XfireZ51

I’m not sure I’d want to block off the crankcase vents. Of course there is the issue, as Marc has described, of a mismatch between cylinder head and IH vents.
But I recently went through a similar exercise. My solution was to use Permatex #2 to seal off the vents from leaking oil into the #2 and #4 cylinder head ports.
This is similar to how I also seal off the coolant ports at the front of each head preventing coolant from seeping into cylinders as well.
Frankly, it would be great if a groove could be machined in the head and IH for use of an O-ring.

I’m not sure I’d want to block off the crankcase vents.

It seems at one time all 3 recessed portion of the head had holes drilled into the crankcase. For some reason, drilled hole was deleted on the front recess. As for the 3 holes on the injector housing, all 3 open into one plenum space. Hole I blocked off sits right on top of head recess without drilled hole. This dead end was creating a puddle of oil which with crankcase pressure and ineffective sealing due to bowing of the iH was being pushed out.

XfireZ51 · 01-27-2020

Ah! Thx for the clarification. But let me suggest u still consider Permatex around the other 2 vents. I detected oil seepage on the back ones as well.

secondchance · 01-27-2020

Quote:

Originally Posted by XfireZ51

Ah! Thx for the clarification. But let me suggest u still consider Permatex around the other 2 vents. I detected oil seepage on the back ones as well.

I used Permatex copper sealant around PCV vents and around coolant port to be sure.

XfireZ51 · 01-27-2020

Marc Haibeck · 01-29-2020

I have found that the grommet for the PCV tube can leak and fill the area below it with oil. I remove the grommet, clean it and reinstall it with sealer.

About 40% of the grommets were installed at the factory with the inside lip folded. This can cause a leak. I cut the folded lip off before reinstalling the grommet with sealer.

Or you can buy new grommets from Jerry. They don't need sealer to obtain an oil seal.

01-27-2020	#1
secondchance Join Date: Aug 2006 Location: McLean, VA Posts: 3,723	Injector housing oil leak Pooling of oil between the passenger side head and injector housing has been driving me nuts for some time. More like forever! Last week searching through Net Registry forum, I ran across an old thread (I think 2013?) discussing variations on heads and IH depending on early vs. later design and started to understand the subject a bit. So, last Saturday, once again, off with the plenum followed by passenger side injector housing. https://www.flickr.com/photos/158930...posted-public/ https://www.flickr.com/photos/158930...posted-public/ As suspected, "jug handle" cast into the head between #2 and #4 cylinder has no vent hole and dead ends resulting in oil pooling. This results in eventual seepage through the gasket. Solution,I reasoned, was to plug the hole and eliminated oil pooling. I ordered a Dorman 555-018 (1" engine plug) but it turned out to be a shade too big. I called Phil (WAZOO Master) and after a quick discussion ran over to his house. Phil took a look and machines a aluminum plug on his milling machine, a dab of Loctite 641 (I think), and taps it into place. https://www.flickr.com/photos/158930...posted-public/ https://www.flickr.com/photos/158930...posted-public/ https://www.flickr.com/photos/158930...posted-public/ After the surgery, out of curiosity, we check for flatness and wouldn't you know it? Offending area obviously is bowing out in the middle. No wonder i couldn't get it to seal! Injector housing was reinstalled Saturday afternoon, drove into work this morning and am happy to report - no more oil leakage between the IH and the head! Last edited by secondchance; 01-27-2020 at 08:48 AM.

01-27-2020	#3
XfireZ51 Join Date: May 2007 Location: Chicagoland, IL Posts: 9,709	Re: Injector housing oil leak I’m not sure I’d want to block off the crankcase vents. Of course there is the issue, as Marc has described, of a mismatch between cylinder head and IH vents. But I recently went through a similar exercise. My solution was to use Permatex #2 to seal off the vents from leaking oil into the #2 and #4 cylinder head ports. This is similar to how I also seal off the coolant ports at the front of each head preventing coolant from seeping into cylinders as well. Frankly, it would be great if a groove could be machined in the head and IH for use of an O-ring. __________________ [SIGPIC][/SIGPIC]Former Membership Chairman Former ZR-1 Registry - BOD 1972 Corvette 4speed base Coupe SOLD long time ago 1984 Corvette Z-51/4+3 SOLD 1992 Corvette ZR-1 Aqua/Gray #474 SOLD 1992 Corvette ZR-1 Black Rose/Cognac #458 2014 Honda VFR Interceptor DX

01-27-2020	#5
XfireZ51 Join Date: May 2007 Location: Chicagoland, IL Posts: 9,709	Re: Injector housing oil leak Ah! Thx for the clarification. But let me suggest u still consider Permatex around the other 2 vents. I detected oil seepage on the back ones as well. __________________ [SIGPIC][/SIGPIC]Former Membership Chairman Former ZR-1 Registry - BOD 1972 Corvette 4speed base Coupe SOLD long time ago 1984 Corvette Z-51/4+3 SOLD 1992 Corvette ZR-1 Aqua/Gray #474 SOLD 1992 Corvette ZR-1 Black Rose/Cognac #458 2014 Honda VFR Interceptor DX

01-27-2020	#7
XfireZ51 Join Date: May 2007 Location: Chicagoland, IL Posts: 9,709	Re: Injector housing oil leak __________________ [SIGPIC][/SIGPIC]Former Membership Chairman Former ZR-1 Registry - BOD 1972 Corvette 4speed base Coupe SOLD long time ago 1984 Corvette Z-51/4+3 SOLD 1992 Corvette ZR-1 Aqua/Gray #474 SOLD 1992 Corvette ZR-1 Black Rose/Cognac #458 2014 Honda VFR Interceptor DX

01-29-2020	#8
Marc Haibeck Join Date: May 2007 Location: Addison IL Posts: 250	Re: Injector housing oil leak I have found that the grommet for the PCV tube can leak and fill the area below it with oil. I remove the grommet, clean it and reinstall it with sealer. About 40% of the grommets were installed at the factory with the inside lip folded. This can cause a leak. I cut the folded lip off before reinstalling the grommet with sealer. Or you can buy new grommets from Jerry. They don't need sealer to obtain an oil seal.

01-27-2020	#2
secondchance Join Date: Aug 2006 Location: McLean, VA Posts: 3,723	Re: Injector housing oil leak One more thing. It may be I ended up with early version with injector housing when I had it powder coated. There seems to be variations on injector housings from 90 to 95. I am saying this because when I was at Dempsey's, I recall looking at R. Kreigh's injector housing from 95 ZR-1 and particular PCV port on his IH I believe was blocked off.