Head Leakage

[supraguy31]

Hey all,

Just need to know if I have a Blow HG. Im getting oil leaking between the Block and the Head right under the Exhaust side cam Gears.

You can see where is is coming from, I thought that it might be the Cam Seal so I replaced them, Any Suggestions or do I just need to retorque the Head Bolts

Robert

 

[jdub]

Hey all,

Just need to know if I have a Blow HG. Im getting oil leaking between the Block and the Head right under the Exhaust side cam Gears.

You can see where is is coming from, I thought that it might be the Cam Seal so I replaced them, Any Suggestions or do I just need to retorque the Head Bolts

Robert

Is it coming from the forward part of the head between the top of the front plate (the big cast aluminum part with the water pump housing) and the head?

 

[supraguy31]

Yes, That is exactly where its coming from. Its not alot but enough to make it run down the block and some of it is going into the Lower timing Belt cover. Its like the oil is Splititng the Edge of the lower timing plate, Half inside it and the other half is running down the edge of the Water pump and blowing on top of the PS Pump.

Tell me this isnt a BHG or is this the seals behind that Plate. If so, I have them, I bought a Kit that had the Crankcase Seal, Timing Belt Case Seal, Water Pump Gasket and the other 2 Gaskets behind that Plate.

Robert

 

[jetjock]

Could be the CPS O ring, a common failure point.

 

[supraguy31]

Could be the CPS O ring, a common failure point.

Would it leak from the Area that I Discribed if its the CPS o-ring. If so, I have a Kit of O-rings that I can Replace it with.

Robert

 

[jdub]

Yes, That is exactly where its coming from. Its not alot but enough to make it run down the block and some of it is going into the Lower timing Belt cover. Its like the oil is Splititng the Edge of the lower timing plate, Half inside it and the other half is running down the edge of the Water pump and blowing on top of the PS Pump.

Tell me this isnt a BHG or is this the seals behind that Plate. If so, I have them, I bought a Kit that had the Crankcase Seal, Timing Belt Case Seal, Water Pump Gasket and the other 2 Gaskets behind that Plate.

Robert

PM Quote

That is Exacly where the oil is coming from. Please tell me this isnt a Blown Head Gasket and its the Gaskets that are Behind that Plate.

If so, I got those, Just wasnt for sure if that could have been it.

No oil in the water at all. Just that small seapage that I have no Idea where its coming from. I heard that there was a small Plug behind that Plate that might be loose. Its just like the one on the back of the motor behind the Flywheel. Could it be leaking from there.

Reason I ask this is because when I had the motor Built, The builder left that rear Plug out and as soon as I turned the motor off, Oil just started Pouring out of it.

Robert

Ok...I'm gonna respond to this and your PM. When the block was decked, the front plate should have been machined at the same time so the upper surface of the aluminum front plate is even with the top of the block. The top of the front plate can be a little lower, but not higher than the block deck. If it is higher, the head will not sit perfectly flat on the top of the block...and that can lead to a BHG...and you can get oil seepage from the front of the motor.

If the front plate upper surface was machined at or slightly below the block deck, you still have to put a high-temp sealant (like Copper RTV) along the upper aluminum surface of the front plate. You want to be very careful and NOT get it on the block deck and do it before you place the HG on the block. The most critical areas are the two ends (pass & drivers side) of the front plate where it mates up with the block or you will get oil seepage...here's a pic:

http://gallery.sanitylapse.com/v/supra/displayimage.php?album=90&pos=6

The guy's hand is over the other side, but you get the idea. And take a look at what JJ said about the CPS O-Ring...it's a very common place to leak as well. You can get the O-ring from Toyota (it's cheap) and it is a heck of a lot easier to fix than what I described above.

Hope this helps.

 

[3p141592654]

JD, when I did this I put two beads along the interface between the timing cover and block as shown here in the TSRM

http://www.cygnusx1.net/supra/library/TSRM/em/EM_55.html

A little bit does get squeezed out onto the block surface. I assume that is okay.

Its weird to me that oil leaks here. I thought it is coolant that lives in that cavity behind the timing cover. Maybe the oil comes from the block to head oil feed hole nearby?

 

[jetjock]

Would it leak from the Area that I Discribed if its the CPS o-ring. If so, I have a Kit of O-rings that I can Replace it with.

Robert

Not sure as I'm not totally clear on your description of the leak but might as well check the easy and common stuff first. Jdub seems to have a better handle on the area you described so follow his lead too.

The CPS O ring is easy to do though. If it turns out to be that there's no need to set the crankshaft to # 1 TDC as the book says. Just open the CPS and mark the rotor to the housing before removal. Better to open it anyway to check out what's going on and clean out the oil that usually gets in there.

 

[jdub]

JD, when I did this I put two beads along the interface between the timing cover and block as shown here in the TSRM

http://www.cygnusx1.net/supra/library/TSRM/em/EM_55.html

A little bit does get squeezed out onto the block surface. I assume that is okay.

Its weird to me that oil leaks here. I thought it is coolant that lives in that cavity behind the timing cover. Maybe the oil comes from the block to head oil feed hole nearby?

Yeah...a little bit on the block surface is probably no big deal. If you over do it though, it can interfer with the HG seal...and we know that's not a good thing.

I'm not sure where exactly the oil comes from, (the two holes on the forward center of the block one is oil, one is the index pin) but I've seen couple of leaks in these areas, especially on the pass side. I see your logic on coolant, but I'm sure it's coolant in the oval passages on either side of the cylinders.

The other thing to check in this area is the cam seals and valve cover gaskets (plus the CPS O-ring already mentioned). I went after this area since he mentioned the motor was recently rebuilt.

Oil seepage/leaks can be a real pain to ferret out...you gotta clean the suspect area really good then run the motor. You can use a Q-tip (lots of them ) to help trace where the oil is coming from...just dab your way around/up looking for clean (relatively) oil on the cotton.

 

[jetjock]

UV trace, the only way to go. Baby powder sometimes works too. Trust me on these techniques, I own a Lycoming

 

[Joel W.]

^^ They don't even use a "gasket" do they, Jetjock?..Just mated surfaces.. :dunno:

Dad says when they stop leaking oil is when you have a problem LOL

 

[IJ.]

^^ They don't even use a "gasket" do they, Jetjock?..Just mated surfaces.. :dunno:

Dad says when they stop leaking oil is when you have a problem LOL

Nah just means it's time to put more in RIGHT NOW !

 

[jetjock]

They use gaskets in other places but yeah, the crankcase halves are machined surfaces. They use a silk thread to seal them. They often still leak though as every power pulse tries to shove the cases apart. And Heaven help your wallet if the through bolts lose preload and the cases start fretting. Mine isn't too bad but in general nothing leaks oil more than a Lyc. It's pretty ironic considering the application.

Lol yeah, when they stop leaking bad things tend to happen. That big fan out front stops for example. I'm not sure what it does except keep the pilot cool because when it stops turning they sure start sweating

 

[jetjock]

Nah just means it's time to put more in RIGHT NOW !

View attachment 6643

 

[IJ.]

LMAO I have a mate with a Cub and posted that pic ages ago !
(I said he was winding the elastic band)

 

[jdub]

UV trace, the only way to go. Baby powder sometimes works too. Trust me on these techniques, I own a Lycoming

hey JJ do you happen to have a link to the UV leak detector you use?

Lol yeah, when they stop leaking bad things tend to happen. That big fan out front stops for example. I'm not sure what it does except keep the pilot cool because when it stops turning they sure start sweating

LOL...Fan stoppage is a bad thing. Gotta start looking around for the nearest piece of flat surface...it's not like you can just pull over I can still remember when my instructor pulled the motor on me the 1st time in a Cessina 172...looked at me and said "what ya gonna do now" :biglaugh:

 

[IJ.]

hey JJ do you happen to have a link to the UV leak detector you use?




LOL...Fan stoppage is a bad thing. Gotta start looking around for the nearest piece of flat surface...it's not like you can just pull over I can still remember when my instructor pulled the motor on me the 1st time in a Cessina 172...looked at me and said "what ya gonna do now" :biglaugh:

Flap?

Could have been worse could have been a 152 !! :aigo: (at least it wouldn't be far to fall)

 

[jetjock]

Jdub, I'm fond of the Spectroline stuff sold by Tracer Products:: http://tinyurl.com/lnppz

That said, just go to the local auto store and buy some UV dye. InterDynamics sells most of the consumer versions and has oil, coolant, and A/C types. Get a cheap LED UV light from any A/C supply or several other places. They beat the big old heavy UV lights sold in the Tracer kits. I'll hunt down a good one for you if you like as I also need one to replace the abomination I have now.

Yeah, I don't know what worries me more: The Lyc in my single or the Ivchenko in the Albatros. I just know both are out to get me

 

[supraguy31]

Ok, Im going to give you all a Exact Spot where the oil seems to be coming from.

Look at the Head and where the Plate meet on the Passenger side. If you see where the Plate Dips in under the head a little, I have about a 11/2" wide trail of oil leaking from there.

Directly under the Exhaust cam Seal....

Robert

 

[jdub]

Flap?

Heehee...he got a big kick out of it. (shocked look on Jdubs face :icon_eek: ) The nice thing is a 172 has a pretty darn good glide ratio :naughty:

Yeah, I don't know what worries me more: The Lyc in my single or the Ivchenko in the Albatros. I just know both are out to get me

Know the feeling well...is the Ivchenko a Russian motor? How is the cycle time before you gotta tear it down?

Lost a motor in the Viper once over downtown Miami with two full bags of gas under each wing...couldn't drop them and napalm Coconut Grove. Made it back to Homestead and touched down at 160 KIAS...only time I ever had to take a cable...hit it at about 100 knots.

Thanks for the link...don't need it now, stuck it in the archives for when I do

Directly under the Exhaust cam Seal....

Robert...think you answered your own question I bet ya blew the cam seal...IJ can chime in on replacing it...not too bad.