North American Turbocoupe Organization



Oil blowing out of breather cap?
SteveX82 Offline
Posting Freak
#1
Well, I went to the track last night and was a bit disappointed...the car hasn't been trapping anywhere near as high as it did last year (i'm down about 4mph despite playing more and more with the fuel and timing curves), and oil continues to be blown out of the breather cap at high boost (and seemingly only at high boost...i haven't seen this problem on the street with ~20psi).

* I'm running a k&n open element breather.
* I've tested the PCV valve out of the car up to ~40psi and it held perfectly.
* A hot compression test last night showed 160,170,165,170psi from front to back.
* The head was just rebuilt about 5k miles ago with new ford valvestem seals.

Does anybody have any ideas why it's still blowing oil like this? The car doesn't consume a drop of oil, and there's no smoke on startup (which would point towards the bad valvestem seals). Maybe it's possible that the seals can only hold back so much intake pressure and 24-25psi pushes them past their limit? I might try throwing one of those brake booster check valves inline with the PCV just to eliminate that, but I'm still open to any other suggestions and thoughts. Thanks.

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Estoril blue 1987 TC 5spd, 146k miles, a237, Bailey BOV, spec stg3 clutch, spearco FMIC, t3/t4 50 trim / stage III .63, 3" exhaust, eec-tuner, lm1 wb, 55pph injectors
Best 1/4 mile: 12.89 @ 106mph on 25psi, 1.78 60'
Estoril blue 1987 TC 5spd, 148k mi, a237, Bailey BOV, spec stg3 clutch, spearco FMIC, 50 trim t3/t4, 3" exhaust, Bamafuel, LM1, 55pph
Best 1/4 mile: 12.31 @ 110mph on 25psi
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martin0660 Offline
Posting Freak
#2
Not a lot of help, but have you done a leakdown test as well?

Really out there, but its not overfull of oil is it? If the dipstick was partly pushed out, you could be reading the level as low, while its actually high.

I hate to say it but,it would seem that blowing oil with a loss of HP would indicate ring sealing. I hope I'm wrong, but there are really only a few ways to get pressure into the valvecover.

I'm also chasing a demon. Mine is visible smoke on decel (and decel only). The valve seals were new with the head last spring, and they are teflon seals. Some have told me that this wasnt a good choice and I'm swapping them tommorrow for the FelPro ones. I've already been through the PCV system ,so that pretty much leaves rings for me if this dont fix it.

Bob Myers

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My 88 Thunderbird TC Pictures, Updated 5-8 with a few drag pics
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Pete D Offline
Administrator
#3
Steve, I'm with Bob on the leak down test.

Bob, what kind of shape were the valve guides themselves in?
Pete Dunham


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martin0660 Offline
Posting Freak
#4
Quote:Originally posted by Pete D:
Bob, what kind of shape were the valve guides themselves in?

Pete, they were great. All in spec when the big valves went in. I'm goint to change the VS anyway, its only a couple of hours for me.

Steve, I dont have a leakdown gauge set myself, so I'm as interested in what that shows you.

Bob Myers


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My 88 Thunderbird TC Pictures, Updated 5-8 with a few drag pics
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bybowtie Offline
Senior Member
#5
OK this may sound strange but it is true.. I had a GEN 2 DSM Eclipse that I was running 18-20psi on.. At stock levels everything was fine.I found however that at the elevated boost levels tha the oil cap seal would allow blow-by.The oddest thing.Unfortunately it wasnt until the engine let go that I figured this out(I was doing the normal fix ad test routine trying to find the culprit gaskets etc) Anyways when it let go I got to talking with some friends that race them and found that the plastic cap would distort under the higher pressure thus leaking..
OK now more in topic. Could this be the possible cause but the breather element instead of the cap?
So whats your point?
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RDOG Offline
Posting Freak
#6
All I can say is I should have listend to these guys when they told me to do a leak down test. Instead I pulled the head and stripped it and had the head pressure tested-nothing. Then I had the machine shop tear down the short block and test the rings-nothing. Now after paying to have the head pressure tested and another set of seals installed and paying to have my bird towed back to the shop and checked, I now am going to do the leak down test. I should have done the leakdown first and probably would have saved me lots of time and money, and I could have pointed a finger at the ead builder or the machine shop. Listen to these guys, I found out the hard way-right in the wallet [Image: frown.gif] Wish me luck guys! They are putting in head studs this time and then doing the leak down test. Hope this time everything is A-OK. Again, Steve do the leakdown. You will probably thank them all after.

[This message has been edited by RDOG (edited 05-13-2005).]
1986 Turbo Coupe. Boport StageIII head, Boport 2.1, Performance Techniques 50 trim hybird, StageII.63, stinger 3" exhaust, Phenolic spacer, Boglog header,NPR FMIC intercooler setup, kirban fpr, bigrmotorsports fuel rail, diablo water meth kit, CAI, remote mount TFI, CHE rear adj control arms, MAC girdle, 8.8 rear disc, aluminum drive shaft, H&R lowerings springs Tbird Turbo Specific, y MAS!!
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martin0660 Offline
Posting Freak
#7
You find anything yet Steve?

I worked on mine today, and found the #3 Exhaust, valve seal about half off the guide. I hope yours is that simple.

BTW, what did it run that night?

Bob Myers

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My 88 Thunderbird TC Pictures, Updated 5-8 with a few drag pics
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SteveX82 Offline
Posting Freak
#8
I had the valvecover off anyways yesterday, so I took as good of a look as I could with the head still on the car, and all the valve seals seemed to be seated just fine.

I figured to do one last test to eliminate the PCV as the culprit and reassembled everything, but plugged the PCV tube entirely. Sure enough, oil still sprayed out after a couple of 3rd gear pulls at 24psi. I'll be heading out tomorrow to buy a leakdown tester.

As unlikely as it seems considering the excellent compression numbers, I'm really hoping the rings are shot...not only would this give me an excuse to build up a worthy shortblock, but it would explain why the car is relatively slow for as much boost as I've been throwing at it.

The car was doing pretty consistent 13.2-13.3's @ 103.5-104.5mph on easy 1.93 60' launches. I saw no point in hammering the car out of hole if it wasn't going to trap high enough to get me a lower et. This is down 2-3mph from last season, which was in turn down ~2mph from the runs a few months before my 12.89 pass.

I'll give an update tomorrow after doing the leakdown test. Glad to hear that you chased down your gremlin already, Bob. Did you just reseat the valve seal, or are you replacing it (or them?) with a new one?

[This message has been edited by SteveX82 (edited 05-15-2005).]
Estoril blue 1987 TC 5spd, 148k mi, a237, Bailey BOV, spec stg3 clutch, spearco FMIC, 50 trim t3/t4, 3" exhaust, Bamafuel, LM1, 55pph
Best 1/4 mile: 12.31 @ 110mph on 25psi
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martin0660 Offline
Posting Freak
#9
Quote:Originally posted by SteveX82:
Did you just reseat the valve seal, or are you replacing it (or them?) with a new one?

They are done, I replaced them all with the FelPro metal body / Viton type for now. I snuck them in there with the head on the car. The one that was off was beat up pretty good, and several other were kinda bell shaped at the bottom. These were supposed to be the "good" seals, although they arent teflon.

On the bright side, I suspect this is why I was getting some light ping above 22#'s. I just ordered a new helmet, so I'm going back Thursday night (weather permitting) to try some more boost [Image: biggrin.gif]

On the dark side, I suspect a new shortblock is in the near future for me as well. My air compressor cycled more than I thought it should keeping the valves up.

Let me know what you end with for a leak down tester. I should probably invest in one too.

Bob Myers

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My 88 Thunderbird TC Pictures, Updated 5-8 with a few drag pics
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Pete D Offline
Administrator
#10
Steve, I think Matt S posted this recently.
http://carshop.carshopinc.com/product_in...9233/CSLDT
Pete Dunham


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