[DeTomaso] Oil Smoke From Breathers

Mon Apr 25 02:42:05 EDT 2011

I suggest doing a leakdown test.

3000 - 4000 rpm sounds like it is at max torque, which is where you will 
have max cylinder pressure.

Bad valve guides or valve stem seals will not show up on a leakdown test.

Ring and valve seal problems will show up, and they will be easily 
identifiable. Hissing when you open the oil cap -> ring seal, hissing 
through the carb -> intake valve, hissing thought the exhaust -> exhaust 
valve.

Thomas

2011-04-25 05:33, Will Kooiman skrev:
> Ok, #3 guess is a non-functioning PCV.  It sounds like you're on the right
> track.
>
> -----Original Message-----
> From: Dan Courtney [mailto:dfcex at pacbell.net]
> Sent: Sunday, April 24, 2011 10:25 PM
> To: John Taphorn; Dan Courtney; wkooiman at earthlink.net;
> detomaso at realbig.com; Pantdino
> Subject: Re: [DeTomaso] Oil Smoke From Breathers
>
> The oil smoke/mist only comes out from the breather, not the exhaust, and
> only between 3,000 - 4,000 rpm's under acceleration. Enough fumes to draw
> glares from Prius drivers (and to stink up the passenger compartment).
> I don't think it's rings, and I believe a clogged drain hole in the heads
> would produce smoke from the exhaust on deceleration.
> The engine builder suggested I install a catch-can, but that feels like
> turning a blind eye to a potential problem.
> I'll try a different PCV valve tomorrow.
> If the problem is valve guides, or valve stem seals, would that show in a
> leak-down test?
>
> Dan
>
> Dan Courtney
> 22 Years of Excellent Representation
> Excalibur Commercial Real Estate Services
> La Jolla, CA
> (858) 551-5455 P
> (858) 551-5456 F
>
> --------------------------------------------------
> From: "John Taphorn"<jtaphorn at kingwoodcable.com>
> Sent: Sunday, April 24, 2011 5:28 PM
> To: "Dan Courtney"<dfcex at excaliburre.com>;<wkooiman at earthlink.net>;
> <detomaso at realbig.com>; "Pantdino"<pantdino at aol.com>
> Subject: Re: [DeTomaso] Oil Smoke From Breathers
>
>> Remember that there is a difference between static and dynamic
>> compression. Dan's cam may be of longer duration and the valve timing
>> overlap may bleed off cylinder pressure at low RPMs when the incoming
>> mixture has less inertia.
>>
>> JT
>> ----- Original Message -----
>> From: "Dan Courtney"<dfcex at pacbell.net>
>> To:<dfcex at excaliburre.com>;<wkooiman at earthlink.net>;
>> <detomaso at realbig.com>; "Pantdino"<pantdino at aol.com>
>> Sent: Sunday, April 24, 2011 7:02 PM
>> Subject: Re: [DeTomaso] Oil Smoke From Breathers
>>
>>
>>> Jim,
>>>
>>> All plugs were out, no throttle and the engine was ice cold (hadn't been
>>> fired for a month - header replacement). Each of the cylinders was almost
>
>>> exactly 150 psi.
>>> The previous test, a year earlier, had all eight between 185&  200 psi,
>>> with a warm engine, all lugs out, no throttle.
>>>
>>> Dan
>>> Dan Courtney
>>> 22 Years of Excellent Representation
>>> Excalibur Commercial Real Estate Services
>>> La Jolla, CA
>>> (858) 551-5455 P
>>> (858) 551-5456 F
>>>
>>>
>>> From: Pantdino
>>> Sent: Sunday, April 24, 2011 12:54 PM
>>> To: dfcex at excaliburre.com ; wkooiman at earthlink.net ; detomaso at realbig.com
>>> Subject: Re: [DeTomaso] Oil Smoke From Breathers
>>>
>>>
>>> I realize compression checks are inexact and the most important thing is
>>> the cylinders all being the same, but 150 seems a bit low to me for
>>> 10.5:1 CR.
>>> I have little experience with these matters, but I had cause to recently
>>> test 2 motors-- both done with the engine hot, all plugs removed, and the
>
>>> throttle being held wide open.
>>>
>>> Triumph TR6, supposed CR either 7.75 or 8.5:1----  5 cylinders 135-137,
>>> one 125
>>>
>>> Fiat Abarth with supposed CR 10.0:1----  2 cylinders 175, 2 cylinders195
>>>
>>> Was your test done under those conditions?
>>>
>>> Jim
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>> -----Original Message-----
>>> From: Dan Courtney<dfcex at pacbell.net>
>>> To: dfcex at excaliburre.com; wkooiman at earthlink.net; detomaso at realbig.com;
>>> Pantdino<pantdino at aol.com>
>>> Sent: Sat, Apr 23, 2011 11:53 pm
>>> Subject: Re: [DeTomaso] Oil Smoke From Breathers
>>>
>>>
>>> About 10:5 - 1.
>>> Dan
>>>
>>> Dan Courtney
>>> 22 Years of Excellent Representation
>>> Excalibur Commercial Real Estate Services
>>> La Jolla, CA
>>> (858) 551-5455 P
>>> (858) 551-5456 F
>>>
>>>
>>> From: Pantdino
>>> Sent: Saturday, April 23, 2011 11:17 PM
>>> To: dfcex at excaliburre.com ; wkooiman at earthlink.net ; detomaso at realbig.com
>>> Subject: Re: [DeTomaso] Oil Smoke From Breathers
>>>
>>>
>>> Just out of curiosity, what compression ratio are you running to get 150?
>>>
>>>
>>>
>>>
>>>
>>> -----Original Message-----
>>> From: Dan Courtney<dfcex at pacbell.net>
>>> To: Will Kooiman<wkooiman at earthlink.net>; 'Dan Courtney'
>>> <dfcex at excaliburre.com>;
>>> detomaso at realbig.com
>>> Sent: Sat, Apr 23, 2011 11:11 pm
>>> Subject: Re: [DeTomaso] Oil Smoke From Breathers
>>>
>>>
>>>
>>> Thanks Will,
>>> Also, I did a compression test. All 8 are at 150 psi. I already changed
>>> the
>>> PCV, but maybe got a defective one, so I'm trying another tomorrow.
>>>
>>> Dan
>>>
>>> Dan Courtney
>>> 22 Years of Excellent Representation
>>> Excalibur Commercial Real Estate Services
>>> La Jolla, CA
>>> (858) 551-5455 P
>>> (858) 551-5456 F
>>>
>>> --------------------------------------------------
>>> From: "Will Kooiman"<wkooiman at earthlink.net>
>>> Sent: Saturday, April 23, 2011 9:53 PM
>>> To: "'Dan Courtney'"<dfcex at excaliburre.com>;<detomaso at realbig.com>
>>> Subject: RE: [DeTomaso] Oil Smoke From Breathers
>>>
>>>> #1 valve seal popped off
>>>>
>>>> #2 rings not seated yet
>>>>
>>>> That's 2 guesses.
>>>>
>>>> -----Original Message-----
>>>> From: detomaso-bounces at realbig.com [mailto:detomaso-bounces at realbig.com]
>>>> On
>>>> Behalf Of Dan Courtney
>>>> Sent: Saturday, April 23, 2011 11:22 PM
>>>> To: detomaso at realbig.com
>>>> Subject: [DeTomaso] Oil Smoke From Breathers
>>>>
>>>> Anybody have a guess as to highly visible oil smoke coming from the
>>>> breathers, mainly between 3,000&  4,000 rpms?
>>>> Valve guides? (Only 4,000 miles on the guides and it's been doing this
>>>> since
>>>> the most recent assembly).
>>>>
>>>> Thanks for your suggestions,
>>>> Dan
>>>>
>>>> Dan Courtney
>>>> 22 Years of Excellent Representation
>>>> Excalibur Commercial Real Estate Services
>>>> La Jolla, CA
>>>> (858) 551-5455 P
>>>> (858) 551-5456 F
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Real life:   Thomas Törnblom             Email:	   thomas at hax.se
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