I go along with Ray’s idea…check the valve seals.  My nearly-spot-on maxim
that when something goes wrong, first check that with which you last messed.
If it didn’t smoke before the valve job and now it does, perhaps all was not
done properly.  Our old Dodge Caravan developed a serious smoking problem
(not a good thing in SoCal where you can’t even smoke on the beach) which
was discovered to be an exhaust valve guide extruding into the exhaust port
leaving nothing for the seal to seat on.  You should have seen the stuff on
the exhaust valve…ugh.

 

I’d posit that perhaps a seal has dislodged and is not sealing any more.

 

Ralph Alder

Team Orphan Aerodyne

 

  _____  

From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Bob Bundy
Sent: Monday, July 21, 2008 8:17 PM
To: [email protected]; Ray Ayala
Subject: Re: Tailpipe smoking under load. 

 

I know it sounds like that but the valves were taken out inspected and the
valve stem seals replaced just two weeks ago. Initially I thought it was
that before the head was redone as well. I would have thought the machine
shop would have caught anything wrong. 

 

Bob

----- Original Message ----- 

From: Ray Ayala <mailto:[EMAIL PROTECTED]>  

To: Bob Bundy <mailto:[EMAIL PROTECTED]>  ; [email protected] 

Sent: Monday, July 21, 2008 8:08 PM

Subject: Re: Tailpipe smoking under load. 

 

Sounds like oil getting sucked down one or more intake stems under vacuum
and then burning under subsequent load.  Check to see if that 1 in 3 times
happens to be follow a longer-than-normal vacuum condition.

----- Original Message ----- 

From: Bob Bundy <mailto:[EMAIL PROTECTED]>  

To: [email protected] 

Sent: Monday, July 21, 2008 7:42 PM

Subject: Tailpipe smoking under load. 

 

I seem to have one cylinder burning oil. But I’m having a horrible time
trying to diagnose

 

1) Smokes on hard accel under load with boost only. Not at all under vacuum.
Does it maybe 1 in three times it smokes a pretty good cloud and not every
time. 

2) Definitely have oil consumption but not a huge amount. Less than ¼ quart
per tank I think a little more on the track. 

2) Spark plug in #1 will have some sticky Oil residue but not really wet.
Gets kind of gummy occasionally All others look perfect. 

3) Compression test shows all cylinders within a couple psi of each other. 

4) Leak down less than 5% at 100psi in all cylinders. 

5) Absolutely no blowby showing up in my catch can on the breather side

6) Changing PCV valve made no difference. 

7) Valves and guides and valve seals are freshly redone due to burnt exhaust
valve on #1

8) RC 750cc injectors replaced because thought might have caused lean
condition burning #1 valve 

9) The cylinder bores ant the tops of the Pistons all looked fine when I had
the head off to have the valve fixed. 

9) Doesn’t seem to be down on power 338.2 hp 295 ft.lb at 17psi on the Dyno
Dynamics dyno Yesterday afrs safely in the 11.8 to 11.4 range. Grayish smoke
cloud out the tailpipe on the dyno but not really a total smoke out. Some of
the Hondas were worse. 

 

Any Ideas? I never noticed the smoke before until just before I burned the
exhaust valve. Now the smoke cloud is really unsightly and I’m worried I’m
going to do more expensive damage running it further. 

 

Bob


  _____  


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