Puff of oil smoke on start-up????
 

So, once upon a time, I had this motor rebuilt. 20 hrs ago to be exact. It ended up having the wrong risers on it, having reversion. Changed the exhuast, now i seem to be good there. Before the exhuast was changed, I noticed on start ups, i would get a quick puff of oil smoke. Called the engine builder, told me it was due to the type of seals he used (pc seals) and the bronze guides he installed. He said it's normal, run it.

Half way into summer, i was tracking down an oil leak, pulled the valve cover, and found that i had one valve guide that had pulled loose and was moving with the exhuast valve. Took it in, had the heads pulled, had three of the guides replaced becuase the engine guy wanted, and repressed the rest. Said that one guide came loose due to running with the wrong exhuast before we caught it, and it quenched with the valve, pulling it loose. After the fix, i know longer had a puff of oil smoke on start up. Imagine that.

Now, after about 6 hours from that fix, I am getting it again. Difference, it is only on a cold start, or after sitting for 5+ hours after being run. Before, it was every time. I'm worried that i have another guide coming or is loose. I called the builder, he said he never understood why it quit smoking on start up to begin with, and still says it is normal, and not to worry about it and run it......... Well, i'm worried about it, and i will probably pull the valve covers off and turn the motor over and check for loose guides.

I've seen motors with time on them give a puff of smoke on start up, usually meaning leaky valve seals. But difference is this motor has hardly any time on it. It shouldn't smoke in my opinion...........

Any other opinions on this matter??

I used the pc seals for as many years as I can remember. In the last 2 years, I have had some engines that have done the same as yours. On one, I pulled the exhaust off and saw oil running down the exhaust valve stem and puddling on top of the valve. The engine hadn't run in several days or more.
I talked to a buddy that has worked for Merc for over 25 years. He told me about their endurance testing with the pc valve stem seals and even he was blown away by the oil consumption. I have since switched seals and will not be returning to the pc seals. I would recommend having your builder remove them.
Eddie

Eddie is such a smart fellow!! :drink: Take that advice and check the guides.. If a few came lose I bet you have more that came lose.
I had the same problem with PC seals but never smoked on start up just drank oil..Sounds like someone missed the press fit of a bronze guide. :eek:

None were missed, the builder had both heads, and repressed everyone of them and changed out three, along with all new exhuast valves. Engine runs fine, just don't trust those heads anymore.

Had the same problem. I had some engines that would use oil and others that wouldn't. Some in the same boat:drink: I never could figure out where it went. They didn't leak, didn't smoke, etc. It was all in the seals. Once I got away from the pc seals, end of problem. I have done enough now without the pc seals to know that they were the problem. Never again.
Eddie

If i find that the guides are not moving, should i just run it with the seals? I think the guides had to be machined to work with those seals........... Other than some oil consumption, there should be no other risks, correct? What seals would you recommend? I know there was the umbrella type on there to begin with, and after 75 hours, some were broke off already.

I believe the clearance tolerance is .0017-.0027..We would take the spring off on the exhaust on the blower motor,after 3 seasons it would puff alittle.My Hustler Whipple motor doesn't puff or use any oil. Eddie are you using the same seals?

If anybody needs the ones that come in the Fel Pro kits I have around 10 sets,3/8's ,500 guide.

dif styles

Yes Rob, those are the seals I am using. I believe they are made by US Seal. I buy them from a buddy in boxes of 100, but I am not sure where he gets them from. I do know they can be bought from US Seal. I am not positive that they make them, but I'm pretty sure they do. They are excellent seals. They are also much easier to install than the pc seals. So far they have held up great with no oil burn at all.
Eddie

Eddie Weve gotten them from PEP and epw.



Felpro kit ones

Puff of smoke on starrtup only means exhaust seals. Oil leaks into the exhaust and quickly burns off when you fire it. While the engine is running the pressure of the exhaust doesnt let anymore oil to leak in.