C1 Smoke on Start up

**Kenneth B.** · August 22, 2008, 02:22 PM

Re: C1 Smoke on Start up

Originally posted by Mark Radin (46367)

Hi -

1959 C1

My 283 was recently rebuilt, but on initial start up it smoked a little. That problem is getting worse. My thought is that the new umbrella stem seals were installed wrong, or are badly fitting. My plan is to replace those with OEM O rings. During the rebuild the heads were checked and machined with new valves and rifled "brass" valve stems installed.

Once running the car is smoke free, idles well and has good oil pressure. Comments - as normal - will be greatly appreciated. Thanks

Is it white or black smoke ?
KEN

**Mark R.** · August 22, 2008, 02:47 PM

Re: C1 Smoke on Start up

Its white Ken.

**Kent D.** · August 22, 2008, 02:54 PM

Re: C1 Smoke on Start up

You have a water leak into the combustion cylinders.

**Mark R.** · August 22, 2008, 03:17 PM

Re: C1 Smoke on Start up

Its smoke (100%) not steam. Its grey smoke, and the car uses no water at all.

**Jamie F.** · August 22, 2008, 03:31 PM

Re: C1 Smoke on Start up

Blue (oil) smoke on start up is usually always oil leaking past the valve guides while the car is sitting. Sometimes it can look a little Grayish. I think your first inclination of guides seals is probably correct.

**Mark R.** · August 22, 2008, 03:40 PM

Re: C1 Smoke on Start up

Thanks for the note. Would you look to replace the umbrella seals or fit OEM "O" ring seals?

**Jamie F.** · August 22, 2008, 03:52 PM

Re: C1 Smoke on Start up

Well, good question. Usually the aftermarket umbrella seals do a great job. Much more effective than the OE o-ring seals. So unless the seals are really loose, or riding up high for some reason you may want to check a couple other things.
You can check the position of the seals when you pull the valve cover. Then check to see if the oil is draining well out of the top of the head? If it pools in one area, sometimes usually at the rear, it will natually run down that valve stem.
The other might be that the guides are not tight, or the knurling too deep.

**Mark R.** · August 22, 2008, 04:26 PM

Re: C1 Smoke on Start up

Thanks. Can you expand on your last sentence. I really appreciate your help and time. Mark

**Jamie F.** · August 22, 2008, 05:26 PM

Re: C1 Smoke on Start up

Mark, what I was refering to are the valve guides themselves. Usually guides are "knurled" or sometime completely replaced. Knurling is just what it sounds like, where a cutter is inserted into the valve guide and cuts a twist groove down the length of the guide. This displaces metal up from the cut and then a ream is inserted that returns the guide diameter to the original size. Sometime when the guides are really worn the cutter can be too thick and make a wide groove that allows oil to travel down it just like those gumball machine you see where the ball goes round and round down to the bottom. You stated that "Brass valve stems" were installed, which I really don't know what that means? Maybe new brass valve guides?? Either way if oil is making it's way down passed the valve guides they are probably too loose. The seals are only a bandaid.

**Stuart F.** · August 22, 2008, 06:04 PM

Re: C1 Smoke on Start up

It seems safe to say that it is probably something to do with your valve guides, as that was the main change you had done top side. Not many people will misapply valve seals. You referred to them as being "Rifled Brass". Not being familiar with the term, or process, or the use of such valve guides, I question their suitability for your street application or perhaps they need to be run in a little longer to seat and control oil. Maybes someone can shed a little light on these guides for us.

Many of the engine "wizards" are at Carlisle this weekend, so don't expect too much until early next week. you may want to repost your concerns then.

Stu Fox

**Mark A.** · August 22, 2008, 09:57 PM

Re: C1 Smoke on Start up

If you had the valve guides knurled, it is usually a temporary fix of a loose valve guide. It is best to replace the guides with the correct replacements. When guides are knurled, there is much less contact area of the guide to the valve stem. Therefore they wear more quickly, and the original problem of a loose fitting valve stem returns. This will contribute to the problem of oil leaking past the seals into the combustion chamber.

**Joel T.** · August 23, 2008, 02:11 PM

Re: C1 Smoke on Start up

Question.....

Are you running solid lifters or hydraulics?? I had a problem, similar to yours with my 1963. With a rebuild, I went with a new solid lifer cam and matching lifters. The car smoked basically all the time and I spend months trying to figure out what was going on. Chased many "wild gooses". Turns out that new style solid lifers pump 15-20% more oil to the heads than did the originals. This means that the original style valve seals will not do the job under any circumstance and I needed to install "positive" valve seals. This involved milling the tops of the valve guides flat and installing the new seals. Interestingly enough not all engine builders know this... The guys that do restoration work should... guys that build competition motors do not necessarily know... which was the case with my motor.

Hopefully this may be of some help to you.

Joel

**John H.** · August 25, 2008, 07:00 PM

Re: C1 Smoke on Start up

Knurling valve guides is regarded in some circles as a temporary band-aid fix instead of replacing them, which is the correct cure for worn guides.

**Mark R.** · August 26, 2008, 01:27 PM

Re: C1 Smoke on Start up

The machinest who worked on the heads, installed sleeves into the guides and they were spirilled on the face that looks at the valve stems (rifled - like the inside of a rifle barrel.)