Question: What is the effect of a slight oil burning on a catalytic converter

[killain]

Is there any damage done to the catalytic converter ? I have a daily driver 89 with 110.000 miles on it. It runs swell, but it has a slight problem with the valve guide & seals, upon start in the mornings, I get a slight buff of blue smoke. Once it warms up it's fine. And for the rest of the day no smoke. Only the next morning it's back. Can this damage the Catalytic converter ? The converter is original and it passes PA emissions inspection every year ? Just wondering.

 

[Hib Halverson]

Excessive oil consumption will damage cats.

Is that a problem in your situation? It depends on the rate of oil consumption and the current condition of the converter. You'll find out the next time you go to get an emissions test.

 

[killain]

Excessive oil consumption will damage cats.

Is that a problem in your situation? It depends on the rate of oil consumption and the current condition of the converter. You'll find out the next time you go to get an emissions test.

Thank you Hib, I didn't want to bother you with this little problem. most likely I'll have to replace the heads completely. I've been paging through a Summit Racing catalog. There are some really dirt cheap heads, they cost so much less that it is dumb to rebuilt the set I have. There is a company called "Dart" who can provide the same head in cast iron for $685.00, and Edelbrock has Aluminum which as configured would give me a slight boost in HP for $900.00. I just have to figure out the how and when. Thank you Again. But thank you !

 

[Hib Halverson]

Thank you Hib, I didn't want to bother you with this little problem. most likely I'll have to replace the heads completely. I've been paging through a Summit Racing catalog. There are some really dirt cheap heads, they cost so much less that it is dumb to rebuilt the set I have. There is a company called "Dart" who can provide the same head in cast iron for $685.00, and Edelbrock has Aluminum which as configured would give me a slight boost in HP for $900.00. I just have to figure out the how and when. Thank you Again. But thank you !

Do not install "dirt cheap" iron heads on an L98 originally equipped with aluminum heads.

You're better to have the heads on your 89, "rebuilt". A valve job, new guides and stem seals will cost far less than new heads.

 

[killain]

Heads rework !

Do not install "dirt cheap" iron heads on an L98 originally equipped with aluminum heads.

You're better to have the heads on your 89, "rebuilt". A valve job, new guides and stem seals will cost far less than new heads.

Well Ok, but everyone has been telling the best way to go was a new set of Edalbrock aluminum replacement heads. The 'E' series heads will improve the combustion process as well. The 'E' series are designed as R&R OEM styled replacements? I'm not sure if this isn't a better way to go ? I would never put the cast iron heads on it, I just mentioned them to give you an idea of the price difference. Thank you !

 

[c4c5specialist]

Orings vs umbrella seals and oil consumption with catalysts

HI there,

Yes, the puff of blue smoke on start up is common with all L83/L98 engines. This is due to the Oring seals at the top of the valve stem cracking, allowing oil down the valve stem and past the guides to the exhaust stream. The first hot exhaust cycle burns the oil residue in the exhaust port and thus the blue smoke.

Once your converters are at light off, it burns the residue in the converters. And with the engine running, the minute amount of oil seeping past the valve guides lubricates them to reduce wear. And in truth, you would have to be burning more than a quart in 1000 miles for it to really ruin your cat.

There are many different types of valve stem seals and having installed both umbrella and positive seal valve stem seals, they both work.

I personally prefer the positive valve stem seals, due to the fact that they seal to the valve guide and virtually eliminate the oil loss past the valve guides and oil puffs at first start up.

At 110,000, Im not so sure that you need cylinder heads unless your tech can document actual valve stem to guide wear.

So, I would recommend that you simply get the stem to guide clearance checked and then make your decision from there.

Valve stem seals can be changed in the car and you do not have to remove the cylinder heads.

Allthebest, Paul

 

[killain]

Valve stem seals . . .

HI there,

Yes, the puff of blue smoke on start up is common with all L83/L98 engines. This is due to the Oring seals at the top of the valve stem cracking, allowing oil down the valve stem and past the guides to the exhaust stream. The first hot exhaust cycle burns the oil residue in the exhaust port and thus the blue smoke.

Once your converters are at light off, it burns the residue in the converters. And with the engine running, the minute amount of oil seeping past the valve guides lubricates them to reduce wear. And in truth, you would have to be burning more than a quart in 1000 miles for it to really ruin your cat.

There are many different types of valve stem seals and having installed both umbrella and positive seal valve stem seals, they both work.

I personally prefer the positive valve stem seals, due to the fact that they seal to the valve guide and virtually eliminate the oil loss past the valve guides and oil puffs at first start up.

At 110,000, Im not so sure that you need cylinder heads unless your tech can document actual valve stem to guide wear.

So, I would recommend that you simply get the stem to guide clearance checked and then make your decision from there.

Valve stem seals can be changed in the car and you do not have to remove the cylinder heads.

Allthebest, Paul

Ok Thank you Paul. I will check with my shop to see how they can go about changing the seals to Positive Seal, valve stem seals. I know the seals can be done in the car with the piston at the upper most position and air pressure or stuffing some plain old cloths line rope stuffed into the cylinder and pushing the piston to it's upper most position which pinned the valves closed. This car was to the most extent, cared for. So I tend to think that it is a dried out seal problem. The compression is great and the oil pressure it perfect 30PSI at idle in gear. I've been running Mobil Super 7500 which is designed for hi mileage vehicles, & Supposedly has additives which help swell rubber seals & gaskets. Of the number of Valve stem seals,: Which flavor would you recommend Paul, "Victor Reinz" or "Seal Power" ? Thank you again Paul !

 

[killain]

Positive seal valve seals ?

HI there,

Yes, the puff of blue smoke on start up is common with all L83/L98 engines. This is due to the Oring seals at the top of the valve stem cracking, allowing oil down the valve stem and past the guides to the exhaust stream. The first hot exhaust cycle burns the oil residue in the exhaust port and thus the blue smoke.

Once your converters are at light off, it burns the residue in the converters. And with the engine running, the minute amount of oil seeping past the valve guides lubricates them to reduce wear. And in truth, you would have to be burning more than a quart in 1000 miles for it to really ruin your cat.

There are many different types of valve stem seals and having installed both umbrella and positive seal valve stem seals, they both work.

I personally prefer the positive valve stem seals, due to the fact that they seal to the valve guide and virtually eliminate the oil loss past the valve guides and oil puffs at first start up.

At 110,000, Im not so sure that you need cylinder heads unless your tech can document actual valve stem to guide wear.

So, I would recommend that you simply get the stem to guide clearance checked and then make your decision from there.

Valve stem seals can be changed in the car and you do not have to remove the cylinder heads.

Allthebest, Paul

Do the heads need any machining to accept the 'Positive' seal valve seals instead of the 'Umbrellas' type seals ? Thank you Paul !

 

[c4c5specialist]

HI there,

I have used both manufacturers of positive valve stem seals with excellent results so IMO, it really doesnt matter.

They are usually all made out of VITON and are extremely reliable.

No, you should NOT need any head machining to do this job, as the seals are engineered to slide onto the OEM valve guide diameter without issue.

Allthebest, Paul