Firstfives.org

For my daily beater - finally fouling a plug from oil

Let's here some suggestions for cheapy head R&R (Mike w?) ideas

Head runs cool; just burns a lot of oil.

Peter,

MikeW is the one who I learned it from...replacing the valve stem seals dramatically cuts down on oil usage. No new valve guides or valves just new seals. So you are out the cost of a head gasket set and your time.

I did just the above on my E28 533i and oil consumption dropped from around 1 qt/1000 miles to less that a quart every 3-4000 miles. All of the valve stem seals were hard and brittle and all the exhaust seals were in more than one piece. It it a fair amount of labor to R&R the head and tear it down to replace the seals. As long as you don't mind and do it yourself it is still a relatively cheap fix.

That being said, if you are fouling a plug from oil I tend to think something more is going on. A broken ring, damage to the cylinder, etc. My 533i had 255k when I did the valve stem seals and using 1 qt/1000 miles didn't come close to fouling plugs. However, MikeW knows a lot more than me so I will defer to his response.


Craig

Craig in Davis wrote:Peter,

MikeW is the one who I learned it from...replacing the valve stem seals dramatically cuts down on oil usage. No new valve guides or valves just new seals. So you are out the cost of a head gasket set and your time.

I did just the above on my E28 533i and oil consumption dropped from around 1 qt/1000 miles to less that a quart every 3-4000 miles. All of the valve stem seals were hard and brittle and all the exhaust seals were in more than one piece. It it a fair amount of labor to R&R the head and tear it down to replace the seals. As long as you don't mind and do it yourself it is still a relatively cheap fix.

That being said, if you are fouling a plug from oil I tend to think something more is going on. A broken ring, damage to the cylinder, etc. My 533i had 255k when I did the valve stem seals and using 1 qt/1000 miles didn't come close to fouling plugs. However, MikeW knows a lot more than me so I will defer to his response.


Craig

Thanks Craig
I checked compression on the dead hole and it was 150; I guess I should do leakdown as well.

Did I hear my name??? While I've never seen one go that bad that it fouled a plug, I too have taken oil consumption from a quart every 6-700 miles to less than a quart between changes just with valve guide seals. They can go in as little as a 100K, but 200K is probably closer to average. Or find a head off a B34 engine, apparently 85 is when they started using Viton seals instead of neoprene for the seals, and Viton has much greater heat resistance. I've changed some before that were literlly crispy, not just hard enough to crack, but more like almost shatter into powder. Not quite, but almost. Those were off a euro car, an 82 732i. New seals, slapped that head onto a E23 I had at the time and it had zero oil consumption when I sold it a couple of years later with 286K on it.

Mike W. wrote:Did I hear my name??? While I've never seen one go that bad that it fouled a plug, I too have taken oil consumption from a quart every 6-700 miles to less than a quart between changes just with valve guide seals. They can go in as little as a 100K, but 200K is probably closer to average. Or find a head off a B34 engine, apparently 85 is when they started using Viton seals instead of neoprene for the seals, and Viton has much greater heat resistance. I've changed some before that were literlly crispy, not just hard enough to crack, but more like almost shatter into powder. Not quite, but almost. Those were off a euro car, an 82 732i. New seals, slapped that head onto a E23 I had at the time and it had zero oil consumption when I sold it a couple of years later with 286K on it.

Should I get any machining done?
thanks!

If it's flat, which you can either measure with a straight edge like a good 2' level, or take to a machine shop, and the gasket isn't leaking, no, it really isn't necessary to have any machining done. New valve guides are nice, but aren't really going to make much difference.

Go over the head with a fine tooth comb, especially between the exhaust valve seat and the coolant passages to check for cracks, but short of that, if it looks good it probably is. Oh, do the bubbles check before you tear it down, check for bubbles in the coolant tank with it running. Turbulance is fine and to be expected, but if you actually see bubbles, it suggests a crack. Lack of symptoms is no guarantee of lack of trouble, they can develop slowly without any problems except maybe a slight loss of coolant, or be starting to crack, but not completely thru yet. And by slight, I mean perhaps needing to top off every 6 or 8 weeks. Don't be surprised if you see the start of a crack, then it's new head time as plentiful as the later heads are.