Thread: is 10W30 on my old ford 289 burning oil

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I'll add to Denny's post which I fully agree with.

"Rebuilt" means a lot of things to different mechanics - maybe a valve job with new seals is his definition. Mine definition of rebuilt is to install new valve guides, probably new valves, springs and rockers and retainers and locks plus a 3 angle valve job. Remember - a 289 is OLD and my guess is that you never had new guides installed as it is fairly expensive and is a job for a very well eqiupped shop. Some folks like the bronze guides - I don't except for a race type engine that is renewed regularly. Bronze is just a fancy copper alloy and is by that nature soft. My preference for a street engine is iron. Iron has by nature a lubricity factor (high carbon content) and wears slowly. Also, you may have a high lift camshaft that may be messing with operating angle/geometry - and Fords seem to have this characteristic with their rocker arms, rail type especially - and this in turn causes valve stem and guide wear. Roller rockers will alleviate this a bunch.

Another thing to consider is to have a leak down compression test made - you may just have some rings that are worn or even broken which will foul plugs as well.

Just some food for thought !!!!

For what it's worth I think bronze guides rock.

Older Navy (or phospher) bronze guides did tend to wear out quicker than a cast iron guide. But the newer materials used are managanese or Aluminum bronze alloys that are much harder and wear resistent. The bronze guides allow you to run lower clearances for improved oil control and bearing support of the stem and they will not wear down the valve stem. Also you don't really want to run a stainless valve in cast iron.

Kitz

Does it smoke on startup then clear up? - typically valve guides.
Smokes constantly? - typically rings or possibly valve guides also.