289 To rebuild or to not rebuild

Not sure what to do. Pulled a '67 289 with 74,000 original miles out to have some body work done. Engine is covered in oil, slime and crap but ran reasonably well before pulling it aside from fine tuning (I'm assuming).

The emission testing showed 229ppm of Hydrocarbons with a fail being 401ppm while driving. Idle test showed them being 159ppm with a fail being 928ppm.

Carbon Monoxide was read as 2.37% with a fail being 4.43% while driving and the idle test was 2.65% with a fail being 4.54%

Lastly, the oxide/nitrogen NOx was read as 1495ppm with a fail being 3753ppm.

As these numbers mean little to me in regards to the condition of the engine, I am hoping they mean something to someone here with more knowledge than I have.

Yes, I could have done a compression test before pulling the engine, but weather and lack of a helper made the pulling of the engine come sooner than expected. I might be able to do one on the stand, but would have to overcome some clearance issues first.

Thanks.

Did you run or drive this car? Did it smoke or use oil? Any engine noise? What are your plans for the car. If it is a driver and you are not going to beat on it then it should be fine the way it is. If you start whooping an old ending it will start smoking. I have an orignal miles unknown engine in my Galaxie and it runs and drives fine. I dont beat on it at all.

Looking at your post, the motor seems to be in pretty good condition according to the emissions. That usually tells a lot about the motor. Low compression, bad rings, valves, etc. would not pass those standards. Not referring to the bottom end. If it ain't knocking, keep on rocking.

Thanks for that. I plan on just driving the thing once its back together but didn't want to spend money on unnecessary things.

Lastly, I was told that if I was to get the heads done, it could bring out piston ring problems because I would be raising the compression by redoing the heads and that would put more pressure on older rings...basically been told to do both rings and heads but not to do just one of the two.

Is there truth to that?

Originally Posted by '67 Drop Top

Lastly, I was told that if I was to get the heads done, it could bring out piston ring problems because I would be raising the compression by redoing the heads and that would put more pressure on older rings...basically been told to do both rings and heads but not to do just one of the two.

Is there truth to that?

I have heard that too. If your engine is relatively fresh, with less than 20,000 miles upon it, then doesn't matter. Yours is worn. I got about 150,000 out of mine before being rebuilt. But then too all the valves became junk and were replaced. I could not stop on a hill without the compresion leaking off and the car then beginning to coast (either direction).

To rebuild a 289 ought to cost you maybe $400 in parts, cleaning and some machine shop work. If you do much of teh stuff yourself, got started on the heads then you are that much quicker to getting on to the road again. Ought to be ready for spring then.

Others here will mention how they got amazing fuel mileage once it got rebuilt, then 20,000 miles later... wa-hoppened?



Wm.

Don't believe it for one second!!!!


Piston rings go bad when they loose their OUTWARD Expansion.

Their outward expansion is what keeps the compression steady, the will not be adversely effected by higher downward pressures unless there is chatter that would break them, and you do NOT get chattering ring's from higher compression, therefore just doing your heads will not harm your engine.

Don't believe everything you hear, before fully thinking over the logic in your own head... The rings loose integrity by loosing their outward pressure which keeps them against the cylinder wall.

Those shops just want the extra work.

Point well taken. I'm going to go as far as replacing oil-related gaskets, maybe head gaskets, seals (including valve) and pumps (oil, water and fuel). Other than that, I believe the motor is fine.

Not wanting to be offensive here, but you are going to replace the head gaskets because????? I mean strip it down far enough to actually replace the head gasket and that's all your there for ? Seems pointless to me...what's the value in performing that work. That you have a new head gasket?

I happen to like the looks of fresh gaskets on a nicely painted engine! I know they don't come that way from Ford, but it's my preference. I usually check everything out anyway, just to be sure of no impending problems. I say, change the head gaskets too, if you want.

While you are changing all the gaskets, I would change the timing gear and chain.